Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1375580
| From | Mel Gorman <mgorman@techsingularity.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 13/22] mm, page_alloc: Remove redundant check for empty zonelist |
| Date | 2016-04-11 10:20 +0200 |
| Message-ID | <rmFeH-2HC-27@gated-at.bofh.it> (permalink) |
| References | <rmFeF-2HC-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
A check is made for an empty zonelist early in the page allocator fast path but it's unnecessary. The check after first_zones_zonelist call should catch that situation. Removing the first check is slower for machines with memoryless nodes but that is a corner case that can live with the overhead. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> --- mm/page_alloc.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index df03ccc7f07c..e50e754ec9eb 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3374,14 +3374,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, if (should_fail_alloc_page(gfp_mask, order)) return NULL; - /* - * Check the zones suitable for the gfp_mask contain at least one - * valid zone. It's possible to have an empty zonelist as a result - * of __GFP_THISNODE and a memoryless node - */ - if (unlikely(!zonelist->_zonerefs->zone)) - return NULL; - if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE) alloc_flags |= ALLOC_CMA; -- 2.6.4
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 00/21] Optimise page alloc/free fast paths Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 08/22] mm, page_alloc: Convert alloc_flags to unsigned Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 04/22] mm, page_alloc: Inline zone_statistics Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 21/22] cpuset: use static key better and convert to new API Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 11/22] mm, page_alloc: Remove unnecessary initialisation in get_page_from_freelist Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 14/22] mm, page_alloc: Simplify last cpupid reset Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 13/22] mm, page_alloc: Remove redundant check for empty zonelist Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 09/22] mm, page_alloc: Convert nr_fair_skipped to bool Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 15/22] mm, page_alloc: Move might_sleep_if check to the allocator slowpath Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 20/22] mm, page_alloc: Check multiple page fields with a single branch Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 12/22] mm, page_alloc: Remove unnecessary initialisation from __alloc_pages_nodemask() Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 19/22] mm, page_alloc: Avoid looking up the first zone in a zonelist twice Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 05/22] mm, page_alloc: Inline the fast path of the zonelist iterator Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 02/22] mm, page_alloc: Use new PageAnonHead helper in the free page fast path Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 16/22] mm, page_alloc: Move __GFP_HARDWALL modifications out of the fastpath Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 17/22] mm, page_alloc: Reduce cost of fair zone allocation policy retry Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:20 +0200 [PATCH 18/22] mm, page_alloc: Shortcut watermark checks for order-0 pages Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:30 +0200 Re: [PATCH 00/21] Optimise page alloc/free fast paths Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:30 +0200 [PATCH 06/22] mm, page_alloc: Use __dec_zone_state for order-0 page allocation Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:30 +0200 [PATCH 10/22] mm, page_alloc: Remove unnecessary local variable in get_page_from_freelist Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:30 +0200 [PATCH 07/22] mm, page_alloc: Avoid unnecessary zone lookups during pageblock operations Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:30 +0200 [PATCH 01/22] mm, page_alloc: Only check PageCompound for high-order pages Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:40 +0200 [PATCH 03/22] mm, page_alloc: Reduce branches in zone_statistics Mel Gorman <mgorman@techsingularity.net> - 2016-04-11 10:40 +0200
csiph-web