]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
thp, memcg: split hugepage for memcg oom on cow
authorDavid Rientjes <rientjes@google.com>
Tue, 29 May 2012 22:06:23 +0000 (15:06 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 29 May 2012 23:22:19 +0000 (16:22 -0700)
commit1f1d06c34f7675026326cd9f39ff91e4555cf355
treeb2493685179e3b222c915002648c3baba56318d2
parentbde8bd8a1d5242589ddcaef8e017b48b207c4729
thp, memcg: split hugepage for memcg oom on cow

On COW, a new hugepage is allocated and charged to the memcg.  If the
system is oom or the charge to the memcg fails, however, the fault
handler will return VM_FAULT_OOM which results in an oom kill.

Instead, it's possible to fallback to splitting the hugepage so that the
COW results only in an order-0 page being allocated and charged to the
memcg which has a higher liklihood to succeed.  This is expensive
because the hugepage must be split in the page fault handler, but it is
much better than unnecessarily oom killing a process.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/huge_memory.c
mm/memory.c