[PATCH] mm,compaction: Do not schedule work on other CPUs for compaction
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From: Mel Gorman on 6 May 2010 11:10 Migration normally requires a call to migrate_prep() as a preparation step. This schedules work on all CPUs for pagevecs to be drained. This makes sense for move_pages and memory hot-remove but is unnecessary for memory compaction. To avoid queueing work on multiple CPUs, this patch introduces migrate_prep_local() which drains just local pagevecs. This patch can be either merged with mmcompaction-memory-compaction-core.patch or placed immediately after it to clarify why migrate_prep_local() was introduced. Signed-off-by: Mel Gorman <mel(a)csn.ul.ie> --- include/linux/migrate.h | 2 ++ mm/compaction.c | 2 +- mm/migrate.c | 11 ++++++++++- 3 files changed, 13 insertions(+), 2 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 05d2292..6dec3ef 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -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); @@ -32,6 +33,7 @@ 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, diff --git a/mm/compaction.c b/mm/compaction.c index bd13560..94cce51 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -383,7 +383,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) cc->free_pfn = cc->migrate_pfn + zone->spanned_pages; cc->free_pfn &= ~(pageblock_nr_pages-1); - migrate_prep(); + migrate_prep_local(); while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) { unsigned long nr_migrate, nr_remaining; diff --git a/mm/migrate.c b/mm/migrate.c index 053fd39..d99ec15 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -40,7 +40,8 @@ /* * migrate_prep() needs to be called before we start compiling a list of pages - * to be migrated using isolate_lru_page(). + * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is + * undesirable, use migrate_prep_local() */ int migrate_prep(void) { @@ -55,6 +56,14 @@ int migrate_prep(void) return 0; } +/* Do the necessary work of migrate_prep but not if it involves other CPUs */ +int migrate_prep_local(void) +{ + lru_add_drain(); + + return 0; +} + /* * Add isolated pages on the list back to the LRU under page lock * to avoid leaking evictable pages back onto unevictable list. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |