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mm: migrate: Introduce migrate_misplaced_page()

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Note: This was originally based on Peter's patch "mm/migrate: Introduce
	migrate_misplaced_page()" but borrows extremely heavily from Andrea's
	"autonuma: memory follows CPU algorithm and task/mm_autonuma stats
	collection". The end result is barely recognisable so signed-offs
	had to be dropped. If original authors are ok with it, I'll
	re-add the signed-off-bys.

Add migrate_misplaced_page() which deals with migrating pages from
faults.

Based-on-work-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Based-on-work-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Based-on-work-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
This commit is contained in:
Peter Zijlstra 2012-10-25 14:16:34 +02:00 committed by Mel Gorman
parent 771fb4d806
commit 7039e1dbec
2 changed files with 117 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
include/linux/migrate.h
View file

@ -13,6 +13,7 @@ enum migrate_reason {
MR_MEMORY_HOTPLUG,
MR_SYSCALL, /* also applies to cpusets */
MR_MEMPOLICY_MBIND,
MR_NUMA_MISPLACED,
MR_CMA
};
@ -73,4 +74,14 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
#define fail_migrate_page NULL
#endif /* CONFIG_MIGRATION */
#ifdef CONFIG_NUMA_BALANCING
extern int migrate_misplaced_page(struct page *page, int node);
#else
static inline int migrate_misplaced_page(struct page *page, int node)
{
return -EAGAIN; /* can't migrate now */
}
#endif /* CONFIG_NUMA_BALANCING */
#endif /* _LINUX_MIGRATE_H */

108
mm/migrate.c
View file

@ -282,7 +282,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page,
struct buffer_head *head, enum migrate_mode mode)
{
int expected_count;
int expected_count = 0;
void **pslot;
if (!mapping) {
@ -1415,4 +1415,108 @@ int migrate_vmas(struct mm_struct *mm, const nodemask_t *to,
}
return err;
}
#endif
#ifdef CONFIG_NUMA_BALANCING
/*
* Returns true if this is a safe migration target node for misplaced NUMA
* pages. Currently it only checks the watermarks which crude
*/
static bool migrate_balanced_pgdat(struct pglist_data *pgdat,
int nr_migrate_pages)
{
int z;
for (z = pgdat->nr_zones - 1; z >= 0; z--) {
struct zone *zone = pgdat->node_zones + z;
if (!populated_zone(zone))
continue;
if (zone->all_unreclaimable)
continue;
/* Avoid waking kswapd by allocating pages_to_migrate pages. */
if (!zone_watermark_ok(zone, 0,
high_wmark_pages(zone) +
nr_migrate_pages,
0, 0))
continue;
return true;
}
return false;
}
static struct page *alloc_misplaced_dst_page(struct page *page,
unsigned long data,
int **result)
{
int nid = (int) data;
struct page *newpage;
newpage = alloc_pages_exact_node(nid,
(GFP_HIGHUSER_MOVABLE | GFP_THISNODE |
__GFP_NOMEMALLOC | __GFP_NORETRY |
__GFP_NOWARN) &
~GFP_IOFS, 0);
return newpage;
}
/*
* Attempt to migrate a misplaced page to the specified destination
* node. Caller is expected to have an elevated reference count on
* the page that will be dropped by this function before returning.
*/
int migrate_misplaced_page(struct page *page, int node)
{
int isolated = 0;
LIST_HEAD(migratepages);
/*
* Don't migrate pages that are mapped in multiple processes.
* TODO: Handle false sharing detection instead of this hammer
*/
if (page_mapcount(page) != 1) {
put_page(page);
goto out;
}
/* Avoid migrating to a node that is nearly full */
if (migrate_balanced_pgdat(NODE_DATA(node), 1)) {
int page_lru;
if (isolate_lru_page(page)) {
put_page(page);
goto out;
}
isolated = 1;
/*
* Page is isolated which takes a reference count so now the
* callers reference can be safely dropped without the page
* disappearing underneath us during migration
*/
put_page(page);
page_lru = page_is_file_cache(page);
inc_zone_page_state(page, NR_ISOLATED_ANON + page_lru);
list_add(&page->lru, &migratepages);
}
if (isolated) {
int nr_remaining;
nr_remaining = migrate_pages(&migratepages,
alloc_misplaced_dst_page,
node, false, MIGRATE_ASYNC,
MR_NUMA_MISPLACED);
if (nr_remaining) {
putback_lru_pages(&migratepages);
isolated = 0;
}
}
BUG_ON(!list_empty(&migratepages));
out:
return isolated;
}
#endif /* CONFIG_NUMA_BALANCING */
#endif /* CONFIG_NUMA */