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  1. 06 5月, 2016 1 次提交
  3. 29 4月, 2016 2 次提交
  5. 26 3月, 2016 1 次提交
  7. 18 3月, 2016 7 次提交
    • K
      thp: fix deadlock in split_huge_pmd() · 5f737714
      由 Kirill A. Shutemov 提交于 
      split_huge_pmd() tries to munlock page with munlock_vma_page().  That
requires the page to locked.

If the is locked by caller, we would get a deadlock:

	Unable to find swap-space signature
	INFO: task trinity-c85:1907 blocked for more than 120 seconds.
	      Not tainted 4.4.0-00032-gf19d0bdced41-dirty #1606
	"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
	trinity-c85     D ffff88084d997608     0  1907    309 0x00000000
	Call Trace:
	  schedule+0x9f/0x1c0
	  schedule_timeout+0x48e/0x600
	  io_schedule_timeout+0x1c3/0x390
	  bit_wait_io+0x29/0xd0
	  __wait_on_bit_lock+0x94/0x140
	  __lock_page+0x1d4/0x280
	  __split_huge_pmd+0x5a8/0x10f0
	  split_huge_pmd_address+0x1d9/0x230
	  try_to_unmap_one+0x540/0xc70
	  rmap_walk_anon+0x284/0x810
	  rmap_walk_locked+0x11e/0x190
	  try_to_unmap+0x1b1/0x4b0
	  split_huge_page_to_list+0x49d/0x18a0
	  follow_page_mask+0xa36/0xea0
	  SyS_move_pages+0xaf3/0x1570
	  entry_SYSCALL_64_fastpath+0x12/0x6b
	2 locks held by trinity-c85/1907:
	 #0:  (&mm->mmap_sem){++++++}, at:  SyS_move_pages+0x933/0x1570
	 #1:  (&anon_vma->rwsem){++++..}, at:  split_huge_page_to_list+0x402/0x18a0

I don't think the deadlock is triggerable without split_huge_page()
simplifilcation patchset.

But munlock_vma_page() here is wrong: we want to munlock the page
unconditionally, no need in rmap lookup, that munlock_vma_page() does.

Let's use clear_page_mlock() instead.  It can be called under ptl.

Fixes: e90309c9 ("thp: allow mlocked THP again")
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5f737714
    • K
      thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers · fec89c10
      由 Kirill A. Shutemov 提交于 
      freeze_page() and unfreeze_page() helpers evolved in rather complex
beasts.  It would be nice to cut complexity of this code.

This patch rewrites freeze_page() using standard try_to_unmap().
unfreeze_page() is rewritten with remove_migration_ptes().

The result is much simpler.

But the new variant is somewhat slower for PTE-mapped THPs.  Current
helpers iterates over VMAs the compound page is mapped to, and then over
ptes within this VMA.  New helpers iterates over small page, then over
VMA the small page mapped to, and only then find relevant pte.

We have short cut for PMD-mapped THP: we directly install migration
entries on PMD split.

I don't think the slowdown is critical, considering how much simpler
result is and that split_huge_page() is quite rare nowadays.  It only
happens due memory pressure or migration.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fec89c10
    • K
      rmap: extend try_to_unmap() to be usable by split_huge_page() · 2a52bcbc
      由 Kirill A. Shutemov 提交于 
      Add support for two ttu_flags:

  - TTU_SPLIT_HUGE_PMD would split PMD if it's there, before trying to
    unmap page;

  - TTU_RMAP_LOCKED indicates that caller holds relevant rmap lock;

Also, change rwc->done to !page_mapcount() instead of !page_mapped().
try_to_unmap() works on pte level, so we are really interested in the
mappedness of this small page rather than of the compound page it's a
part of.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2a52bcbc
    • J
      mm: coalesce split strings · 756a025f
      由 Joe Perches 提交于 
      Kernel style prefers a single string over split strings when the string is
'user-visible'.

Miscellanea:

 - Add a missing newline
 - Realign arguments
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: Tejun Heo <tj@kernel.org>	[percpu]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      756a025f
    • J
      mm: introduce page reference manipulation functions · fe896d18
      由 Joonsoo Kim 提交于 
      The success of CMA allocation largely depends on the success of
migration and key factor of it is page reference count.  Until now, page
reference is manipulated by direct calling atomic functions so we cannot
follow up who and where manipulate it.  Then, it is hard to find actual
reason of CMA allocation failure.  CMA allocation should be guaranteed
to succeed so finding offending place is really important.

In this patch, call sites where page reference is manipulated are
converted to introduced wrapper function.  This is preparation step to
add tracepoint to each page reference manipulation function.  With this
facility, we can easily find reason of CMA allocation failure.  There is
no functional change in this patch.

In addition, this patch also converts reference read sites.  It will
help a second step that renames page._count to something else and
prevents later attempt to direct access to it (Suggested by Andrew).
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fe896d18
    • M
      mm: thp: set THP defrag by default to madvise and add a stall-free defrag option · 444eb2a4
      由 Mel Gorman 提交于 
      THP defrag is enabled by default to direct reclaim/compact but not wake
kswapd in the event of a THP allocation failure.  The problem is that
THP allocation requests potentially enter reclaim/compaction.  This
potentially incurs a severe stall that is not guaranteed to be offset by
reduced TLB misses.  While there has been considerable effort to reduce
the impact of reclaim/compaction, it is still a high cost and workloads
that should fit in memory fail to do so.  Specifically, a simple
anon/file streaming workload will enter direct reclaim on NUMA at least
even though the working set size is 80% of RAM.  It's been years and
it's time to throw in the towel.

First, this patch defines THP defrag as follows;

 madvise: A failed allocation will direct reclaim/compact if the application requests it
 never:   Neither reclaim/compact nor wake kswapd
 defer:   A failed allocation will wake kswapd/kcompactd
 always:  A failed allocation will direct reclaim/compact (historical behaviour)
          khugepaged defrag will enter direct/reclaim but not wake kswapd.

Next it sets the default defrag option to be "madvise" to only enter
direct reclaim/compaction for applications that specifically requested
it.

Lastly, it removes a check from the page allocator slowpath that is
related to __GFP_THISNODE to allow "defer" to work.  The callers that
really cares are slub/slab and they are updated accordingly.  The slab
one may be surprising because it also corrects a comment as kswapd was
never woken up by that path.

This means that a THP fault will no longer stall for most applications
by default and the ideal for most users that get THP if they are
immediately available.  There are still options for users that prefer a
stall at startup of a new application by either restoring historical
behaviour with "always" or pick a half-way point with "defer" where
kswapd does some of the work in the background and wakes kcompactd if
necessary.  THP defrag for khugepaged remains enabled and will enter
direct/reclaim but no wakeup kswapd or kcompactd.

After this patch a THP allocation failure will quickly fallback and rely
on khugepaged to recover the situation at some time in the future.  In
some cases, this will reduce THP usage but the benefit of THP is hard to
measure and not a universal win where as a stall to reclaim/compaction
is definitely measurable and can be painful.

The first test for this is using "usemem" to read a large file and write
a large anonymous mapping (to avoid the zero page) multiple times.  The
total size of the mappings is 80% of RAM and the benchmark simply
measures how long it takes to complete.  It uses multiple threads to see
if that is a factor.  On UMA, the performance is almost identical so is
not reported but on NUMA, we see this

usemem
                                   4.4.0                 4.4.0
                          kcompactd-v1r1         nodefrag-v1r3
Amean    System-1       102.86 (  0.00%)       46.81 ( 54.50%)
Amean    System-4        37.85 (  0.00%)       34.02 ( 10.12%)
Amean    System-7        48.12 (  0.00%)       46.89 (  2.56%)
Amean    System-12       51.98 (  0.00%)       56.96 ( -9.57%)
Amean    System-21       80.16 (  0.00%)       79.05 (  1.39%)
Amean    System-30      110.71 (  0.00%)      107.17 (  3.20%)
Amean    System-48      127.98 (  0.00%)      124.83 (  2.46%)
Amean    Elapsd-1       185.84 (  0.00%)      105.51 ( 43.23%)
Amean    Elapsd-4        26.19 (  0.00%)       25.58 (  2.33%)
Amean    Elapsd-7        21.65 (  0.00%)       21.62 (  0.16%)
Amean    Elapsd-12       18.58 (  0.00%)       17.94 (  3.43%)
Amean    Elapsd-21       17.53 (  0.00%)       16.60 (  5.33%)
Amean    Elapsd-30       17.45 (  0.00%)       17.13 (  1.84%)
Amean    Elapsd-48       15.40 (  0.00%)       15.27 (  0.82%)

For a single thread, the benchmark completes 43.23% faster with this
patch applied with smaller benefits as the thread increases.  Similar,
notice the large reduction in most cases in system CPU usage.  The
overall CPU time is

               4.4.0       4.4.0
        kcompactd-v1r1 nodefrag-v1r3
User        10357.65    10438.33
System       3988.88     3543.94
Elapsed      2203.01     1634.41

Which is substantial. Now, the reclaim figures

                                 4.4.0       4.4.0
                          kcompactd-v1r1nodefrag-v1r3
Minor Faults                 128458477   278352931
Major Faults                   2174976         225
Swap Ins                      16904701           0
Swap Outs                     17359627           0
Allocation stalls                43611           0
DMA allocs                           0           0
DMA32 allocs                  19832646    19448017
Normal allocs                614488453   580941839
Movable allocs                       0           0
Direct pages scanned          24163800           0
Kswapd pages scanned                 0           0
Kswapd pages reclaimed               0           0
Direct pages reclaimed        20691346           0
Compaction stalls                42263           0
Compaction success                 938           0
Compaction failures              41325           0

This patch eliminates almost all swapping and direct reclaim activity.
There is still overhead but it's from NUMA balancing which does not
identify that it's pointless trying to do anything with this workload.

I also tried the thpscale benchmark which forces a corner case where
compaction can be used heavily and measures the latency of whether base
or huge pages were used

thpscale Fault Latencies
                                       4.4.0                 4.4.0
                              kcompactd-v1r1         nodefrag-v1r3
Amean    fault-base-1      5288.84 (  0.00%)     2817.12 ( 46.73%)
Amean    fault-base-3      6365.53 (  0.00%)     3499.11 ( 45.03%)
Amean    fault-base-5      6526.19 (  0.00%)     4363.06 ( 33.15%)
Amean    fault-base-7      7142.25 (  0.00%)     4858.08 ( 31.98%)
Amean    fault-base-12    13827.64 (  0.00%)    10292.11 ( 25.57%)
Amean    fault-base-18    18235.07 (  0.00%)    13788.84 ( 24.38%)
Amean    fault-base-24    21597.80 (  0.00%)    24388.03 (-12.92%)
Amean    fault-base-30    26754.15 (  0.00%)    19700.55 ( 26.36%)
Amean    fault-base-32    26784.94 (  0.00%)    19513.57 ( 27.15%)
Amean    fault-huge-1      4223.96 (  0.00%)     2178.57 ( 48.42%)
Amean    fault-huge-3      2194.77 (  0.00%)     2149.74 (  2.05%)
Amean    fault-huge-5      2569.60 (  0.00%)     2346.95 (  8.66%)
Amean    fault-huge-7      3612.69 (  0.00%)     2997.70 ( 17.02%)
Amean    fault-huge-12     3301.75 (  0.00%)     6727.02 (-103.74%)
Amean    fault-huge-18     6696.47 (  0.00%)     6685.72 (  0.16%)
Amean    fault-huge-24     8000.72 (  0.00%)     9311.43 (-16.38%)
Amean    fault-huge-30    13305.55 (  0.00%)     9750.45 ( 26.72%)
Amean    fault-huge-32     9981.71 (  0.00%)    10316.06 ( -3.35%)

The average time to fault pages is substantially reduced in the majority
of caseds but with the obvious caveat that fewer THPs are actually used
in this adverse workload

                                   4.4.0                 4.4.0
                          kcompactd-v1r1         nodefrag-v1r3
Percentage huge-1         0.71 (  0.00%)       14.04 (1865.22%)
Percentage huge-3        10.77 (  0.00%)       33.05 (206.85%)
Percentage huge-5        60.39 (  0.00%)       38.51 (-36.23%)
Percentage huge-7        45.97 (  0.00%)       34.57 (-24.79%)
Percentage huge-12       68.12 (  0.00%)       40.07 (-41.17%)
Percentage huge-18       64.93 (  0.00%)       47.82 (-26.35%)
Percentage huge-24       62.69 (  0.00%)       44.23 (-29.44%)
Percentage huge-30       43.49 (  0.00%)       55.38 ( 27.34%)
Percentage huge-32       50.72 (  0.00%)       51.90 (  2.35%)

                                 4.4.0       4.4.0
                          kcompactd-v1r1nodefrag-v1r3
Minor Faults                  37429143    47564000
Major Faults                      1916        1558
Swap Ins                          1466        1079
Swap Outs                      2936863      149626
Allocation stalls                62510           3
DMA allocs                           0           0
DMA32 allocs                   6566458     6401314
Normal allocs                216361697   216538171
Movable allocs                       0           0
Direct pages scanned          25977580       17998
Kswapd pages scanned                 0     3638931
Kswapd pages reclaimed               0      207236
Direct pages reclaimed         8833714          88
Compaction stalls               103349           5
Compaction success                 270           4
Compaction failures             103079           1

Note again that while this does swap as it's an aggressive workload, the
direct relcim activity and allocation stalls is substantially reduced.
There is some kswapd activity but ftrace showed that the kswapd activity
was due to normal wakeups from 4K pages being allocated.
Compaction-related stalls and activity are almost eliminated.

I also tried the stutter benchmark.  For this, I do not have figures for
NUMA but it's something that does impact UMA so I'll report what is
available

stutter
                                 4.4.0                 4.4.0
                        kcompactd-v1r1         nodefrag-v1r3
Min         mmap      7.3571 (  0.00%)      7.3438 (  0.18%)
1st-qrtle   mmap      7.5278 (  0.00%)     17.9200 (-138.05%)
2nd-qrtle   mmap      7.6818 (  0.00%)     21.6055 (-181.25%)
3rd-qrtle   mmap     11.0889 (  0.00%)     21.8881 (-97.39%)
Max-90%     mmap     27.8978 (  0.00%)     22.1632 ( 20.56%)
Max-93%     mmap     28.3202 (  0.00%)     22.3044 ( 21.24%)
Max-95%     mmap     28.5600 (  0.00%)     22.4580 ( 21.37%)
Max-99%     mmap     29.6032 (  0.00%)     25.5216 ( 13.79%)
Max         mmap   4109.7289 (  0.00%)   4813.9832 (-17.14%)
Mean        mmap     12.4474 (  0.00%)     19.3027 (-55.07%)

This benchmark is trying to fault an anonymous mapping while there is a
heavy IO load -- a scenario that desktop users used to complain about
frequently.  This shows a mix because the ideal case of mapping with THP
is not hit as often.  However, note that 99% of the mappings complete
13.79% faster.  The CPU usage here is particularly interesting

               4.4.0       4.4.0
        kcompactd-v1r1nodefrag-v1r3
User           67.50        0.99
System       1327.88       91.30
Elapsed      2079.00     2128.98

And once again we look at the reclaim figures

                                 4.4.0       4.4.0
                          kcompactd-v1r1nodefrag-v1r3
Minor Faults                 335241922  1314582827
Major Faults                       715         819
Swap Ins                             0           0
Swap Outs                            0           0
Allocation stalls               532723           0
DMA allocs                           0           0
DMA32 allocs                1822364341  1177950222
Normal allocs               1815640808  1517844854
Movable allocs                       0           0
Direct pages scanned          21892772           0
Kswapd pages scanned          20015890    41879484
Kswapd pages reclaimed        19961986    41822072
Direct pages reclaimed        21892741           0
Compaction stalls              1065755           0
Compaction success                 514           0
Compaction failures            1065241           0

Allocation stalls and all direct reclaim activity is eliminated as well
as compaction-related stalls.

THP gives impressive gains in some cases but only if they are quickly
available.  We're not going to reach the point where they are completely
free so lets take the costs out of the fast paths finally and defer the
cost to kswapd, kcompactd and khugepaged where it belongs.
Signed-off-by: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NRik van Riel <riel@redhat.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      444eb2a4
    • K
      thp, vmstats: count deferred split events · f9719a03
      由 Kirill A. Shutemov 提交于 
      Count how many times we put a THP in split queue.  Currently, it happens
on partial unmap of a THP.

Rapidly growing value can indicate that an application behaves
unfriendly wrt THP: often fault in huge page and then unmap part of it.
This leads to unnecessary memory fragmentation and the application may
require tuning.

The event also can help with debugging kernel [mis-]behaviour.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f9719a03
  9. 16 3月, 2016 1 次提交
  11. 03 3月, 2016 1 次提交
  13. 25 2月, 2016 1 次提交
  15. 19 2月, 2016 1 次提交
  17. 15 2月, 2016 1 次提交
    • A
      powerpc/mm: Fix Multi hit ERAT cause by recent THP update · c777e2a8
      由 Aneesh Kumar K.V 提交于 
      With ppc64 we use the deposited pgtable_t to store the hash pte slot
information. We should not withdraw the deposited pgtable_t without
marking the pmd none. This ensure that low level hash fault handling
will skip this huge pte and we will handle them at upper levels.

Recent change to pmd splitting changed the above in order to handle the
race between pmd split and exit_mmap. The race is explained below.

Consider following race:

		CPU0				CPU1
shrink_page_list()
  add_to_swap()
    split_huge_page_to_list()
      __split_huge_pmd_locked()
        pmdp_huge_clear_flush_notify()
	// pmd_none() == true
					exit_mmap()
					  unmap_vmas()
					    zap_pmd_range()
					      // no action on pmd since pmd_none() == true
	pmd_populate()

As result the THP will not be freed. The leak is detected by check_mm():

	BUG: Bad rss-counter state mm:ffff880058d2e580 idx:1 val:512

The above required us to not mark pmd none during a pmd split.

The fix for ppc is to clear the huge pte of _PAGE_USER, so that low
level fault handling code skip this pte. At higher level we do take ptl
lock. That should serialze us against the pmd split. Once the lock is
acquired we do check the pmd again using pmd_same. That should always
return false for us and hence we should retry the access. We do the
pmd_same check in all case after taking plt with
THP (do_huge_pmd_wp_page, do_huge_pmd_numa_page and
huge_pmd_set_accessed)

Also make sure we wait for irq disable section in other cpus to finish
before flipping a huge pte entry with a regular pmd entry. Code paths
like find_linux_pte_or_hugepte depend on irq disable to get
a stable pte_t pointer. A parallel thp split need to make sure we
don't convert a pmd pte to a regular pmd entry without waiting for the
irq disable section to finish.

Fixes: eef1b3ba ("thp: implement split_huge_pmd()")
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      c777e2a8
  19. 06 2月, 2016 1 次提交
  21. 04 2月, 2016 4 次提交
  23. 22 1月, 2016 2 次提交
  25. 21 1月, 2016 2 次提交
    • K
      thp: fix interrupt unsafe locking in split_huge_page() · 0b9b6fff
      由 Kirill A. Shutemov 提交于 
      split_queue_lock can be taken from interrupt context in some cases, but
I forgot to convert locking in split_huge_page() to interrupt-safe
primitives.

Let's fix this.

lockdep output:

  ======================================================
  [ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]
  4.4.0+ #259 Tainted: G        W
  ------------------------------------------------------
  syz-executor/18183 [HC0[0]:SC0[2]:HE0:SE0] is trying to acquire:
   (split_queue_lock){+.+...}, at: free_transhuge_page+0x24/0x90 mm/huge_memory.c:3436

  and this task is already holding:
   (slock-AF_INET){+.-...}, at: spin_lock_bh include/linux/spinlock.h:307
   (slock-AF_INET){+.-...}, at: lock_sock_fast+0x45/0x120 net/core/sock.c:2462
  which would create a new lock dependency:
   (slock-AF_INET){+.-...} -> (split_queue_lock){+.+...}

  but this new dependency connects a SOFTIRQ-irq-safe lock:
   (slock-AF_INET){+.-...}
  ... which became SOFTIRQ-irq-safe at:
     mark_irqflags kernel/locking/lockdep.c:2799
     __lock_acquire+0xfd8/0x4700 kernel/locking/lockdep.c:3162
     lock_acquire+0x1dc/0x430 kernel/locking/lockdep.c:3585
     __raw_spin_lock include/linux/spinlock_api_smp.h:144
     _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
     spin_lock include/linux/spinlock.h:302
     udp_queue_rcv_skb+0x781/0x1550 net/ipv4/udp.c:1680
     flush_stack+0x50/0x330 net/ipv6/udp.c:799
     __udp4_lib_mcast_deliver+0x694/0x7f0 net/ipv4/udp.c:1798
     __udp4_lib_rcv+0x17dc/0x23e0 net/ipv4/udp.c:1888
     udp_rcv+0x21/0x30 net/ipv4/udp.c:2108
     ip_local_deliver_finish+0x2b3/0xa50 net/ipv4/ip_input.c:216
     NF_HOOK_THRESH include/linux/netfilter.h:226
     NF_HOOK include/linux/netfilter.h:249
     ip_local_deliver+0x1c4/0x2f0 net/ipv4/ip_input.c:257
     dst_input include/net/dst.h:498
     ip_rcv_finish+0x5ec/0x1730 net/ipv4/ip_input.c:365
     NF_HOOK_THRESH include/linux/netfilter.h:226
     NF_HOOK include/linux/netfilter.h:249
     ip_rcv+0x963/0x1080 net/ipv4/ip_input.c:455
     __netif_receive_skb_core+0x1620/0x2f80 net/core/dev.c:4154
     __netif_receive_skb+0x2a/0x160 net/core/dev.c:4189
     netif_receive_skb_internal+0x1b5/0x390 net/core/dev.c:4217
     napi_skb_finish net/core/dev.c:4542
     napi_gro_receive+0x2bd/0x3c0 net/core/dev.c:4572
     e1000_clean_rx_irq+0x4e2/0x1100 drivers/net/ethernet/intel/e1000e/netdev.c:1038
     e1000_clean+0xa08/0x24a0 drivers/net/ethernet/intel/e1000/e1000_main.c:3819
     napi_poll net/core/dev.c:5074
     net_rx_action+0x7eb/0xdf0 net/core/dev.c:5139
     __do_softirq+0x26a/0x920 kernel/softirq.c:273
     invoke_softirq kernel/softirq.c:350
     irq_exit+0x18f/0x1d0 kernel/softirq.c:391
     exiting_irq ./arch/x86/include/asm/apic.h:659
     do_IRQ+0x86/0x1a0 arch/x86/kernel/irq.c:252
     ret_from_intr+0x0/0x20 arch/x86/entry/entry_64.S:520
     arch_safe_halt ./arch/x86/include/asm/paravirt.h:117
     default_idle+0x52/0x2e0 arch/x86/kernel/process.c:304
     arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:295
     default_idle_call+0x48/0xa0 kernel/sched/idle.c:92
     cpuidle_idle_call kernel/sched/idle.c:156
     cpu_idle_loop kernel/sched/idle.c:252
     cpu_startup_entry+0x554/0x710 kernel/sched/idle.c:300
     rest_init+0x192/0x1a0 init/main.c:412
     start_kernel+0x678/0x69e init/main.c:683
     x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:195
     x86_64_start_kernel+0x158/0x167 arch/x86/kernel/head64.c:184

  to a SOFTIRQ-irq-unsafe lock:
   (split_queue_lock){+.+...}
   which became SOFTIRQ-irq-unsafe at:
     mark_irqflags kernel/locking/lockdep.c:2817
     __lock_acquire+0x146e/0x4700 kernel/locking/lockdep.c:3162
     lock_acquire+0x1dc/0x430 kernel/locking/lockdep.c:3585
     __raw_spin_lock include/linux/spinlock_api_smp.h:144
     _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
     spin_lock include/linux/spinlock.h:302
     split_huge_page_to_list+0xcc0/0x1c50 mm/huge_memory.c:3399
     split_huge_page include/linux/huge_mm.h:99
     queue_pages_pte_range+0xa38/0xef0 mm/mempolicy.c:507
     walk_pmd_range mm/pagewalk.c:50
     walk_pud_range mm/pagewalk.c:90
     walk_pgd_range mm/pagewalk.c:116
     __walk_page_range+0x653/0xcd0 mm/pagewalk.c:204
     walk_page_range+0xfe/0x2b0 mm/pagewalk.c:281
     queue_pages_range+0xfb/0x130 mm/mempolicy.c:687
     migrate_to_node mm/mempolicy.c:1004
     do_migrate_pages+0x370/0x4e0 mm/mempolicy.c:1109
     SYSC_migrate_pages mm/mempolicy.c:1453
     SyS_migrate_pages+0x640/0x730 mm/mempolicy.c:1374
     entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185

  other info that might help us debug this:

   Possible interrupt unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(split_queue_lock);
                                 local_irq_disable();
                                 lock(slock-AF_INET);
                                 lock(split_queue_lock);
    <Interrupt>
      lock(slock-AF_INET);
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0b9b6fff
    • A
      mm: avoid uninitialized variable in tracepoint · 629d9d1c
      由 Arnd Bergmann 提交于 
      A newly added tracepoint in the hugepage code uses a variable in the
error handling that is not initialized at that point:

include/trace/events/huge_memory.h:81:230: error: 'isolated' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The result is relatively harmless, as the trace data will in rare
cases contain incorrect data.

This works around the problem by adding an explicit initialization.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 7d2eba05 ("mm: add tracepoint for scanning pages")
Reviewed-by: NEbru Akagunduz <ebru.akagunduz@gmail.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      629d9d1c
  27. 18 1月, 2016 1 次提交
  29. 16 1月, 2016 14 次提交