diff options
| -rw-r--r-- | mm/compaction.c | 54 |
1 files changed, 28 insertions, 26 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index b6984e234fdf..bcce7897e17a 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -384,6 +384,20 @@ static bool suitable_migration_target(struct page *page) } /* + * Returns the start pfn of the last page block in a zone. This is the starting + * point for full compaction of a zone. Compaction searches for free pages from + * the end of each zone, while isolate_freepages_block scans forward inside each + * page block. + */ +static unsigned long start_free_pfn(struct zone *zone) +{ + unsigned long free_pfn; + free_pfn = zone->zone_start_pfn + zone->spanned_pages; + free_pfn &= ~(pageblock_nr_pages-1); + return free_pfn; +} + +/* * Based on information in the current compact_control, find blocks * suitable for isolating free pages from and then isolate them. */ @@ -422,17 +436,6 @@ static void isolate_freepages(struct zone *zone, pfn -= pageblock_nr_pages) { unsigned long isolated; - /* - * Skip ahead if another thread is compacting in the area - * simultaneously. If we wrapped around, we can only skip - * ahead if zone->compact_cached_free_pfn also wrapped to - * above our starting point. - */ - if (cc->order > 0 && (!cc->wrapped || - zone->compact_cached_free_pfn > - cc->start_free_pfn)) - pfn = min(pfn, zone->compact_cached_free_pfn); - if (!pfn_valid(pfn)) continue; @@ -474,7 +477,15 @@ static void isolate_freepages(struct zone *zone, */ if (isolated) { high_pfn = max(high_pfn, pfn); - if (cc->order > 0) + + /* + * If the free scanner has wrapped, update + * compact_cached_free_pfn to point to the highest + * pageblock with free pages. This reduces excessive + * scanning of full pageblocks near the end of the + * zone + */ + if (cc->order > 0 && cc->wrapped) zone->compact_cached_free_pfn = high_pfn; } } @@ -484,6 +495,11 @@ static void isolate_freepages(struct zone *zone, cc->free_pfn = high_pfn; cc->nr_freepages = nr_freepages; + + /* If compact_cached_free_pfn is reset then set it now */ + if (cc->order > 0 && !cc->wrapped && + zone->compact_cached_free_pfn == start_free_pfn(zone)) + zone->compact_cached_free_pfn = high_pfn; } /* @@ -570,20 +586,6 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, return ISOLATE_SUCCESS; } -/* - * Returns the start pfn of the last page block in a zone. This is the starting - * point for full compaction of a zone. Compaction searches for free pages from - * the end of each zone, while isolate_freepages_block scans forward inside each - * page block. - */ -static unsigned long start_free_pfn(struct zone *zone) -{ - unsigned long free_pfn; - free_pfn = zone->zone_start_pfn + zone->spanned_pages; - free_pfn &= ~(pageblock_nr_pages-1); - return free_pfn; -} - static int compact_finished(struct zone *zone, struct compact_control *cc) { |