From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>,
Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 09/22] mm, compaction: Use free lists to quickly locate a migration source
Date: Fri, 8 Feb 2019 18:10:47 +0100 [thread overview]
Message-ID: <7b698aca-bd47-7d5c-a114-145b813b7bdb@suse.cz> (raw)
In-Reply-To: <20190118175136.31341-10-mgorman@techsingularity.net>
On 1/18/19 6:51 PM, Mel Gorman wrote:
> The migration scanner is a linear scan of a zone with a potentiall large
> search space. Furthermore, many pageblocks are unusable such as those
> filled with reserved pages or partially filled with pages that cannot
> migrate. These still get scanned in the common case of allocating a THP
> and the cost accumulates.
>
> The patch uses a partial search of the free lists to locate a migration
> source candidate that is marked as MOVABLE when allocating a THP. It
> prefers picking a block with a larger number of free pages already on
> the basis that there are fewer pages to migrate to free the entire block.
> The lowest PFN found during searches is tracked as the basis of the start
> for the linear search after the first search of the free list fails.
> After the search, the free list is shuffled so that the next search will
> not encounter the same page. If the search fails then the subsequent
> searches will be shorter and the linear scanner is used.
>
> If this search fails, or if the request is for a small or
> unmovable/reclaimable allocation then the linear scanner is still used. It
> is somewhat pointless to use the list search in those cases. Small free
> pages must be used for the search and there is no guarantee that movable
> pages are located within that block that are contiguous.
>
> 5.0.0-rc1 5.0.0-rc1
> noboost-v3r10 findmig-v3r15
> Amean fault-both-3 3771.41 ( 0.00%) 3390.40 ( 10.10%)
> Amean fault-both-5 5409.05 ( 0.00%) 5082.28 ( 6.04%)
> Amean fault-both-7 7040.74 ( 0.00%) 7012.51 ( 0.40%)
> Amean fault-both-12 11887.35 ( 0.00%) 11346.63 ( 4.55%)
> Amean fault-both-18 16718.19 ( 0.00%) 15324.19 ( 8.34%)
> Amean fault-both-24 21157.19 ( 0.00%) 16088.50 * 23.96%*
> Amean fault-both-30 21175.92 ( 0.00%) 18723.42 * 11.58%*
> Amean fault-both-32 21339.03 ( 0.00%) 18612.01 * 12.78%*
>
> 5.0.0-rc1 5.0.0-rc1
> noboost-v3r10 findmig-v3r15
> Percentage huge-3 86.50 ( 0.00%) 89.83 ( 3.85%)
> Percentage huge-5 92.52 ( 0.00%) 91.96 ( -0.61%)
> Percentage huge-7 92.44 ( 0.00%) 92.85 ( 0.44%)
> Percentage huge-12 92.98 ( 0.00%) 92.74 ( -0.25%)
> Percentage huge-18 91.70 ( 0.00%) 91.71 ( 0.02%)
> Percentage huge-24 91.59 ( 0.00%) 92.13 ( 0.60%)
> Percentage huge-30 90.14 ( 0.00%) 93.79 ( 4.04%)
> Percentage huge-32 90.03 ( 0.00%) 91.27 ( 1.37%)
>
> This shows an improvement in allocation latencies with similar allocation
> success rates. While not presented, there was a 31% reduction in migration
> scanning and a 8% reduction on system CPU usage. A 2-socket machine showed
> similar benefits.
>
> [vbabka@suse.cz: Migrate block that was found-fast, some optimisations]
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
With the followup fix,
Acked-by: Vlastimil Babka <Vbabka@suse.cz>
next prev parent reply other threads:[~2019-02-08 17:10 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-18 17:51 [PATCH 00/22] Increase success rates and reduce latency of compaction v3 Mel Gorman
2019-01-18 17:51 ` [PATCH 01/22] mm, compaction: Shrink compact_control Mel Gorman
2019-01-18 17:51 ` [PATCH 02/22] mm, compaction: Rearrange compact_control Mel Gorman
2019-01-18 17:51 ` [PATCH 03/22] mm, compaction: Remove last_migrated_pfn from compact_control Mel Gorman
2019-01-18 17:51 ` [PATCH 04/22] mm, compaction: Remove unnecessary zone parameter in some instances Mel Gorman
2019-01-18 17:51 ` [PATCH 05/22] mm, compaction: Rename map_pages to split_map_pages Mel Gorman
2019-01-18 17:51 ` [PATCH 06/22] mm, migrate: Immediately fail migration of a page with no migration handler Mel Gorman
2019-01-18 17:51 ` [PATCH 07/22] mm, compaction: Always finish scanning of a full pageblock Mel Gorman
2019-01-18 17:51 ` [PATCH 08/22] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction Mel Gorman
2019-01-18 17:51 ` [PATCH 09/22] mm, compaction: Use free lists to quickly locate a migration source Mel Gorman
2019-01-31 13:55 ` Vlastimil Babka
2019-01-31 14:12 ` Vlastimil Babka
2019-02-01 15:06 ` Mel Gorman
2019-02-04 8:55 ` [PATCH] mm, compaction: Use free lists to quickly locate a migration source -fix Mel Gorman
2019-02-08 17:10 ` Vlastimil Babka [this message]
2019-01-18 17:51 ` [PATCH 10/22] mm, compaction: Keep migration source private to a single compaction instance Mel Gorman
2019-01-18 17:51 ` [PATCH 11/22] mm, compaction: Use free lists to quickly locate a migration target Mel Gorman
2019-01-31 14:52 ` Vlastimil Babka
2019-02-01 14:51 ` Mel Gorman
2019-02-01 14:58 ` Vlastimil Babka
2019-02-04 12:01 ` [PATCH] mm, compaction: Use free lists to quickly locate a migration source -fix Mel Gorman
2021-01-12 5:19 ` [PATCH] mm, compaction: make sure we isolate a valid freepage when high_pfn is used Rokudo Yan
2021-01-12 9:10 ` Mel Gorman
2021-01-12 9:47 ` [PATCH] mm, compaction: move high_pfn to the for loop scope Rokudo Yan
2021-01-12 10:45 ` Mel Gorman
2021-01-12 10:48 ` Vlastimil Babka
2021-01-12 22:27 ` Andrew Morton
2021-01-18 7:41 ` Rokudo Yan
2021-01-18 9:42 ` Mel Gorman
2019-01-18 17:51 ` [PATCH 12/22] mm, compaction: Avoid rescanning the same pageblock multiple times Mel Gorman
2019-01-18 17:51 ` [PATCH 13/22] mm, compaction: Finish pageblock scanning on contention Mel Gorman
2019-01-18 17:51 ` [PATCH 14/22] mm, compaction: Check early for huge pages encountered by the migration scanner Mel Gorman
2019-01-18 17:51 ` [PATCH 15/22] mm, compaction: Keep cached migration PFNs synced for unusable pageblocks Mel Gorman
2019-01-18 17:51 ` [PATCH 16/22] mm, compaction: Rework compact_should_abort as compact_check_resched Mel Gorman
2019-01-18 17:51 ` [PATCH 17/22] mm, compaction: Do not consider a need to reschedule as contention Mel Gorman
2019-01-18 17:51 ` [PATCH 18/22] mm, compaction: Reduce premature advancement of the migration target scanner Mel Gorman
2019-01-18 17:51 ` [PATCH 19/22] mm, compaction: Round-robin the order while searching the free lists for a target Mel Gorman
2019-01-18 17:51 ` [PATCH 20/22] mm, compaction: Sample pageblocks for free pages Mel Gorman
2019-01-31 15:39 ` Vlastimil Babka
2019-01-18 17:51 ` [PATCH 21/22] mm, compaction: Be selective about what pageblocks to clear skip hints Mel Gorman
2019-01-31 15:45 ` Vlastimil Babka
2019-01-18 17:51 ` [PATCH 22/22] mm, compaction: Capture a page under direct compaction Mel Gorman
2019-01-31 16:11 ` Vlastimil Babka
2019-02-01 14:38 ` [PATCH] mm, compaction: Capture a page under direct compaction -fix Mel Gorman
2019-01-24 8:53 ` [PATCH 00/22] Increase success rates and reduce latency of compaction v3 Mel Gorman
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=7b698aca-bd47-7d5c-a114-145b813b7bdb@suse.cz \
--to=vbabka@suse.cz \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=rientjes@google.com \
/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;
as well as URLs for NNTP newsgroup(s).