From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 16/24] mm, page_alloc: Move __GFP_HARDWALL modifications out of the fastpath
Date: Tue, 12 Apr 2016 11:12:17 +0100 [thread overview]
Message-ID: <1460455945-29644-17-git-send-email-mgorman@techsingularity.net> (raw)
In-Reply-To: <1460455945-29644-1-git-send-email-mgorman@techsingularity.net>
__GFP_HARDWALL only has meaning in the context of cpusets but the fast path
always applies the flag on the first attempt. Move the manipulations into
the cpuset paths where they will be masked by a static branch in the common
case.
With the other micro-optimisations in this series combined, the impact on
a page allocator microbenchmark is
4.6.0-rc2 4.6.0-rc2
decstat-v1r20 micro-v1r20
Min alloc-odr0-1 381.00 ( 0.00%) 377.00 ( 1.05%)
Min alloc-odr0-2 275.00 ( 0.00%) 273.00 ( 0.73%)
Min alloc-odr0-4 229.00 ( 0.00%) 226.00 ( 1.31%)
Min alloc-odr0-8 199.00 ( 0.00%) 196.00 ( 1.51%)
Min alloc-odr0-16 186.00 ( 0.00%) 183.00 ( 1.61%)
Min alloc-odr0-32 179.00 ( 0.00%) 175.00 ( 2.23%)
Min alloc-odr0-64 174.00 ( 0.00%) 172.00 ( 1.15%)
Min alloc-odr0-128 172.00 ( 0.00%) 170.00 ( 1.16%)
Min alloc-odr0-256 181.00 ( 0.00%) 183.00 ( -1.10%)
Min alloc-odr0-512 193.00 ( 0.00%) 191.00 ( 1.04%)
Min alloc-odr0-1024 201.00 ( 0.00%) 199.00 ( 1.00%)
Min alloc-odr0-2048 206.00 ( 0.00%) 204.00 ( 0.97%)
Min alloc-odr0-4096 212.00 ( 0.00%) 210.00 ( 0.94%)
Min alloc-odr0-8192 215.00 ( 0.00%) 213.00 ( 0.93%)
Min alloc-odr0-16384 216.00 ( 0.00%) 214.00 ( 0.93%)
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
mm/page_alloc.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 73dc0413e997..219e0d05ed88 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3353,7 +3353,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
struct page *page;
unsigned int cpuset_mems_cookie;
unsigned int alloc_flags = ALLOC_WMARK_LOW|ALLOC_FAIR;
- gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
+ gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
struct alloc_context ac = {
.high_zoneidx = gfp_zone(gfp_mask),
.zonelist = zonelist,
@@ -3362,6 +3362,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
};
if (cpusets_enabled()) {
+ alloc_mask |= __GFP_HARDWALL;
alloc_flags |= ALLOC_CPUSET;
if (!ac.nodemask)
ac.nodemask = &cpuset_current_mems_allowed;
@@ -3391,7 +3392,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
ac.classzone_idx = zonelist_zone_idx(preferred_zoneref);
/* First allocation attempt */
- alloc_mask = gfp_mask|__GFP_HARDWALL;
page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
if (unlikely(!page)) {
/*
@@ -3417,8 +3417,10 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
* the mask is being updated. If a page allocation is about to fail,
* check if the cpuset changed during allocation and if so, retry.
*/
- if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) {
+ alloc_mask = gfp_mask;
goto retry_cpuset;
+ }
return page;
}
--
2.6.4
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next prev parent reply other threads:[~2016-04-12 10:13 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-12 10:12 [PATCH 00/24] Optimise page alloc/free fast paths v2 Mel Gorman
2016-04-12 10:12 ` [PATCH 01/24] mm, page_alloc: Only check PageCompound for high-order pages Mel Gorman
2016-04-12 10:12 ` [PATCH 02/24] mm, page_alloc: Use new PageAnonHead helper in the free page fast path Mel Gorman
2016-04-12 10:12 ` [PATCH 03/24] mm, page_alloc: Reduce branches in zone_statistics Mel Gorman
2016-04-12 10:12 ` [PATCH 04/24] mm, page_alloc: Inline zone_statistics Mel Gorman
2016-04-12 10:12 ` [PATCH 05/24] mm, page_alloc: Inline the fast path of the zonelist iterator Mel Gorman
2016-04-12 10:12 ` [PATCH 06/24] mm, page_alloc: Use __dec_zone_state for order-0 page allocation Mel Gorman
2016-04-12 10:12 ` [PATCH 07/24] mm, page_alloc: Avoid unnecessary zone lookups during pageblock operations Mel Gorman
2016-04-12 10:12 ` [PATCH 08/24] mm, page_alloc: Convert alloc_flags to unsigned Mel Gorman
2016-04-12 10:12 ` [PATCH 09/24] mm, page_alloc: Convert nr_fair_skipped to bool Mel Gorman
2016-04-12 10:12 ` [PATCH 10/24] mm, page_alloc: Remove unnecessary local variable in get_page_from_freelist Mel Gorman
2016-04-12 10:12 ` [PATCH 11/24] mm, page_alloc: Remove unnecessary initialisation " Mel Gorman
2016-04-12 10:12 ` [PATCH 12/24] mm, page_alloc: Remove unnecessary initialisation from __alloc_pages_nodemask() Mel Gorman
2016-04-12 10:12 ` [PATCH 13/24] mm, page_alloc: Remove redundant check for empty zonelist Mel Gorman
2016-04-12 10:12 ` [PATCH 14/24] mm, page_alloc: Simplify last cpupid reset Mel Gorman
2016-04-12 10:12 ` [PATCH 15/24] mm, page_alloc: Move might_sleep_if check to the allocator slowpath Mel Gorman
2016-04-12 10:12 ` Mel Gorman [this message]
2016-04-12 10:12 ` [PATCH 17/24] mm, page_alloc: Reduce cost of fair zone allocation policy retry Mel Gorman
2016-04-12 10:12 ` [PATCH 18/24] mm, page_alloc: Shortcut watermark checks for order-0 pages Mel Gorman
2016-04-12 10:12 ` [PATCH 19/24] mm, page_alloc: Avoid looking up the first zone in a zonelist twice Mel Gorman
2016-04-12 10:12 ` [PATCH 20/24] mm, page_alloc: Check multiple page fields with a single branch Mel Gorman
2016-04-12 10:12 ` [PATCH 21/24] cpuset: use static key better and convert to new API Mel Gorman
2016-04-12 10:12 ` [PATCH 22/24] mm, page_alloc: Check once if a zone has isolated pageblocks Mel Gorman
2016-04-12 10:12 ` [PATCH 23/24] mm, page_alloc: Remove unnecessary variable from free_pcppages_bulk Mel Gorman
2016-04-12 10:12 ` [PATCH 24/24] mm, page_alloc: Do not lookup pcp migratetype during bulk free Mel Gorman
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