Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

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

Browse source 
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
Show stats Download patch file Download diff file Expand all files Collapse all files

6
kernel/fork.c
View file

@ -414,7 +414,10 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
unsigned long charge; unsigned long charge;
uprobe_start_dup_mmap(); 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); flush_cache_dup_mm(oldmm);
uprobe_dup_mmap(oldmm, mm); uprobe_dup_mmap(oldmm, mm);
/* /*
@ -526,6 +529,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
up_write(&mm->mmap_sem); up_write(&mm->mmap_sem);
flush_tlb_mm(oldmm); flush_tlb_mm(oldmm);
up_write(&oldmm->mmap_sem); up_write(&oldmm->mmap_sem);
fail_uprobe_end:
uprobe_end_dup_mmap(); uprobe_end_dup_mmap();
return retval; return retval;
fail_nomem_anon_vma_fork: fail_nomem_anon_vma_fork: