From: Michal Hocko <mhocko@xxxxxxxx> Subject: 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@xxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Alex Belits <alex.belits@xxxxxxxxxx> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Cc: David Daney <david.daney@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: NeilBrown <neilb@xxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/migrate.h | 2 +- mm/mempolicy.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff -puN include/linux/migrate.h~mm-migration-do-not-trigger-oom-killer-when-migrating-memory include/linux/migrate.h --- a/include/linux/migrate.h~mm-migration-do-not-trigger-oom-killer-when-migrating-memory +++ a/include/linux/migrate.h @@ -34,7 +34,7 @@ extern char *migrate_reason_names[MR_TYP 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 -puN mm/mempolicy.c~mm-migration-do-not-trigger-oom-killer-when-migrating-memory mm/mempolicy.c --- a/mm/mempolicy.c~mm-migration-do-not-trigger-oom-killer-when-migrating-memory +++ a/mm/mempolicy.c @@ -1078,7 +1078,8 @@ static struct page *new_page(struct page /* * 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 _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
