68711a7463
Memory migration uses a callback defined by the caller to determine how to allocate destination pages. When migration fails for a source page, however, it frees the destination page back to the system. This patch adds a memory migration callback defined by the caller to determine how to free destination pages. If a caller, such as memory compaction, builds its own freelist for migration targets, this can reuse already freed memory instead of scanning additional memory. If the caller provides a function to handle freeing of destination pages, it is called when page migration fails. If the caller passes NULL then freeing back to the system will be handled as usual. This patch introduces no functional change. Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
133 lines
4.2 KiB
C
133 lines
4.2 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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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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* The balloon page migration introduces this special case where a 'distinct'
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* return code is used to flag a successful page migration to unmap_and_move().
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* This approach is necessary because page migration can race against balloon
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* deflation procedure, and for such case we could introduce a nasty page leak
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* if a successfully migrated balloon page gets released concurrently with
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* migration's unmap_and_move() wrap-up steps.
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*/
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#define MIGRATEPAGE_SUCCESS 0
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#define MIGRATEPAGE_BALLOON_SUCCESS 1 /* special ret code for balloon page
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* sucessful migration case.
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*/
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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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};
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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 *,
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struct page *, struct page *, enum migrate_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 migrate_prep(void);
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extern int migrate_prep_local(void);
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extern int migrate_vmas(struct mm_struct *mm,
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const nodemask_t *from, const nodemask_t *to,
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unsigned long flags);
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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 migrate_prep(void) { return -ENOSYS; }
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static inline int migrate_prep_local(void) { return -ENOSYS; }
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static inline int migrate_vmas(struct mm_struct *mm,
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const nodemask_t *from, const nodemask_t *to,
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unsigned long flags)
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{
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return -ENOSYS;
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}
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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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/* Possible settings for the migrate_page() method in address_operations */
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#define migrate_page NULL
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#endif /* CONFIG_MIGRATION */
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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 void wait_migrate_huge_page(struct anon_vma *anon_vma, 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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extern bool migrate_ratelimited(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 void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd)
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{
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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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static inline bool migrate_ratelimited(int node)
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{
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return false;
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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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