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author | Kirill Tkhai <ktkhai@virtuozzo.com> | 2018-03-19 18:32:10 +0300 |
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committer | Tejun Heo <tj@kernel.org> | 2018-03-19 09:38:50 -0700 |
commit | f52ba1fef7b92e74d58efef8eae7b6f48c6d218d (patch) | |
tree | be3bfd5e52ea11827506db4397dcd29e9dd6a83e /mm | |
parent | 71546d100422bcc2c543dadeb9328728997cd23a (diff) | |
download | linux-f52ba1fef7b92e74d58efef8eae7b6f48c6d218d.tar.bz2 |
mm: Allow to kill tasks doing pcpu_alloc() and waiting for pcpu_balance_workfn()
In case of memory deficit and low percpu memory pages,
pcpu_balance_workfn() takes pcpu_alloc_mutex for a long
time (as it makes memory allocations itself and waits
for memory reclaim). If tasks doing pcpu_alloc() are
choosen by OOM killer, they can't exit, because they
are waiting for the mutex.
The patch makes pcpu_alloc() to care about killing signal
and use mutex_lock_killable(), when it's allowed by GFP
flags. This guarantees, a task does not miss SIGKILL
from OOM killer.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/percpu.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index 15a398c00791..9297098519a6 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1373,8 +1373,17 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, return NULL; } - if (!is_atomic) - mutex_lock(&pcpu_alloc_mutex); + if (!is_atomic) { + /* + * pcpu_balance_workfn() allocates memory under this mutex, + * and it may wait for memory reclaim. Allow current task + * to become OOM victim, in case of memory pressure. + */ + if (gfp & __GFP_NOFAIL) + mutex_lock(&pcpu_alloc_mutex); + else if (mutex_lock_killable(&pcpu_alloc_mutex)) + return NULL; + } spin_lock_irqsave(&pcpu_lock, flags); |