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  1. 20 9月, 2006 1 次提交
  3. 02 9月, 2006 1 次提交
  5. 06 8月, 2006 1 次提交
  7. 15 7月, 2006 2 次提交
    • S
      [PATCH] delay accounting taskstats interface send tgid once · ad4ecbcb
      由 Shailabh Nagar 提交于 
      Send per-tgid data only once during exit of a thread group instead of once
with each member thread exit.

Currently, when a thread exits, besides its per-tid data, the per-tgid data
of its thread group is also sent out, if its thread group is non-empty.
The per-tgid data sent consists of the sum of per-tid stats for all
*remaining* threads of the thread group.

This patch modifies this sending in two ways:

- the per-tgid data is sent only when the last thread of a thread group
  exits.  This cuts down heavily on the overhead of sending/receiving
  per-tgid data, especially when other exploiters of the taskstats
  interface aren't interested in per-tgid stats

- the semantics of the per-tgid data sent are changed.  Instead of being
  the sum of per-tid data for remaining threads, the value now sent is the
  true total accumalated statistics for all threads that are/were part of
  the thread group.

The patch also addresses a minor issue where failure of one accounting
subsystem to fill in the taskstats structure was causing the send of
taskstats to not be sent at all.

The patch has been tested for stability and run cerberus for over 4 hours
on an SMP.

[akpm@osdl.org: bugfixes]
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NBalbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      ad4ecbcb
    • S
      [PATCH] per-task-delay-accounting: setup · ca74e92b
      由 Shailabh Nagar 提交于 
      Initialization code related to collection of per-task "delay" statistics which
measure how long it had to wait for cpu, sync block io, swapping etc.  The
collection of statistics and the interface are in other patches.  This patch
sets up the data structures and allows the statistics collection to be
disabled through a kernel boot parameter.
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NBalbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      ca74e92b
  9. 11 7月, 2006 1 次提交
  11. 04 7月, 2006 5 次提交
    • I
      [PATCH] sched: cleanup, remove task_t, convert to struct task_struct · 36c8b586
      由 Ingo Molnar 提交于 
      cleanup: remove task_t and convert all the uses to struct task_struct. I
introduced it for the scheduler anno and it was a mistake.

Conversion was mostly scripted, the result was reviewed and all
secondary whitespace and style impact (if any) was fixed up by hand.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      36c8b586
    • I
      [PATCH] lockdep: annotate ->mmap_sem · ad339451
      由 Ingo Molnar 提交于 
      Teach special (recursive) locking code to the lock validator.  Has no effect
on non-lockdep kernels.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      ad339451
    • I
      [PATCH] lockdep: core · fbb9ce95
      由 Ingo Molnar 提交于 
      Do 'make oldconfig' and accept all the defaults for new config options -
reboot into the kernel and if everything goes well it should boot up fine and
you should have /proc/lockdep and /proc/lockdep_stats files.

Typically if the lock validator finds some problem it will print out
voluminous debug output that begins with "BUG: ..." and which syslog output
can be used by kernel developers to figure out the precise locking scenario.

What does the lock validator do?  It "observes" and maps all locking rules as
they occur dynamically (as triggered by the kernel's natural use of spinlocks,
rwlocks, mutexes and rwsems).  Whenever the lock validator subsystem detects a
new locking scenario, it validates this new rule against the existing set of
rules.  If this new rule is consistent with the existing set of rules then the
new rule is added transparently and the kernel continues as normal.  If the
new rule could create a deadlock scenario then this condition is printed out.

When determining validity of locking, all possible "deadlock scenarios" are
considered: assuming arbitrary number of CPUs, arbitrary irq context and task
context constellations, running arbitrary combinations of all the existing
locking scenarios.  In a typical system this means millions of separate
scenarios.  This is why we call it a "locking correctness" validator - for all
rules that are observed the lock validator proves it with mathematical
certainty that a deadlock could not occur (assuming that the lock validator
implementation itself is correct and its internal data structures are not
corrupted by some other kernel subsystem).  [see more details and conditionals
of this statement in include/linux/lockdep.h and
Documentation/lockdep-design.txt]

Furthermore, this "all possible scenarios" property of the validator also
enables the finding of complex, highly unlikely multi-CPU multi-context races
via single single-context rules, increasing the likelyhood of finding bugs
drastically.  In practical terms: the lock validator already found a bug in
the upstream kernel that could only occur on systems with 3 or more CPUs, and
which needed 3 very unlikely code sequences to occur at once on the 3 CPUs.
That bug was found and reported on a single-CPU system (!).  So in essence a
race will be found "piecemail-wise", triggering all the necessary components
for the race, without having to reproduce the race scenario itself!  In its
short existence the lock validator found and reported many bugs before they
actually caused a real deadlock.

To further increase the efficiency of the validator, the mapping is not per
"lock instance", but per "lock-class".  For example, all struct inode objects
in the kernel have inode->inotify_mutex.  If there are 10,000 inodes cached,
then there are 10,000 lock objects.  But ->inotify_mutex is a single "lock
type", and all locking activities that occur against ->inotify_mutex are
"unified" into this single lock-class.  The advantage of the lock-class
approach is that all historical ->inotify_mutex uses are mapped into a single
(and as narrow as possible) set of locking rules - regardless of how many
different tasks or inode structures it took to build this set of rules.  The
set of rules persist during the lifetime of the kernel.

To see the rough magnitude of checking that the lock validator does, here's a
portion of /proc/lockdep_stats, fresh after bootup:

 lock-classes:                            694 [max: 2048]
 direct dependencies:                  1598 [max: 8192]
 indirect dependencies:               17896
 all direct dependencies:             16206
 dependency chains:                    1910 [max: 8192]
 in-hardirq chains:                      17
 in-softirq chains:                     105
 in-process chains:                    1065
 stack-trace entries:                 38761 [max: 131072]
 combined max dependencies:         2033928
 hardirq-safe locks:                     24
 hardirq-unsafe locks:                  176
 softirq-safe locks:                     53
 softirq-unsafe locks:                  137
 irq-safe locks:                         59
 irq-unsafe locks:                      176

The lock validator has observed 1598 actual single-thread locking patterns,
and has validated all possible 2033928 distinct locking scenarios.

More details about the design of the lock validator can be found in
Documentation/lockdep-design.txt, which can also found at:

   http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt

[bunk@stusta.de: cleanups]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      fbb9ce95
    • I
      [PATCH] lockdep: irqtrace subsystem, core · de30a2b3
      由 Ingo Molnar 提交于 
      Accurate hard-IRQ-flags and softirq-flags state tracing.

This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      de30a2b3
    • I
      [PATCH] lockdep: better lock debugging · 9a11b49a
      由 Ingo Molnar 提交于 
      Generic lock debugging:

 - generalized lock debugging framework. For example, a bug in one lock
   subsystem turns off debugging in all lock subsystems.

 - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
   the mutex/rtmutex debugging code: it caused way too much prototype
   hackery, and lockdep will give the same information anyway.

 - ability to do silent tests

 - check lock freeing in vfree too.

 - more finegrained debugging options, to allow distributions to
   turn off more expensive debugging features.

There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes.  (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)

Here are the current debugging options:

CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y

which do:

 config DEBUG_MUTEXES
          bool "Mutex debugging, basic checks"

 config DEBUG_LOCK_ALLOC
         bool "Detect incorrect freeing of live mutexes"
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      9a11b49a
  13. 01 7月, 2006 1 次提交
  15. 28 6月, 2006 2 次提交
  17. 27 6月, 2006 2 次提交
  19. 26 6月, 2006 1 次提交
    • K
      [PATCH] pacct: add pacct_struct to fix some pacct bugs. · 0e464814
      由 KaiGai Kohei 提交于 
      The pacct facility need an i/o operation when an accounting record is
generated.  There is a possibility to wake OOM killer up.  If OOM killer is
activated, it kills some processes to make them release process memory
regions.

But acct_process() is called in the killed processes context before calling
exit_mm(), so those processes cannot release own memory.  In the results, any
processes stop in this point and it finally cause a system stall.
      0e464814
  21. 23 6月, 2006 2 次提交
  23. 01 5月, 2006 1 次提交
  25. 20 4月, 2006 2 次提交
  27. 15 4月, 2006 1 次提交
  29. 01 4月, 2006 3 次提交
    • K
      [PATCH] wrong error path in dup_fd() leading to oopses in RCU · 42862298
      由 Kirill Korotaev 提交于 
      Wrong error path in dup_fd() - it should return NULL on error,
not an address of already freed memory :/

Triggered by OpenVZ stress test suite.

What is interesting is that it was causing different oopses in RCU like
below:
Call Trace:
   [<c013492c>] rcu_do_batch+0x2c/0x80
   [<c0134bdd>] rcu_process_callbacks+0x3d/0x70
   [<c0126cf3>] tasklet_action+0x73/0xe0
   [<c01269aa>] __do_softirq+0x10a/0x130
   [<c01058ff>] do_softirq+0x4f/0x60
   =======================
   [<c0113817>] smp_apic_timer_interrupt+0x77/0x110
   [<c0103b54>] apic_timer_interrupt+0x1c/0x24
  Code:  Bad EIP value.
   <0>Kernel panic - not syncing: Fatal exception in interrupt
Signed-Off-By: NPavel Emelianov <xemul@sw.ru>
Signed-Off-By: NDmitry Mishin <dim@openvz.org>
Signed-Off-By: NKirill Korotaev <dev@openvz.org>
Signed-Off-By: NLinus Torvalds <torvalds@osdl.org>
      42862298
    • E
      [PATCH] pidhash: Refactor the pid hash table · 92476d7f
      由 Eric W. Biederman 提交于 
      Simplifies the code, reduces the need for 4 pid hash tables, and makes the
code more capable.

In the discussions I had with Oleg it was felt that to a large extent the
cleanup itself justified the work.  With struct pid being dynamically
allocated meant we could create the hash table entry when the pid was
allocated and free the hash table entry when the pid was freed.  Instead of
playing with the hash lists when ever a process would attach or detach to a
process.

For myself the fact that it gave what my previous task_ref patch gave for free
with simpler code was a big win.  The problem is that if you hold a reference
to struct task_struct you lock in 10K of low memory.  If you do that in a user
controllable way like /proc does, with an unprivileged but hostile user space
application with typical resource limits of 1000 fds and 100 processes I can
trigger the OOM killer by consuming all of low memory with task structs, on a
machine wight 1GB of low memory.

If I instead hold a reference to struct pid which holds a pointer to my
task_struct, I don't suffer from that problem because struct pid is 2 orders
of magnitude smaller.  In fact struct pid is small enough that most other
kernel data structures dwarf it, so simply limiting the number of referring
data structures is enough to prevent exhaustion of low memory.

This splits the current struct pid into two structures, struct pid and struct
pid_link, and reduces our number of hash tables from PIDTYPE_MAX to just one.
struct pid_link is the per process linkage into the hash tables and lives in
struct task_struct.  struct pid is given an indepedent lifetime, and holds
pointers to each of the pid types.

The independent life of struct pid simplifies attach_pid, and detach_pid,
because we are always manipulating the list of pids and not the hash table.
In addition in giving struct pid an indpendent life it makes the concept much
more powerful.

Kernel data structures can now embed a struct pid * instead of a pid_t and
not suffer from pid wrap around problems or from keeping unnecessarily
large amounts of memory allocated.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      92476d7f
    • A
      [PATCH] resurrect __put_task_struct · 158d9ebd
      由 Andrew Morton 提交于 
      This just got nuked in mainline.  Bring it back because Eric's patches use it.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      158d9ebd
  31. 29 3月, 2006 9 次提交
  33. 28 3月, 2006 1 次提交
  35. 27 3月, 2006 2 次提交
  37. 24 3月, 2006 2 次提交
    • P
      [PATCH] cpuset memory spread slab cache optimizations · c61afb18
      由 Paul Jackson 提交于 
      The hooks in the slab cache allocator code path for support of NUMA
mempolicies and cpuset memory spreading are in an important code path.  Many
systems will use neither feature.

This patch optimizes those hooks down to a single check of some bits in the
current tasks task_struct flags.  For non NUMA systems, this hook and related
code is already ifdef'd out.

The optimization is done by using another task flag, set if the task is using
a non-default NUMA mempolicy.  Taking this flag bit along with the
PF_SPREAD_PAGE and PF_SPREAD_SLAB flag bits added earlier in this 'cpuset
memory spreading' patch set, one can check for the combination of any of these
special case memory placement mechanisms with a single test of the current
tasks task_struct flags.

This patch also tightens up the code, to save a few bytes of kernel text
space, and moves some of it out of line.  Due to the nested inlines called
from multiple places, we were ending up with three copies of this code, which
once we get off the main code path (for local node allocation) seems a bit
wasteful of instruction memory.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      c61afb18
    • J
      [PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23 · 2056a782
      由 Jens Axboe 提交于 
      Signed-off-by: NJens Axboe <axboe@suse.de>
      2056a782