prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable

PR_SET_THP_DISABLE requires 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>
Acked-by: Alex Thorlton <athorlton@sgi.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 16:26:05 -07:00 committed by Linus Torvalds
parent f268dfe905
commit 17b0573d77

View file

@ -2246,7 +2246,8 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
case PR_SET_THP_DISABLE:
if (arg3 || arg4 || arg5)
return -EINVAL;
down_write(&me->mm->mmap_sem);
if (down_write_killable(&me->mm->mmap_sem))
return -EINTR;
if (arg2)
me->mm->def_flags |= VM_NOHUGEPAGE;
else