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| author | David Rientjes <rientjes@google.com> | 2012-05-29 15:06:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-29 16:22:19 -0700 |
| commit | 1f1d06c34f7675026326cd9f39ff91e4555cf355 (patch) | |
| tree | b2493685179e3b222c915002648c3baba56318d2 /mm/huge_memory.c | |
| parent | bde8bd8a1d5242589ddcaef8e017b48b207c4729 (diff) | |
| download | op-kernel-dev-1f1d06c34f7675026326cd9f39ff91e4555cf355.zip op-kernel-dev-1f1d06c34f7675026326cd9f39ff91e4555cf355.tar.gz | |
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>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d7d7165..edfeb8c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -952,6 +952,8 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, count_vm_event(THP_FAULT_FALLBACK); ret = do_huge_pmd_wp_page_fallback(mm, vma, address, pmd, orig_pmd, page, haddr); + if (ret & VM_FAULT_OOM) + split_huge_page(page); put_page(page); goto out; } @@ -959,6 +961,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { put_page(new_page); + split_huge_page(page); put_page(page); ret |= VM_FAULT_OOM; goto out; |
