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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-09-21 20:02:27 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:17:33 -0400
commit35451beecbd7c86ce3249d543594517a5fe9a0cd (patch)
treee72759e6e6fcd142ab85c607a9b3dd3e1c016eed /mm/swapfile.c
parenta913e182ab9484308e870af37a14d372742d53b0 (diff)
ksm: unmerge is an origin of OOMs
Just as the swapoff system call allocates many pages of RAM to various processes, perhaps triggering OOM, so "echo 2 >/sys/kernel/mm/ksm/run" (unmerge) is liable to allocate many pages of RAM to various processes, perhaps triggering OOM; and each is normally run from a modest admin process (swapoff or shell), easily repeated until it succeeds. So treat unmerge_and_remove_all_rmap_items() in the same way that we treat try_to_unuse(): generalize PF_SWAPOFF to PF_OOM_ORIGIN, and bracket both with that, to ask the OOM killer to kill them first, to prevent them from spawning more and more OOM kills. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Izik Eidus <ieidus@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 74f1102e8749..f1bf19daadc6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1575,9 +1575,9 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
1575 p->flags &= ~SWP_WRITEOK; 1575 p->flags &= ~SWP_WRITEOK;
1576 spin_unlock(&swap_lock); 1576 spin_unlock(&swap_lock);
1577 1577
1578 current->flags |= PF_SWAPOFF; 1578 current->flags |= PF_OOM_ORIGIN;
1579 err = try_to_unuse(type); 1579 err = try_to_unuse(type);
1580 current->flags &= ~PF_SWAPOFF; 1580 current->flags &= ~PF_OOM_ORIGIN;
1581 1581
1582 if (err) { 1582 if (err) {
1583 /* re-insert swap space back into swap_list */ 1583 /* re-insert swap space back into swap_list */