From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Jesper Dangaard Brouer <brouer@redhat.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 02/28] mm, page_alloc: Use new PageAnonHead helper in the free page fast path
Date: Fri, 15 Apr 2016 09:58:54 +0100 [thread overview]
Message-ID: <1460710760-32601-3-git-send-email-mgorman@techsingularity.net> (raw)
In-Reply-To: <1460710760-32601-1-git-send-email-mgorman@techsingularity.net>
The PageAnon check always checks for compound_head but this is a relatively
expensive check if the caller already knows the page is a head page. This
patch creates a helper and uses it in the page free path which only operates
on head pages.
With this patch and "Only check PageCompound for high-order pages", the
performance difference on a page allocator microbenchmark is;
4.6.0-rc2 4.6.0-rc2
vanilla nocompound-v1r20
Min alloc-odr0-1 425.00 ( 0.00%) 417.00 ( 1.88%)
Min alloc-odr0-2 313.00 ( 0.00%) 308.00 ( 1.60%)
Min alloc-odr0-4 257.00 ( 0.00%) 253.00 ( 1.56%)
Min alloc-odr0-8 224.00 ( 0.00%) 221.00 ( 1.34%)
Min alloc-odr0-16 208.00 ( 0.00%) 205.00 ( 1.44%)
Min alloc-odr0-32 199.00 ( 0.00%) 199.00 ( 0.00%)
Min alloc-odr0-64 195.00 ( 0.00%) 193.00 ( 1.03%)
Min alloc-odr0-128 192.00 ( 0.00%) 191.00 ( 0.52%)
Min alloc-odr0-256 204.00 ( 0.00%) 200.00 ( 1.96%)
Min alloc-odr0-512 213.00 ( 0.00%) 212.00 ( 0.47%)
Min alloc-odr0-1024 219.00 ( 0.00%) 219.00 ( 0.00%)
Min alloc-odr0-2048 225.00 ( 0.00%) 225.00 ( 0.00%)
Min alloc-odr0-4096 230.00 ( 0.00%) 231.00 ( -0.43%)
Min alloc-odr0-8192 235.00 ( 0.00%) 234.00 ( 0.43%)
Min alloc-odr0-16384 235.00 ( 0.00%) 234.00 ( 0.43%)
Min free-odr0-1 215.00 ( 0.00%) 191.00 ( 11.16%)
Min free-odr0-2 152.00 ( 0.00%) 136.00 ( 10.53%)
Min free-odr0-4 119.00 ( 0.00%) 107.00 ( 10.08%)
Min free-odr0-8 106.00 ( 0.00%) 96.00 ( 9.43%)
Min free-odr0-16 97.00 ( 0.00%) 87.00 ( 10.31%)
Min free-odr0-32 91.00 ( 0.00%) 83.00 ( 8.79%)
Min free-odr0-64 89.00 ( 0.00%) 81.00 ( 8.99%)
Min free-odr0-128 88.00 ( 0.00%) 80.00 ( 9.09%)
Min free-odr0-256 106.00 ( 0.00%) 95.00 ( 10.38%)
Min free-odr0-512 116.00 ( 0.00%) 111.00 ( 4.31%)
Min free-odr0-1024 125.00 ( 0.00%) 118.00 ( 5.60%)
Min free-odr0-2048 133.00 ( 0.00%) 126.00 ( 5.26%)
Min free-odr0-4096 136.00 ( 0.00%) 130.00 ( 4.41%)
Min free-odr0-8192 138.00 ( 0.00%) 130.00 ( 5.80%)
Min free-odr0-16384 137.00 ( 0.00%) 130.00 ( 5.11%)
There is a sizable boost to the free allocator performance. While there
is an apparent boost on the allocation side, it's likely a co-incidence
or due to the patches slightly reducing cache footprint.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
include/linux/page-flags.h | 7 ++++++-
mm/page_alloc.c | 2 +-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index f4ed4f1b0c77..ccd04ee1ba2d 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -371,10 +371,15 @@ PAGEFLAG(Idle, idle, PF_ANY)
#define PAGE_MAPPING_KSM 2
#define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
+static __always_inline int PageAnonHead(struct page *page)
+{
+ return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
+}
+
static __always_inline int PageAnon(struct page *page)
{
page = compound_head(page);
- return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
+ return PageAnonHead(page);
}
#ifdef CONFIG_KSM
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5d205bcfe10d..6812de41f698 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1048,7 +1048,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order)
bad += free_pages_check(page + i);
}
}
- if (PageAnon(page))
+ if (PageAnonHead(page))
page->mapping = NULL;
bad += free_pages_check(page);
if (bad)
--
2.6.4
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next prev parent reply other threads:[~2016-04-15 8:59 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-15 8:58 [PATCH 00/28] Optimise page alloc/free fast paths v3 Mel Gorman
2016-04-15 8:58 ` [PATCH 01/28] mm, page_alloc: Only check PageCompound for high-order pages Mel Gorman
2016-04-25 9:33 ` Vlastimil Babka
2016-04-26 10:33 ` Mel Gorman
2016-04-26 11:20 ` Vlastimil Babka
2016-04-15 8:58 ` Mel Gorman [this message]
2016-04-25 9:56 ` [PATCH 02/28] mm, page_alloc: Use new PageAnonHead helper in the free page fast path Vlastimil Babka
2016-04-15 8:58 ` [PATCH 03/28] mm, page_alloc: Reduce branches in zone_statistics Mel Gorman
2016-04-25 11:15 ` Vlastimil Babka
2016-04-15 8:58 ` [PATCH 04/28] mm, page_alloc: Inline zone_statistics Mel Gorman
2016-04-25 11:17 ` Vlastimil Babka
2016-04-15 8:58 ` [PATCH 05/28] mm, page_alloc: Inline the fast path of the zonelist iterator Mel Gorman
2016-04-25 14:50 ` Vlastimil Babka
2016-04-26 10:30 ` Mel Gorman
2016-04-26 11:05 ` Vlastimil Babka
2016-04-15 8:58 ` [PATCH 06/28] mm, page_alloc: Use __dec_zone_state for order-0 page allocation Mel Gorman
2016-04-26 11:25 ` Vlastimil Babka
2016-04-15 8:58 ` [PATCH 07/28] mm, page_alloc: Avoid unnecessary zone lookups during pageblock operations Mel Gorman
2016-04-26 11:29 ` Vlastimil Babka
2016-04-15 8:59 ` [PATCH 08/28] mm, page_alloc: Convert alloc_flags to unsigned Mel Gorman
2016-04-26 11:31 ` Vlastimil Babka
2016-04-15 8:59 ` [PATCH 09/28] mm, page_alloc: Convert nr_fair_skipped to bool Mel Gorman
2016-04-26 11:37 ` Vlastimil Babka
2016-04-15 8:59 ` [PATCH 10/28] mm, page_alloc: Remove unnecessary local variable in get_page_from_freelist Mel Gorman
2016-04-26 11:38 ` Vlastimil Babka
2016-04-15 8:59 ` [PATCH 11/28] mm, page_alloc: Remove unnecessary initialisation " Mel Gorman
2016-04-26 11:39 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 13/28] mm, page_alloc: Remove redundant check for empty zonelist Mel Gorman
2016-04-15 9:07 ` [PATCH 14/28] mm, page_alloc: Simplify last cpupid reset Mel Gorman
2016-04-26 13:30 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 15/28] mm, page_alloc: Move might_sleep_if check to the allocator slowpath Mel Gorman
2016-04-26 13:41 ` Vlastimil Babka
2016-04-26 14:50 ` Mel Gorman
2016-04-26 15:16 ` Vlastimil Babka
2016-04-26 16:29 ` Mel Gorman
2016-04-15 9:07 ` [PATCH 16/28] mm, page_alloc: Move __GFP_HARDWALL modifications out of the fastpath Mel Gorman
2016-04-26 14:13 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 17/28] mm, page_alloc: Check once if a zone has isolated pageblocks Mel Gorman
2016-04-26 14:27 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 18/28] mm, page_alloc: Shorten the page allocator fast path Mel Gorman
2016-04-26 15:23 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 19/28] mm, page_alloc: Reduce cost of fair zone allocation policy retry Mel Gorman
2016-04-26 17:24 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 20/28] mm, page_alloc: Shortcut watermark checks for order-0 pages Mel Gorman
2016-04-26 17:32 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 21/28] mm, page_alloc: Avoid looking up the first zone in a zonelist twice Mel Gorman
2016-04-26 17:46 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 22/28] mm, page_alloc: Remove field from alloc_context Mel Gorman
2016-04-15 9:07 ` [PATCH 23/28] mm, page_alloc: Check multiple page fields with a single branch Mel Gorman
2016-04-26 18:41 ` Vlastimil Babka
2016-04-27 10:07 ` Mel Gorman
2016-04-15 9:07 ` [PATCH 24/28] mm, page_alloc: Remove unnecessary variable from free_pcppages_bulk Mel Gorman
2016-04-26 18:43 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 25/28] mm, page_alloc: Inline pageblock lookup in page free fast paths Mel Gorman
2016-04-26 19:10 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 26/28] cpuset: use static key better and convert to new API Mel Gorman
2016-04-26 19:49 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 27/28] mm, page_alloc: Defer debugging checks of freed pages until a PCP drain Mel Gorman
2016-04-27 11:59 ` Vlastimil Babka
2016-04-27 12:01 ` [PATCH 1/3] mm, page_alloc: un-inline the bad part of free_pages_check Vlastimil Babka
2016-04-27 12:01 ` [PATCH 2/3] mm, page_alloc: pull out side effects from free_pages_check Vlastimil Babka
2016-04-27 12:41 ` Mel Gorman
2016-04-27 13:00 ` Vlastimil Babka
2016-04-27 12:01 ` [PATCH 3/3] mm, page_alloc: don't duplicate code in free_pcp_prepare Vlastimil Babka
2016-04-27 12:37 ` [PATCH 1/3] mm, page_alloc: un-inline the bad part of free_pages_check Mel Gorman
2016-04-27 12:53 ` Vlastimil Babka
2016-04-15 9:07 ` [PATCH 28/28] mm, page_alloc: Defer debugging checks of pages allocated from the PCP Mel Gorman
2016-04-27 14:06 ` Vlastimil Babka
2016-04-27 15:31 ` Mel Gorman
2016-05-17 6:41 ` Naoya Horiguchi
2016-05-18 7:51 ` Vlastimil Babka
2016-05-18 7:55 ` Vlastimil Babka
2016-05-18 8:49 ` Mel Gorman
2016-04-26 12:04 ` [PATCH 13/28] mm, page_alloc: Remove redundant check for empty zonelist Vlastimil Babka
2016-04-26 13:00 ` Mel Gorman
2016-04-26 19:11 ` Andrew Morton
2016-04-15 12:44 ` [PATCH 00/28] Optimise page alloc/free fast paths v3 Jesper Dangaard Brouer
2016-04-15 13:08 ` Mel Gorman
2016-04-16 7:21 ` [PATCH 12/28] mm, page_alloc: Remove unnecessary initialisation from __alloc_pages_nodemask() Mel Gorman
2016-04-26 11:41 ` Vlastimil Babka
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