From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 28/28] mm, page_alloc: Defer debugging checks of pages allocated from the PCP
Date: Wed, 27 Apr 2016 16:06:11 +0200 [thread overview]
Message-ID: <5720C753.2000804@suse.cz> (raw)
In-Reply-To: <1460711275-1130-16-git-send-email-mgorman@techsingularity.net>
On 04/15/2016 11:07 AM, Mel Gorman wrote:
> Every page allocated checks a number of page fields for validity. This
> catches corruption bugs of pages that are already freed but it is expensive.
> This patch weakens the debugging check by checking PCP pages only when
> the PCP lists are being refilled. All compound pages are checked. This
> potentially avoids debugging checks entirely if the PCP lists are never
> emptied and refilled so some corruption issues may be missed. Full checking
> requires DEBUG_VM.
>
> With the two deferred debugging patches applied, the impact to a page
> allocator microbenchmark is
>
> 4.6.0-rc3 4.6.0-rc3
> inline-v3r6 deferalloc-v3r7
> Min alloc-odr0-1 344.00 ( 0.00%) 317.00 ( 7.85%)
> Min alloc-odr0-2 248.00 ( 0.00%) 231.00 ( 6.85%)
> Min alloc-odr0-4 209.00 ( 0.00%) 192.00 ( 8.13%)
> Min alloc-odr0-8 181.00 ( 0.00%) 166.00 ( 8.29%)
> Min alloc-odr0-16 168.00 ( 0.00%) 154.00 ( 8.33%)
> Min alloc-odr0-32 161.00 ( 0.00%) 148.00 ( 8.07%)
> Min alloc-odr0-64 158.00 ( 0.00%) 145.00 ( 8.23%)
> Min alloc-odr0-128 156.00 ( 0.00%) 143.00 ( 8.33%)
> Min alloc-odr0-256 168.00 ( 0.00%) 154.00 ( 8.33%)
> Min alloc-odr0-512 178.00 ( 0.00%) 167.00 ( 6.18%)
> Min alloc-odr0-1024 186.00 ( 0.00%) 174.00 ( 6.45%)
> Min alloc-odr0-2048 192.00 ( 0.00%) 180.00 ( 6.25%)
> Min alloc-odr0-4096 198.00 ( 0.00%) 184.00 ( 7.07%)
> Min alloc-odr0-8192 200.00 ( 0.00%) 188.00 ( 6.00%)
> Min alloc-odr0-16384 201.00 ( 0.00%) 188.00 ( 6.47%)
> Min free-odr0-1 189.00 ( 0.00%) 180.00 ( 4.76%)
> Min free-odr0-2 132.00 ( 0.00%) 126.00 ( 4.55%)
> Min free-odr0-4 104.00 ( 0.00%) 99.00 ( 4.81%)
> Min free-odr0-8 90.00 ( 0.00%) 85.00 ( 5.56%)
> Min free-odr0-16 84.00 ( 0.00%) 80.00 ( 4.76%)
> Min free-odr0-32 80.00 ( 0.00%) 76.00 ( 5.00%)
> Min free-odr0-64 78.00 ( 0.00%) 74.00 ( 5.13%)
> Min free-odr0-128 77.00 ( 0.00%) 73.00 ( 5.19%)
> Min free-odr0-256 94.00 ( 0.00%) 91.00 ( 3.19%)
> Min free-odr0-512 108.00 ( 0.00%) 112.00 ( -3.70%)
> Min free-odr0-1024 115.00 ( 0.00%) 118.00 ( -2.61%)
> Min free-odr0-2048 120.00 ( 0.00%) 125.00 ( -4.17%)
> Min free-odr0-4096 123.00 ( 0.00%) 129.00 ( -4.88%)
> Min free-odr0-8192 126.00 ( 0.00%) 130.00 ( -3.17%)
> Min free-odr0-16384 126.00 ( 0.00%) 131.00 ( -3.97%)
>
> Note that the free paths for large numbers of pages is impacted as the
> debugging cost gets shifted into that path when the page data is no longer
> necessarily cache-hot.
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Unlike the free path, there are no duplications here, which is nice.
Some un-inlining of bad page check should still work here though imho:
next prev parent reply other threads:[~2016-04-27 14:06 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 ` [PATCH 02/28] mm, page_alloc: Use new PageAnonHead helper in the free page fast path Mel Gorman
2016-04-25 9:56 ` 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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5720C753.2000804@suse.cz \
--to=vbabka@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=brouer@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox