From 0f55685627d6dd2beda55a82abc02297f0f8e5c2 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 12 Jul 2017 14:36:58 -0700 Subject: [PATCH] mm, migration: do not trigger OOM killer when migrating memory Page migration (for memory hotplug, soft_offline_page or mbind) needs to allocate a new memory. This can trigger an oom killer if the target memory is depleated. Although quite unlikely, still possible, especially for the memory hotplug (offlining of memoery). Up to now we didn't really have reasonable means to back off. __GFP_NORETRY can fail just too easily and __GFP_THISNODE sticks to a single node and that is not suitable for all callers. But now that we have __GFP_RETRY_MAYFAIL we should use it. It is preferable to fail the migration than disrupt the system by killing some processes. Link: http://lkml.kernel.org/r/20170623085345.11304-7-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Vlastimil Babka Cc: Alex Belits Cc: Chris Wilson Cc: Christoph Hellwig Cc: Darrick J. Wong Cc: David Daney Cc: Johannes Weiner Cc: Mel Gorman Cc: NeilBrown Cc: Ralf Baechle Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/migrate.h | 2 +- mm/mempolicy.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 4634da5..3e0d405 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -34,7 +34,7 @@ extern char *migrate_reason_names[MR_TYPES]; static inline struct page *new_page_nodemask(struct page *page, int preferred_nid, nodemask_t *nodemask) { - gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE; + gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL; if (PageHuge(page)) return alloc_huge_page_nodemask(page_hstate(compound_head(page)), diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 7d8e562..d911fa5 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1078,7 +1078,8 @@ static struct page *new_page(struct page *page, unsigned long start, int **x) /* * if !vma, alloc_page_vma() will use task or system default policy */ - return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); + return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL, + vma, address); } #else -- 2.7.4