Commit 748446bb authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

mm: compaction: memory compaction core 



This patch is the core of a mechanism which compacts memory in a zone by
relocating movable pages towards the end of the zone.

A single compaction run involves a migration scanner and a free scanner.
Both scanners operate on pageblock-sized areas in the zone.  The migration
scanner starts at the bottom of the zone and searches for all movable
pages within each area, isolating them onto a private list called
migratelist.  The free scanner starts at the top of the zone and searches
for suitable areas and consumes the free pages within making them
available for the migration scanner.  The pages isolated for migration are
then migrated to the newly isolated free pages.

[aarcange@redhat.com: Fix unsafe optimisation]
[mel@csn.ul.ie: do not schedule work on other CPUs for compaction]
Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c175a0ce

include/linux/compaction.h

0 → 100644
+9 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_COMPACTION_H

#define _LINUX_COMPACTION_H



/* Return values for compact_zone() */

#define COMPACT_CONTINUE	0

#define COMPACT_PARTIAL		1

#define COMPACT_COMPLETE	2



#endif /* _LINUX_COMPACTION_H */

include/linux/migrate.h

+2 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ extern int fail_migrate_page(struct address_space *, 
			struct page *, struct page *);



extern int migrate_prep(void);

extern int migrate_prep_local(void);

extern int migrate_vmas(struct mm_struct *mm,

		const nodemask_t *from, const nodemask_t *to,

		unsigned long flags);
@@ -30,6 +31,7 @@ static inline int migrate_pages(struct list_head *l, new_page_t x, 
		unsigned long private, int offlining) { return -ENOSYS; }



static inline int migrate_prep(void) { return -ENOSYS; }

static inline int migrate_prep_local(void) { return -ENOSYS; }



static inline int migrate_vmas(struct mm_struct *mm,

		const nodemask_t *from, const nodemask_t *to,

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -337,6 +337,7 @@ void put_page(struct page *page); 
void put_pages_list(struct list_head *pages);



void split_page(struct page *page, unsigned int order);

int split_free_page(struct page *page);



/*

 * Compound pages have a destructor function.  Provide a

include/linux/swap.h

+1 −0
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ enum { 
};



#define SWAP_CLUSTER_MAX 32

#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX



#define SWAP_MAP_MAX	0x3e	/* Max duplication count, in first swap_map */

#define SWAP_MAP_BAD	0x3f	/* Note pageblock is bad, in first swap_map */

include/linux/vmstat.h

+3 −0
Original line number Diff line number Diff line
@@ -43,6 +43,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 
		KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,

		KSWAPD_SKIP_CONGESTION_WAIT,

		PAGEOUTRUN, ALLOCSTALL, PGROTATED,

#ifdef CONFIG_COMPACTION

		COMPACTBLOCKS, COMPACTPAGES, COMPACTPAGEFAILED,

#endif

#ifdef CONFIG_HUGETLB_PAGE

		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,

#endif

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