From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: compaction: Do not accidentally skip pageblocks in the migrate scanner
Date: Thu, 20 Dec 2012 17:45:50 -0500 [thread overview]
Message-ID: <50D3951E.50107@redhat.com> (raw)
In-Reply-To: <20121220142232.GA13367@suse.de>
On 12/20/2012 09:22 AM, Mel Gorman wrote:
> Compaction uses the ALIGN macro incorrectly with the migrate scanner by
> adding pageblock_nr_pages to a PFN. It happened to work when initially
> implemented as the starting PFN was also aligned but with caching restarts
> and isolating in smaller chunks this is no longer always true. The impact is
> that the migrate scanner scans outside its current pageblock. As pfn_valid()
> is still checked properly it does not cause any failure and the impact
> of the bug is that in some cases it will scan more than necessary when
> it crosses a page boundary but by no more than COMPACT_CLUSTER_MAX. It
> is highly unlikely this is even measurable but it's still wrong so this
> patch addresses the problem.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
prev parent reply other threads:[~2012-12-20 22:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-20 14:22 [PATCH] mm: compaction: Do not accidentally skip pageblocks in the migrate scanner Mel Gorman
2012-12-20 22:45 ` Rik van Riel [this message]
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=50D3951E.50107@redhat.com \
--to=riel@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
/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).