linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@osdl.org>
To: Robin Holt <holt@sgi.com>
Cc: john@johnmccutchan.com, holt@sgi.com,
	linux-kernel@vger.kernel.org, rml@novell.com, arnd@arndb.de,
	hch@lst.de
Subject: Re: udevd is killing file write performance.
Date: Wed, 22 Feb 2006 12:05:47 -0800	[thread overview]
Message-ID: <20060222120547.2ae23a16.akpm@osdl.org> (raw)
In-Reply-To: <20060222175030.GB30556@lnx-holt.americas.sgi.com>

Robin Holt <holt@sgi.com> wrote:
>
> Let me reiterate, I know _VERY_ little about filesystems.  Can the
>  dentry->d_lock be changed to a read/write lock?

Well, it could, but I suspect that won't help - the hold times in there
will be very short so the problem is more likely acquisition frequency.

However it's a bit strange that this function is the bottleneck.  If their
workload is doing large numbers of reads or writes from large numbers of
processes against the same file then they should be hitting heavy
contention on other locks, such as i_sem and/or tree_lock and/or lru_lock
and others.

Can you tell us more about the kernel-visible behaviour of this app?

  reply	other threads:[~2006-02-22 20:06 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-22 13:42 udevd is killing file write performance Robin Holt
2006-02-22 13:55 ` Andrew Morton
2006-02-22 16:48 ` John McCutchan
2006-02-22 17:50   ` Robin Holt
2006-02-22 20:05     ` Andrew Morton [this message]
2006-02-22 21:50       ` Jeff V. Merkey
2006-02-23 12:56       ` Robin Holt
2006-02-23 13:42         ` David Chinner
2006-02-22 22:52     ` John McCutchan
2006-02-22 23:12       ` Andrew Morton
2006-02-22 23:41         ` John McCutchan
2006-02-24  0:14           ` Andrew Morton
2006-02-24  0:14           ` Andrew Morton
2006-02-24  5:47             ` John McCutchan
2006-02-24  6:00               ` Andrew Morton
2006-02-24  7:07                 ` Nick Piggin
2006-02-24  7:16                   ` Andrew Morton
2006-02-24  7:19                     ` Nick Piggin
2006-02-26 16:58                       ` John McCutchan
2006-02-24 18:56                   ` Robin Holt
2006-02-25  2:44                     ` Nick Piggin
2006-02-25 15:53                     ` [patch] inotify: lock avoidance with parent watch status in dentry Nick Piggin
2006-02-28  0:48                       ` Andrew Morton
2006-02-26 16:55                   ` udevd is killing file write performance John McCutchan
2006-02-27 10:11                     ` Nick Piggin
2006-02-27 20:17                       ` John McCutchan
2006-02-23 20:38         ` Benjamin LaHaise

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=20060222120547.2ae23a16.akpm@osdl.org \
    --to=akpm@osdl.org \
    --cc=arnd@arndb.de \
    --cc=hch@lst.de \
    --cc=holt@sgi.com \
    --cc=john@johnmccutchan.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rml@novell.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).