a6bc32b899
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT mode that avoids writing back pages to backing storage. Async compaction maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT. For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is used. This avoids sync compaction stalling for an excessive length of time, particularly when copying files to a USB stick where there might be a large number of dirty pages backed by a filesystem that does not support ->writepages. [aarcange@redhat.com: This patch is heavily based on Andrea's work] [akpm@linux-foundation.org: fix fs/nfs/write.c build] [akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
82 lines
2.5 KiB
C
82 lines
2.5 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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typedef struct page *new_page_t(struct page *, unsigned long private, int **);
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/*
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* MIGRATE_ASYNC means never block
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* MIGRATE_SYNC_LIGHT in the current implementation means to allow blocking
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* on most operations but not ->writepage as the potential stall time
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* is too significant
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* MIGRATE_SYNC will block when migrating pages
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*/
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enum migrate_mode {
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MIGRATE_ASYNC,
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MIGRATE_SYNC_LIGHT,
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MIGRATE_SYNC,
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};
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#ifdef CONFIG_MIGRATION
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#define PAGE_MIGRATION 1
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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_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 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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#define PAGE_MIGRATION 0
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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_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_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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