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mm, fork: make dup_mmap wait for mmap_sem for write killable 

dup_mmap needs to lock current's mm mmap_sem for write.  If the waiting
task gets killed by the oom killer it would block oom_reaper from
asynchronous address space reclaim and reduce the chances of timely OOM
resolving.  Wait for the lock in the killable mode and return with EINTR
if the task got killed while waiting.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michal Hocko 2016-05-23 16:25:48 -07:00 committed by Linus Torvalds
parent 4e80153a60
commit 7c05126793
1 changed files with 5 additions and 1 deletions
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6
kernel/fork.c
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@ -414,7 +414,10 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
unsigned long charge;
uprobe_start_dup_mmap();
down_write(&oldmm->mmap_sem);
if (down_write_killable(&oldmm->mmap_sem)) {
retval = -EINTR;
goto fail_uprobe_end;
}
flush_cache_dup_mm(oldmm);
uprobe_dup_mmap(oldmm, mm);
/*
@ -526,6 +529,7 @@ out:
up_write(&mm->mmap_sem);
flush_tlb_mm(oldmm);
up_write(&oldmm->mmap_sem);
fail_uprobe_end:
uprobe_end_dup_mmap();
return retval;
fail_nomem_anon_vma_fork: