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提交 5f34fe1c 编写于 作者: L Linus Torvalds
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Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
  stacktrace: provide save_stack_trace_tsk() weak alias
  rcu: provide RCU options on non-preempt architectures too
  printk: fix discarding message when recursion_bug
  futex: clean up futex_(un)lock_pi fault handling
  "Tree RCU": scalable classic RCU implementation
  futex: rename field in futex_q to clarify single waiter semantics
  x86/swiotlb: add default swiotlb_arch_range_needs_mapping
  x86/swiotlb: add default phys<->bus conversion
  x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
  x86: add swiotlb allocation functions
  swiotlb: consolidate swiotlb info message printing
  swiotlb: support bouncing of HighMem pages
  swiotlb: factor out copy to/from device
  swiotlb: add arch hook to force mapping
  swiotlb: allow architectures to override phys<->bus<->phys conversions
  swiotlb: add comment where we handle the overflow of a dma mask on 32 bit
  rcu: fix rcutorture behavior during reboot
  resources: skip sanity check of busy resources
  swiotlb: move some definitions to header
  swiotlb: allow architectures to override swiotlb pool allocation
  ...

Fix up trivial conflicts in
  arch/x86/kernel/Makefile
  arch/x86/mm/init_32.c
  include/linux/hardirq.h
as per Ingo's suggestions.
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Documentation/RCU/00-INDEX
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......@@ -16,6 +16,8 @@ RTFP.txt
- List of RCU papers (bibliography) going back to 1980.
torture.txt
- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
trace.txt
- CONFIG_RCU_TRACE debugfs files and formats
UP.txt
- RCU on Uniprocessor Systems
whatisRCU.txt
......
Documentation/RCU/trace.txt 0 → 100644
浏览文件 @ 5f34fe1c
CONFIG_RCU_TRACE debugfs Files and Formats
The rcupreempt and rcutree implementations of RCU provide debugfs trace
output that summarizes counters and state. This information is useful for
debugging RCU itself, and can sometimes also help to debug abuses of RCU.
Note that the rcuclassic implementation of RCU does not provide debugfs
trace output.
The following sections describe the debugfs files and formats for
preemptable RCU (rcupreempt) and hierarchical RCU (rcutree).
Preemptable RCU debugfs Files and Formats
This implementation of RCU provides three debugfs files under the
top-level directory RCU: rcu/rcuctrs (which displays the per-CPU
counters used by preemptable RCU) rcu/rcugp (which displays grace-period
counters), and rcu/rcustats (which internal counters for debugging RCU).
The output of "cat rcu/rcuctrs" looks as follows:
CPU last cur F M
0 5 -5 0 0
1 -1 0 0 0
2 0 1 0 0
3 0 1 0 0
4 0 1 0 0
5 0 1 0 0
6 0 2 0 0
7 0 -1 0 0
8 0 1 0 0
ggp = 26226, state = waitzero
The per-CPU fields are as follows:
o "CPU" gives the CPU number. Offline CPUs are not displayed.
o "last" gives the value of the counter that is being decremented
for the current grace period phase. In the example above,
the counters sum to 4, indicating that there are still four
RCU read-side critical sections still running that started
before the last counter flip.
o "cur" gives the value of the counter that is currently being
both incremented (by rcu_read_lock()) and decremented (by
rcu_read_unlock()). In the example above, the counters sum to
1, indicating that there is only one RCU read-side critical section
still running that started after the last counter flip.
o "F" indicates whether RCU is waiting for this CPU to acknowledge
a counter flip. In the above example, RCU is not waiting on any,
which is consistent with the state being "waitzero" rather than
"waitack".
o "M" indicates whether RCU is waiting for this CPU to execute a
memory barrier. In the above example, RCU is not waiting on any,
which is consistent with the state being "waitzero" rather than
"waitmb".
o "ggp" is the global grace-period counter.
o "state" is the RCU state, which can be one of the following:
o "idle": there is no grace period in progress.
o "waitack": RCU just incremented the global grace-period
counter, which has the effect of reversing the roles of
the "last" and "cur" counters above, and is waiting for
all the CPUs to acknowledge the flip. Once the flip has
been acknowledged, CPUs will no longer be incrementing
what are now the "last" counters, so that their sum will
decrease monotonically down to zero.
o "waitzero": RCU is waiting for the sum of the "last" counters
to decrease to zero.
o "waitmb": RCU is waiting for each CPU to execute a memory
barrier, which ensures that instructions from a given CPU's
last RCU read-side critical section cannot be reordered
with instructions following the memory-barrier instruction.
The output of "cat rcu/rcugp" looks as follows:
oldggp=48870 newggp=48873
Note that reading from this file provokes a synchronize_rcu(). The
"oldggp" value is that of "ggp" from rcu/rcuctrs above, taken before
executing the synchronize_rcu(), and the "newggp" value is also the
"ggp" value, but taken after the synchronize_rcu() command returns.
The output of "cat rcu/rcugp" looks as follows:
na=1337955 nl=40 wa=1337915 wl=44 da=1337871 dl=0 dr=1337871 di=1337871
1=50989 e1=6138 i1=49722 ie1=82 g1=49640 a1=315203 ae1=265563 a2=49640
z1=1401244 ze1=1351605 z2=49639 m1=5661253 me1=5611614 m2=49639
These are counters tracking internal preemptable-RCU events, however,
some of them may be useful for debugging algorithms using RCU. In
particular, the "nl", "wl", and "dl" values track the number of RCU
callbacks in various states. The fields are as follows:
o "na" is the total number of RCU callbacks that have been enqueued
since boot.
o "nl" is the number of RCU callbacks waiting for the previous
grace period to end so that they can start waiting on the next
grace period.
o "wa" is the total number of RCU callbacks that have started waiting
for a grace period since boot. "na" should be roughly equal to
"nl" plus "wa".
o "wl" is the number of RCU callbacks currently waiting for their
grace period to end.
o "da" is the total number of RCU callbacks whose grace periods
have completed since boot. "wa" should be roughly equal to
"wl" plus "da".
o "dr" is the total number of RCU callbacks that have been removed
from the list of callbacks ready to invoke. "dr" should be roughly
equal to "da".
o "di" is the total number of RCU callbacks that have been invoked
since boot. "di" should be roughly equal to "da", though some
early versions of preemptable RCU had a bug so that only the
last CPU's count of invocations was displayed, rather than the
sum of all CPU's counts.
o "1" is the number of calls to rcu_try_flip(). This should be
roughly equal to the sum of "e1", "i1", "a1", "z1", and "m1"
described below. In other words, the number of times that
the state machine is visited should be equal to the sum of the
number of times that each state is visited plus the number of
times that the state-machine lock acquisition failed.
o "e1" is the number of times that rcu_try_flip() was unable to
acquire the fliplock.
o "i1" is the number of calls to rcu_try_flip_idle().
o "ie1" is the number of times rcu_try_flip_idle() exited early
due to the calling CPU having no work for RCU.
o "g1" is the number of times that rcu_try_flip_idle() decided
to start a new grace period. "i1" should be roughly equal to
"ie1" plus "g1".
o "a1" is the number of calls to rcu_try_flip_waitack().
o "ae1" is the number of times that rcu_try_flip_waitack() found
that at least one CPU had not yet acknowledge the new grace period
(AKA "counter flip").
o "a2" is the number of time rcu_try_flip_waitack() found that
all CPUs had acknowledged. "a1" should be roughly equal to
"ae1" plus "a2". (This particular output was collected on
a 128-CPU machine, hence the smaller-than-usual fraction of
calls to rcu_try_flip_waitack() finding all CPUs having already
acknowledged.)
o "z1" is the number of calls to rcu_try_flip_waitzero().
o "ze1" is the number of times that rcu_try_flip_waitzero() found
that not all of the old RCU read-side critical sections had
completed.
o "z2" is the number of times that rcu_try_flip_waitzero() finds
the sum of the counters equal to zero, in other words, that
all of the old RCU read-side critical sections had completed.
The value of "z1" should be roughly equal to "ze1" plus
"z2".
o "m1" is the number of calls to rcu_try_flip_waitmb().
o "me1" is the number of times that rcu_try_flip_waitmb() finds
that at least one CPU has not yet executed a memory barrier.
o "m2" is the number of times that rcu_try_flip_waitmb() finds that
all CPUs have executed a memory barrier.
Hierarchical RCU debugfs Files and Formats
This implementation of RCU provides three debugfs files under the
top-level directory RCU: rcu/rcudata (which displays fields in struct
rcu_data), rcu/rcugp (which displays grace-period counters), and
rcu/rcuhier (which displays the struct rcu_node hierarchy).
The output of "cat rcu/rcudata" looks as follows:
rcu:
0 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=1 rp=3c2a dt=23301/73 dn=2 df=1882 of=0 ri=2126 ql=2 b=10
1 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=3 rp=39a6 dt=78073/1 dn=2 df=1402 of=0 ri=1875 ql=46 b=10
2 c=4010 g=4010 pq=1 pqc=4010 qp=0 rpfq=-5 rp=1d12 dt=16646/0 dn=2 df=3140 of=0 ri=2080 ql=0 b=10
3 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=2b50 dt=21159/1 dn=2 df=2230 of=0 ri=1923 ql=72 b=10
4 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1644 dt=5783/1 dn=2 df=3348 of=0 ri=2805 ql=7 b=10
5 c=4012 g=4013 pq=0 pqc=4011 qp=1 rpfq=3 rp=1aac dt=5879/1 dn=2 df=3140 of=0 ri=2066 ql=10 b=10
6 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=ed8 dt=5847/1 dn=2 df=3797 of=0 ri=1266 ql=10 b=10
7 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1fa2 dt=6199/1 dn=2 df=2795 of=0 ri=2162 ql=28 b=10
rcu_bh:
0 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-145 rp=21d6 dt=23301/73 dn=2 df=0 of=0 ri=0 ql=0 b=10
1 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-170 rp=20ce dt=78073/1 dn=2 df=26 of=0 ri=5 ql=0 b=10
2 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-83 rp=fbd dt=16646/0 dn=2 df=28 of=0 ri=4 ql=0 b=10
3 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-105 rp=178c dt=21159/1 dn=2 df=28 of=0 ri=2 ql=0 b=10
4 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-30 rp=b54 dt=5783/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
5 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-29 rp=df5 dt=5879/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
6 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-28 rp=788 dt=5847/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
7 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-53 rp=1098 dt=6199/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
The first section lists the rcu_data structures for rcu, the second for
rcu_bh. Each section has one line per CPU, or eight for this 8-CPU system.
The fields are as follows:
o The number at the beginning of each line is the CPU number.
CPUs numbers followed by an exclamation mark are offline,
but have been online at least once since boot. There will be
no output for CPUs that have never been online, which can be
a good thing in the surprisingly common case where NR_CPUS is
substantially larger than the number of actual CPUs.
o "c" is the count of grace periods that this CPU believes have
completed. CPUs in dynticks idle mode may lag quite a ways
behind, for example, CPU 4 under "rcu" above, which has slept
through the past 25 RCU grace periods. It is not unusual to
see CPUs lagging by thousands of grace periods.
o "g" is the count of grace periods that this CPU believes have
started. Again, CPUs in dynticks idle mode may lag behind.
If the "c" and "g" values are equal, this CPU has already
reported a quiescent state for the last RCU grace period that
it is aware of, otherwise, the CPU believes that it owes RCU a
quiescent state.
o "pq" indicates that this CPU has passed through a quiescent state
for the current grace period. It is possible for "pq" to be
"1" and "c" different than "g", which indicates that although
the CPU has passed through a quiescent state, either (1) this
CPU has not yet reported that fact, (2) some other CPU has not
yet reported for this grace period, or (3) both.
o "pqc" indicates which grace period the last-observed quiescent
state for this CPU corresponds to. This is important for handling
the race between CPU 0 reporting an extended dynticks-idle
quiescent state for CPU 1 and CPU 1 suddenly waking up and
reporting its own quiescent state. If CPU 1 was the last CPU
for the current grace period, then the CPU that loses this race
will attempt to incorrectly mark CPU 1 as having checked in for
the next grace period!
o "qp" indicates that RCU still expects a quiescent state from
this CPU.
o "rpfq" is the number of rcu_pending() calls on this CPU required
to induce this CPU to invoke force_quiescent_state().
o "rp" is low-order four hex digits of the count of how many times
rcu_pending() has been invoked on this CPU.
o "dt" is the current value of the dyntick counter that is incremented
when entering or leaving dynticks idle state, either by the
scheduler or by irq. The number after the "/" is the interrupt
nesting depth when in dyntick-idle state, or one greater than
the interrupt-nesting depth otherwise.
This field is displayed only for CONFIG_NO_HZ kernels.
o "dn" is the current value of the dyntick counter that is incremented
when entering or leaving dynticks idle state via NMI. If both
the "dt" and "dn" values are even, then this CPU is in dynticks
idle mode and may be ignored by RCU. If either of these two
counters is odd, then RCU must be alert to the possibility of
an RCU read-side critical section running on this CPU.
This field is displayed only for CONFIG_NO_HZ kernels.
o "df" is the number of times that some other CPU has forced a
quiescent state on behalf of this CPU due to this CPU being in
dynticks-idle state.
This field is displayed only for CONFIG_NO_HZ kernels.
o "of" is the number of times that some other CPU has forced a
quiescent state on behalf of this CPU due to this CPU being
offline. In a perfect world, this might neve happen, but it
turns out that offlining and onlining a CPU can take several grace
periods, and so there is likely to be an extended period of time
when RCU believes that the CPU is online when it really is not.
Please note that erring in the other direction (RCU believing a
CPU is offline when it is really alive and kicking) is a fatal
error, so it makes sense to err conservatively.
o "ri" is the number of times that RCU has seen fit to send a
reschedule IPI to this CPU in order to get it to report a
quiescent state.
o "ql" is the number of RCU callbacks currently residing on
this CPU. This is the total number of callbacks, regardless
of what state they are in (new, waiting for grace period to
start, waiting for grace period to end, ready to invoke).
o "b" is the batch limit for this CPU. If more than this number
of RCU callbacks is ready to invoke, then the remainder will
be deferred.
The output of "cat rcu/rcugp" looks as follows:
rcu: completed=33062 gpnum=33063
rcu_bh: completed=464 gpnum=464
Again, this output is for both "rcu" and "rcu_bh". The fields are
taken from the rcu_state structure, and are as follows:
o "completed" is the number of grace periods that have completed.
It is comparable to the "c" field from rcu/rcudata in that a
CPU whose "c" field matches the value of "completed" is aware
that the corresponding RCU grace period has completed.
o "gpnum" is the number of grace periods that have started. It is
comparable to the "g" field from rcu/rcudata in that a CPU
whose "g" field matches the value of "gpnum" is aware that the
corresponding RCU grace period has started.
If these two fields are equal (as they are for "rcu_bh" above),
then there is no grace period in progress, in other words, RCU
is idle. On the other hand, if the two fields differ (as they
do for "rcu" above), then an RCU grace period is in progress.
The output of "cat rcu/rcuhier" looks as follows, with very long lines:
c=6902 g=6903 s=2 jfq=3 j=72c7 nfqs=13142/nfqsng=0(13142) fqlh=6
1/1 0:127 ^0
3/3 0:35 ^0 0/0 36:71 ^1 0/0 72:107 ^2 0/0 108:127 ^3
3/3f 0:5 ^0 2/3 6:11 ^1 0/0 12:17 ^2 0/0 18:23 ^3 0/0 24:29 ^4 0/0 30:35 ^5 0/0 36:41 ^0 0/0 42:47 ^1 0/0 48:53 ^2 0/0 54:59 ^3 0/0 60:65 ^4 0/0 66:71 ^5 0/0 72:77 ^0 0/0 78:83 ^1 0/0 84:89 ^2 0/0 90:95 ^3 0/0 96:101 ^4 0/0 102:107 ^5 0/0 108:113 ^0 0/0 114:119 ^1 0/0 120:125 ^2 0/0 126:127 ^3
rcu_bh:
c=-226 g=-226 s=1 jfq=-5701 j=72c7 nfqs=88/nfqsng=0(88) fqlh=0
0/1 0:127 ^0
0/3 0:35 ^0 0/0 36:71 ^1 0/0 72:107 ^2 0/0 108:127 ^3
0/3f 0:5 ^0 0/3 6:11 ^1 0/0 12:17 ^2 0/0 18:23 ^3 0/0 24:29 ^4 0/0 30:35 ^5 0/0 36:41 ^0 0/0 42:47 ^1 0/0 48:53 ^2 0/0 54:59 ^3 0/0 60:65 ^4 0/0 66:71 ^5 0/0 72:77 ^0 0/0 78:83 ^1 0/0 84:89 ^2 0/0 90:95 ^3 0/0 96:101 ^4 0/0 102:107 ^5 0/0 108:113 ^0 0/0 114:119 ^1 0/0 120:125 ^2 0/0 126:127 ^3
This is once again split into "rcu" and "rcu_bh" portions. The fields are
as follows:
o "c" is exactly the same as "completed" under rcu/rcugp.
o "g" is exactly the same as "gpnum" under rcu/rcugp.
o "s" is the "signaled" state that drives force_quiescent_state()'s
state machine.
o "jfq" is the number of jiffies remaining for this grace period
before force_quiescent_state() is invoked to help push things
along. Note that CPUs in dyntick-idle mode thoughout the grace
period will not report on their own, but rather must be check by
some other CPU via force_quiescent_state().
o "j" is the low-order four hex digits of the jiffies counter.
Yes, Paul did run into a number of problems that turned out to
be due to the jiffies counter no longer counting. Why do you ask?
o "nfqs" is the number of calls to force_quiescent_state() since
boot.
o "nfqsng" is the number of useless calls to force_quiescent_state(),
where there wasn't actually a grace period active. This can
happen due to races. The number in parentheses is the difference
between "nfqs" and "nfqsng", or the number of times that
force_quiescent_state() actually did some real work.
o "fqlh" is the number of calls to force_quiescent_state() that
exited immediately (without even being counted in nfqs above)
due to contention on ->fqslock.
o Each element of the form "1/1 0:127 ^0" represents one struct
rcu_node. Each line represents one level of the hierarchy, from
root to leaves. It is best to think of the rcu_data structures
as forming yet another level after the leaves. Note that there
might be either one, two, or three levels of rcu_node structures,
depending on the relationship between CONFIG_RCU_FANOUT and
CONFIG_NR_CPUS.
o The numbers separated by the "/" are the qsmask followed
by the qsmaskinit. The qsmask will have one bit
set for each entity in the next lower level that
has not yet checked in for the current grace period.
The qsmaskinit will have one bit for each entity that is
currently expected to check in during each grace period.
The value of qsmaskinit is assigned to that of qsmask
at the beginning of each grace period.
For example, for "rcu", the qsmask of the first entry
of the lowest level is 0x14, meaning that we are still
waiting for CPUs 2 and 4 to check in for the current
grace period.
o The numbers separated by the ":" are the range of CPUs
served by this struct rcu_node. This can be helpful
in working out how the hierarchy is wired together.
For example, the first entry at the lowest level shows
"0:5", indicating that it covers CPUs 0 through 5.
o The number after the "^" indicates the bit in the
next higher level rcu_node structure that this
rcu_node structure corresponds to.
For example, the first entry at the lowest level shows
"^0", indicating that it corresponds to bit zero in
the first entry at the middle level.
Documentation/lockstat.txt
浏览文件 @ 5f34fe1c
......@@ -71,35 +71,50 @@ Look at the current lock statistics:
# less /proc/lock_stat
01 lock_stat version 0.2
01 lock_stat version 0.3
02 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
03 class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
04 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
05
06 &inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60
07 &inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38
08 --------------------------
09 &inode->i_data.tree_lock 0 [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190
10
11 ...............................................................................................................................................................................................
12
13 dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24
14 -----------
15 dcache_lock 180 [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230
16 dcache_lock 165 [<ffffffff802c002a>] d_alloc+0x15a/0x210
17 dcache_lock 33 [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70
18 dcache_lock 1 [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130
06 &mm->mmap_sem-W: 233 538 18446744073708 22924.27 607243.51 1342 45806 1.71 8595.89 1180582.34
07 &mm->mmap_sem-R: 205 587 18446744073708 28403.36 731975.00 1940 412426 0.58 187825.45 6307502.88
08 ---------------
09 &mm->mmap_sem 487 [<ffffffff8053491f>] do_page_fault+0x466/0x928
10 &mm->mmap_sem 179 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
11 &mm->mmap_sem 279 [<ffffffff80210a57>] sys_mmap+0x75/0xce
12 &mm->mmap_sem 76 [<ffffffff802a490b>] sys_munmap+0x32/0x59
13 ---------------
14 &mm->mmap_sem 270 [<ffffffff80210a57>] sys_mmap+0x75/0xce
15 &mm->mmap_sem 431 [<ffffffff8053491f>] do_page_fault+0x466/0x928
16 &mm->mmap_sem 138 [<ffffffff802a490b>] sys_munmap+0x32/0x59
17 &mm->mmap_sem 145 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
18
19 ...............................................................................................................................................................................................
20
21 dcache_lock: 621 623 0.52 118.26 1053.02 6745 91930 0.29 316.29 118423.41
22 -----------
23 dcache_lock 179 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
24 dcache_lock 113 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
25 dcache_lock 99 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
26 dcache_lock 104 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
27 -----------
28 dcache_lock 192 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
29 dcache_lock 98 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
30 dcache_lock 72 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
31 dcache_lock 112 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
This excerpt shows the first two lock class statistics. Line 01 shows the
output version - each time the format changes this will be updated. Line 02-04
show the header with column descriptions. Lines 05-10 and 13-18 show the actual
show the header with column descriptions. Lines 05-18 and 20-31 show the actual
statistics. These statistics come in two parts; the actual stats separated by a
short separator (line 08, 14) from the contention points.
short separator (line 08, 13) from the contention points.
The first lock (05-10) is a read/write lock, and shows two lines above the
The first lock (05-18) is a read/write lock, and shows two lines above the
short separator. The contention points don't match the column descriptors,
they have two: contentions and [<IP>] symbol.
they have two: contentions and [<IP>] symbol. The second set of contention
points are the points we're contending with.
The integer part of the time values is in us.
View the top contending locks:
......
arch/powerpc/platforms/pseries/rtasd.c
浏览文件 @ 5f34fe1c
......@@ -208,6 +208,7 @@ void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
break;
case ERR_TYPE_KERNEL_PANIC:
default:
WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
spin_unlock_irqrestore(&rtasd_log_lock, s);
return;
}
......@@ -227,6 +228,7 @@ void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
/* Check to see if we need to or have stopped logging */
if (fatal || !logging_enabled) {
logging_enabled = 0;
WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
spin_unlock_irqrestore(&rtasd_log_lock, s);
return;
}
......@@ -249,11 +251,13 @@ void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
else
rtas_log_start += 1;
WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
spin_unlock_irqrestore(&rtasd_log_lock, s);
wake_up_interruptible(&rtas_log_wait);
break;
case ERR_TYPE_KERNEL_PANIC:
default:
WARN_ON_ONCE(!irqs_disabled()); /* @@@ DEBUG @@@ */
spin_unlock_irqrestore(&rtasd_log_lock, s);
return;
}
......
arch/um/include/asm/system.h
浏览文件 @ 5f34fe1c
......@@ -11,21 +11,21 @@ extern int get_signals(void);
extern void block_signals(void);
extern void unblock_signals(void);
#define local_save_flags(flags) do { typecheck(unsigned long, flags); \
#define raw_local_save_flags(flags) do { typecheck(unsigned long, flags); \
(flags) = get_signals(); } while(0)
#define local_irq_restore(flags) do { typecheck(unsigned long, flags); \
#define raw_local_irq_restore(flags) do { typecheck(unsigned long, flags); \
set_signals(flags); } while(0)
#define local_irq_save(flags) do { local_save_flags(flags); \
local_irq_disable(); } while(0)
#define raw_local_irq_save(flags) do { raw_local_save_flags(flags); \
raw_local_irq_disable(); } while(0)
#define local_irq_enable() unblock_signals()
#define local_irq_disable() block_signals()
#define raw_local_irq_enable() unblock_signals()
#define raw_local_irq_disable() block_signals()
#define irqs_disabled() \
({ \
unsigned long flags; \
local_save_flags(flags); \
raw_local_save_flags(flags); \
(flags == 0); \
})
......
arch/x86/include/asm/dma-mapping.h
浏览文件 @ 5f34fe1c
......@@ -65,7 +65,7 @@ static inline struct dma_mapping_ops *get_dma_ops(struct device *dev)
return dma_ops;
else
return dev->archdata.dma_ops;
#endif /* _ASM_X86_DMA_MAPPING_H */
#endif
}
/* Make sure we keep the same behaviour */
......
arch/x86/include/asm/iommu.h
浏览文件 @ 5f34fe1c
......@@ -7,8 +7,6 @@ extern struct dma_mapping_ops nommu_dma_ops;
extern int force_iommu, no_iommu;
extern int iommu_detected;
extern unsigned long iommu_nr_pages(unsigned long addr, unsigned long len);
/* 10 seconds */
#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
......
arch/x86/include/asm/pci.h
浏览文件 @ 5f34fe1c
......@@ -84,6 +84,8 @@ static inline void pci_dma_burst_advice(struct pci_dev *pdev,
static inline void early_quirks(void) { }
#endif
extern void pci_iommu_alloc(void);
#endif /* __KERNEL__ */
#ifdef CONFIG_X86_32
......
arch/x86/include/asm/pci_64.h
浏览文件 @ 5f34fe1c
......@@ -23,7 +23,6 @@ extern int (*pci_config_write)(int seg, int bus, int dev, int fn,
int reg, int len, u32 value);
extern void dma32_reserve_bootmem(void);
extern void pci_iommu_alloc(void);
/* The PCI address space does equal the physical memory
* address space. The networking and block device layers use
......
arch/x86/include/asm/uaccess.h
浏览文件 @ 5f34fe1c
......@@ -157,6 +157,7 @@ extern int __get_user_bad(void);
int __ret_gu; \
unsigned long __val_gu; \
__chk_user_ptr(ptr); \
might_fault(); \
switch (sizeof(*(ptr))) { \
case 1: \
__get_user_x(1, __ret_gu, __val_gu, ptr); \
......@@ -241,6 +242,7 @@ extern void __put_user_8(void);
int __ret_pu; \
__typeof__(*(ptr)) __pu_val; \
__chk_user_ptr(ptr); \
might_fault(); \
__pu_val = x; \
switch (sizeof(*(ptr))) { \
case 1: \
......
arch/x86/include/asm/uaccess_32.h
浏览文件 @ 5f34fe1c
......@@ -82,8 +82,8 @@ __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
static __always_inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_sleep();
return __copy_to_user_inatomic(to, from, n);
might_fault();
return __copy_to_user_inatomic(to, from, n);
}
static __always_inline unsigned long
......@@ -137,7 +137,7 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
static __always_inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_sleep();
might_fault();
if (__builtin_constant_p(n)) {
unsigned long ret;
......@@ -159,7 +159,7 @@ __copy_from_user(void *to, const void __user *from, unsigned long n)
static __always_inline unsigned long __copy_from_user_nocache(void *to,
const void __user *from, unsigned long n)
{
might_sleep();
might_fault();
if (__builtin_constant_p(n)) {
unsigned long ret;
......
arch/x86/include/asm/uaccess_64.h
浏览文件 @ 5f34fe1c
......@@ -29,6 +29,8 @@ static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size)
{
int ret = 0;
might_fault();
if (!__builtin_constant_p(size))
return copy_user_generic(dst, (__force void *)src, size);
switch (size) {
......@@ -71,6 +73,8 @@ static __always_inline __must_check
int __copy_to_user(void __user *dst, const void *src, unsigned size)
{
int ret = 0;
might_fault();
if (!__builtin_constant_p(size))
return copy_user_generic((__force void *)dst, src, size);
switch (size) {
......@@ -113,6 +117,8 @@ static __always_inline __must_check
int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
{
int ret = 0;
might_fault();
if (!__builtin_constant_p(size))
return copy_user_generic((__force void *)dst,
(__force void *)src, size);
......
arch/x86/kernel/Makefile
浏览文件 @ 5f34fe1c
......@@ -109,6 +109,8 @@ obj-$(CONFIG_MICROCODE) += microcode.o
obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
obj-$(CONFIG_SWIOTLB) += pci-swiotlb_64.o # NB rename without _64
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
......@@ -122,7 +124,6 @@ ifeq ($(CONFIG_X86_64),y)
obj-$(CONFIG_GART_IOMMU) += pci-gart_64.o aperture_64.o
obj-$(CONFIG_CALGARY_IOMMU) += pci-calgary_64.o tce_64.o
obj-$(CONFIG_AMD_IOMMU) += amd_iommu_init.o amd_iommu.o
obj-$(CONFIG_SWIOTLB) += pci-swiotlb_64.o
obj-$(CONFIG_PCI_MMCONFIG) += mmconf-fam10h_64.o
endif
arch/x86/kernel/pci-dma.c
浏览文件 @ 5f34fe1c
......@@ -101,11 +101,15 @@ static void __init dma32_free_bootmem(void)
dma32_bootmem_ptr = NULL;
dma32_bootmem_size = 0;
}
#endif
void __init pci_iommu_alloc(void)
{
#ifdef CONFIG_X86_64
/* free the range so iommu could get some range less than 4G */
dma32_free_bootmem();
#endif
/*
* The order of these functions is important for
* fall-back/fail-over reasons
......@@ -121,15 +125,6 @@ void __init pci_iommu_alloc(void)
pci_swiotlb_init();
}
unsigned long iommu_nr_pages(unsigned long addr, unsigned long len)
{
unsigned long size = roundup((addr & ~PAGE_MASK) + len, PAGE_SIZE);
return size >> PAGE_SHIFT;
}
EXPORT_SYMBOL(iommu_nr_pages);
#endif
void *dma_generic_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_addr, gfp_t flag)
{
......
arch/x86/kernel/pci-swiotlb_64.c
浏览文件 @ 5f34fe1c
......@@ -3,6 +3,8 @@
#include <linux/pci.h>
#include <linux/cache.h>
#include <linux/module.h>
#include <linux/swiotlb.h>
#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <asm/iommu.h>
......@@ -11,6 +13,31 @@
int swiotlb __read_mostly;
void *swiotlb_alloc_boot(size_t size, unsigned long nslabs)
{
return alloc_bootmem_low_pages(size);
}
void *swiotlb_alloc(unsigned order, unsigned long nslabs)
{
return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
}
dma_addr_t swiotlb_phys_to_bus(phys_addr_t paddr)
{
return paddr;
}
phys_addr_t swiotlb_bus_to_phys(dma_addr_t baddr)
{
return baddr;
}
int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
{
return 0;
}
static dma_addr_t
swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
int direction)
......@@ -50,8 +77,10 @@ struct dma_mapping_ops swiotlb_dma_ops = {
void __init pci_swiotlb_init(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
#ifdef CONFIG_X86_64
if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
swiotlb = 1;
#endif
if (swiotlb_force)
swiotlb = 1;
if (swiotlb) {
......
arch/x86/lib/usercopy_32.c
浏览文件 @ 5f34fe1c
......@@ -39,7 +39,7 @@ static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned lon
#define __do_strncpy_from_user(dst, src, count, res) \
do { \
int __d0, __d1, __d2; \
might_sleep(); \
might_fault(); \
__asm__ __volatile__( \
" testl %1,%1\n" \
" jz 2f\n" \
......@@ -126,7 +126,7 @@ EXPORT_SYMBOL(strncpy_from_user);
#define __do_clear_user(addr,size) \
do { \
int __d0; \
might_sleep(); \
might_fault(); \
__asm__ __volatile__( \
"0: rep; stosl\n" \
" movl %2,%0\n" \
......@@ -155,7 +155,7 @@ do { \
unsigned long
clear_user(void __user *to, unsigned long n)
{
might_sleep();
might_fault();
if (access_ok(VERIFY_WRITE, to, n))
__do_clear_user(to, n);
return n;
......@@ -197,7 +197,7 @@ long strnlen_user(const char __user *s, long n)
unsigned long mask = -__addr_ok(s);
unsigned long res, tmp;
might_sleep();
might_fault();
__asm__ __volatile__(
" testl %0, %0\n"
......
arch/x86/lib/usercopy_64.c
浏览文件 @ 5f34fe1c
......@@ -15,7 +15,7 @@
#define __do_strncpy_from_user(dst,src,count,res) \
do { \
long __d0, __d1, __d2; \
might_sleep(); \
might_fault(); \
__asm__ __volatile__( \
" testq %1,%1\n" \
" jz 2f\n" \
......@@ -64,7 +64,7 @@ EXPORT_SYMBOL(strncpy_from_user);
unsigned long __clear_user(void __user *addr, unsigned long size)
{
long __d0;
might_sleep();
might_fault();
/* no memory constraint because it doesn't change any memory gcc knows
about */
asm volatile(
......
arch/x86/mm/init_32.c
浏览文件 @ 5f34fe1c
......@@ -21,6 +21,7 @@
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/pci.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/bootmem.h>
......@@ -967,6 +968,8 @@ void __init mem_init(void)
int codesize, reservedpages, datasize, initsize;
int tmp;
pci_iommu_alloc();
#ifdef CONFIG_FLATMEM
BUG_ON(!mem_map);
#endif
......
include/asm-generic/bug.h
浏览文件 @ 5f34fe1c
......@@ -41,15 +41,14 @@ struct bug_entry {
#ifndef __WARN
#ifndef __ASSEMBLY__
extern void warn_on_slowpath(const char *file, const int line);
extern void warn_slowpath(const char *file, const int line,
const char *fmt, ...) __attribute__((format(printf, 3, 4)));
#define WANT_WARN_ON_SLOWPATH
#endif
#define __WARN() warn_on_slowpath(__FILE__, __LINE__)
#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
#define __WARN() warn_slowpath(__FILE__, __LINE__, NULL)
#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
#else
#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
#endif
#ifndef WARN_ON
......
include/linux/bottom_half.h
浏览文件 @ 5f34fe1c
......@@ -2,7 +2,6 @@
#define _LINUX_BH_H
extern void local_bh_disable(void);
extern void __local_bh_enable(void);
extern void _local_bh_enable(void);
extern void local_bh_enable(void);
extern void local_bh_enable_ip(unsigned long ip);
......
include/linux/debug_locks.h
浏览文件 @ 5f34fe1c
......@@ -17,7 +17,7 @@ extern int debug_locks_off(void);
({ \
int __ret = 0; \
\
if (unlikely(c)) { \
if (!oops_in_progress && unlikely(c)) { \
if (debug_locks_off() && !debug_locks_silent) \
WARN_ON(1); \
__ret = 1; \
......
include/linux/futex.h
浏览文件 @ 5f34fe1c
......@@ -25,7 +25,8 @@ union ktime;
#define FUTEX_WAKE_BITSET 10
#define FUTEX_PRIVATE_FLAG 128
#define FUTEX_CMD_MASK ~FUTEX_PRIVATE_FLAG
#define FUTEX_CLOCK_REALTIME 256
#define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME)
#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
......@@ -164,6 +165,8 @@ union futex_key {
} both;
};
#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }
#ifdef CONFIG_FUTEX
extern void exit_robust_list(struct task_struct *curr);
extern void exit_pi_state_list(struct task_struct *curr);
......
include/linux/hardirq.h
浏览文件 @ 5f34fe1c
......@@ -119,13 +119,17 @@ static inline void account_system_vtime(struct task_struct *tsk)
}
#endif
#if defined(CONFIG_PREEMPT_RCU) && defined(CONFIG_NO_HZ)
#if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU)
extern void rcu_irq_enter(void);
extern void rcu_irq_exit(void);
extern void rcu_nmi_enter(void);
extern void rcu_nmi_exit(void);
#else
# define rcu_irq_enter() do { } while (0)
# define rcu_irq_exit() do { } while (0)
#endif /* CONFIG_PREEMPT_RCU */
# define rcu_nmi_enter() do { } while (0)
# define rcu_nmi_exit() do { } while (0)
#endif /* #if defined(CONFIG_NO_HZ) && !defined(CONFIG_CLASSIC_RCU) */
/*
* It is safe to do non-atomic ops on ->hardirq_context,
......@@ -135,7 +139,6 @@ extern void rcu_irq_exit(void);
*/
#define __irq_enter() \
do { \
rcu_irq_enter(); \
account_system_vtime(current); \
add_preempt_count(HARDIRQ_OFFSET); \
trace_hardirq_enter(); \
......@@ -154,7 +157,6 @@ extern void irq_enter(void);
trace_hardirq_exit(); \
account_system_vtime(current); \
sub_preempt_count(HARDIRQ_OFFSET); \
rcu_irq_exit(); \
} while (0)
/*
......@@ -166,11 +168,14 @@ extern void irq_exit(void);
do { \
ftrace_nmi_enter(); \
lockdep_off(); \
rcu_nmi_enter(); \
__irq_enter(); \
} while (0)
#define nmi_exit() \
do { \
__irq_exit(); \
rcu_nmi_exit(); \
lockdep_on(); \
ftrace_nmi_exit(); \
} while (0)
......
include/linux/kernel.h
浏览文件 @ 5f34fe1c
......@@ -141,6 +141,15 @@ extern int _cond_resched(void);
(__x < 0) ? -__x : __x; \
})
#ifdef CONFIG_PROVE_LOCKING
void might_fault(void);
#else
static inline void might_fault(void)
{
might_sleep();
}
#endif
extern struct atomic_notifier_head panic_notifier_list;
extern long (*panic_blink)(long time);
NORET_TYPE void panic(const char * fmt, ...)
......@@ -188,6 +197,8 @@ extern unsigned long long memparse(const char *ptr, char **retptr);
extern int core_kernel_text(unsigned long addr);
extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
extern int func_ptr_is_kernel_text(void *ptr);
struct pid;
extern struct pid *session_of_pgrp(struct pid *pgrp);
......
include/linux/lockdep.h
浏览文件 @ 5f34fe1c
......@@ -73,6 +73,8 @@ struct lock_class_key {
struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
};
#define LOCKSTAT_POINTS 4
/*
* The lock-class itself:
*/
......@@ -119,7 +121,8 @@ struct lock_class {
int name_version;
#ifdef CONFIG_LOCK_STAT
unsigned long contention_point[4];
unsigned long contention_point[LOCKSTAT_POINTS];
unsigned long contending_point[LOCKSTAT_POINTS];
#endif
};
......@@ -144,6 +147,7 @@ enum bounce_type {
struct lock_class_stats {
unsigned long contention_point[4];
unsigned long contending_point[4];
struct lock_time read_waittime;
struct lock_time write_waittime;
struct lock_time read_holdtime;
......@@ -165,6 +169,7 @@ struct lockdep_map {
const char *name;
#ifdef CONFIG_LOCK_STAT
int cpu;
unsigned long ip;
#endif
};
......@@ -309,8 +314,15 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
extern void lock_release(struct lockdep_map *lock, int nested,
unsigned long ip);
extern void lock_set_subclass(struct lockdep_map *lock, unsigned int subclass,
unsigned long ip);
extern void lock_set_class(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, unsigned int subclass,
unsigned long ip);
static inline void lock_set_subclass(struct lockdep_map *lock,
unsigned int subclass, unsigned long ip)
{
lock_set_class(lock, lock->name, lock->key, subclass, ip);
}
# define INIT_LOCKDEP .lockdep_recursion = 0,
......@@ -328,6 +340,7 @@ static inline void lockdep_on(void)
# define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
# define lock_release(l, n, i) do { } while (0)
# define lock_set_class(l, n, k, s, i) do { } while (0)
# define lock_set_subclass(l, s, i) do { } while (0)
# define lockdep_init() do { } while (0)
# define lockdep_info() do { } while (0)
......@@ -356,7 +369,7 @@ struct lock_class_key { };
#ifdef CONFIG_LOCK_STAT
extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
extern void lock_acquired(struct lockdep_map *lock);
extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
#define LOCK_CONTENDED(_lock, try, lock) \
do { \
......@@ -364,13 +377,13 @@ do { \
lock_contended(&(_lock)->dep_map, _RET_IP_); \
lock(_lock); \
} \
lock_acquired(&(_lock)->dep_map); \
lock_acquired(&(_lock)->dep_map, _RET_IP_); \
} while (0)
#else /* CONFIG_LOCK_STAT */
#define lock_contended(lockdep_map, ip) do {} while (0)
#define lock_acquired(lockdep_map) do {} while (0)
#define lock_acquired(lockdep_map, ip) do {} while (0)
#define LOCK_CONTENDED(_lock, try, lock) \
lock(_lock)
......@@ -481,4 +494,22 @@ static inline void print_irqtrace_events(struct task_struct *curr)
# define lock_map_release(l) do { } while (0)
#endif
#ifdef CONFIG_PROVE_LOCKING
# define might_lock(lock) \
do { \
typecheck(struct lockdep_map *, &(lock)->dep_map); \
lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \
lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
} while (0)
# define might_lock_read(lock) \
do { \
typecheck(struct lockdep_map *, &(lock)->dep_map); \
lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \
lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
} while (0)
#else
# define might_lock(lock) do { } while (0)
# define might_lock_read(lock) do { } while (0)
#endif
#endif /* __LINUX_LOCKDEP_H */
include/linux/mutex.h
浏览文件 @ 5f34fe1c
......@@ -144,6 +144,8 @@ extern int __must_check mutex_lock_killable(struct mutex *lock);
/*
* NOTE: mutex_trylock() follows the spin_trylock() convention,
* not the down_trylock() convention!
*
* Returns 1 if the mutex has been acquired successfully, and 0 on contention.
*/
extern int mutex_trylock(struct mutex *lock);
extern void mutex_unlock(struct mutex *lock);
......
include/linux/rcuclassic.h
浏览文件 @ 5f34fe1c
......@@ -41,7 +41,7 @@
#include <linux/seqlock.h>
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */
#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rcp->jiffies_stall */
#define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ) /* for rcp->jiffies_stall */
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
......
include/linux/rcupdate.h
浏览文件 @ 5f34fe1c
......@@ -52,11 +52,15 @@ struct rcu_head {
void (*func)(struct rcu_head *head);
};
#ifdef CONFIG_CLASSIC_RCU
#if defined(CONFIG_CLASSIC_RCU)
#include <linux/rcuclassic.h>
#else /* #ifdef CONFIG_CLASSIC_RCU */
#elif defined(CONFIG_TREE_RCU)
#include <linux/rcutree.h>
#elif defined(CONFIG_PREEMPT_RCU)
#include <linux/rcupreempt.h>
#endif /* #else #ifdef CONFIG_CLASSIC_RCU */
#else
#error "Unknown RCU implementation specified to kernel configuration"
#endif /* #else #if defined(CONFIG_CLASSIC_RCU) */
#define RCU_HEAD_INIT { .next = NULL, .func = NULL }
#define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
......
include/linux/rcutree.h 0 → 100644
浏览文件 @ 5f34fe1c
/*
* Read-Copy Update mechanism for mutual exclusion (tree-based version)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2008
*
* Author: Dipankar Sarma <dipankar@in.ibm.com>
* Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
*
* Based on the original work by Paul McKenney <paulmck@us.ibm.com>
* and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU
*/
#ifndef __LINUX_RCUTREE_H
#define __LINUX_RCUTREE_H
#include <linux/cache.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/percpu.h>
#include <linux/cpumask.h>
#include <linux/seqlock.h>
/*
* Define shape of hierarchy based on NR_CPUS and CONFIG_RCU_FANOUT.
* In theory, it should be possible to add more levels straightforwardly.
* In practice, this has not been tested, so there is probably some
* bug somewhere.
*/
#define MAX_RCU_LVLS 3
#define RCU_FANOUT (CONFIG_RCU_FANOUT)
#define RCU_FANOUT_SQ (RCU_FANOUT * RCU_FANOUT)
#define RCU_FANOUT_CUBE (RCU_FANOUT_SQ * RCU_FANOUT)
#if NR_CPUS <= RCU_FANOUT
# define NUM_RCU_LVLS 1
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 (NR_CPUS)
# define NUM_RCU_LVL_2 0
# define NUM_RCU_LVL_3 0
#elif NR_CPUS <= RCU_FANOUT_SQ
# define NUM_RCU_LVLS 2
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 (((NR_CPUS) + RCU_FANOUT - 1) / RCU_FANOUT)
# define NUM_RCU_LVL_2 (NR_CPUS)
# define NUM_RCU_LVL_3 0
#elif NR_CPUS <= RCU_FANOUT_CUBE
# define NUM_RCU_LVLS 3
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 (((NR_CPUS) + RCU_FANOUT_SQ - 1) / RCU_FANOUT_SQ)
# define NUM_RCU_LVL_2 (((NR_CPUS) + (RCU_FANOUT) - 1) / (RCU_FANOUT))
# define NUM_RCU_LVL_3 NR_CPUS
#else
# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
#endif /* #if (NR_CPUS) <= RCU_FANOUT */
#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3)
#define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
/*
* Dynticks per-CPU state.
*/
struct rcu_dynticks {
int dynticks_nesting; /* Track nesting level, sort of. */
int dynticks; /* Even value for dynticks-idle, else odd. */
int dynticks_nmi; /* Even value for either dynticks-idle or */
/* not in nmi handler, else odd. So this */
/* remains even for nmi from irq handler. */
};
/*
* Definition for node within the RCU grace-period-detection hierarchy.
*/
struct rcu_node {
spinlock_t lock;
unsigned long qsmask; /* CPUs or groups that need to switch in */
/* order for current grace period to proceed.*/
unsigned long qsmaskinit;
/* Per-GP initialization for qsmask. */
unsigned long grpmask; /* Mask to apply to parent qsmask. */
int grplo; /* lowest-numbered CPU or group here. */
int grphi; /* highest-numbered CPU or group here. */
u8 grpnum; /* CPU/group number for next level up. */
u8 level; /* root is at level 0. */
struct rcu_node *parent;
} ____cacheline_internodealigned_in_smp;
/* Index values for nxttail array in struct rcu_data. */
#define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */
#define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */
#define RCU_NEXT_READY_TAIL 2 /* Also RCU_NEXT head. */
#define RCU_NEXT_TAIL 3
#define RCU_NEXT_SIZE 4
/* Per-CPU data for read-copy update. */
struct rcu_data {
/* 1) quiescent-state and grace-period handling : */
long completed; /* Track rsp->completed gp number */
/* in order to detect GP end. */
long gpnum; /* Highest gp number that this CPU */
/* is aware of having started. */
long passed_quiesc_completed;
/* Value of completed at time of qs. */
bool passed_quiesc; /* User-mode/idle loop etc. */
bool qs_pending; /* Core waits for quiesc state. */
bool beenonline; /* CPU online at least once. */
struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
unsigned long grpmask; /* Mask to apply to leaf qsmask. */
/* 2) batch handling */
/*
* If nxtlist is not NULL, it is partitioned as follows.
* Any of the partitions might be empty, in which case the
* pointer to that partition will be equal to the pointer for
* the following partition. When the list is empty, all of
* the nxttail elements point to nxtlist, which is NULL.
*
* [*nxttail[RCU_NEXT_READY_TAIL], NULL = *nxttail[RCU_NEXT_TAIL]):
* Entries that might have arrived after current GP ended
* [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
* Entries known to have arrived before current GP ended
* [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
* Entries that batch # <= ->completed - 1: waiting for current GP
* [nxtlist, *nxttail[RCU_DONE_TAIL]):
* Entries that batch # <= ->completed
* The grace period for these entries has completed, and
* the other grace-period-completed entries may be moved
* here temporarily in rcu_process_callbacks().
*/
struct rcu_head *nxtlist;
struct rcu_head **nxttail[RCU_NEXT_SIZE];
long qlen; /* # of queued callbacks */
long blimit; /* Upper limit on a processed batch */
#ifdef CONFIG_NO_HZ
/* 3) dynticks interface. */
struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */
int dynticks_snap; /* Per-GP tracking for dynticks. */
int dynticks_nmi_snap; /* Per-GP tracking for dynticks_nmi. */
#endif /* #ifdef CONFIG_NO_HZ */
/* 4) reasons this CPU needed to be kicked by force_quiescent_state */
#ifdef CONFIG_NO_HZ
unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */
#endif /* #ifdef CONFIG_NO_HZ */
unsigned long offline_fqs; /* Kicked due to being offline. */
unsigned long resched_ipi; /* Sent a resched IPI. */
/* 5) state to allow this CPU to force_quiescent_state on others */
long n_rcu_pending; /* rcu_pending() calls since boot. */
long n_rcu_pending_force_qs; /* when to force quiescent states. */
int cpu;
};
/* Values for signaled field in struct rcu_state. */
#define RCU_GP_INIT 0 /* Grace period being initialized. */
#define RCU_SAVE_DYNTICK 1 /* Need to scan dyntick state. */
#define RCU_FORCE_QS 2 /* Need to force quiescent state. */
#ifdef CONFIG_NO_HZ
#define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK
#else /* #ifdef CONFIG_NO_HZ */
#define RCU_SIGNAL_INIT RCU_FORCE_QS
#endif /* #else #ifdef CONFIG_NO_HZ */
#define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rsp->jiffies_stall */
#define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ) /* for rsp->jiffies_stall */
#define RCU_STALL_RAT_DELAY 2 /* Allow other CPUs time */
/* to take at least one */
/* scheduling clock irq */
/* before ratting on them. */
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
/*
* RCU global state, including node hierarchy. This hierarchy is
* represented in "heap" form in a dense array. The root (first level)
* of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
* level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
* and the third level in ->node[m+1] and following (->node[m+1] referenced
* by ->level[2]). The number of levels is determined by the number of
* CPUs and by CONFIG_RCU_FANOUT. Small systems will have a "hierarchy"
* consisting of a single rcu_node.
*/
struct rcu_state {
struct rcu_node node[NUM_RCU_NODES]; /* Hierarchy. */
struct rcu_node *level[NUM_RCU_LVLS]; /* Hierarchy levels. */
u32 levelcnt[MAX_RCU_LVLS + 1]; /* # nodes in each level. */
u8 levelspread[NUM_RCU_LVLS]; /* kids/node in each level. */
struct rcu_data *rda[NR_CPUS]; /* array of rdp pointers. */
/* The following fields are guarded by the root rcu_node's lock. */
u8 signaled ____cacheline_internodealigned_in_smp;
/* Force QS state. */
long gpnum; /* Current gp number. */
long completed; /* # of last completed gp. */
spinlock_t onofflock; /* exclude on/offline and */
/* starting new GP. */
spinlock_t fqslock; /* Only one task forcing */
/* quiescent states. */
unsigned long jiffies_force_qs; /* Time at which to invoke */
/* force_quiescent_state(). */
unsigned long n_force_qs; /* Number of calls to */
/* force_quiescent_state(). */
unsigned long n_force_qs_lh; /* ~Number of calls leaving */
/* due to lock unavailable. */
unsigned long n_force_qs_ngp; /* Number of calls leaving */
/* due to no GP active. */
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
unsigned long gp_start; /* Time at which GP started, */
/* but in jiffies. */
unsigned long jiffies_stall; /* Time at which to check */
/* for CPU stalls. */
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
#ifdef CONFIG_NO_HZ
long dynticks_completed; /* Value of completed @ snap. */
#endif /* #ifdef CONFIG_NO_HZ */
};
extern struct rcu_state rcu_state;
DECLARE_PER_CPU(struct rcu_data, rcu_data);
extern struct rcu_state rcu_bh_state;
DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
/*
* Increment the quiescent state counter.
* The counter is a bit degenerated: We do not need to know
* how many quiescent states passed, just if there was at least
* one since the start of the grace period. Thus just a flag.
*/
static inline void rcu_qsctr_inc(int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
rdp->passed_quiesc = 1;
rdp->passed_quiesc_completed = rdp->completed;
}
static inline void rcu_bh_qsctr_inc(int cpu)
{
struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
rdp->passed_quiesc = 1;
rdp->passed_quiesc_completed = rdp->completed;
}
extern int rcu_pending(int cpu);
extern int rcu_needs_cpu(int cpu);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
extern struct lockdep_map rcu_lock_map;
# define rcu_read_acquire() \
lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
# define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_)
#else
# define rcu_read_acquire() do { } while (0)
# define rcu_read_release() do { } while (0)
#endif
static inline void __rcu_read_lock(void)
{
preempt_disable();
__acquire(RCU);
rcu_read_acquire();
}
static inline void __rcu_read_unlock(void)
{
rcu_read_release();
__release(RCU);
preempt_enable();
}
static inline void __rcu_read_lock_bh(void)
{
local_bh_disable();
__acquire(RCU_BH);
rcu_read_acquire();
}
static inline void __rcu_read_unlock_bh(void)
{
rcu_read_release();
__release(RCU_BH);
local_bh_enable();
}
#define __synchronize_sched() synchronize_rcu()
#define call_rcu_sched(head, func) call_rcu(head, func)
static inline void rcu_init_sched(void)
{
}
extern void __rcu_init(void);
extern void rcu_check_callbacks(int cpu, int user);
extern void rcu_restart_cpu(int cpu);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
#ifdef CONFIG_NO_HZ
void rcu_enter_nohz(void);
void rcu_exit_nohz(void);
#else /* CONFIG_NO_HZ */
static inline void rcu_enter_nohz(void)
{
}
static inline void rcu_exit_nohz(void)
{
}
#endif /* CONFIG_NO_HZ */
#endif /* __LINUX_RCUTREE_H */
include/linux/swiotlb.h
浏览文件 @ 5f34fe1c
......@@ -7,9 +7,31 @@ struct device;
struct dma_attrs;
struct scatterlist;
/*
* Maximum allowable number of contiguous slabs to map,
* must be a power of 2. What is the appropriate value ?
* The complexity of {map,unmap}_single is linearly dependent on this value.
*/
#define IO_TLB_SEGSIZE 128
/*
* log of the size of each IO TLB slab. The number of slabs is command line
* controllable.
*/
#define IO_TLB_SHIFT 11
extern void
swiotlb_init(void);
extern void *swiotlb_alloc_boot(size_t bytes, unsigned long nslabs);
extern void *swiotlb_alloc(unsigned order, unsigned long nslabs);
extern dma_addr_t swiotlb_phys_to_bus(phys_addr_t address);
extern phys_addr_t swiotlb_bus_to_phys(dma_addr_t address);
extern int swiotlb_arch_range_needs_mapping(void *ptr, size_t size);
extern void
*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags);
......
include/linux/uaccess.h
浏览文件 @ 5f34fe1c
......@@ -78,7 +78,7 @@ static inline unsigned long __copy_from_user_nocache(void *to,
\
set_fs(KERNEL_DS); \
pagefault_disable(); \
ret = __get_user(retval, (__force typeof(retval) __user *)(addr)); \
ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval)); \
pagefault_enable(); \
set_fs(old_fs); \
ret; \
......
init/Kconfig
浏览文件 @ 5f34fe1c
......@@ -936,10 +936,90 @@ source "block/Kconfig"
config PREEMPT_NOTIFIERS
bool
choice
prompt "RCU Implementation"
default CLASSIC_RCU
config CLASSIC_RCU
def_bool !PREEMPT_RCU
bool "Classic RCU"
help
This option selects the classic RCU implementation that is
designed for best read-side performance on non-realtime
systems. Classic RCU is the default. Note that the
PREEMPT_RCU symbol is used to select/deselect this option.
systems.
Select this option if you are unsure.
config TREE_RCU
bool "Tree-based hierarchical RCU"
help
This option selects the RCU implementation that is
designed for very large SMP system with hundreds or
thousands of CPUs.
config PREEMPT_RCU
bool "Preemptible RCU"
depends on PREEMPT
help
This option reduces the latency of the kernel by making certain
RCU sections preemptible. Normally RCU code is non-preemptible, if
this option is selected then read-only RCU sections become
preemptible. This helps latency, but may expose bugs due to
now-naive assumptions about each RCU read-side critical section
remaining on a given CPU through its execution.
endchoice
config RCU_TRACE
bool "Enable tracing for RCU"
depends on TREE_RCU || PREEMPT_RCU
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
Say Y here if you want to enable RCU tracing
Say N if you are unsure.
config RCU_FANOUT
int "Tree-based hierarchical RCU fanout value"
range 2 64 if 64BIT
range 2 32 if !64BIT
depends on TREE_RCU
default 64 if 64BIT
default 32 if !64BIT
help
This option controls the fanout of hierarchical implementations
of RCU, allowing RCU to work efficiently on machines with
large numbers of CPUs. This value must be at least the cube
root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
systems and up to 262,144 for 64-bit systems.
Select a specific number if testing RCU itself.
Take the default if unsure.
config RCU_FANOUT_EXACT
bool "Disable tree-based hierarchical RCU auto-balancing"
depends on TREE_RCU
default n
help
This option forces use of the exact RCU_FANOUT value specified,
regardless of imbalances in the hierarchy. This is useful for
testing RCU itself, and might one day be useful on systems with
strong NUMA behavior.
Without RCU_FANOUT_EXACT, the code will balance the hierarchy.
Say N if unsure.
config TREE_RCU_TRACE
def_bool RCU_TRACE && TREE_RCU
select DEBUG_FS
help
This option provides tracing for the TREE_RCU implementation,
permitting Makefile to trivially select kernel/rcutree_trace.c.
config PREEMPT_RCU_TRACE
def_bool RCU_TRACE && PREEMPT_RCU
select DEBUG_FS
help
This option provides tracing for the PREEMPT_RCU implementation,
permitting Makefile to trivially select kernel/rcupreempt_trace.c.
kernel/Kconfig.preempt
浏览文件 @ 5f34fe1c
......@@ -52,28 +52,3 @@ config PREEMPT
endchoice
config PREEMPT_RCU
bool "Preemptible RCU"
depends on PREEMPT
default n
help
This option reduces the latency of the kernel by making certain
RCU sections preemptible. Normally RCU code is non-preemptible, if
this option is selected then read-only RCU sections become
preemptible. This helps latency, but may expose bugs due to
now-naive assumptions about each RCU read-side critical section
remaining on a given CPU through its execution.
Say N if you are unsure.
config RCU_TRACE
bool "Enable tracing for RCU - currently stats in debugfs"
depends on PREEMPT_RCU
select DEBUG_FS
default y
help
This option provides tracing in RCU which presents stats
in debugfs for debugging RCU implementation.
Say Y here if you want to enable RCU tracing
Say N if you are unsure.
kernel/Makefile
浏览文件 @ 5f34fe1c
......@@ -73,10 +73,10 @@ obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
obj-$(CONFIG_CLASSIC_RCU) += rcuclassic.o
obj-$(CONFIG_TREE_RCU) += rcutree.o
obj-$(CONFIG_PREEMPT_RCU) += rcupreempt.o
ifeq ($(CONFIG_PREEMPT_RCU),y)
obj-$(CONFIG_RCU_TRACE) += rcupreempt_trace.o
endif
obj-$(CONFIG_TREE_RCU_TRACE) += rcutree_trace.o
obj-$(CONFIG_PREEMPT_RCU_TRACE) += rcupreempt_trace.o
obj-$(CONFIG_RELAY) += relay.o
obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
......
kernel/exit.c
浏览文件 @ 5f34fe1c
......@@ -1328,10 +1328,10 @@ static int wait_task_zombie(struct task_struct *p, int options,
* group, which consolidates times for all threads in the
* group including the group leader.
*/
thread_group_cputime(p, &cputime);
spin_lock_irq(&p->parent->sighand->siglock);
psig = p->parent->signal;
sig = p->signal;
thread_group_cputime(p, &cputime);
psig->cutime =
cputime_add(psig->cutime,
cputime_add(cputime.utime,
......
kernel/extable.c
浏览文件 @ 5f34fe1c
......@@ -67,3 +67,19 @@ int kernel_text_address(unsigned long addr)
return 1;
return module_text_address(addr) != NULL;
}
/*
* On some architectures (PPC64, IA64) function pointers
* are actually only tokens to some data that then holds the
* real function address. As a result, to find if a function
* pointer is part of the kernel text, we need to do some
* special dereferencing first.
*/
int func_ptr_is_kernel_text(void *ptr)
{
unsigned long addr;
addr = (unsigned long) dereference_function_descriptor(ptr);
if (core_kernel_text(addr))
return 1;
return module_text_address(addr) != NULL;
}
kernel/futex.c
浏览文件 @ 5f34fe1c
......@@ -92,11 +92,12 @@ struct futex_pi_state {
* A futex_q has a woken state, just like tasks have TASK_RUNNING.
* It is considered woken when plist_node_empty(&q->list) || q->lock_ptr == 0.
* The order of wakup is always to make the first condition true, then
* wake up q->waiters, then make the second condition true.
* wake up q->waiter, then make the second condition true.
*/
struct futex_q {
struct plist_node list;
wait_queue_head_t waiters;
/* There can only be a single waiter */
wait_queue_head_t waiter;
/* Which hash list lock to use: */
spinlock_t *lock_ptr;
......@@ -122,24 +123,6 @@ struct futex_hash_bucket {
static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
/*
* Take mm->mmap_sem, when futex is shared
*/
static inline void futex_lock_mm(struct rw_semaphore *fshared)
{
if (fshared)
down_read(fshared);
}
/*
* Release mm->mmap_sem, when the futex is shared
*/
static inline void futex_unlock_mm(struct rw_semaphore *fshared)
{
if (fshared)
up_read(fshared);
}
/*
* We hash on the keys returned from get_futex_key (see below).
*/
......@@ -161,6 +144,45 @@ static inline int match_futex(union futex_key *key1, union futex_key *key2)
&& key1->both.offset == key2->both.offset);
}
/*
* Take a reference to the resource addressed by a key.
* Can be called while holding spinlocks.
*
*/
static void get_futex_key_refs(union futex_key *key)
{
if (!key->both.ptr)
return;
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
atomic_inc(&key->shared.inode->i_count);
break;
case FUT_OFF_MMSHARED:
atomic_inc(&key->private.mm->mm_count);
break;
}
}
/*
* Drop a reference to the resource addressed by a key.
* The hash bucket spinlock must not be held.
*/
static void drop_futex_key_refs(union futex_key *key)
{
if (!key->both.ptr)
return;
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
iput(key->shared.inode);
break;
case FUT_OFF_MMSHARED:
mmdrop(key->private.mm);
break;
}
}
/**
* get_futex_key - Get parameters which are the keys for a futex.
* @uaddr: virtual address of the futex
......@@ -179,12 +201,10 @@ static inline int match_futex(union futex_key *key1, union futex_key *key2)
* For other futexes, it points to &current->mm->mmap_sem and
* caller must have taken the reader lock. but NOT any spinlocks.
*/
static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared,
union futex_key *key)
static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct page *page;
int err;
......@@ -208,100 +228,50 @@ static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared,
return -EFAULT;
key->private.mm = mm;
key->private.address = address;
get_futex_key_refs(key);
return 0;
}
/*
* The futex is hashed differently depending on whether
* it's in a shared or private mapping. So check vma first.
*/
vma = find_extend_vma(mm, address);
if (unlikely(!vma))
return -EFAULT;
/*
* Permissions.
*/
if (unlikely((vma->vm_flags & (VM_IO|VM_READ)) != VM_READ))
return (vma->vm_flags & VM_IO) ? -EPERM : -EACCES;
again:
err = get_user_pages_fast(address, 1, 0, &page);
if (err < 0)
return err;
lock_page(page);
if (!page->mapping) {
unlock_page(page);
put_page(page);
goto again;
}
/*
* Private mappings are handled in a simple way.
*
* NOTE: When userspace waits on a MAP_SHARED mapping, even if
* it's a read-only handle, it's expected that futexes attach to
* the object not the particular process. Therefore we use
* VM_MAYSHARE here, not VM_SHARED which is restricted to shared
* mappings of _writable_ handles.
* the object not the particular process.
*/
if (likely(!(vma->vm_flags & VM_MAYSHARE))) {
key->both.offset |= FUT_OFF_MMSHARED; /* reference taken on mm */
if (PageAnon(page)) {
key->both.offset |= FUT_OFF_MMSHARED; /* ref taken on mm */
key->private.mm = mm;
key->private.address = address;
return 0;
} else {
key->both.offset |= FUT_OFF_INODE; /* inode-based key */
key->shared.inode = page->mapping->host;
key->shared.pgoff = page->index;
}
/*
* Linear file mappings are also simple.
*/
key->shared.inode = vma->vm_file->f_path.dentry->d_inode;
key->both.offset |= FUT_OFF_INODE; /* inode-based key. */
if (likely(!(vma->vm_flags & VM_NONLINEAR))) {
key->shared.pgoff = (((address - vma->vm_start) >> PAGE_SHIFT)
+ vma->vm_pgoff);
return 0;
}
get_futex_key_refs(key);
/*
* We could walk the page table to read the non-linear
* pte, and get the page index without fetching the page
* from swap. But that's a lot of code to duplicate here
* for a rare case, so we simply fetch the page.
*/
err = get_user_pages(current, mm, address, 1, 0, 0, &page, NULL);
if (err >= 0) {
key->shared.pgoff =
page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
put_page(page);
return 0;
}
return err;
}
/*
* Take a reference to the resource addressed by a key.
* Can be called while holding spinlocks.
*
*/
static void get_futex_key_refs(union futex_key *key)
{
if (key->both.ptr == NULL)
return;
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
atomic_inc(&key->shared.inode->i_count);
break;
case FUT_OFF_MMSHARED:
atomic_inc(&key->private.mm->mm_count);
break;
}
unlock_page(page);
put_page(page);
return 0;
}
/*
* Drop a reference to the resource addressed by a key.
* The hash bucket spinlock must not be held.
*/
static void drop_futex_key_refs(union futex_key *key)
static inline
void put_futex_key(int fshared, union futex_key *key)
{
if (!key->both.ptr)
return;
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
iput(key->shared.inode);
break;
case FUT_OFF_MMSHARED:
mmdrop(key->private.mm);
break;
}
drop_futex_key_refs(key);
}
static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)
......@@ -328,10 +298,8 @@ static int get_futex_value_locked(u32 *dest, u32 __user *from)
/*
* Fault handling.
* if fshared is non NULL, current->mm->mmap_sem is already held
*/
static int futex_handle_fault(unsigned long address,
struct rw_semaphore *fshared, int attempt)
static int futex_handle_fault(unsigned long address, int attempt)
{
struct vm_area_struct * vma;
struct mm_struct *mm = current->mm;
......@@ -340,8 +308,7 @@ static int futex_handle_fault(unsigned long address,
if (attempt > 2)
return ret;
if (!fshared)
down_read(&mm->mmap_sem);
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (vma && address >= vma->vm_start &&
(vma->vm_flags & VM_WRITE)) {
......@@ -361,8 +328,7 @@ static int futex_handle_fault(unsigned long address,
current->min_flt++;
}
}
if (!fshared)
up_read(&mm->mmap_sem);
up_read(&mm->mmap_sem);
return ret;
}
......@@ -385,6 +351,7 @@ static int refill_pi_state_cache(void)
/* pi_mutex gets initialized later */
pi_state->owner = NULL;
atomic_set(&pi_state->refcount, 1);
pi_state->key = FUTEX_KEY_INIT;
current->pi_state_cache = pi_state;
......@@ -469,7 +436,7 @@ void exit_pi_state_list(struct task_struct *curr)
struct list_head *next, *head = &curr->pi_state_list;
struct futex_pi_state *pi_state;
struct futex_hash_bucket *hb;
union futex_key key;
union futex_key key = FUTEX_KEY_INIT;
if (!futex_cmpxchg_enabled)
return;
......@@ -614,7 +581,7 @@ static void wake_futex(struct futex_q *q)
* The lock in wake_up_all() is a crucial memory barrier after the
* plist_del() and also before assigning to q->lock_ptr.
*/
wake_up_all(&q->waiters);
wake_up(&q->waiter);
/*
* The waiting task can free the futex_q as soon as this is written,
* without taking any locks. This must come last.
......@@ -726,20 +693,17 @@ double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
* Wake up all waiters hashed on the physical page that is mapped
* to this virtual address:
*/
static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
int nr_wake, u32 bitset)
static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
struct plist_head *head;
union futex_key key;
union futex_key key = FUTEX_KEY_INIT;
int ret;
if (!bitset)
return -EINVAL;
futex_lock_mm(fshared);
ret = get_futex_key(uaddr, fshared, &key);
if (unlikely(ret != 0))
goto out;
......@@ -767,7 +731,7 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
spin_unlock(&hb->lock);
out:
futex_unlock_mm(fshared);
put_futex_key(fshared, &key);
return ret;
}
......@@ -776,19 +740,16 @@ static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
* to this virtual address:
*/
static int
futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
u32 __user *uaddr2,
futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
int nr_wake, int nr_wake2, int op)
{
union futex_key key1, key2;
union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
struct futex_hash_bucket *hb1, *hb2;
struct plist_head *head;
struct futex_q *this, *next;
int ret, op_ret, attempt = 0;
retryfull:
futex_lock_mm(fshared);
ret = get_futex_key(uaddr1, fshared, &key1);
if (unlikely(ret != 0))
goto out;
......@@ -833,18 +794,12 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
*/
if (attempt++) {
ret = futex_handle_fault((unsigned long)uaddr2,
fshared, attempt);
attempt);
if (ret)
goto out;
goto retry;
}
/*
* If we would have faulted, release mmap_sem,
* fault it in and start all over again.
*/
futex_unlock_mm(fshared);
ret = get_user(dummy, uaddr2);
if (ret)
return ret;
......@@ -880,7 +835,8 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
if (hb1 != hb2)
spin_unlock(&hb2->lock);
out:
futex_unlock_mm(fshared);
put_futex_key(fshared, &key2);
put_futex_key(fshared, &key1);
return ret;
}
......@@ -889,19 +845,16 @@ futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
* Requeue all waiters hashed on one physical page to another
* physical page.
*/
static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
u32 __user *uaddr2,
static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
int nr_wake, int nr_requeue, u32 *cmpval)
{
union futex_key key1, key2;
union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
struct futex_hash_bucket *hb1, *hb2;
struct plist_head *head1;
struct futex_q *this, *next;
int ret, drop_count = 0;
retry:
futex_lock_mm(fshared);
ret = get_futex_key(uaddr1, fshared, &key1);
if (unlikely(ret != 0))
goto out;
......@@ -924,12 +877,6 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
if (hb1 != hb2)
spin_unlock(&hb2->lock);
/*
* If we would have faulted, release mmap_sem, fault
* it in and start all over again.
*/
futex_unlock_mm(fshared);
ret = get_user(curval, uaddr1);
if (!ret)
......@@ -981,7 +928,8 @@ static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
drop_futex_key_refs(&key1);
out:
futex_unlock_mm(fshared);
put_futex_key(fshared, &key2);
put_futex_key(fshared, &key1);
return ret;
}
......@@ -990,7 +938,7 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)
{
struct futex_hash_bucket *hb;
init_waitqueue_head(&q->waiters);
init_waitqueue_head(&q->waiter);
get_futex_key_refs(&q->key);
hb = hash_futex(&q->key);
......@@ -1103,8 +1051,7 @@ static void unqueue_me_pi(struct futex_q *q)
* private futexes.
*/
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
struct task_struct *newowner,
struct rw_semaphore *fshared)
struct task_struct *newowner, int fshared)
{
u32 newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
struct futex_pi_state *pi_state = q->pi_state;
......@@ -1183,7 +1130,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
handle_fault:
spin_unlock(q->lock_ptr);
ret = futex_handle_fault((unsigned long)uaddr, fshared, attempt++);
ret = futex_handle_fault((unsigned long)uaddr, attempt++);
spin_lock(q->lock_ptr);
......@@ -1203,12 +1150,13 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
* In case we must use restart_block to restart a futex_wait,
* we encode in the 'flags' shared capability
*/
#define FLAGS_SHARED 1
#define FLAGS_SHARED 0x01
#define FLAGS_CLOCKRT 0x02
static long futex_wait_restart(struct restart_block *restart);
static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
u32 val, ktime_t *abs_time, u32 bitset)
static int futex_wait(u32 __user *uaddr, int fshared,
u32 val, ktime_t *abs_time, u32 bitset, int clockrt)
{
struct task_struct *curr = current;
DECLARE_WAITQUEUE(wait, curr);
......@@ -1225,8 +1173,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
q.pi_state = NULL;
q.bitset = bitset;
retry:
futex_lock_mm(fshared);
q.key = FUTEX_KEY_INIT;
ret = get_futex_key(uaddr, fshared, &q.key);
if (unlikely(ret != 0))
goto out_release_sem;
......@@ -1258,12 +1205,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
if (unlikely(ret)) {
queue_unlock(&q, hb);
/*
* If we would have faulted, release mmap_sem, fault it in and
* start all over again.
*/
futex_unlock_mm(fshared);
ret = get_user(uval, uaddr);
if (!ret)
......@@ -1277,12 +1218,6 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
/* Only actually queue if *uaddr contained val. */
queue_me(&q, hb);
/*
* Now the futex is queued and we have checked the data, we
* don't want to hold mmap_sem while we sleep.
*/
futex_unlock_mm(fshared);
/*
* There might have been scheduling since the queue_me(), as we
* cannot hold a spinlock across the get_user() in case it
......@@ -1294,7 +1229,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
/* add_wait_queue is the barrier after __set_current_state. */
__set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&q.waiters, &wait);
add_wait_queue(&q.waiter, &wait);
/*
* !plist_node_empty() is safe here without any lock.
* q.lock_ptr != 0 is not safe, because of ordering against wakeup.
......@@ -1307,8 +1242,10 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
slack = current->timer_slack_ns;
if (rt_task(current))
slack = 0;
hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
HRTIMER_MODE_ABS);
hrtimer_init_on_stack(&t.timer,
clockrt ? CLOCK_REALTIME :
CLOCK_MONOTONIC,
HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
......@@ -1363,6 +1300,8 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
if (fshared)
restart->futex.flags |= FLAGS_SHARED;
if (clockrt)
restart->futex.flags |= FLAGS_CLOCKRT;
return -ERESTART_RESTARTBLOCK;
}
......@@ -1370,7 +1309,7 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
queue_unlock(&q, hb);
out_release_sem:
futex_unlock_mm(fshared);
put_futex_key(fshared, &q.key);
return ret;
}
......@@ -1378,15 +1317,16 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
static long futex_wait_restart(struct restart_block *restart)
{
u32 __user *uaddr = (u32 __user *)restart->futex.uaddr;
struct rw_semaphore *fshared = NULL;
int fshared = 0;
ktime_t t;
t.tv64 = restart->futex.time;
restart->fn = do_no_restart_syscall;
if (restart->futex.flags & FLAGS_SHARED)
fshared = &current->mm->mmap_sem;
fshared = 1;
return (long)futex_wait(uaddr, fshared, restart->futex.val, &t,
restart->futex.bitset);
restart->futex.bitset,
restart->futex.flags & FLAGS_CLOCKRT);
}
......@@ -1396,7 +1336,7 @@ static long futex_wait_restart(struct restart_block *restart)
* if there are waiters then it will block, it does PI, etc. (Due to
* races the kernel might see a 0 value of the futex too.)
*/
static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
static int futex_lock_pi(u32 __user *uaddr, int fshared,
int detect, ktime_t *time, int trylock)
{
struct hrtimer_sleeper timeout, *to = NULL;
......@@ -1419,8 +1359,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
q.pi_state = NULL;
retry:
futex_lock_mm(fshared);
q.key = FUTEX_KEY_INIT;
ret = get_futex_key(uaddr, fshared, &q.key);
if (unlikely(ret != 0))
goto out_release_sem;
......@@ -1509,7 +1448,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
* exit to complete.
*/
queue_unlock(&q, hb);
futex_unlock_mm(fshared);
cond_resched();
goto retry;
......@@ -1541,12 +1479,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
*/
queue_me(&q, hb);
/*
* Now the futex is queued and we have checked the data, we
* don't want to hold mmap_sem while we sleep.
*/
futex_unlock_mm(fshared);
WARN_ON(!q.pi_state);
/*
* Block on the PI mutex:
......@@ -1559,7 +1491,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
ret = ret ? 0 : -EWOULDBLOCK;
}
futex_lock_mm(fshared);
spin_lock(q.lock_ptr);
if (!ret) {
......@@ -1625,7 +1556,6 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
/* Unqueue and drop the lock */
unqueue_me_pi(&q);
futex_unlock_mm(fshared);
if (to)
destroy_hrtimer_on_stack(&to->timer);
......@@ -1635,34 +1565,30 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
queue_unlock(&q, hb);
out_release_sem:
futex_unlock_mm(fshared);
put_futex_key(fshared, &q.key);
if (to)
destroy_hrtimer_on_stack(&to->timer);
return ret;
uaddr_faulted:
/*
* We have to r/w *(int __user *)uaddr, but we can't modify it
* non-atomically. Therefore, if get_user below is not
* enough, we need to handle the fault ourselves, while
* still holding the mmap_sem.
*
* ... and hb->lock. :-) --ANK
* We have to r/w *(int __user *)uaddr, and we have to modify it
* atomically. Therefore, if we continue to fault after get_user()
* below, we need to handle the fault ourselves, while still holding
* the mmap_sem. This can occur if the uaddr is under contention as
* we have to drop the mmap_sem in order to call get_user().
*/
queue_unlock(&q, hb);
if (attempt++) {
ret = futex_handle_fault((unsigned long)uaddr, fshared,
attempt);
ret = futex_handle_fault((unsigned long)uaddr, attempt);
if (ret)
goto out_release_sem;
goto retry_unlocked;
}
futex_unlock_mm(fshared);
ret = get_user(uval, uaddr);
if (!ret && (uval != -EFAULT))
if (!ret)
goto retry;
if (to)
......@@ -1675,13 +1601,13 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
* This is the in-kernel slowpath: we look up the PI state (if any),
* and do the rt-mutex unlock.
*/
static int futex_unlock_pi(u32 __user *uaddr, struct rw_semaphore *fshared)
static int futex_unlock_pi(u32 __user *uaddr, int fshared)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
u32 uval;
struct plist_head *head;
union futex_key key;
union futex_key key = FUTEX_KEY_INIT;
int ret, attempt = 0;
retry:
......@@ -1692,10 +1618,6 @@ static int futex_unlock_pi(u32 __user *uaddr, struct rw_semaphore *fshared)
*/
if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current))
return -EPERM;
/*
* First take all the futex related locks:
*/
futex_lock_mm(fshared);
ret = get_futex_key(uaddr, fshared, &key);
if (unlikely(ret != 0))
......@@ -1754,34 +1676,30 @@ static int futex_unlock_pi(u32 __user *uaddr, struct rw_semaphore *fshared)
out_unlock:
spin_unlock(&hb->lock);
out:
futex_unlock_mm(fshared);
put_futex_key(fshared, &key);
return ret;
pi_faulted:
/*
* We have to r/w *(int __user *)uaddr, but we can't modify it
* non-atomically. Therefore, if get_user below is not
* enough, we need to handle the fault ourselves, while
* still holding the mmap_sem.
*
* ... and hb->lock. --ANK
* We have to r/w *(int __user *)uaddr, and we have to modify it
* atomically. Therefore, if we continue to fault after get_user()
* below, we need to handle the fault ourselves, while still holding
* the mmap_sem. This can occur if the uaddr is under contention as
* we have to drop the mmap_sem in order to call get_user().
*/
spin_unlock(&hb->lock);
if (attempt++) {
ret = futex_handle_fault((unsigned long)uaddr, fshared,
attempt);
ret = futex_handle_fault((unsigned long)uaddr, attempt);
if (ret)
goto out;
uval = 0;
goto retry_unlocked;
}
futex_unlock_mm(fshared);
ret = get_user(uval, uaddr);
if (!ret && (uval != -EFAULT))
if (!ret)
goto retry;
return ret;
......@@ -1908,8 +1826,7 @@ int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi)
* PI futexes happens in exit_pi_state():
*/
if (!pi && (uval & FUTEX_WAITERS))
futex_wake(uaddr, &curr->mm->mmap_sem, 1,
FUTEX_BITSET_MATCH_ANY);
futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
}
return 0;
}
......@@ -2003,18 +1920,22 @@ void exit_robust_list(struct task_struct *curr)
long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3)
{
int ret = -ENOSYS;
int clockrt, ret = -ENOSYS;
int cmd = op & FUTEX_CMD_MASK;
struct rw_semaphore *fshared = NULL;
int fshared = 0;
if (!(op & FUTEX_PRIVATE_FLAG))
fshared = &current->mm->mmap_sem;
fshared = 1;
clockrt = op & FUTEX_CLOCK_REALTIME;
if (clockrt && cmd != FUTEX_WAIT_BITSET)
return -ENOSYS;
switch (cmd) {
case FUTEX_WAIT:
val3 = FUTEX_BITSET_MATCH_ANY;
case FUTEX_WAIT_BITSET:
ret = futex_wait(uaddr, fshared, val, timeout, val3);
ret = futex_wait(uaddr, fshared, val, timeout, val3, clockrt);
break;
case FUTEX_WAKE:
val3 = FUTEX_BITSET_MATCH_ANY;
......
kernel/irq/manage.c
浏览文件 @ 5f34fe1c
......@@ -673,6 +673,18 @@ int request_irq(unsigned int irq, irq_handler_t handler,
struct irq_desc *desc;
int retval;
/*
* handle_IRQ_event() always ignores IRQF_DISABLED except for
* the _first_ irqaction (sigh). That can cause oopsing, but
* the behavior is classified as "will not fix" so we need to
* start nudging drivers away from using that idiom.
*/
if ((irqflags & (IRQF_SHARED|IRQF_DISABLED))
== (IRQF_SHARED|IRQF_DISABLED))
pr_warning("IRQ %d/%s: IRQF_DISABLED is not "
"guaranteed on shared IRQs\n",
irq, devname);
#ifdef CONFIG_LOCKDEP
/*
* Lockdep wants atomic interrupt handlers:
......
kernel/lockdep.c
浏览文件 @ 5f34fe1c
......@@ -137,16 +137,16 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock)
#ifdef CONFIG_LOCK_STAT
static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
static int lock_contention_point(struct lock_class *class, unsigned long ip)
static int lock_point(unsigned long points[], unsigned long ip)
{
int i;
for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
if (class->contention_point[i] == 0) {
class->contention_point[i] = ip;
for (i = 0; i < LOCKSTAT_POINTS; i++) {
if (points[i] == 0) {
points[i] = ip;
break;
}
if (class->contention_point[i] == ip)
if (points[i] == ip)
break;
}
......@@ -186,6 +186,9 @@ struct lock_class_stats lock_stats(struct lock_class *class)
for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
stats.contention_point[i] += pcs->contention_point[i];
for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
stats.contending_point[i] += pcs->contending_point[i];
lock_time_add(&pcs->read_waittime, &stats.read_waittime);
lock_time_add(&pcs->write_waittime, &stats.write_waittime);
......@@ -210,6 +213,7 @@ void clear_lock_stats(struct lock_class *class)
memset(cpu_stats, 0, sizeof(struct lock_class_stats));
}
memset(class->contention_point, 0, sizeof(class->contention_point));
memset(class->contending_point, 0, sizeof(class->contending_point));
}
static struct lock_class_stats *get_lock_stats(struct lock_class *class)
......@@ -288,14 +292,12 @@ void lockdep_off(void)
{
current->lockdep_recursion++;
}
EXPORT_SYMBOL(lockdep_off);
void lockdep_on(void)
{
current->lockdep_recursion--;
}
EXPORT_SYMBOL(lockdep_on);
/*
......@@ -577,7 +579,8 @@ static void print_lock_class_header(struct lock_class *class, int depth)
/*
* printk all lock dependencies starting at <entry>:
*/
static void print_lock_dependencies(struct lock_class *class, int depth)
static void __used
print_lock_dependencies(struct lock_class *class, int depth)
{
struct lock_list *entry;
......@@ -2509,7 +2512,6 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name,
if (subclass)
register_lock_class(lock, subclass, 1);
}
EXPORT_SYMBOL_GPL(lockdep_init_map);
/*
......@@ -2690,8 +2692,9 @@ static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
}
static int
__lock_set_subclass(struct lockdep_map *lock,
unsigned int subclass, unsigned long ip)
__lock_set_class(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, unsigned int subclass,
unsigned long ip)
{
struct task_struct *curr = current;
struct held_lock *hlock, *prev_hlock;
......@@ -2718,6 +2721,7 @@ __lock_set_subclass(struct lockdep_map *lock,
return print_unlock_inbalance_bug(curr, lock, ip);
found_it:
lockdep_init_map(lock, name, key, 0);
class = register_lock_class(lock, subclass, 0);
hlock->class_idx = class - lock_classes + 1;
......@@ -2902,9 +2906,9 @@ static void check_flags(unsigned long flags)
#endif
}
void
lock_set_subclass(struct lockdep_map *lock,
unsigned int subclass, unsigned long ip)
void lock_set_class(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, unsigned int subclass,
unsigned long ip)
{
unsigned long flags;
......@@ -2914,13 +2918,12 @@ lock_set_subclass(struct lockdep_map *lock,
raw_local_irq_save(flags);
current->lockdep_recursion = 1;
check_flags(flags);
if (__lock_set_subclass(lock, subclass, ip))
if (__lock_set_class(lock, name, key, subclass, ip))
check_chain_key(current);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_set_subclass);
EXPORT_SYMBOL_GPL(lock_set_class);
/*
* We are not always called with irqs disabled - do that here,
......@@ -2944,7 +2947,6 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_acquire);
void lock_release(struct lockdep_map *lock, int nested,
......@@ -2962,7 +2964,6 @@ void lock_release(struct lockdep_map *lock, int nested,
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_release);
#ifdef CONFIG_LOCK_STAT
......@@ -3000,7 +3001,7 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
struct held_lock *hlock, *prev_hlock;
struct lock_class_stats *stats;
unsigned int depth;
int i, point;
int i, contention_point, contending_point;
depth = curr->lockdep_depth;
if (DEBUG_LOCKS_WARN_ON(!depth))
......@@ -3024,18 +3025,22 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
found_it:
hlock->waittime_stamp = sched_clock();
point = lock_contention_point(hlock_class(hlock), ip);
contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
contending_point = lock_point(hlock_class(hlock)->contending_point,
lock->ip);
stats = get_lock_stats(hlock_class(hlock));
if (point < ARRAY_SIZE(stats->contention_point))
stats->contention_point[point]++;
if (contention_point < LOCKSTAT_POINTS)
stats->contention_point[contention_point]++;
if (contending_point < LOCKSTAT_POINTS)
stats->contending_point[contending_point]++;
if (lock->cpu != smp_processor_id())
stats->bounces[bounce_contended + !!hlock->read]++;
put_lock_stats(stats);
}
static void
__lock_acquired(struct lockdep_map *lock)
__lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
struct task_struct *curr = current;
struct held_lock *hlock, *prev_hlock;
......@@ -3084,6 +3089,7 @@ __lock_acquired(struct lockdep_map *lock)
put_lock_stats(stats);
lock->cpu = cpu;
lock->ip = ip;
}
void lock_contended(struct lockdep_map *lock, unsigned long ip)
......@@ -3105,7 +3111,7 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
}
EXPORT_SYMBOL_GPL(lock_contended);
void lock_acquired(struct lockdep_map *lock)
void lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
......@@ -3118,7 +3124,7 @@ void lock_acquired(struct lockdep_map *lock)
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion = 1;
__lock_acquired(lock);
__lock_acquired(lock, ip);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
......@@ -3442,7 +3448,6 @@ void debug_show_all_locks(void)
if (unlock)
read_unlock(&tasklist_lock);
}
EXPORT_SYMBOL_GPL(debug_show_all_locks);
/*
......@@ -3463,7 +3468,6 @@ void debug_show_held_locks(struct task_struct *task)
{
__debug_show_held_locks(task);
}
EXPORT_SYMBOL_GPL(debug_show_held_locks);
void lockdep_sys_exit(void)
......
kernel/lockdep_proc.c
浏览文件 @ 5f34fe1c
......@@ -470,11 +470,12 @@ static void seq_line(struct seq_file *m, char c, int offset, int length)
static void snprint_time(char *buf, size_t bufsiz, s64 nr)
{
unsigned long rem;
s64 div;
s32 rem;
nr += 5; /* for display rounding */
rem = do_div(nr, 1000); /* XXX: do_div_signed */
snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, (int)rem/10);
div = div_s64_rem(nr, 1000, &rem);
snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
}
static void seq_time(struct seq_file *m, s64 time)
......@@ -556,7 +557,7 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
if (stats->read_holdtime.nr)
namelen += 2;
for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
for (i = 0; i < LOCKSTAT_POINTS; i++) {
char sym[KSYM_SYMBOL_LEN];
char ip[32];
......@@ -573,6 +574,23 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
stats->contention_point[i],
ip, sym);
}
for (i = 0; i < LOCKSTAT_POINTS; i++) {
char sym[KSYM_SYMBOL_LEN];
char ip[32];
if (class->contending_point[i] == 0)
break;
if (!i)
seq_line(m, '-', 40-namelen, namelen);
sprint_symbol(sym, class->contending_point[i]);
snprintf(ip, sizeof(ip), "[<%p>]",
(void *)class->contending_point[i]);
seq_printf(m, "%40s %14lu %29s %s\n", name,
stats->contending_point[i],
ip, sym);
}
if (i) {
seq_puts(m, "\n");
seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
......@@ -582,7 +600,7 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
static void seq_header(struct seq_file *m)
{
seq_printf(m, "lock_stat version 0.2\n");
seq_printf(m, "lock_stat version 0.3\n");
seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
"%14s %14s\n",
......
kernel/mutex.c
浏览文件 @ 5f34fe1c
......@@ -59,7 +59,7 @@ EXPORT_SYMBOL(__mutex_init);
* We also put the fastpath first in the kernel image, to make sure the
* branch is predicted by the CPU as default-untaken.
*/
static void noinline __sched
static __used noinline void __sched
__mutex_lock_slowpath(atomic_t *lock_count);
/***
......@@ -96,7 +96,7 @@ void inline __sched mutex_lock(struct mutex *lock)
EXPORT_SYMBOL(mutex_lock);
#endif
static noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
/***
* mutex_unlock - release the mutex
......@@ -184,7 +184,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
}
done:
lock_acquired(&lock->dep_map);
lock_acquired(&lock->dep_map, ip);
/* got the lock - rejoice! */
mutex_remove_waiter(lock, &waiter, task_thread_info(task));
debug_mutex_set_owner(lock, task_thread_info(task));
......@@ -268,7 +268,7 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
/*
* Release the lock, slowpath:
*/
static noinline void
static __used noinline void
__mutex_unlock_slowpath(atomic_t *lock_count)
{
__mutex_unlock_common_slowpath(lock_count, 1);
......@@ -313,7 +313,7 @@ int __sched mutex_lock_killable(struct mutex *lock)
}
EXPORT_SYMBOL(mutex_lock_killable);
static noinline void __sched
static __used noinline void __sched
__mutex_lock_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
......
kernel/notifier.c
浏览文件 @ 5f34fe1c
......@@ -82,6 +82,14 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl,
while (nb && nr_to_call) {
next_nb = rcu_dereference(nb->next);
#ifdef CONFIG_DEBUG_NOTIFIERS
if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) {
WARN(1, "Invalid notifier called!");
nb = next_nb;
continue;
}
#endif
ret = nb->notifier_call(nb, val, v);
if (nr_calls)
......
kernel/panic.c
浏览文件 @ 5f34fe1c
......@@ -21,6 +21,7 @@
#include <linux/debug_locks.h>
#include <linux/random.h>
#include <linux/kallsyms.h>
#include <linux/dmi.h>
int panic_on_oops;
static unsigned long tainted_mask;
......@@ -321,36 +322,27 @@ void oops_exit(void)
}
#ifdef WANT_WARN_ON_SLOWPATH
void warn_on_slowpath(const char *file, int line)
{
char function[KSYM_SYMBOL_LEN];
unsigned long caller = (unsigned long) __builtin_return_address(0);
sprint_symbol(function, caller);
printk(KERN_WARNING "------------[ cut here ]------------\n");
printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
line, function);
print_modules();
dump_stack();
print_oops_end_marker();
add_taint(TAINT_WARN);
}
EXPORT_SYMBOL(warn_on_slowpath);
void warn_slowpath(const char *file, int line, const char *fmt, ...)
{
va_list args;
char function[KSYM_SYMBOL_LEN];
unsigned long caller = (unsigned long)__builtin_return_address(0);
const char *board;
sprint_symbol(function, caller);
printk(KERN_WARNING "------------[ cut here ]------------\n");
printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
line, function);
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
board = dmi_get_system_info(DMI_PRODUCT_NAME);
if (board)
printk(KERN_WARNING "Hardware name: %s\n", board);
if (fmt) {
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
}
print_modules();
dump_stack();
......
kernel/posix-cpu-timers.c
浏览文件 @ 5f34fe1c
......@@ -58,21 +58,21 @@ void thread_group_cputime(
struct task_struct *tsk,
struct task_cputime *times)
{
struct signal_struct *sig;
struct task_cputime *totals, *tot;
int i;
struct task_cputime *tot;
sig = tsk->signal;
if (unlikely(!sig) || !sig->cputime.totals) {
totals = tsk->signal->cputime.totals;
if (!totals) {
times->utime = tsk->utime;
times->stime = tsk->stime;
times->sum_exec_runtime = tsk->se.sum_exec_runtime;
return;
}
times->stime = times->utime = cputime_zero;
times->sum_exec_runtime = 0;
for_each_possible_cpu(i) {
tot = per_cpu_ptr(tsk->signal->cputime.totals, i);
tot = per_cpu_ptr(totals, i);
times->utime = cputime_add(times->utime, tot->utime);
times->stime = cputime_add(times->stime, tot->stime);
times->sum_exec_runtime += tot->sum_exec_runtime;
......
kernel/printk.c
浏览文件 @ 5f34fe1c
......@@ -662,7 +662,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
if (recursion_bug) {
recursion_bug = 0;
strcpy(printk_buf, recursion_bug_msg);
printed_len = sizeof(recursion_bug_msg);
printed_len = strlen(recursion_bug_msg);
}
/* Emit the output into the temporary buffer */
printed_len += vscnprintf(printk_buf + printed_len,
......
kernel/rcuclassic.c
浏览文件 @ 5f34fe1c
......@@ -191,7 +191,7 @@ static void print_other_cpu_stall(struct rcu_ctrlblk *rcp)
/* OK, time to rat on our buddy... */
printk(KERN_ERR "RCU detected CPU stalls:");
printk(KERN_ERR "INFO: RCU detected CPU stalls:");
for_each_possible_cpu(cpu) {
if (cpu_isset(cpu, rcp->cpumask))
printk(" %d", cpu);
......@@ -204,7 +204,7 @@ static void print_cpu_stall(struct rcu_ctrlblk *rcp)
{
unsigned long flags;
printk(KERN_ERR "RCU detected CPU %d stall (t=%lu/%lu jiffies)\n",
printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu/%lu jiffies)\n",
smp_processor_id(), jiffies,
jiffies - rcp->gp_start);
dump_stack();
......
kernel/rcupreempt.c
浏览文件 @ 5f34fe1c
......@@ -551,6 +551,16 @@ void rcu_irq_exit(void)
}
}
void rcu_nmi_enter(void)
{
rcu_irq_enter();
}
void rcu_nmi_exit(void)
{
rcu_irq_exit();
}
static void dyntick_save_progress_counter(int cpu)
{
struct rcu_dyntick_sched *rdssp = &per_cpu(rcu_dyntick_sched, cpu);
......
kernel/rcupreempt_trace.c
浏览文件 @ 5f34fe1c
......@@ -149,12 +149,12 @@ static void rcupreempt_trace_sum(struct rcupreempt_trace *sp)
sp->done_length += cp->done_length;
sp->done_add += cp->done_add;
sp->done_remove += cp->done_remove;
atomic_set(&sp->done_invoked, atomic_read(&cp->done_invoked));
atomic_add(atomic_read(&cp->done_invoked), &sp->done_invoked);
sp->rcu_check_callbacks += cp->rcu_check_callbacks;
atomic_set(&sp->rcu_try_flip_1,
atomic_read(&cp->rcu_try_flip_1));
atomic_set(&sp->rcu_try_flip_e1,
atomic_read(&cp->rcu_try_flip_e1));
atomic_add(atomic_read(&cp->rcu_try_flip_1),
&sp->rcu_try_flip_1);
atomic_add(atomic_read(&cp->rcu_try_flip_e1),
&sp->rcu_try_flip_e1);
sp->rcu_try_flip_i1 += cp->rcu_try_flip_i1;
sp->rcu_try_flip_ie1 += cp->rcu_try_flip_ie1;
sp->rcu_try_flip_g1 += cp->rcu_try_flip_g1;
......
kernel/rcutorture.c
浏览文件 @ 5f34fe1c
......@@ -39,6 +39,7 @@
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
......@@ -108,7 +109,6 @@ struct rcu_torture {
int rtort_mbtest;
};
static int fullstop = 0; /* stop generating callbacks at test end. */
static LIST_HEAD(rcu_torture_freelist);
static struct rcu_torture *rcu_torture_current = NULL;
static long rcu_torture_current_version = 0;
......@@ -136,6 +136,30 @@ static int stutter_pause_test = 0;
#endif
int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
#define FULLSTOP_SIGNALED 1 /* Bail due to signal. */
#define FULLSTOP_CLEANUP 2 /* Orderly shutdown. */
static int fullstop; /* stop generating callbacks at test end. */
DEFINE_MUTEX(fullstop_mutex); /* protect fullstop transitions and */
/* spawning of kthreads. */
/*
* Detect and respond to a signal-based shutdown.
*/
static int
rcutorture_shutdown_notify(struct notifier_block *unused1,
unsigned long unused2, void *unused3)
{
if (fullstop)
return NOTIFY_DONE;
if (signal_pending(current)) {
mutex_lock(&fullstop_mutex);
if (!ACCESS_ONCE(fullstop))
fullstop = FULLSTOP_SIGNALED;
mutex_unlock(&fullstop_mutex);
}
return NOTIFY_DONE;
}
/*
* Allocate an element from the rcu_tortures pool.
*/
......@@ -199,11 +223,12 @@ rcu_random(struct rcu_random_state *rrsp)
static void
rcu_stutter_wait(void)
{
while (stutter_pause_test || !rcutorture_runnable)
while ((stutter_pause_test || !rcutorture_runnable) && !fullstop) {
if (rcutorture_runnable)
schedule_timeout_interruptible(1);
else
schedule_timeout_interruptible(round_jiffies_relative(HZ));
}
}
/*
......@@ -599,7 +624,7 @@ rcu_torture_writer(void *arg)
rcu_stutter_wait();
} while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
while (!kthread_should_stop())
while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
schedule_timeout_uninterruptible(1);
return 0;
}
......@@ -624,7 +649,7 @@ rcu_torture_fakewriter(void *arg)
} while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
while (!kthread_should_stop())
while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
schedule_timeout_uninterruptible(1);
return 0;
}
......@@ -734,7 +759,7 @@ rcu_torture_reader(void *arg)
VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
if (irqreader && cur_ops->irqcapable)
del_timer_sync(&t);
while (!kthread_should_stop())
while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
schedule_timeout_uninterruptible(1);
return 0;
}
......@@ -831,7 +856,7 @@ rcu_torture_stats(void *arg)
do {
schedule_timeout_interruptible(stat_interval * HZ);
rcu_torture_stats_print();
} while (!kthread_should_stop());
} while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
return 0;
}
......@@ -899,7 +924,7 @@ rcu_torture_shuffle(void *arg)
do {
schedule_timeout_interruptible(shuffle_interval * HZ);
rcu_torture_shuffle_tasks();
} while (!kthread_should_stop());
} while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
return 0;
}
......@@ -914,10 +939,10 @@ rcu_torture_stutter(void *arg)
do {
schedule_timeout_interruptible(stutter * HZ);
stutter_pause_test = 1;
if (!kthread_should_stop())
if (!kthread_should_stop() && !fullstop)
schedule_timeout_interruptible(stutter * HZ);
stutter_pause_test = 0;
} while (!kthread_should_stop());
} while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
return 0;
}
......@@ -934,12 +959,27 @@ rcu_torture_print_module_parms(char *tag)
stutter, irqreader);
}
static struct notifier_block rcutorture_nb = {
.notifier_call = rcutorture_shutdown_notify,
};
static void
rcu_torture_cleanup(void)
{
int i;
fullstop = 1;
mutex_lock(&fullstop_mutex);
if (!fullstop) {
/* If being signaled, let it happen, then exit. */
mutex_unlock(&fullstop_mutex);
schedule_timeout_interruptible(10 * HZ);
if (cur_ops->cb_barrier != NULL)
cur_ops->cb_barrier();
return;
}
fullstop = FULLSTOP_CLEANUP;
mutex_unlock(&fullstop_mutex);
unregister_reboot_notifier(&rcutorture_nb);
if (stutter_task) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
kthread_stop(stutter_task);
......@@ -1015,6 +1055,8 @@ rcu_torture_init(void)
{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
&srcu_ops, &sched_ops, &sched_ops_sync, };
mutex_lock(&fullstop_mutex);
/* Process args and tell the world that the torturer is on the job. */
for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
cur_ops = torture_ops[i];
......@@ -1024,6 +1066,7 @@ rcu_torture_init(void)
if (i == ARRAY_SIZE(torture_ops)) {
printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
torture_type);
mutex_unlock(&fullstop_mutex);
return (-EINVAL);
}
if (cur_ops->init)
......@@ -1146,9 +1189,12 @@ rcu_torture_init(void)
goto unwind;
}
}
register_reboot_notifier(&rcutorture_nb);
mutex_unlock(&fullstop_mutex);
return 0;
unwind:
mutex_unlock(&fullstop_mutex);
rcu_torture_cleanup();
return firsterr;
}
......
kernel/rcutree.c 0 → 100644
浏览文件 @ 5f34fe1c
/*
* Read-Copy Update mechanism for mutual exclusion
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2008
*
* Authors: Dipankar Sarma <dipankar@in.ibm.com>
* Manfred Spraul <manfred@colorfullife.com>
* Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical version
*
* Based on the original work by Paul McKenney <paulmck@us.ibm.com>
* and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/atomic.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/time.h>
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
struct lockdep_map rcu_lock_map =
STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
EXPORT_SYMBOL_GPL(rcu_lock_map);
#endif
/* Data structures. */
#define RCU_STATE_INITIALIZER(name) { \
.level = { &name.node[0] }, \
.levelcnt = { \
NUM_RCU_LVL_0, /* root of hierarchy. */ \
NUM_RCU_LVL_1, \
NUM_RCU_LVL_2, \
NUM_RCU_LVL_3, /* == MAX_RCU_LVLS */ \
}, \
.signaled = RCU_SIGNAL_INIT, \
.gpnum = -300, \
.completed = -300, \
.onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \
.fqslock = __SPIN_LOCK_UNLOCKED(&name.fqslock), \
.n_force_qs = 0, \
.n_force_qs_ngp = 0, \
}
struct rcu_state rcu_state = RCU_STATE_INITIALIZER(rcu_state);
DEFINE_PER_CPU(struct rcu_data, rcu_data);
struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
#ifdef CONFIG_NO_HZ
DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks);
#endif /* #ifdef CONFIG_NO_HZ */
static int blimit = 10; /* Maximum callbacks per softirq. */
static int qhimark = 10000; /* If this many pending, ignore blimit. */
static int qlowmark = 100; /* Once only this many pending, use blimit. */
static void force_quiescent_state(struct rcu_state *rsp, int relaxed);
/*
* Return the number of RCU batches processed thus far for debug & stats.
*/
long rcu_batches_completed(void)
{
return rcu_state.completed;
}
EXPORT_SYMBOL_GPL(rcu_batches_completed);
/*
* Return the number of RCU BH batches processed thus far for debug & stats.
*/
long rcu_batches_completed_bh(void)
{
return rcu_bh_state.completed;
}
EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
/*
* Does the CPU have callbacks ready to be invoked?
*/
static int
cpu_has_callbacks_ready_to_invoke(struct rcu_data *rdp)
{
return &rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL];
}
/*
* Does the current CPU require a yet-as-unscheduled grace period?
*/
static int
cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
{
/* ACCESS_ONCE() because we are accessing outside of lock. */
return *rdp->nxttail[RCU_DONE_TAIL] &&
ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum);
}
/*
* Return the root node of the specified rcu_state structure.
*/
static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
{
return &rsp->node[0];
}
#ifdef CONFIG_SMP
/*
* If the specified CPU is offline, tell the caller that it is in
* a quiescent state. Otherwise, whack it with a reschedule IPI.
* Grace periods can end up waiting on an offline CPU when that
* CPU is in the process of coming online -- it will be added to the
* rcu_node bitmasks before it actually makes it online. The same thing
* can happen while a CPU is in the process of coming online. Because this
* race is quite rare, we check for it after detecting that the grace
* period has been delayed rather than checking each and every CPU
* each and every time we start a new grace period.
*/
static int rcu_implicit_offline_qs(struct rcu_data *rdp)
{
/*
* If the CPU is offline, it is in a quiescent state. We can
* trust its state not to change because interrupts are disabled.
*/
if (cpu_is_offline(rdp->cpu)) {
rdp->offline_fqs++;
return 1;
}
/* The CPU is online, so send it a reschedule IPI. */
if (rdp->cpu != smp_processor_id())
smp_send_reschedule(rdp->cpu);
else
set_need_resched();
rdp->resched_ipi++;
return 0;
}
#endif /* #ifdef CONFIG_SMP */
#ifdef CONFIG_NO_HZ
static DEFINE_RATELIMIT_STATE(rcu_rs, 10 * HZ, 5);
/**
* rcu_enter_nohz - inform RCU that current CPU is entering nohz
*
* Enter nohz mode, in other words, -leave- the mode in which RCU
* read-side critical sections can occur. (Though RCU read-side
* critical sections can occur in irq handlers in nohz mode, a possibility
* handled by rcu_irq_enter() and rcu_irq_exit()).
*/
void rcu_enter_nohz(void)
{
unsigned long flags;
struct rcu_dynticks *rdtp;
smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */
local_irq_save(flags);
rdtp = &__get_cpu_var(rcu_dynticks);
rdtp->dynticks++;
rdtp->dynticks_nesting--;
WARN_ON_RATELIMIT(rdtp->dynticks & 0x1, &rcu_rs);
local_irq_restore(flags);
}
/*
* rcu_exit_nohz - inform RCU that current CPU is leaving nohz
*
* Exit nohz mode, in other words, -enter- the mode in which RCU
* read-side critical sections normally occur.
*/
void rcu_exit_nohz(void)
{
unsigned long flags;
struct rcu_dynticks *rdtp;
local_irq_save(flags);
rdtp = &__get_cpu_var(rcu_dynticks);
rdtp->dynticks++;
rdtp->dynticks_nesting++;
WARN_ON_RATELIMIT(!(rdtp->dynticks & 0x1), &rcu_rs);
local_irq_restore(flags);
smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */
}
/**
* rcu_nmi_enter - inform RCU of entry to NMI context
*
* If the CPU was idle with dynamic ticks active, and there is no
* irq handler running, this updates rdtp->dynticks_nmi to let the
* RCU grace-period handling know that the CPU is active.
*/
void rcu_nmi_enter(void)
{
struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks);
if (rdtp->dynticks & 0x1)
return;
rdtp->dynticks_nmi++;
WARN_ON_RATELIMIT(!(rdtp->dynticks_nmi & 0x1), &rcu_rs);
smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */
}
/**
* rcu_nmi_exit - inform RCU of exit from NMI context
*
* If the CPU was idle with dynamic ticks active, and there is no
* irq handler running, this updates rdtp->dynticks_nmi to let the
* RCU grace-period handling know that the CPU is no longer active.
*/
void rcu_nmi_exit(void)
{
struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks);
if (rdtp->dynticks & 0x1)
return;
smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */
rdtp->dynticks_nmi++;
WARN_ON_RATELIMIT(rdtp->dynticks_nmi & 0x1, &rcu_rs);
}
/**
* rcu_irq_enter - inform RCU of entry to hard irq context
*
* If the CPU was idle with dynamic ticks active, this updates the
* rdtp->dynticks to let the RCU handling know that the CPU is active.
*/
void rcu_irq_enter(void)
{
struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks);
if (rdtp->dynticks_nesting++)
return;
rdtp->dynticks++;
WARN_ON_RATELIMIT(!(rdtp->dynticks & 0x1), &rcu_rs);
smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */
}
/**
* rcu_irq_exit - inform RCU of exit from hard irq context
*
* If the CPU was idle with dynamic ticks active, update the rdp->dynticks
* to put let the RCU handling be aware that the CPU is going back to idle
* with no ticks.
*/
void rcu_irq_exit(void)
{
struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks);
if (--rdtp->dynticks_nesting)
return;
smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */
rdtp->dynticks++;
WARN_ON_RATELIMIT(rdtp->dynticks & 0x1, &rcu_rs);
/* If the interrupt queued a callback, get out of dyntick mode. */
if (__get_cpu_var(rcu_data).nxtlist ||
__get_cpu_var(rcu_bh_data).nxtlist)
set_need_resched();
}
/*
* Record the specified "completed" value, which is later used to validate
* dynticks counter manipulations. Specify "rsp->completed - 1" to
* unconditionally invalidate any future dynticks manipulations (which is
* useful at the beginning of a grace period).
*/
static void dyntick_record_completed(struct rcu_state *rsp, long comp)
{
rsp->dynticks_completed = comp;
}
#ifdef CONFIG_SMP
/*
* Recall the previously recorded value of the completion for dynticks.
*/
static long dyntick_recall_completed(struct rcu_state *rsp)
{
return rsp->dynticks_completed;
}
/*
* Snapshot the specified CPU's dynticks counter so that we can later
* credit them with an implicit quiescent state. Return 1 if this CPU
* is already in a quiescent state courtesy of dynticks idle mode.
*/
static int dyntick_save_progress_counter(struct rcu_data *rdp)
{
int ret;
int snap;
int snap_nmi;
snap = rdp->dynticks->dynticks;
snap_nmi = rdp->dynticks->dynticks_nmi;
smp_mb(); /* Order sampling of snap with end of grace period. */
rdp->dynticks_snap = snap;
rdp->dynticks_nmi_snap = snap_nmi;
ret = ((snap & 0x1) == 0) && ((snap_nmi & 0x1) == 0);
if (ret)
rdp->dynticks_fqs++;
return ret;
}
/*
* Return true if the specified CPU has passed through a quiescent
* state by virtue of being in or having passed through an dynticks
* idle state since the last call to dyntick_save_progress_counter()
* for this same CPU.
*/
static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
{
long curr;
long curr_nmi;
long snap;
long snap_nmi;
curr = rdp->dynticks->dynticks;
snap = rdp->dynticks_snap;
curr_nmi = rdp->dynticks->dynticks_nmi;
snap_nmi = rdp->dynticks_nmi_snap;
smp_mb(); /* force ordering with cpu entering/leaving dynticks. */
/*
* If the CPU passed through or entered a dynticks idle phase with
* no active irq/NMI handlers, then we can safely pretend that the CPU
* already acknowledged the request to pass through a quiescent
* state. Either way, that CPU cannot possibly be in an RCU
* read-side critical section that started before the beginning
* of the current RCU grace period.
*/
if ((curr != snap || (curr & 0x1) == 0) &&
(curr_nmi != snap_nmi || (curr_nmi & 0x1) == 0)) {
rdp->dynticks_fqs++;
return 1;
}
/* Go check for the CPU being offline. */
return rcu_implicit_offline_qs(rdp);
}
#endif /* #ifdef CONFIG_SMP */
#else /* #ifdef CONFIG_NO_HZ */
static void dyntick_record_completed(struct rcu_state *rsp, long comp)
{
}
#ifdef CONFIG_SMP
/*
* If there are no dynticks, then the only way that a CPU can passively
* be in a quiescent state is to be offline. Unlike dynticks idle, which
* is a point in time during the prior (already finished) grace period,
* an offline CPU is always in a quiescent state, and thus can be
* unconditionally applied. So just return the current value of completed.
*/
static long dyntick_recall_completed(struct rcu_state *rsp)
{
return rsp->completed;
}
static int dyntick_save_progress_counter(struct rcu_data *rdp)
{
return 0;
}
static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
{
return rcu_implicit_offline_qs(rdp);
}
#endif /* #ifdef CONFIG_SMP */
#endif /* #else #ifdef CONFIG_NO_HZ */
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
static void record_gp_stall_check_time(struct rcu_state *rsp)
{
rsp->gp_start = jiffies;
rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_CHECK;
}
static void print_other_cpu_stall(struct rcu_state *rsp)
{
int cpu;
long delta;
unsigned long flags;
struct rcu_node *rnp = rcu_get_root(rsp);
struct rcu_node *rnp_cur = rsp->level[NUM_RCU_LVLS - 1];
struct rcu_node *rnp_end = &rsp->node[NUM_RCU_NODES];
/* Only let one CPU complain about others per time interval. */
spin_lock_irqsave(&rnp->lock, flags);
delta = jiffies - rsp->jiffies_stall;
if (delta < RCU_STALL_RAT_DELAY || rsp->gpnum == rsp->completed) {
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
spin_unlock_irqrestore(&rnp->lock, flags);
/* OK, time to rat on our buddy... */
printk(KERN_ERR "INFO: RCU detected CPU stalls:");
for (; rnp_cur < rnp_end; rnp_cur++) {
if (rnp_cur->qsmask == 0)
continue;
for (cpu = 0; cpu <= rnp_cur->grphi - rnp_cur->grplo; cpu++)
if (rnp_cur->qsmask & (1UL << cpu))
printk(" %d", rnp_cur->grplo + cpu);
}
printk(" (detected by %d, t=%ld jiffies)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start));
force_quiescent_state(rsp, 0); /* Kick them all. */
}
static void print_cpu_stall(struct rcu_state *rsp)
{
unsigned long flags;
struct rcu_node *rnp = rcu_get_root(rsp);
printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu jiffies)\n",
smp_processor_id(), jiffies - rsp->gp_start);
dump_stack();
spin_lock_irqsave(&rnp->lock, flags);
if ((long)(jiffies - rsp->jiffies_stall) >= 0)
rsp->jiffies_stall =
jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
spin_unlock_irqrestore(&rnp->lock, flags);
set_need_resched(); /* kick ourselves to get things going. */
}
static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
{
long delta;
struct rcu_node *rnp;
delta = jiffies - rsp->jiffies_stall;
rnp = rdp->mynode;
if ((rnp->qsmask & rdp->grpmask) && delta >= 0) {
/* We haven't checked in, so go dump stack. */
print_cpu_stall(rsp);
} else if (rsp->gpnum != rsp->completed &&
delta >= RCU_STALL_RAT_DELAY) {
/* They had two time units to dump stack, so complain. */
print_other_cpu_stall(rsp);
}
}
#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
static void record_gp_stall_check_time(struct rcu_state *rsp)
{
}
static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
{
}
#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
/*
* Update CPU-local rcu_data state to record the newly noticed grace period.
* This is used both when we started the grace period and when we notice
* that someone else started the grace period.
*/
static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp)
{
rdp->qs_pending = 1;
rdp->passed_quiesc = 0;
rdp->gpnum = rsp->gpnum;
rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
RCU_JIFFIES_TILL_FORCE_QS;
}
/*
* Did someone else start a new RCU grace period start since we last
* checked? Update local state appropriately if so. Must be called
* on the CPU corresponding to rdp.
*/
static int
check_for_new_grace_period(struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
int ret = 0;
local_irq_save(flags);
if (rdp->gpnum != rsp->gpnum) {
note_new_gpnum(rsp, rdp);
ret = 1;
}
local_irq_restore(flags);
return ret;
}
/*
* Start a new RCU grace period if warranted, re-initializing the hierarchy
* in preparation for detecting the next grace period. The caller must hold
* the root node's ->lock, which is released before return. Hard irqs must
* be disabled.
*/
static void
rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
__releases(rcu_get_root(rsp)->lock)
{
struct rcu_data *rdp = rsp->rda[smp_processor_id()];
struct rcu_node *rnp = rcu_get_root(rsp);
struct rcu_node *rnp_cur;
struct rcu_node *rnp_end;
if (!cpu_needs_another_gp(rsp, rdp)) {
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
/* Advance to a new grace period and initialize state. */
rsp->gpnum++;
rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
RCU_JIFFIES_TILL_FORCE_QS;
record_gp_stall_check_time(rsp);
dyntick_record_completed(rsp, rsp->completed - 1);
note_new_gpnum(rsp, rdp);
/*
* Because we are first, we know that all our callbacks will
* be covered by this upcoming grace period, even the ones
* that were registered arbitrarily recently.
*/
rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
/* Special-case the common single-level case. */
if (NUM_RCU_NODES == 1) {
rnp->qsmask = rnp->qsmaskinit;
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
spin_unlock(&rnp->lock); /* leave irqs disabled. */
/* Exclude any concurrent CPU-hotplug operations. */
spin_lock(&rsp->onofflock); /* irqs already disabled. */
/*
* Set the quiescent-state-needed bits in all the non-leaf RCU
* nodes for all currently online CPUs. This operation relies
* on the layout of the hierarchy within the rsp->node[] array.
* Note that other CPUs will access only the leaves of the
* hierarchy, which still indicate that no grace period is in
* progress. In addition, we have excluded CPU-hotplug operations.
*
* We therefore do not need to hold any locks. Any required
* memory barriers will be supplied by the locks guarding the
* leaf rcu_nodes in the hierarchy.
*/
rnp_end = rsp->level[NUM_RCU_LVLS - 1];
for (rnp_cur = &rsp->node[0]; rnp_cur < rnp_end; rnp_cur++)
rnp_cur->qsmask = rnp_cur->qsmaskinit;
/*
* Now set up the leaf nodes. Here we must be careful. First,
* we need to hold the lock in order to exclude other CPUs, which
* might be contending for the leaf nodes' locks. Second, as
* soon as we initialize a given leaf node, its CPUs might run
* up the rest of the hierarchy. We must therefore acquire locks
* for each node that we touch during this stage. (But we still
* are excluding CPU-hotplug operations.)
*
* Note that the grace period cannot complete until we finish
* the initialization process, as there will be at least one
* qsmask bit set in the root node until that time, namely the
* one corresponding to this CPU.
*/
rnp_end = &rsp->node[NUM_RCU_NODES];
rnp_cur = rsp->level[NUM_RCU_LVLS - 1];
for (; rnp_cur < rnp_end; rnp_cur++) {
spin_lock(&rnp_cur->lock); /* irqs already disabled. */
rnp_cur->qsmask = rnp_cur->qsmaskinit;
spin_unlock(&rnp_cur->lock); /* irqs already disabled. */
}
rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */
spin_unlock_irqrestore(&rsp->onofflock, flags);
}
/*
* Advance this CPU's callbacks, but only if the current grace period
* has ended. This may be called only from the CPU to whom the rdp
* belongs.
*/
static void
rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp)
{
long completed_snap;
unsigned long flags;
local_irq_save(flags);
completed_snap = ACCESS_ONCE(rsp->completed); /* outside of lock. */
/* Did another grace period end? */
if (rdp->completed != completed_snap) {
/* Advance callbacks. No harm if list empty. */
rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[RCU_WAIT_TAIL];
rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_READY_TAIL];
rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
/* Remember that we saw this grace-period completion. */
rdp->completed = completed_snap;
}
local_irq_restore(flags);
}
/*
* Similar to cpu_quiet(), for which it is a helper function. Allows
* a group of CPUs to be quieted at one go, though all the CPUs in the
* group must be represented by the same leaf rcu_node structure.
* That structure's lock must be held upon entry, and it is released
* before return.
*/
static void
cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp,
unsigned long flags)
__releases(rnp->lock)
{
/* Walk up the rcu_node hierarchy. */
for (;;) {
if (!(rnp->qsmask & mask)) {
/* Our bit has already been cleared, so done. */
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
rnp->qsmask &= ~mask;
if (rnp->qsmask != 0) {
/* Other bits still set at this level, so done. */
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
mask = rnp->grpmask;
if (rnp->parent == NULL) {
/* No more levels. Exit loop holding root lock. */
break;
}
spin_unlock_irqrestore(&rnp->lock, flags);
rnp = rnp->parent;
spin_lock_irqsave(&rnp->lock, flags);
}
/*
* Get here if we are the last CPU to pass through a quiescent
* state for this grace period. Clean up and let rcu_start_gp()
* start up the next grace period if one is needed. Note that
* we still hold rnp->lock, as required by rcu_start_gp(), which
* will release it.
*/
rsp->completed = rsp->gpnum;
rcu_process_gp_end(rsp, rsp->rda[smp_processor_id()]);
rcu_start_gp(rsp, flags); /* releases rnp->lock. */
}
/*
* Record a quiescent state for the specified CPU, which must either be
* the current CPU or an offline CPU. The lastcomp argument is used to
* make sure we are still in the grace period of interest. We don't want
* to end the current grace period based on quiescent states detected in
* an earlier grace period!
*/
static void
cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp)
{
unsigned long flags;
unsigned long mask;
struct rcu_node *rnp;
rnp = rdp->mynode;
spin_lock_irqsave(&rnp->lock, flags);
if (lastcomp != ACCESS_ONCE(rsp->completed)) {
/*
* Someone beat us to it for this grace period, so leave.
* The race with GP start is resolved by the fact that we
* hold the leaf rcu_node lock, so that the per-CPU bits
* cannot yet be initialized -- so we would simply find our
* CPU's bit already cleared in cpu_quiet_msk() if this race
* occurred.
*/
rdp->passed_quiesc = 0; /* try again later! */
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
mask = rdp->grpmask;
if ((rnp->qsmask & mask) == 0) {
spin_unlock_irqrestore(&rnp->lock, flags);
} else {
rdp->qs_pending = 0;
/*
* This GP can't end until cpu checks in, so all of our
* callbacks can be processed during the next GP.
*/
rdp = rsp->rda[smp_processor_id()];
rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
cpu_quiet_msk(mask, rsp, rnp, flags); /* releases rnp->lock */
}
}
/*
* Check to see if there is a new grace period of which this CPU
* is not yet aware, and if so, set up local rcu_data state for it.
* Otherwise, see if this CPU has just passed through its first
* quiescent state for this grace period, and record that fact if so.
*/
static void
rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
{
/* If there is now a new grace period, record and return. */
if (check_for_new_grace_period(rsp, rdp))
return;
/*
* Does this CPU still need to do its part for current grace period?
* If no, return and let the other CPUs do their part as well.
*/
if (!rdp->qs_pending)
return;
/*
* Was there a quiescent state since the beginning of the grace
* period? If no, then exit and wait for the next call.
*/
if (!rdp->passed_quiesc)
return;
/* Tell RCU we are done (but cpu_quiet() will be the judge of that). */
cpu_quiet(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed);
}
#ifdef CONFIG_HOTPLUG_CPU
/*
* Remove the outgoing CPU from the bitmasks in the rcu_node hierarchy
* and move all callbacks from the outgoing CPU to the current one.
*/
static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
{
int i;
unsigned long flags;
long lastcomp;
unsigned long mask;
struct rcu_data *rdp = rsp->rda[cpu];
struct rcu_data *rdp_me;
struct rcu_node *rnp;
/* Exclude any attempts to start a new grace period. */
spin_lock_irqsave(&rsp->onofflock, flags);
/* Remove the outgoing CPU from the masks in the rcu_node hierarchy. */
rnp = rdp->mynode;
mask = rdp->grpmask; /* rnp->grplo is constant. */
do {
spin_lock(&rnp->lock); /* irqs already disabled. */
rnp->qsmaskinit &= ~mask;
if (rnp->qsmaskinit != 0) {
spin_unlock(&rnp->lock); /* irqs already disabled. */
break;
}
mask = rnp->grpmask;
spin_unlock(&rnp->lock); /* irqs already disabled. */
rnp = rnp->parent;
} while (rnp != NULL);
lastcomp = rsp->completed;
spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
/* Being offline is a quiescent state, so go record it. */
cpu_quiet(cpu, rsp, rdp, lastcomp);
/*
* Move callbacks from the outgoing CPU to the running CPU.
* Note that the outgoing CPU is now quiscent, so it is now
* (uncharacteristically) safe to access it rcu_data structure.
* Note also that we must carefully retain the order of the
* outgoing CPU's callbacks in order for rcu_barrier() to work
* correctly. Finally, note that we start all the callbacks
* afresh, even those that have passed through a grace period
* and are therefore ready to invoke. The theory is that hotplug
* events are rare, and that if they are frequent enough to
* indefinitely delay callbacks, you have far worse things to
* be worrying about.
*/
rdp_me = rsp->rda[smp_processor_id()];
if (rdp->nxtlist != NULL) {
*rdp_me->nxttail[RCU_NEXT_TAIL] = rdp->nxtlist;
rdp_me->nxttail[RCU_NEXT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
rdp->nxtlist = NULL;
for (i = 0; i < RCU_NEXT_SIZE; i++)
rdp->nxttail[i] = &rdp->nxtlist;
rdp_me->qlen += rdp->qlen;
rdp->qlen = 0;
}
local_irq_restore(flags);
}
/*
* Remove the specified CPU from the RCU hierarchy and move any pending
* callbacks that it might have to the current CPU. This code assumes
* that at least one CPU in the system will remain running at all times.
* Any attempt to offline -all- CPUs is likely to strand RCU callbacks.
*/
static void rcu_offline_cpu(int cpu)
{
__rcu_offline_cpu(cpu, &rcu_state);
__rcu_offline_cpu(cpu, &rcu_bh_state);
}
#else /* #ifdef CONFIG_HOTPLUG_CPU */
static void rcu_offline_cpu(int cpu)
{
}
#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
/*
* Invoke any RCU callbacks that have made it to the end of their grace
* period. Thottle as specified by rdp->blimit.
*/
static void rcu_do_batch(struct rcu_data *rdp)
{
unsigned long flags;
struct rcu_head *next, *list, **tail;
int count;
/* If no callbacks are ready, just return.*/
if (!cpu_has_callbacks_ready_to_invoke(rdp))
return;
/*
* Extract the list of ready callbacks, disabling to prevent
* races with call_rcu() from interrupt handlers.
*/
local_irq_save(flags);
list = rdp->nxtlist;
rdp->nxtlist = *rdp->nxttail[RCU_DONE_TAIL];
*rdp->nxttail[RCU_DONE_TAIL] = NULL;
tail = rdp->nxttail[RCU_DONE_TAIL];
for (count = RCU_NEXT_SIZE - 1; count >= 0; count--)
if (rdp->nxttail[count] == rdp->nxttail[RCU_DONE_TAIL])
rdp->nxttail[count] = &rdp->nxtlist;
local_irq_restore(flags);
/* Invoke callbacks. */
count = 0;
while (list) {
next = list->next;
prefetch(next);
list->func(list);
list = next;
if (++count >= rdp->blimit)
break;
}
local_irq_save(flags);
/* Update count, and requeue any remaining callbacks. */
rdp->qlen -= count;
if (list != NULL) {
*tail = rdp->nxtlist;
rdp->nxtlist = list;
for (count = 0; count < RCU_NEXT_SIZE; count++)
if (&rdp->nxtlist == rdp->nxttail[count])
rdp->nxttail[count] = tail;
else
break;
}
/* Reinstate batch limit if we have worked down the excess. */
if (rdp->blimit == LONG_MAX && rdp->qlen <= qlowmark)
rdp->blimit = blimit;
local_irq_restore(flags);
/* Re-raise the RCU softirq if there are callbacks remaining. */
if (cpu_has_callbacks_ready_to_invoke(rdp))
raise_softirq(RCU_SOFTIRQ);
}
/*
* Check to see if this CPU is in a non-context-switch quiescent state
* (user mode or idle loop for rcu, non-softirq execution for rcu_bh).
* Also schedule the RCU softirq handler.
*
* This function must be called with hardirqs disabled. It is normally
* invoked from the scheduling-clock interrupt. If rcu_pending returns
* false, there is no point in invoking rcu_check_callbacks().
*/
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
(idle_cpu(cpu) && !in_softirq() &&
hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user
* mode or from the idle loop, and if this is not a
* nested interrupt. In this case, the CPU is in
* a quiescent state, so count it.
*
* No memory barrier is required here because both
* rcu_qsctr_inc() and rcu_bh_qsctr_inc() reference
* only CPU-local variables that other CPUs neither
* access nor modify, at least not while the corresponding
* CPU is online.
*/
rcu_qsctr_inc(cpu);
rcu_bh_qsctr_inc(cpu);
} else if (!in_softirq()) {
/*
* Get here if this CPU did not take its interrupt from
* softirq, in other words, if it is not interrupting
* a rcu_bh read-side critical section. This is an _bh
* critical section, so count it.
*/
rcu_bh_qsctr_inc(cpu);
}
raise_softirq(RCU_SOFTIRQ);
}
#ifdef CONFIG_SMP
/*
* Scan the leaf rcu_node structures, processing dyntick state for any that
* have not yet encountered a quiescent state, using the function specified.
* Returns 1 if the current grace period ends while scanning (possibly
* because we made it end).
*/
static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp,
int (*f)(struct rcu_data *))
{
unsigned long bit;
int cpu;
unsigned long flags;
unsigned long mask;
struct rcu_node *rnp_cur = rsp->level[NUM_RCU_LVLS - 1];
struct rcu_node *rnp_end = &rsp->node[NUM_RCU_NODES];
for (; rnp_cur < rnp_end; rnp_cur++) {
mask = 0;
spin_lock_irqsave(&rnp_cur->lock, flags);
if (rsp->completed != lastcomp) {
spin_unlock_irqrestore(&rnp_cur->lock, flags);
return 1;
}
if (rnp_cur->qsmask == 0) {
spin_unlock_irqrestore(&rnp_cur->lock, flags);
continue;
}
cpu = rnp_cur->grplo;
bit = 1;
for (; cpu <= rnp_cur->grphi; cpu++, bit <<= 1) {
if ((rnp_cur->qsmask & bit) != 0 && f(rsp->rda[cpu]))
mask |= bit;
}
if (mask != 0 && rsp->completed == lastcomp) {
/* cpu_quiet_msk() releases rnp_cur->lock. */
cpu_quiet_msk(mask, rsp, rnp_cur, flags);
continue;
}
spin_unlock_irqrestore(&rnp_cur->lock, flags);
}
return 0;
}
/*
* Force quiescent states on reluctant CPUs, and also detect which
* CPUs are in dyntick-idle mode.
*/
static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
{
unsigned long flags;
long lastcomp;
struct rcu_data *rdp = rsp->rda[smp_processor_id()];
struct rcu_node *rnp = rcu_get_root(rsp);
u8 signaled;
if (ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum))
return; /* No grace period in progress, nothing to force. */
if (!spin_trylock_irqsave(&rsp->fqslock, flags)) {
rsp->n_force_qs_lh++; /* Inexact, can lose counts. Tough! */
return; /* Someone else is already on the job. */
}
if (relaxed &&
(long)(rsp->jiffies_force_qs - jiffies) >= 0 &&
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) >= 0)
goto unlock_ret; /* no emergency and done recently. */
rsp->n_force_qs++;
spin_lock(&rnp->lock);
lastcomp = rsp->completed;
signaled = rsp->signaled;
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
rdp->n_rcu_pending_force_qs = rdp->n_rcu_pending +
RCU_JIFFIES_TILL_FORCE_QS;
if (lastcomp == rsp->gpnum) {
rsp->n_force_qs_ngp++;
spin_unlock(&rnp->lock);
goto unlock_ret; /* no GP in progress, time updated. */
}
spin_unlock(&rnp->lock);
switch (signaled) {
case RCU_GP_INIT:
break; /* grace period still initializing, ignore. */
case RCU_SAVE_DYNTICK:
if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK)
break; /* So gcc recognizes the dead code. */
/* Record dyntick-idle state. */
if (rcu_process_dyntick(rsp, lastcomp,
dyntick_save_progress_counter))
goto unlock_ret;
/* Update state, record completion counter. */
spin_lock(&rnp->lock);
if (lastcomp == rsp->completed) {
rsp->signaled = RCU_FORCE_QS;
dyntick_record_completed(rsp, lastcomp);
}
spin_unlock(&rnp->lock);
break;
case RCU_FORCE_QS:
/* Check dyntick-idle state, send IPI to laggarts. */
if (rcu_process_dyntick(rsp, dyntick_recall_completed(rsp),
rcu_implicit_dynticks_qs))
goto unlock_ret;
/* Leave state in case more forcing is required. */
break;
}
unlock_ret:
spin_unlock_irqrestore(&rsp->fqslock, flags);
}
#else /* #ifdef CONFIG_SMP */
static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
{
set_need_resched();
}
#endif /* #else #ifdef CONFIG_SMP */
/*
* This does the RCU processing work from softirq context for the
* specified rcu_state and rcu_data structures. This may be called
* only from the CPU to whom the rdp belongs.
*/
static void
__rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
/*
* If an RCU GP has gone long enough, go check for dyntick
* idle CPUs and, if needed, send resched IPIs.
*/
if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0)
force_quiescent_state(rsp, 1);
/*
* Advance callbacks in response to end of earlier grace
* period that some other CPU ended.
*/
rcu_process_gp_end(rsp, rdp);
/* Update RCU state based on any recent quiescent states. */
rcu_check_quiescent_state(rsp, rdp);
/* Does this CPU require a not-yet-started grace period? */
if (cpu_needs_another_gp(rsp, rdp)) {
spin_lock_irqsave(&rcu_get_root(rsp)->lock, flags);
rcu_start_gp(rsp, flags); /* releases above lock */
}
/* If there are callbacks ready, invoke them. */
rcu_do_batch(rdp);
}
/*
* Do softirq processing for the current CPU.
*/
static void rcu_process_callbacks(struct softirq_action *unused)
{
/*
* Memory references from any prior RCU read-side critical sections
* executed by the interrupted code must be seen before any RCU
* grace-period manipulations below.
*/
smp_mb(); /* See above block comment. */
__rcu_process_callbacks(&rcu_state, &__get_cpu_var(rcu_data));
__rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));
/*
* Memory references from any later RCU read-side critical sections
* executed by the interrupted code must be seen after any RCU
* grace-period manipulations above.
*/
smp_mb(); /* See above block comment. */
}
static void
__call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
struct rcu_state *rsp)
{
unsigned long flags;
struct rcu_data *rdp;
head->func = func;
head->next = NULL;
smp_mb(); /* Ensure RCU update seen before callback registry. */
/*
* Opportunistically note grace-period endings and beginnings.
* Note that we might see a beginning right after we see an
* end, but never vice versa, since this CPU has to pass through
* a quiescent state betweentimes.
*/
local_irq_save(flags);
rdp = rsp->rda[smp_processor_id()];
rcu_process_gp_end(rsp, rdp);
check_for_new_grace_period(rsp, rdp);
/* Add the callback to our list. */
*rdp->nxttail[RCU_NEXT_TAIL] = head;
rdp->nxttail[RCU_NEXT_TAIL] = &head->next;
/* Start a new grace period if one not already started. */
if (ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum)) {
unsigned long nestflag;
struct rcu_node *rnp_root = rcu_get_root(rsp);
spin_lock_irqsave(&rnp_root->lock, nestflag);
rcu_start_gp(rsp, nestflag); /* releases rnp_root->lock. */
}
/* Force the grace period if too many callbacks or too long waiting. */
if (unlikely(++rdp->qlen > qhimark)) {
rdp->blimit = LONG_MAX;
force_quiescent_state(rsp, 0);
} else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0)
force_quiescent_state(rsp, 1);
local_irq_restore(flags);
}
/*
* Queue an RCU callback for invocation after a grace period.
*/
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
__call_rcu(head, func, &rcu_state);
}
EXPORT_SYMBOL_GPL(call_rcu);
/*
* Queue an RCU for invocation after a quicker grace period.
*/
void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
__call_rcu(head, func, &rcu_bh_state);
}
EXPORT_SYMBOL_GPL(call_rcu_bh);
/*
* Check to see if there is any immediate RCU-related work to be done
* by the current CPU, for the specified type of RCU, returning 1 if so.
* The checks are in order of increasing expense: checks that can be
* carried out against CPU-local state are performed first. However,
* we must check for CPU stalls first, else we might not get a chance.
*/
static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
{
rdp->n_rcu_pending++;
/* Check for CPU stalls, if enabled. */
check_cpu_stall(rsp, rdp);
/* Is the RCU core waiting for a quiescent state from this CPU? */
if (rdp->qs_pending)
return 1;
/* Does this CPU have callbacks ready to invoke? */
if (cpu_has_callbacks_ready_to_invoke(rdp))
return 1;
/* Has RCU gone idle with this CPU needing another grace period? */
if (cpu_needs_another_gp(rsp, rdp))
return 1;
/* Has another RCU grace period completed? */
if (ACCESS_ONCE(rsp->completed) != rdp->completed) /* outside of lock */
return 1;
/* Has a new RCU grace period started? */
if (ACCESS_ONCE(rsp->gpnum) != rdp->gpnum) /* outside of lock */
return 1;
/* Has an RCU GP gone long enough to send resched IPIs &c? */
if (ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum) &&
((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0 ||
(rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending) < 0))
return 1;
/* nothing to do */
return 0;
}
/*
* Check to see if there is any immediate RCU-related work to be done
* by the current CPU, returning 1 if so. This function is part of the
* RCU implementation; it is -not- an exported member of the RCU API.
*/
int rcu_pending(int cpu)
{
return __rcu_pending(&rcu_state, &per_cpu(rcu_data, cpu)) ||
__rcu_pending(&rcu_bh_state, &per_cpu(rcu_bh_data, cpu));
}
/*
* Check to see if any future RCU-related work will need to be done
* by the current CPU, even if none need be done immediately, returning
* 1 if so. This function is part of the RCU implementation; it is -not-
* an exported member of the RCU API.
*/
int rcu_needs_cpu(int cpu)
{
/* RCU callbacks either ready or pending? */
return per_cpu(rcu_data, cpu).nxtlist ||
per_cpu(rcu_bh_data, cpu).nxtlist;
}
/*
* Initialize a CPU's per-CPU RCU data. We take this "scorched earth"
* approach so that we don't have to worry about how long the CPU has
* been gone, or whether it ever was online previously. We do trust the
* ->mynode field, as it is constant for a given struct rcu_data and
* initialized during early boot.
*
* Note that only one online or offline event can be happening at a given
* time. Note also that we can accept some slop in the rsp->completed
* access due to the fact that this CPU cannot possibly have any RCU
* callbacks in flight yet.
*/
static void
rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
{
unsigned long flags;
int i;
long lastcomp;
unsigned long mask;
struct rcu_data *rdp = rsp->rda[cpu];
struct rcu_node *rnp = rcu_get_root(rsp);
/* Set up local state, ensuring consistent view of global state. */
spin_lock_irqsave(&rnp->lock, flags);
lastcomp = rsp->completed;
rdp->completed = lastcomp;
rdp->gpnum = lastcomp;
rdp->passed_quiesc = 0; /* We could be racing with new GP, */
rdp->qs_pending = 1; /* so set up to respond to current GP. */
rdp->beenonline = 1; /* We have now been online. */
rdp->passed_quiesc_completed = lastcomp - 1;
rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
rdp->nxtlist = NULL;
for (i = 0; i < RCU_NEXT_SIZE; i++)
rdp->nxttail[i] = &rdp->nxtlist;
rdp->qlen = 0;
rdp->blimit = blimit;
#ifdef CONFIG_NO_HZ
rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
#endif /* #ifdef CONFIG_NO_HZ */
rdp->cpu = cpu;
spin_unlock(&rnp->lock); /* irqs remain disabled. */
/*
* A new grace period might start here. If so, we won't be part
* of it, but that is OK, as we are currently in a quiescent state.
*/
/* Exclude any attempts to start a new GP on large systems. */
spin_lock(&rsp->onofflock); /* irqs already disabled. */
/* Add CPU to rcu_node bitmasks. */
rnp = rdp->mynode;
mask = rdp->grpmask;
do {
/* Exclude any attempts to start a new GP on small systems. */
spin_lock(&rnp->lock); /* irqs already disabled. */
rnp->qsmaskinit |= mask;
mask = rnp->grpmask;
spin_unlock(&rnp->lock); /* irqs already disabled. */
rnp = rnp->parent;
} while (rnp != NULL && !(rnp->qsmaskinit & mask));
spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
/*
* A new grace period might start here. If so, we will be part of
* it, and its gpnum will be greater than ours, so we will
* participate. It is also possible for the gpnum to have been
* incremented before this function was called, and the bitmasks
* to not be filled out until now, in which case we will also
* participate due to our gpnum being behind.
*/
/* Since it is coming online, the CPU is in a quiescent state. */
cpu_quiet(cpu, rsp, rdp, lastcomp);
local_irq_restore(flags);
}
static void __cpuinit rcu_online_cpu(int cpu)
{
#ifdef CONFIG_NO_HZ
struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
rdtp->dynticks_nesting = 1;
rdtp->dynticks |= 1; /* need consecutive #s even for hotplug. */
rdtp->dynticks_nmi = (rdtp->dynticks_nmi + 1) & ~0x1;
#endif /* #ifdef CONFIG_NO_HZ */
rcu_init_percpu_data(cpu, &rcu_state);
rcu_init_percpu_data(cpu, &rcu_bh_state);
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
/*
* Handle CPU online/offline notifcation events.
*/
static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
rcu_online_cpu(cpu);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
rcu_offline_cpu(cpu);
break;
default:
break;
}
return NOTIFY_OK;
}
/*
* Compute the per-level fanout, either using the exact fanout specified
* or balancing the tree, depending on CONFIG_RCU_FANOUT_EXACT.
*/
#ifdef CONFIG_RCU_FANOUT_EXACT
static void __init rcu_init_levelspread(struct rcu_state *rsp)
{
int i;
for (i = NUM_RCU_LVLS - 1; i >= 0; i--)
rsp->levelspread[i] = CONFIG_RCU_FANOUT;
}
#else /* #ifdef CONFIG_RCU_FANOUT_EXACT */
static void __init rcu_init_levelspread(struct rcu_state *rsp)
{
int ccur;
int cprv;
int i;
cprv = NR_CPUS;
for (i = NUM_RCU_LVLS - 1; i >= 0; i--) {
ccur = rsp->levelcnt[i];
rsp->levelspread[i] = (cprv + ccur - 1) / ccur;
cprv = ccur;
}
}
#endif /* #else #ifdef CONFIG_RCU_FANOUT_EXACT */
/*
* Helper function for rcu_init() that initializes one rcu_state structure.
*/
static void __init rcu_init_one(struct rcu_state *rsp)
{
int cpustride = 1;
int i;
int j;
struct rcu_node *rnp;
/* Initialize the level-tracking arrays. */
for (i = 1; i < NUM_RCU_LVLS; i++)
rsp->level[i] = rsp->level[i - 1] + rsp->levelcnt[i - 1];
rcu_init_levelspread(rsp);
/* Initialize the elements themselves, starting from the leaves. */
for (i = NUM_RCU_LVLS - 1; i >= 0; i--) {
cpustride *= rsp->levelspread[i];
rnp = rsp->level[i];
for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) {
spin_lock_init(&rnp->lock);
rnp->qsmask = 0;
rnp->qsmaskinit = 0;
rnp->grplo = j * cpustride;
rnp->grphi = (j + 1) * cpustride - 1;
if (rnp->grphi >= NR_CPUS)
rnp->grphi = NR_CPUS - 1;
if (i == 0) {
rnp->grpnum = 0;
rnp->grpmask = 0;
rnp->parent = NULL;
} else {
rnp->grpnum = j % rsp->levelspread[i - 1];
rnp->grpmask = 1UL << rnp->grpnum;
rnp->parent = rsp->level[i - 1] +
j / rsp->levelspread[i - 1];
}
rnp->level = i;
}
}
}
/*
* Helper macro for __rcu_init(). To be used nowhere else!
* Assigns leaf node pointers into each CPU's rcu_data structure.
*/
#define RCU_DATA_PTR_INIT(rsp, rcu_data) \
do { \
rnp = (rsp)->level[NUM_RCU_LVLS - 1]; \
j = 0; \
for_each_possible_cpu(i) { \
if (i > rnp[j].grphi) \
j++; \
per_cpu(rcu_data, i).mynode = &rnp[j]; \
(rsp)->rda[i] = &per_cpu(rcu_data, i); \
} \
} while (0)
static struct notifier_block __cpuinitdata rcu_nb = {
.notifier_call = rcu_cpu_notify,
};
void __init __rcu_init(void)
{
int i; /* All used by RCU_DATA_PTR_INIT(). */
int j;
struct rcu_node *rnp;
printk(KERN_WARNING "Experimental hierarchical RCU implementation.\n");
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
rcu_init_one(&rcu_state);
RCU_DATA_PTR_INIT(&rcu_state, rcu_data);
rcu_init_one(&rcu_bh_state);
RCU_DATA_PTR_INIT(&rcu_bh_state, rcu_bh_data);
for_each_online_cpu(i)
rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)i);
/* Register notifier for non-boot CPUs */
register_cpu_notifier(&rcu_nb);
printk(KERN_WARNING "Experimental hierarchical RCU init done.\n");
}
module_param(blimit, int, 0);
module_param(qhimark, int, 0);
module_param(qlowmark, int, 0);
kernel/rcutree_trace.c 0 → 100644
浏览文件 @ 5f34fe1c
/*
* Read-Copy Update tracing for classic implementation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2008
*
* Papers: http://www.rdrop.com/users/paulmck/RCU
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU
*
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/atomic.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d rpfq=%ld rp=%x",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? '!' : ' ',
rdp->completed, rdp->gpnum,
rdp->passed_quiesc, rdp->passed_quiesc_completed,
rdp->qs_pending,
rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending,
(int)(rdp->n_rcu_pending & 0xffff));
#ifdef CONFIG_NO_HZ
seq_printf(m, " dt=%d/%d dn=%d df=%lu",
rdp->dynticks->dynticks,
rdp->dynticks->dynticks_nesting,
rdp->dynticks->dynticks_nmi,
rdp->dynticks_fqs);
#endif /* #ifdef CONFIG_NO_HZ */
seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
seq_printf(m, " ql=%ld b=%ld\n", rdp->qlen, rdp->blimit);
}
#define PRINT_RCU_DATA(name, func, m) \
do { \
int _p_r_d_i; \
\
for_each_possible_cpu(_p_r_d_i) \
func(m, &per_cpu(name, _p_r_d_i)); \
} while (0)
static int show_rcudata(struct seq_file *m, void *unused)
{
seq_puts(m, "rcu:\n");
PRINT_RCU_DATA(rcu_data, print_one_rcu_data, m);
seq_puts(m, "rcu_bh:\n");
PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
return 0;
}
static int rcudata_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcudata, NULL);
}
static struct file_operations rcudata_fops = {
.owner = THIS_MODULE,
.open = rcudata_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d,%ld,%ld",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? "\"Y\"" : "\"N\"",
rdp->completed, rdp->gpnum,
rdp->passed_quiesc, rdp->passed_quiesc_completed,
rdp->qs_pending,
rdp->n_rcu_pending_force_qs - rdp->n_rcu_pending,
rdp->n_rcu_pending);
#ifdef CONFIG_NO_HZ
seq_printf(m, ",%d,%d,%d,%lu",
rdp->dynticks->dynticks,
rdp->dynticks->dynticks_nesting,
rdp->dynticks->dynticks_nmi,
rdp->dynticks_fqs);
#endif /* #ifdef CONFIG_NO_HZ */
seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
seq_printf(m, ",%ld,%ld\n", rdp->qlen, rdp->blimit);
}
static int show_rcudata_csv(struct seq_file *m, void *unused)
{
seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",\"rpfq\",\"rp\",");
#ifdef CONFIG_NO_HZ
seq_puts(m, "\"dt\",\"dt nesting\",\"dn\",\"df\",");
#endif /* #ifdef CONFIG_NO_HZ */
seq_puts(m, "\"of\",\"ri\",\"ql\",\"b\"\n");
seq_puts(m, "\"rcu:\"\n");
PRINT_RCU_DATA(rcu_data, print_one_rcu_data_csv, m);
seq_puts(m, "\"rcu_bh:\"\n");
PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
return 0;
}
static int rcudata_csv_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcudata_csv, NULL);
}
static struct file_operations rcudata_csv_fops = {
.owner = THIS_MODULE,
.open = rcudata_csv_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
{
int level = 0;
struct rcu_node *rnp;
seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
"nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
rsp->completed, rsp->gpnum, rsp->signaled,
(long)(rsp->jiffies_force_qs - jiffies),
(int)(jiffies & 0xffff),
rsp->n_force_qs, rsp->n_force_qs_ngp,
rsp->n_force_qs - rsp->n_force_qs_ngp,
rsp->n_force_qs_lh);
for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
if (rnp->level != level) {
seq_puts(m, "\n");
level = rnp->level;
}
seq_printf(m, "%lx/%lx %d:%d ^%d ",
rnp->qsmask, rnp->qsmaskinit,
rnp->grplo, rnp->grphi, rnp->grpnum);
}
seq_puts(m, "\n");
}
static int show_rcuhier(struct seq_file *m, void *unused)
{
seq_puts(m, "rcu:\n");
print_one_rcu_state(m, &rcu_state);
seq_puts(m, "rcu_bh:\n");
print_one_rcu_state(m, &rcu_bh_state);
return 0;
}
static int rcuhier_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcuhier, NULL);
}
static struct file_operations rcuhier_fops = {
.owner = THIS_MODULE,
.open = rcuhier_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int show_rcugp(struct seq_file *m, void *unused)
{
seq_printf(m, "rcu: completed=%ld gpnum=%ld\n",
rcu_state.completed, rcu_state.gpnum);
seq_printf(m, "rcu_bh: completed=%ld gpnum=%ld\n",
rcu_bh_state.completed, rcu_bh_state.gpnum);
return 0;
}
static int rcugp_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcugp, NULL);
}
static struct file_operations rcugp_fops = {
.owner = THIS_MODULE,
.open = rcugp_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static struct dentry *rcudir, *datadir, *datadir_csv, *hierdir, *gpdir;
static int __init rcuclassic_trace_init(void)
{
rcudir = debugfs_create_dir("rcu", NULL);
if (!rcudir)
goto out;
datadir = debugfs_create_file("rcudata", 0444, rcudir,
NULL, &rcudata_fops);
if (!datadir)
goto free_out;
datadir_csv = debugfs_create_file("rcudata.csv", 0444, rcudir,
NULL, &rcudata_csv_fops);
if (!datadir_csv)
goto free_out;
gpdir = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
if (!gpdir)
goto free_out;
hierdir = debugfs_create_file("rcuhier", 0444, rcudir,
NULL, &rcuhier_fops);
if (!hierdir)
goto free_out;
return 0;
free_out:
if (datadir)
debugfs_remove(datadir);
if (datadir_csv)
debugfs_remove(datadir_csv);
if (gpdir)
debugfs_remove(gpdir);
debugfs_remove(rcudir);
out:
return 1;
}
static void __exit rcuclassic_trace_cleanup(void)
{
debugfs_remove(datadir);
debugfs_remove(datadir_csv);
debugfs_remove(gpdir);
debugfs_remove(hierdir);
debugfs_remove(rcudir);
}
module_init(rcuclassic_trace_init);
module_exit(rcuclassic_trace_cleanup);
MODULE_AUTHOR("Paul E. McKenney");
MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
MODULE_LICENSE("GPL");
kernel/resource.c
浏览文件 @ 5f34fe1c
......@@ -853,6 +853,15 @@ int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
continue;
/*
* if a resource is "BUSY", it's not a hardware resource
* but a driver mapping of such a resource; we don't want
* to warn for those; some drivers legitimately map only
* partial hardware resources. (example: vesafb)
*/
if (p->flags & IORESOURCE_BUSY)
continue;
printk(KERN_WARNING "resource map sanity check conflict: "
"0x%llx 0x%llx 0x%llx 0x%llx %s\n",
(unsigned long long)addr,
......
kernel/sched.c
浏览文件 @ 5f34fe1c
......@@ -4192,7 +4192,6 @@ void account_steal_time(struct task_struct *p, cputime_t steal)
if (p == rq->idle) {
p->stime = cputime_add(p->stime, steal);
account_group_system_time(p, steal);
if (atomic_read(&rq->nr_iowait) > 0)
cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
else
......@@ -4328,7 +4327,7 @@ void __kprobes sub_preempt_count(int val)
/*
* Underflow?
*/
if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
if (DEBUG_LOCKS_WARN_ON(val > preempt_count() - (!!kernel_locked())))
return;
/*
* Is the spinlock portion underflowing?
......
kernel/softirq.c
浏览文件 @ 5f34fe1c
......@@ -102,20 +102,6 @@ void local_bh_disable(void)
EXPORT_SYMBOL(local_bh_disable);
void __local_bh_enable(void)
{
WARN_ON_ONCE(in_irq());
/*
* softirqs should never be enabled by __local_bh_enable(),
* it always nests inside local_bh_enable() sections:
*/
WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET);
sub_preempt_count(SOFTIRQ_OFFSET);
}
EXPORT_SYMBOL_GPL(__local_bh_enable);
/*
* Special-case - softirqs can safely be enabled in
* cond_resched_softirq(), or by __do_softirq(),
......@@ -269,6 +255,7 @@ void irq_enter(void)
{
int cpu = smp_processor_id();
rcu_irq_enter();
if (idle_cpu(cpu) && !in_interrupt()) {
__irq_enter();
tick_check_idle(cpu);
......@@ -295,9 +282,9 @@ void irq_exit(void)
#ifdef CONFIG_NO_HZ
/* Make sure that timer wheel updates are propagated */
if (!in_interrupt() && idle_cpu(smp_processor_id()) && !need_resched())
tick_nohz_stop_sched_tick(0);
rcu_irq_exit();
if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())
tick_nohz_stop_sched_tick(0);
#endif
preempt_enable_no_resched();
}
......
kernel/softlockup.c
浏览文件 @ 5f34fe1c
......@@ -164,7 +164,7 @@ unsigned long __read_mostly sysctl_hung_task_check_count = 1024;
/*
* Zero means infinite timeout - no checking done:
*/
unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120;
unsigned long __read_mostly sysctl_hung_task_timeout_secs = 480;
unsigned long __read_mostly sysctl_hung_task_warnings = 10;
......
kernel/stacktrace.c
浏览文件 @ 5f34fe1c
......@@ -6,6 +6,7 @@
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
......@@ -24,3 +25,13 @@ void print_stack_trace(struct stack_trace *trace, int spaces)
}
EXPORT_SYMBOL_GPL(print_stack_trace);
/*
* Architectures that do not implement save_stack_trace_tsk get this
* weak alias and a once-per-bootup warning (whenever this facility
* is utilized - for example by procfs):
*/
__weak void
save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
}
kernel/sys.c
浏览文件 @ 5f34fe1c
......@@ -907,8 +907,8 @@ void do_sys_times(struct tms *tms)
struct task_cputime cputime;
cputime_t cutime, cstime;
spin_lock_irq(&current->sighand->siglock);
thread_group_cputime(current, &cputime);
spin_lock_irq(&current->sighand->siglock);
cutime = current->signal->cutime;
cstime = current->signal->cstime;
spin_unlock_irq(&current->sighand->siglock);
......
lib/Kconfig.debug
浏览文件 @ 5f34fe1c
......@@ -252,6 +252,14 @@ config DEBUG_OBJECTS_TIMERS
timer routines to track the life time of timer objects and
validate the timer operations.
config DEBUG_OBJECTS_ENABLE_DEFAULT
int "debug_objects bootup default value (0-1)"
range 0 1
default "1"
depends on DEBUG_OBJECTS
help
Debug objects boot parameter default value
config DEBUG_SLAB
bool "Debug slab memory allocations"
depends on DEBUG_KERNEL && SLAB
......@@ -545,6 +553,16 @@ config DEBUG_SG
If unsure, say N.
config DEBUG_NOTIFIERS
bool "Debug notifier call chains"
depends on DEBUG_KERNEL
help
Enable this to turn on sanity checking for notifier call chains.
This is most useful for kernel developers to make sure that
modules properly unregister themselves from notifier chains.
This is a relatively cheap check but if you care about maximum
performance, say N.
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
depends on DEBUG_KERNEL && \
......@@ -619,6 +637,19 @@ config RCU_CPU_STALL_DETECTOR
Say N if you are unsure.
config RCU_CPU_STALL_DETECTOR
bool "Check for stalled CPUs delaying RCU grace periods"
depends on CLASSIC_RCU || TREE_RCU
default n
help
This option causes RCU to printk information on which
CPUs are delaying the current grace period, but only when
the grace period extends for excessive time periods.
Say Y if you want RCU to perform such checks.
Say N if you are unsure.
config KPROBES_SANITY_TEST
bool "Kprobes sanity tests"
depends on DEBUG_KERNEL
......
lib/debugobjects.c
浏览文件 @ 5f34fe1c
......@@ -45,7 +45,9 @@ static struct kmem_cache *obj_cache;
static int debug_objects_maxchain __read_mostly;
static int debug_objects_fixups __read_mostly;
static int debug_objects_warnings __read_mostly;
static int debug_objects_enabled __read_mostly;
static int debug_objects_enabled __read_mostly
= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
static struct debug_obj_descr *descr_test __read_mostly;
static int __init enable_object_debug(char *str)
......
lib/swiotlb.c
浏览文件 @ 5f34fe1c
......@@ -21,9 +21,12 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/swiotlb.h>
#include <linux/string.h>
#include <linux/swiotlb.h>
#include <linux/types.h>
#include <linux/ctype.h>
#include <linux/highmem.h>
#include <asm/io.h>
#include <asm/dma.h>
......@@ -36,22 +39,6 @@
#define OFFSET(val,align) ((unsigned long) \
( (val) & ( (align) - 1)))
#define SG_ENT_VIRT_ADDRESS(sg) (sg_virt((sg)))
#define SG_ENT_PHYS_ADDRESS(sg) virt_to_bus(SG_ENT_VIRT_ADDRESS(sg))
/*
* Maximum allowable number of contiguous slabs to map,
* must be a power of 2. What is the appropriate value ?
* The complexity of {map,unmap}_single is linearly dependent on this value.
*/
#define IO_TLB_SEGSIZE 128
/*
* log of the size of each IO TLB slab. The number of slabs is command line
* controllable.
*/
#define IO_TLB_SHIFT 11
#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
/*
......@@ -102,7 +89,10 @@ static unsigned int io_tlb_index;
* We need to save away the original address corresponding to a mapped entry
* for the sync operations.
*/
static unsigned char **io_tlb_orig_addr;
static struct swiotlb_phys_addr {
struct page *page;
unsigned int offset;
} *io_tlb_orig_addr;
/*
* Protect the above data structures in the map and unmap calls
......@@ -126,6 +116,72 @@ setup_io_tlb_npages(char *str)
__setup("swiotlb=", setup_io_tlb_npages);
/* make io_tlb_overflow tunable too? */
void * __weak swiotlb_alloc_boot(size_t size, unsigned long nslabs)
{
return alloc_bootmem_low_pages(size);
}
void * __weak swiotlb_alloc(unsigned order, unsigned long nslabs)
{
return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
}
dma_addr_t __weak swiotlb_phys_to_bus(phys_addr_t paddr)
{
return paddr;
}
phys_addr_t __weak swiotlb_bus_to_phys(dma_addr_t baddr)
{
return baddr;
}
static dma_addr_t swiotlb_virt_to_bus(volatile void *address)
{
return swiotlb_phys_to_bus(virt_to_phys(address));
}
static void *swiotlb_bus_to_virt(dma_addr_t address)
{
return phys_to_virt(swiotlb_bus_to_phys(address));
}
int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
{
return 0;
}
static dma_addr_t swiotlb_sg_to_bus(struct scatterlist *sg)
{
return swiotlb_phys_to_bus(page_to_phys(sg_page(sg)) + sg->offset);
}
static void swiotlb_print_info(unsigned long bytes)
{
phys_addr_t pstart, pend;
dma_addr_t bstart, bend;
pstart = virt_to_phys(io_tlb_start);
pend = virt_to_phys(io_tlb_end);
bstart = swiotlb_phys_to_bus(pstart);
bend = swiotlb_phys_to_bus(pend);
printk(KERN_INFO "Placing %luMB software IO TLB between %p - %p\n",
bytes >> 20, io_tlb_start, io_tlb_end);
if (pstart != bstart || pend != bend)
printk(KERN_INFO "software IO TLB at phys %#llx - %#llx"
" bus %#llx - %#llx\n",
(unsigned long long)pstart,
(unsigned long long)pend,
(unsigned long long)bstart,
(unsigned long long)bend);
else
printk(KERN_INFO "software IO TLB at phys %#llx - %#llx\n",
(unsigned long long)pstart,
(unsigned long long)pend);
}
/*
* Statically reserve bounce buffer space and initialize bounce buffer data
* structures for the software IO TLB used to implement the DMA API.
......@@ -145,7 +201,7 @@ swiotlb_init_with_default_size(size_t default_size)
/*
* Get IO TLB memory from the low pages
*/
io_tlb_start = alloc_bootmem_low_pages(bytes);
io_tlb_start = swiotlb_alloc_boot(bytes, io_tlb_nslabs);
if (!io_tlb_start)
panic("Cannot allocate SWIOTLB buffer");
io_tlb_end = io_tlb_start + bytes;
......@@ -159,7 +215,7 @@ swiotlb_init_with_default_size(size_t default_size)
for (i = 0; i < io_tlb_nslabs; i++)
io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
io_tlb_index = 0;
io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));
io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
/*
* Get the overflow emergency buffer
......@@ -168,8 +224,7 @@ swiotlb_init_with_default_size(size_t default_size)
if (!io_tlb_overflow_buffer)
panic("Cannot allocate SWIOTLB overflow buffer!\n");
printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n",
virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));
swiotlb_print_info(bytes);
}
void __init
......@@ -202,8 +257,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
bytes = io_tlb_nslabs << IO_TLB_SHIFT;
while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
io_tlb_start = (char *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
order);
io_tlb_start = swiotlb_alloc(order, io_tlb_nslabs);
if (io_tlb_start)
break;
order--;
......@@ -235,12 +289,12 @@ swiotlb_late_init_with_default_size(size_t default_size)
io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
io_tlb_index = 0;
io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL,
get_order(io_tlb_nslabs * sizeof(char *)));
io_tlb_orig_addr = (struct swiotlb_phys_addr *)__get_free_pages(GFP_KERNEL,
get_order(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr)));
if (!io_tlb_orig_addr)
goto cleanup3;
memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *));
memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
/*
* Get the overflow emergency buffer
......@@ -250,9 +304,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
if (!io_tlb_overflow_buffer)
goto cleanup4;
printk(KERN_INFO "Placing %luMB software IO TLB between 0x%lx - "
"0x%lx\n", bytes >> 20,
virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));
swiotlb_print_info(bytes);
return 0;
......@@ -279,16 +331,69 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size)
return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
}
static inline int range_needs_mapping(void *ptr, size_t size)
{
return swiotlb_force || swiotlb_arch_range_needs_mapping(ptr, size);
}
static int is_swiotlb_buffer(char *addr)
{
return addr >= io_tlb_start && addr < io_tlb_end;
}
static struct swiotlb_phys_addr swiotlb_bus_to_phys_addr(char *dma_addr)
{
int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
struct swiotlb_phys_addr buffer = io_tlb_orig_addr[index];
buffer.offset += (long)dma_addr & ((1 << IO_TLB_SHIFT) - 1);
buffer.page += buffer.offset >> PAGE_SHIFT;
buffer.offset &= PAGE_SIZE - 1;
return buffer;
}
static void
__sync_single(struct swiotlb_phys_addr buffer, char *dma_addr, size_t size, int dir)
{
if (PageHighMem(buffer.page)) {
size_t len, bytes;
char *dev, *host, *kmp;
len = size;
while (len != 0) {
unsigned long flags;
bytes = len;
if ((bytes + buffer.offset) > PAGE_SIZE)
bytes = PAGE_SIZE - buffer.offset;
local_irq_save(flags); /* protects KM_BOUNCE_READ */
kmp = kmap_atomic(buffer.page, KM_BOUNCE_READ);
dev = dma_addr + size - len;
host = kmp + buffer.offset;
if (dir == DMA_FROM_DEVICE)
memcpy(host, dev, bytes);
else
memcpy(dev, host, bytes);
kunmap_atomic(kmp, KM_BOUNCE_READ);
local_irq_restore(flags);
len -= bytes;
buffer.page++;
buffer.offset = 0;
}
} else {
void *v = page_address(buffer.page) + buffer.offset;
if (dir == DMA_TO_DEVICE)
memcpy(dma_addr, v, size);
else
memcpy(v, dma_addr, size);
}
}
/*
* Allocates bounce buffer and returns its kernel virtual address.
*/
static void *
map_single(struct device *hwdev, char *buffer, size_t size, int dir)
map_single(struct device *hwdev, struct swiotlb_phys_addr buffer, size_t size, int dir)
{
unsigned long flags;
char *dma_addr;
......@@ -298,11 +403,16 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
unsigned long mask;
unsigned long offset_slots;
unsigned long max_slots;
struct swiotlb_phys_addr slot_buf;
mask = dma_get_seg_boundary(hwdev);
start_dma_addr = virt_to_bus(io_tlb_start) & mask;
start_dma_addr = swiotlb_virt_to_bus(io_tlb_start) & mask;
offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
/*
* Carefully handle integer overflow which can occur when mask == ~0UL.
*/
max_slots = mask + 1
? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
: 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
......@@ -378,10 +488,15 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
* This is needed when we sync the memory. Then we sync the buffer if
* needed.
*/
for (i = 0; i < nslots; i++)
io_tlb_orig_addr[index+i] = buffer + (i << IO_TLB_SHIFT);
slot_buf = buffer;
for (i = 0; i < nslots; i++) {
slot_buf.page += slot_buf.offset >> PAGE_SHIFT;
slot_buf.offset &= PAGE_SIZE - 1;
io_tlb_orig_addr[index+i] = slot_buf;
slot_buf.offset += 1 << IO_TLB_SHIFT;
}
if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
memcpy(dma_addr, buffer, size);
__sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
return dma_addr;
}
......@@ -395,17 +510,17 @@ unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
unsigned long flags;
int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
char *buffer = io_tlb_orig_addr[index];
struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
/*
* First, sync the memory before unmapping the entry
*/
if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
/*
* bounce... copy the data back into the original buffer * and
* delete the bounce buffer.
*/
memcpy(buffer, dma_addr, size);
__sync_single(buffer, dma_addr, size, DMA_FROM_DEVICE);
/*
* Return the buffer to the free list by setting the corresponding
......@@ -437,21 +552,18 @@ static void
sync_single(struct device *hwdev, char *dma_addr, size_t size,
int dir, int target)
{
int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
char *buffer = io_tlb_orig_addr[index];
buffer += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
switch (target) {
case SYNC_FOR_CPU:
if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
memcpy(buffer, dma_addr, size);
__sync_single(buffer, dma_addr, size, DMA_FROM_DEVICE);
else
BUG_ON(dir != DMA_TO_DEVICE);
break;
case SYNC_FOR_DEVICE:
if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
memcpy(dma_addr, buffer, size);
__sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
else
BUG_ON(dir != DMA_FROM_DEVICE);
break;
......@@ -473,7 +585,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_mask = hwdev->coherent_dma_mask;
ret = (void *)__get_free_pages(flags, order);
if (ret && !is_buffer_dma_capable(dma_mask, virt_to_bus(ret), size)) {
if (ret && !is_buffer_dma_capable(dma_mask, swiotlb_virt_to_bus(ret), size)) {
/*
* The allocated memory isn't reachable by the device.
* Fall back on swiotlb_map_single().
......@@ -488,13 +600,16 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
* swiotlb_map_single(), which will grab memory from
* the lowest available address range.
*/
ret = map_single(hwdev, NULL, size, DMA_FROM_DEVICE);
struct swiotlb_phys_addr buffer;
buffer.page = virt_to_page(NULL);
buffer.offset = 0;
ret = map_single(hwdev, buffer, size, DMA_FROM_DEVICE);
if (!ret)
return NULL;
}
memset(ret, 0, size);
dev_addr = virt_to_bus(ret);
dev_addr = swiotlb_virt_to_bus(ret);
/* Confirm address can be DMA'd by device */
if (!is_buffer_dma_capable(dma_mask, dev_addr, size)) {
......@@ -554,8 +669,9 @@ dma_addr_t
swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
int dir, struct dma_attrs *attrs)
{
dma_addr_t dev_addr = virt_to_bus(ptr);
dma_addr_t dev_addr = swiotlb_virt_to_bus(ptr);
void *map;
struct swiotlb_phys_addr buffer;
BUG_ON(dir == DMA_NONE);
/*
......@@ -563,19 +679,22 @@ swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
* we can safely return the device addr and not worry about bounce
* buffering it.
*/
if (!address_needs_mapping(hwdev, dev_addr, size) && !swiotlb_force)
if (!address_needs_mapping(hwdev, dev_addr, size) &&
!range_needs_mapping(ptr, size))
return dev_addr;
/*
* Oh well, have to allocate and map a bounce buffer.
*/
map = map_single(hwdev, ptr, size, dir);
buffer.page = virt_to_page(ptr);
buffer.offset = (unsigned long)ptr & ~PAGE_MASK;
map = map_single(hwdev, buffer, size, dir);
if (!map) {
swiotlb_full(hwdev, size, dir, 1);
map = io_tlb_overflow_buffer;
}
dev_addr = virt_to_bus(map);
dev_addr = swiotlb_virt_to_bus(map);
/*
* Ensure that the address returned is DMA'ble
......@@ -605,7 +724,7 @@ void
swiotlb_unmap_single_attrs(struct device *hwdev, dma_addr_t dev_addr,
size_t size, int dir, struct dma_attrs *attrs)
{
char *dma_addr = bus_to_virt(dev_addr);
char *dma_addr = swiotlb_bus_to_virt(dev_addr);
BUG_ON(dir == DMA_NONE);
if (is_swiotlb_buffer(dma_addr))
......@@ -635,7 +754,7 @@ static void
swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
size_t size, int dir, int target)
{
char *dma_addr = bus_to_virt(dev_addr);
char *dma_addr = swiotlb_bus_to_virt(dev_addr);
BUG_ON(dir == DMA_NONE);
if (is_swiotlb_buffer(dma_addr))
......@@ -666,7 +785,7 @@ swiotlb_sync_single_range(struct device *hwdev, dma_addr_t dev_addr,
unsigned long offset, size_t size,
int dir, int target)
{
char *dma_addr = bus_to_virt(dev_addr) + offset;
char *dma_addr = swiotlb_bus_to_virt(dev_addr) + offset;
BUG_ON(dir == DMA_NONE);
if (is_swiotlb_buffer(dma_addr))
......@@ -714,18 +833,20 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
int dir, struct dma_attrs *attrs)
{
struct scatterlist *sg;
void *addr;
struct swiotlb_phys_addr buffer;
dma_addr_t dev_addr;
int i;
BUG_ON(dir == DMA_NONE);
for_each_sg(sgl, sg, nelems, i) {
addr = SG_ENT_VIRT_ADDRESS(sg);
dev_addr = virt_to_bus(addr);
if (swiotlb_force ||
dev_addr = swiotlb_sg_to_bus(sg);
if (range_needs_mapping(sg_virt(sg), sg->length) ||
address_needs_mapping(hwdev, dev_addr, sg->length)) {
void *map = map_single(hwdev, addr, sg->length, dir);
void *map;
buffer.page = sg_page(sg);
buffer.offset = sg->offset;
map = map_single(hwdev, buffer, sg->length, dir);
if (!map) {
/* Don't panic here, we expect map_sg users
to do proper error handling. */
......@@ -735,7 +856,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
sgl[0].dma_length = 0;
return 0;
}
sg->dma_address = virt_to_bus(map);
sg->dma_address = swiotlb_virt_to_bus(map);
} else
sg->dma_address = dev_addr;
sg->dma_length = sg->length;
......@@ -765,11 +886,11 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
BUG_ON(dir == DMA_NONE);
for_each_sg(sgl, sg, nelems, i) {
if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
unmap_single(hwdev, bus_to_virt(sg->dma_address),
if (sg->dma_address != swiotlb_sg_to_bus(sg))
unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
sg->dma_length, dir);
else if (dir == DMA_FROM_DEVICE)
dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
}
}
EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
......@@ -798,11 +919,11 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
BUG_ON(dir == DMA_NONE);
for_each_sg(sgl, sg, nelems, i) {
if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
sync_single(hwdev, bus_to_virt(sg->dma_address),
if (sg->dma_address != swiotlb_sg_to_bus(sg))
sync_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
sg->dma_length, dir, target);
else if (dir == DMA_FROM_DEVICE)
dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
}
}
......@@ -823,7 +944,7 @@ swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
int
swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
{
return (dma_addr == virt_to_bus(io_tlb_overflow_buffer));
return (dma_addr == swiotlb_virt_to_bus(io_tlb_overflow_buffer));
}
/*
......@@ -835,7 +956,7 @@ swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
int
swiotlb_dma_supported(struct device *hwdev, u64 mask)
{
return virt_to_bus(io_tlb_end - 1) <= mask;
return swiotlb_virt_to_bus(io_tlb_end - 1) <= mask;
}
EXPORT_SYMBOL(swiotlb_map_single);
......
mm/memory.c
浏览文件 @ 5f34fe1c
......@@ -3075,3 +3075,18 @@ void print_vma_addr(char *prefix, unsigned long ip)
}
up_read(&current->mm->mmap_sem);
}
#ifdef CONFIG_PROVE_LOCKING
void might_fault(void)
{
might_sleep();
/*
* it would be nicer only to annotate paths which are not under
* pagefault_disable, however that requires a larger audit and
* providing helpers like get_user_atomic.
*/
if (!in_atomic() && current->mm)
might_lock_read(&current->mm->mmap_sem);
}
EXPORT_SYMBOL(might_fault);
#endif
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