Commit 68711a74 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, migration: add destination page freeing callback 



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: default avatarDavid Rientjes <rientjes@google.com>
Reviewed-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 93f39eea

include/linux/migrate.h

+7 −4
Original line number Diff line number Diff line
@@ -5,7 +5,9 @@ 
#include <linux/mempolicy.h>

#include <linux/migrate_mode.h>



typedef struct page *new_page_t(struct page *, unsigned long private, int **);

typedef struct page *new_page_t(struct page *page, unsigned long private,

				int **reason);

typedef void free_page_t(struct page *page, unsigned long private);



/*

 * Return values from addresss_space_operations.migratepage():
@@ -38,7 +40,7 @@ enum migrate_reason { 
extern void putback_movable_pages(struct list_head *l);

extern int migrate_page(struct address_space *,

			struct page *, struct page *, enum migrate_mode);

extern int migrate_pages(struct list_head *l, new_page_t x,

extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,

		unsigned long private, enum migrate_mode mode, int reason);



extern int migrate_prep(void);
@@ -56,8 +58,9 @@ extern int migrate_page_move_mapping(struct address_space *mapping, 
#else



static inline void putback_movable_pages(struct list_head *l) {}

static inline int migrate_pages(struct list_head *l, new_page_t x,

		unsigned long private, enum migrate_mode mode, int reason)

static inline int migrate_pages(struct list_head *l, new_page_t new,

		free_page_t free, unsigned long private, enum migrate_mode mode,

		int reason)

	{ return -ENOSYS; }



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

mm/compaction.c

+1 −1
Original line number Diff line number Diff line
@@ -1016,7 +1016,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) 
		}



		nr_migrate = cc->nr_migratepages;

		err = migrate_pages(&cc->migratepages, compaction_alloc,

		err = migrate_pages(&cc->migratepages, compaction_alloc, NULL,

				(unsigned long)cc,

				cc->sync ? MIGRATE_SYNC_LIGHT : MIGRATE_ASYNC,

				MR_COMPACTION);

mm/memory-failure.c

+2 −2
Original line number Diff line number Diff line
@@ -1503,7 +1503,7 @@ static int soft_offline_huge_page(struct page *page, int flags) 


	/* Keep page count to indicate a given hugepage is isolated. */

	list_move(&hpage->lru, &pagelist);

	ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,

	ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,

				MIGRATE_SYNC, MR_MEMORY_FAILURE);

	if (ret) {

		pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
@@ -1584,7 +1584,7 @@ static int __soft_offline_page(struct page *page, int flags) 
		inc_zone_page_state(page, NR_ISOLATED_ANON +

					page_is_file_cache(page));

		list_add(&page->lru, &pagelist);

		ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,

		ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,

					MIGRATE_SYNC, MR_MEMORY_FAILURE);

		if (ret) {

			if (!list_empty(&pagelist)) {

mm/memory_hotplug.c

+1 −1
Original line number Diff line number Diff line
@@ -1394,7 +1394,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 
		 * alloc_migrate_target should be improooooved!!

		 * migrate_pages returns # of failed pages.

		 */

		ret = migrate_pages(&source, alloc_migrate_target, 0,

		ret = migrate_pages(&source, alloc_migrate_target, NULL, 0,

					MIGRATE_SYNC, MR_MEMORY_HOTPLUG);

		if (ret)

			putback_movable_pages(&source);

mm/mempolicy.c

+2 −2
Original line number Diff line number Diff line
@@ -1028,7 +1028,7 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest, 
			flags | MPOL_MF_DISCONTIG_OK, &pagelist);



	if (!list_empty(&pagelist)) {

		err = migrate_pages(&pagelist, new_node_page, dest,

		err = migrate_pages(&pagelist, new_node_page, NULL, dest,

					MIGRATE_SYNC, MR_SYSCALL);

		if (err)

			putback_movable_pages(&pagelist);
@@ -1277,7 +1277,7 @@ static long do_mbind(unsigned long start, unsigned long len, 
		if (!list_empty(&pagelist)) {

			WARN_ON_ONCE(flags & MPOL_MF_LAZY);

			nr_failed = migrate_pages(&pagelist, new_vma_page,

					(unsigned long)vma,

					NULL, (unsigned long)vma,

					MIGRATE_SYNC, MR_MEMPOLICY_MBIND);

			if (nr_failed)

				putback_movable_pages(&pagelist);

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