From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>, Linux-MM <linux-mm@kvack.org>
Cc: David Rientjes <rientjes@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
ying.huang@intel.com, kirill@shutemov.name,
Andrew Morton <akpm@linux-foundation.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 05/14] mm, compaction: Skip pageblocks with reserved pages
Date: Tue, 18 Dec 2018 09:08:02 +0100 [thread overview]
Message-ID: <b1d38179-4ccf-f34a-dffa-26c7957b8aed@suse.cz> (raw)
In-Reply-To: <20181214230310.572-6-mgorman@techsingularity.net>
On 12/15/18 12:03 AM, Mel Gorman wrote:
> Reserved pages are set at boot time, tend to be clustered and almost
> never become unreserved. When isolating pages for migrating, skip
> the entire pageblock is one PageReserved page is encountered on the
> grounds that it is highly probable the entire pageblock is reserved.
Agreed, but maybe since it's highly probable and not certain, this
skipping should not be done on the highest compaction priority?
> The impact depends on the machine and timing but both thpscale and
> thpfioscale when using MADV_HUGEPAGE show a reduction of scanning and
> fault latency on a 1-socket machine. The 2-socket results were too
> noisy to draw any meaningful conclusion but it's safe to assume less
> scanning is useful.
>
> 1-socket thpfioscale
> 4.20.0-rc6 4.20.0-rc6
> mmotm-20181210 noreserved-v1r4
> Amean fault-base-1 1481.32 ( 0.00%) 1443.63 ( 2.54%)
> Amean fault-huge-1 1118.17 ( 0.00%) 981.30 * 12.24%*
> Amean fault-both-1 1176.43 ( 0.00%) 1052.64 * 10.52%*
>
> Compaction migrate scanned 3860713 3294284
> Compaction free scanned 613786341 433423502
> Kcompactd migrate scanned 408711 291915
> Kcompactd free scanned 242509759 217164988
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
> ---
> mm/compaction.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 3afa4e9188b6..8134dba47584 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -827,6 +827,13 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
> goto isolate_success;
> }
>
> + /*
> + * A reserved page is never freed and tend to be
> + * clustered in the same pageblocks. Skip the block.
> + */
> + if (PageReserved(page))
> + low_pfn = end_pfn;
> +
> goto isolate_fail;
> }
>
>
next prev parent reply other threads:[~2018-12-18 8:08 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-14 23:02 [RFC PATCH 00/14] Increase success rates and reduce latency of compaction v1 Mel Gorman
2018-12-14 23:02 ` [PATCH 01/14] mm, compaction: Shrink compact_control Mel Gorman
2018-12-17 12:27 ` Vlastimil Babka
2018-12-14 23:02 ` [PATCH 02/14] mm, compaction: Rearrange compact_control Mel Gorman
2018-12-17 13:20 ` Vlastimil Babka
2018-12-14 23:02 ` [PATCH 03/14] mm, compaction: Remove last_migrated_pfn from compact_control Mel Gorman
2018-12-17 13:50 ` Vlastimil Babka
2018-12-14 23:03 ` [PATCH 04/14] mm, compaction: Rename map_pages to split_map_pages Mel Gorman
2018-12-17 14:06 ` Vlastimil Babka
2018-12-17 14:30 ` Mel Gorman
2018-12-14 23:03 ` [PATCH 05/14] mm, compaction: Skip pageblocks with reserved pages Mel Gorman
2018-12-18 8:08 ` Vlastimil Babka [this message]
2018-12-18 8:38 ` Mel Gorman
2018-12-14 23:03 ` [PATCH 06/14] mm, migrate: Immediately fail migration of a page with no migration handler Mel Gorman
2018-12-18 9:06 ` Vlastimil Babka
2018-12-18 9:55 ` Mel Gorman
2018-12-20 19:44 ` Yang Shi
2018-12-20 20:31 ` Mel Gorman
2018-12-14 23:03 ` [PATCH 07/14] mm, compaction: Always finish scanning of a full pageblock Mel Gorman
2018-12-18 9:23 ` Vlastimil Babka
2018-12-14 23:03 ` [PATCH 08/14] mm, compaction: Use the page allocator bulk-free helper for lists of pages Mel Gorman
2018-12-18 9:55 ` Vlastimil Babka
2018-12-19 16:04 ` Mel Gorman
2018-12-14 23:03 ` [PATCH 09/14] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction Mel Gorman
2018-12-18 12:36 ` Vlastimil Babka
2018-12-18 13:51 ` Mel Gorman
2018-12-18 13:58 ` Vlastimil Babka
2018-12-18 14:29 ` Mel Gorman
2018-12-14 23:04 ` [PATCH 10/14] mm, compaction: Use free lists to quickly locate a migration source Mel Gorman
2018-12-14 23:05 ` [PATCH 11/14] mm, compaction: Keep migration source private to a single compaction instance Mel Gorman
2018-12-14 23:05 ` [PATCH 12/14] mm, compaction: Use free lists to quickly locate a migration target Mel Gorman
2018-12-14 23:05 ` [PATCH 13/14] mm, compaction: Capture a page under direct compaction Mel Gorman
2018-12-14 23:06 ` [PATCH 14/14] mm, compaction: Do not direct compact remote memory 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=b1d38179-4ccf-f34a-dffa-26c7957b8aed@suse.cz \
--to=vbabka@suse.cz \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@kernel.org \
--cc=rientjes@google.com \
--cc=torvalds@linux-foundation.org \
--cc=ying.huang@intel.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).