From: Al Viro <viro@ZenIV.linux.org.uk>
To: Nick Piggin <npiggin@suse.de>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch 1/2] fs: mnt_want_write speedup
Date: Thu, 2 Apr 2009 19:43:05 +0100 [thread overview]
Message-ID: <20090402184305.GI28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20090402182210.GB17175@wotan.suse.de>
On Thu, Apr 02, 2009 at 08:22:10PM +0200, Nick Piggin wrote:
> On Wed, Mar 18, 2009 at 12:13:43PM -0700, Dave Hansen wrote:
> > On Thu, 2009-03-12 at 05:13 +0100, Nick Piggin wrote:
> > > On Wed, Mar 11, 2009 at 03:11:17PM -0700, Dave Hansen wrote:
> > > > I'm feeling a bit better about these, although I am still honestly quite
> > > > afraid of the barriers. I also didn't like all the #ifdefs much, but
> > > > here's some help on that.
> > >
> > > FWIW, we have this in suse kernels because page fault performance was
> > > so bad compared with SLES10. mnt_want_write & co was I think the 2nd
> > > biggest offender for file backed mappings (after pvops). I think we're
> > > around parity again even with pvops.
> >
> > Page faults themselves? Which path was that from?
>
> Yes. file_update_time.
FWIW, I'm not sure that this optimization is valid. We might eventually
want to go for "don't allow any new writers, remount r/o when existing
ones expire" functionality, so nested mnt_want_write() might eventually
be allowed to fail.
next prev parent reply other threads:[~2009-04-02 18:43 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-10 14:37 [patch 1/2] fs: mnt_want_write speedup Nick Piggin
2009-03-10 14:38 ` [patch 2/2] fs: introduce mnt_clone_write Nick Piggin
2009-03-10 14:55 ` Matthew Wilcox
2009-03-10 15:08 ` Nick Piggin
2009-03-10 14:48 ` [patch 1/2] fs: mnt_want_write speedup Matthew Wilcox
2009-03-10 15:03 ` Nick Piggin
2009-03-10 15:31 ` Nick Piggin
2009-03-11 22:11 ` Dave Hansen
2009-03-12 4:13 ` Nick Piggin
2009-03-18 19:13 ` Dave Hansen
2009-04-02 18:22 ` Nick Piggin
2009-04-02 18:37 ` Dave Hansen
2009-04-02 20:31 ` Christoph Hellwig
2009-04-03 1:29 ` Nick Piggin
2009-04-02 18:43 ` Al Viro [this message]
2009-04-02 18:48 ` Al Viro
2009-04-02 19:08 ` Dave Hansen
2009-04-03 10:31 ` Al Viro
2009-04-03 1:31 ` Nick Piggin
2009-04-02 18:08 ` Andrew Morton
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=20090402184305.GI28946@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=akpm@linux-foundation.org \
--cc=dave@linux.vnet.ibm.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=npiggin@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.