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![Michal Hocko](/assets/img/avatar_default.png)
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 <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alex Belits <alex.belits@cavium.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: David Daney <david.daney@cavium.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: NeilBrown <neilb@suse.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
141 lines
4.3 KiB
C
141 lines
4.3 KiB
C
#ifndef _LINUX_MIGRATE_H
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#define _LINUX_MIGRATE_H
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#include <linux/mm.h>
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#include <linux/mempolicy.h>
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#include <linux/migrate_mode.h>
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#include <linux/hugetlb.h>
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typedef struct page *new_page_t(struct page *page, unsigned long private,
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int **reason);
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typedef void free_page_t(struct page *page, unsigned long private);
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/*
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* Return values from addresss_space_operations.migratepage():
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* - negative errno on page migration failure;
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* - zero on page migration success;
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*/
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#define MIGRATEPAGE_SUCCESS 0
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enum migrate_reason {
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MR_COMPACTION,
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MR_MEMORY_FAILURE,
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MR_MEMORY_HOTPLUG,
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MR_SYSCALL, /* also applies to cpusets */
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MR_MEMPOLICY_MBIND,
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MR_NUMA_MISPLACED,
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MR_CMA,
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MR_TYPES
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};
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/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
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extern char *migrate_reason_names[MR_TYPES];
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static inline struct page *new_page_nodemask(struct page *page,
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int preferred_nid, nodemask_t *nodemask)
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{
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gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL;
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if (PageHuge(page))
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return alloc_huge_page_nodemask(page_hstate(compound_head(page)),
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preferred_nid, nodemask);
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if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE))
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gfp_mask |= __GFP_HIGHMEM;
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return __alloc_pages_nodemask(gfp_mask, 0, preferred_nid, nodemask);
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}
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#ifdef CONFIG_MIGRATION
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extern void putback_movable_pages(struct list_head *l);
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extern int migrate_page(struct address_space *mapping,
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struct page *newpage, struct page *page,
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enum migrate_mode mode);
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extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
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unsigned long private, enum migrate_mode mode, int reason);
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extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
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extern void putback_movable_page(struct page *page);
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extern int migrate_prep(void);
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extern int migrate_prep_local(void);
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extern void migrate_page_copy(struct page *newpage, struct page *page);
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extern int migrate_huge_page_move_mapping(struct address_space *mapping,
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struct page *newpage, struct page *page);
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extern int migrate_page_move_mapping(struct address_space *mapping,
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struct page *newpage, struct page *page,
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struct buffer_head *head, enum migrate_mode mode,
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int extra_count);
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#else
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static inline void putback_movable_pages(struct list_head *l) {}
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static inline int migrate_pages(struct list_head *l, new_page_t new,
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free_page_t free, unsigned long private, enum migrate_mode mode,
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int reason)
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{ return -ENOSYS; }
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static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
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{ return -EBUSY; }
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static inline int migrate_prep(void) { return -ENOSYS; }
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static inline int migrate_prep_local(void) { return -ENOSYS; }
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static inline void migrate_page_copy(struct page *newpage,
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struct page *page) {}
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static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
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struct page *newpage, struct page *page)
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{
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return -ENOSYS;
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}
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#endif /* CONFIG_MIGRATION */
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#ifdef CONFIG_COMPACTION
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extern int PageMovable(struct page *page);
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extern void __SetPageMovable(struct page *page, struct address_space *mapping);
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extern void __ClearPageMovable(struct page *page);
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#else
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static inline int PageMovable(struct page *page) { return 0; };
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static inline void __SetPageMovable(struct page *page,
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struct address_space *mapping)
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{
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}
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static inline void __ClearPageMovable(struct page *page)
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{
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}
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#endif
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#ifdef CONFIG_NUMA_BALANCING
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extern bool pmd_trans_migrating(pmd_t pmd);
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extern int migrate_misplaced_page(struct page *page,
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struct vm_area_struct *vma, int node);
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#else
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static inline bool pmd_trans_migrating(pmd_t pmd)
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{
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return false;
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}
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static inline int migrate_misplaced_page(struct page *page,
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struct vm_area_struct *vma, int node)
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{
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return -EAGAIN; /* can't migrate now */
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}
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#endif /* CONFIG_NUMA_BALANCING */
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#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
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extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
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struct vm_area_struct *vma,
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pmd_t *pmd, pmd_t entry,
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unsigned long address,
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struct page *page, int node);
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#else
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static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
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struct vm_area_struct *vma,
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pmd_t *pmd, pmd_t entry,
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unsigned long address,
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struct page *page, int node)
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{
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return -EAGAIN;
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}
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#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
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#endif /* _LINUX_MIGRATE_H */
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