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authorMel Gorman <mgorman@suse.de>2012-01-10 15:07:14 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-01 12:26:55 -0700
commit71a07f4cf29615d30369760c022972d4875758b3 (patch)
tree83ee43c8c7a6a6773b816316fd0e9e1b97d70eba /mm
parent1126e70953638f9516b6a0b96385799c708815e4 (diff)
mm: reduce the amount of work done when updating min_free_kbytes
commit 938929f14cb595f43cd1a4e63e22d36cab1e4a1f upstream. Stable note: Fixes https://bugzilla.novell.com/show_bug.cgi?id=726210 . Large machines with 1TB or more of RAM take a long time to boot without this patch and may spew out soft lockup warnings. When min_free_kbytes is updated, some pageblocks are marked MIGRATE_RESERVE. Ordinarily, this work is unnoticable as it happens early in boot but on large machines with 1TB of memory, this has been reported to delay boot times, probably due to the NUMA distances involved. The bulk of the work is due to calling calling pageblock_is_reserved() an unnecessary amount of times and accessing far more struct page metadata than is necessary. This patch significantly reduces the amount of work done by setup_zone_migrate_reserve() improving boot times on 1TB machines. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c40
1 files changed, 24 insertions, 16 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 947a7e96f91d..70c049dc4ee1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3418,25 +3418,33 @@ static void setup_zone_migrate_reserve(struct zone *zone)
if (page_to_nid(page) != zone_to_nid(zone))
continue;
- /* Blocks with reserved pages will never free, skip them. */
- block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
- if (pageblock_is_reserved(pfn, block_end_pfn))
- continue;
-
block_migratetype = get_pageblock_migratetype(page);
- /* If this block is reserved, account for it */
- if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
- reserve--;
- continue;
- }
+ /* Only test what is necessary when the reserves are not met */
+ if (reserve > 0) {
+ /*
+ * Blocks with reserved pages will never free, skip
+ * them.
+ */
+ block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
+ if (pageblock_is_reserved(pfn, block_end_pfn))
+ continue;
- /* Suitable for reserving if this block is movable */
- if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
- set_pageblock_migratetype(page, MIGRATE_RESERVE);
- move_freepages_block(zone, page, MIGRATE_RESERVE);
- reserve--;
- continue;
+ /* If this block is reserved, account for it */
+ if (block_migratetype == MIGRATE_RESERVE) {
+ reserve--;
+ continue;
+ }
+
+ /* Suitable for reserving if this block is movable */
+ if (block_migratetype == MIGRATE_MOVABLE) {
+ set_pageblock_migratetype(page,
+ MIGRATE_RESERVE);
+ move_freepages_block(zone, page,
+ MIGRATE_RESERVE);
+ reserve--;
+ continue;
+ }
}
/*