From: John Stultz <john.stultz@linaro.org>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Android Kernel Team <kernel-team@android.com>,
Robert Love <rlove@google.com>, Mel Gorman <mel@csn.ul.ie>,
Hugh Dickins <hughd@google.com>,
Dave Hansen <dave@linux.vnet.ibm.com>,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 2/2] [RFC] fadvise: Add _VOLATILE,_ISVOLATILE, and _NONVOLATILE flags
Date: Tue, 14 Feb 2012 16:29:10 -0800 [thread overview]
Message-ID: <1329265750.2340.17.camel@work-vm> (raw)
In-Reply-To: <20120214235106.GL7479@dastard>
On Wed, 2012-02-15 at 10:51 +1100, Dave Chinner wrote:
> Given that it is a single state bit per page (volatile/non volatile)
> you could just use a radix tree tag for keeping the state. Changing
> the state isn't a performance critical operation, and tagging large
> ranges isn't that expensive (e.g. we do that in the writeback code),
> so I'm not sure the overhead of a separate tree is necessary here....
Hrm. I'll look into this.
> That doesn't help with the reclaim side of things, but I would have
> thought that such functioanlity would be better integrated into the
> VM page cache/lru scanning code than adding a shrinker to shrink the
> page cache additionally on top of what the VM has already done
> before calling the shrinkers. I'm not sure what is best here,
> though...
Yea. My previous version did eviction from shmem_writepage(), I believe
much as you suggest here, but the concern with that is that you could
have a larger volatile range that was for the most part recently in use,
but one idle page causes the entire thing to be evicted first. Using
least-recently-marked-volatile order seems more natural for the use case
(although Dimitry and others have already pointed out that the
inheritance from the coalescing of neighboring ranges results in a
similar issue).
But I'm open to other ideas and arguments.
Thanks again for the feedback!
-john
next prev parent reply other threads:[~2012-02-15 0:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-10 0:16 [PATCH 1/2] [RFC] Range tree implementation John Stultz
2012-02-10 0:16 ` [PATCH 2/2] [RFC] fadvise: Add _VOLATILE,_ISVOLATILE, and _NONVOLATILE flags John Stultz
[not found] ` <CAO6Zf6B6nGqsz5zpT3ixbO-+JWxMsScABasnwo-CVHuMKPqpLQ@mail.gmail.com>
2012-02-12 12:54 ` Fwd: " Dmitry Adamushko
2012-02-17 3:43 ` John Stultz
2012-02-17 5:24 ` John Stultz
2012-02-12 14:08 ` Dmitry Adamushko
2012-02-17 3:49 ` John Stultz
2012-02-14 5:16 ` Dave Chinner
2012-02-14 5:55 ` John Stultz
2012-02-14 23:51 ` Dave Chinner
2012-02-15 0:29 ` John Stultz [this message]
2012-02-15 1:37 ` NeilBrown
2012-02-17 4:45 ` Dave Chinner
2012-02-17 5:27 ` NeilBrown
2012-02-17 5:38 ` John Stultz
2012-02-17 5:21 ` John Stultz
2012-02-20 7:34 ` NeilBrown
2012-02-20 23:25 ` Dave Hansen
-- strict thread matches above, loose matches on Subject: below --
2012-03-16 22:51 [PATCH 0/2] [RFC] Volatile ranges (v4) John Stultz
2012-03-16 22:51 ` [PATCH 2/2] [RFC] fadvise: Add _VOLATILE,_ISVOLATILE, and _NONVOLATILE flags John Stultz
2012-03-17 16:21 ` Dmitry Adamushko
2012-03-18 9:13 ` Dmitry Adamushko
2012-03-20 0:18 ` John Stultz
2012-03-21 4:15 [PATCH 0/2] [RFC] fadivse volatile & range tree (v5) John Stultz
2012-03-21 4:15 ` [PATCH 2/2] [RFC] fadvise: Add _VOLATILE,_ISVOLATILE, and _NONVOLATILE flags John Stultz
2012-04-07 0:08 [PATCH 0/2] [RFC] Volatile Ranges (v6) John Stultz
2012-04-07 0:08 ` [PATCH 2/2] [RFC] fadvise: Add _VOLATILE,_ISVOLATILE, and _NONVOLATILE flags John Stultz
2012-04-14 1:07 [PATCH 0/2][RFC] Volatile Ranges (v7) John Stultz
2012-04-14 1:08 ` [PATCH 2/2] [RFC] fadvise: Add _VOLATILE,_ISVOLATILE, and _NONVOLATILE flags John Stultz
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=1329265750.2340.17.camel@work-vm \
--to=john.stultz@linaro.org \
--cc=akpm@linux-foundation.org \
--cc=dave@linux.vnet.ibm.com \
--cc=david@fromorbit.com \
--cc=hughd@google.com \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mel@csn.ul.ie \
--cc=riel@redhat.com \
--cc=rlove@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).