LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Dave Hansen <dave.hansen@intel.com>
To: Mel Gorman <mgorman@suse.de>, linux-mm@kvack.org
Cc: Minchan Kim <minchan@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] mm: madvise: Ignore repeated MADV_DONTNEED hints
Date: Mon, 02 Feb 2015 14:22:36 -0800 [thread overview]
Message-ID: <54CFF8AC.6010102@intel.com> (raw)
In-Reply-To: <20150202165525.GM2395@suse.de>
On 02/02/2015 08:55 AM, Mel Gorman wrote:
> This patch identifies when a thread is frequently calling MADV_DONTNEED
> on the same region of memory and starts ignoring the hint. On an 8-core
> single-socket machine this was the impact on ebizzy using glibc 2.19.
The manpage, at least, claims that we zero-fill after MADV_DONTNEED is
called:
> MADV_DONTNEED
> Do not expect access in the near future. (For the time being, the application is finished with the given range, so the kernel can free resources
> associated with it.) Subsequent accesses of pages in this range will succeed, but will result either in reloading of the memory contents from the
> underlying mapped file (see mmap(2)) or zero-fill-on-demand pages for mappings without an underlying file.
So if we have anything depending on the behavior that it's _always_
zero-filled after an MADV_DONTNEED, this will break it.
next prev parent reply other threads:[~2015-02-02 22:22 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-02 16:55 Mel Gorman
2015-02-02 22:05 ` Andrew Morton
2015-02-02 22:18 ` Mel Gorman
2015-02-02 22:35 ` Andrew Morton
2015-02-03 0:26 ` Davidlohr Bueso
2015-02-03 10:50 ` Mel Gorman
2015-02-05 21:44 ` Rik van Riel
2015-02-02 22:22 ` Dave Hansen [this message]
2015-02-03 8:19 ` MADV_DONTNEED semantics? Was: " Vlastimil Babka
2015-02-03 10:53 ` Kirill A. Shutemov
2015-02-03 11:42 ` Vlastimil Babka
2015-02-03 16:20 ` Michael Kerrisk (man-pages)
2015-02-04 13:46 ` Vlastimil Babka
2015-02-04 14:00 ` Michael Kerrisk (man-pages)
2015-02-04 17:02 ` Vlastimil Babka
2015-02-04 19:24 ` Michael Kerrisk (man-pages)
2015-02-05 1:07 ` Minchan Kim
2015-02-06 15:41 ` Michael Kerrisk (man-pages)
2015-02-09 6:46 ` Minchan Kim
2015-02-09 9:13 ` Michael Kerrisk (man-pages)
2015-02-05 15:41 ` Michal Hocko
2015-02-06 15:57 ` Michael Kerrisk (man-pages)
2015-02-06 20:45 ` Michal Hocko
2015-02-09 6:50 ` Minchan Kim
2015-02-04 0:09 ` Minchan Kim
2015-02-03 11:16 ` Mel Gorman
2015-02-03 15:21 ` Michal Hocko
2015-02-03 16:25 ` Michael Kerrisk (man-pages)
2015-02-03 9:47 ` Mel Gorman
2015-02-03 10:47 ` Kirill A. Shutemov
2015-02-03 11:21 ` 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=54CFF8AC.6010102@intel.com \
--to=dave.hansen@intel.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=minchan@kernel.org \
--cc=vbabka@suse.cz \
--subject='Re: [RFC PATCH] mm: madvise: Ignore repeated MADV_DONTNEED hints' \
/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
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).