18468d93e5
Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be used within a guest, thus imposing performance penalties associated with the reduced number of transparent huge pages that could be used by the guest workload. This patch introduces a common interface to help a balloon driver on making its page set movable to compaction, and thus allowing the system to better leverage the compation efforts on memory defragmentation. [akpm@linux-foundation.org: use PAGE_FLAGS_CHECK_AT_PREP, s/__balloon_page_flags/page_flags_cleared/, small cleanups] [rientjes@google.com: allow balloon compaction for any system with memory compaction enabled, which is the defconfig] Signed-off-by: Rafael Aquini <aquini@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
85 lines
2.9 KiB
C
85 lines
2.9 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 *, unsigned long private, int **);
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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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#ifdef CONFIG_MIGRATION
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extern void putback_lru_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 x,
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unsigned long private, bool offlining,
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enum migrate_mode mode);
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extern int migrate_huge_page(struct page *, new_page_t x,
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unsigned long private, bool offlining,
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enum migrate_mode mode);
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extern int fail_migrate_page(struct address_space *,
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struct page *, struct 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 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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#else
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static inline void putback_lru_pages(struct list_head *l) {}
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static inline int migrate_pages(struct list_head *l, new_page_t x,
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unsigned long private, bool offlining,
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enum migrate_mode mode) { return -ENOSYS; }
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static inline int migrate_huge_page(struct page *page, new_page_t x,
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unsigned long private, bool offlining,
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enum migrate_mode mode) { 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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#define fail_migrate_page NULL
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#endif /* CONFIG_MIGRATION */
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#endif /* _LINUX_MIGRATE_H */
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