From: Andrew Morton <akpm@osdl.org>
To: john@johnmccutchan.com
Cc: 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: Thu, 23 Feb 2006 16:14:14 -0800 [thread overview]
Message-ID: <20060223161414.3b771e73.akpm@osdl.org> (raw)
In-Reply-To: <1140651662.2985.2.camel@localhost.localdomain>
John McCutchan <john@johnmccutchan.com> wrote:
>
> ...
> >
> > I have a bad feeling about this one. It'd be nice to have an exact
> > understanding of the problen source, but if it's just lots of traffic on
> > ->d_lock we're kinda stuck. I don't expect we'll run off and RCUify
> > d_parent or turn d_lock into a seq_lock or anything liek that.
> >
> > Then again, maybe making d_lock an rwlock _will_ help - if this workload is
> > also hitting tree_lock (Robin?) and we're not seeing suckiness due to that
> > then perhaps the rwlock is magically helping.
> >
> >
> > > instead of your hack.
> >
> > It's not a terribly bad hack - it's just poor-man's hashing, and it's
> > reasonably well-suited to the sorts of machines and workloads which we
> > expect will hit this problem.
> >
>
> If this is as good as it gets, here is a patch (totally untested).
>
> ...
> @@ -538,7 +537,7 @@
> struct dentry *parent;
> struct inode *inode;
>
> - if (!atomic_read (&inotify_watches))
> + if (!atomic_read (&dentry->d_sb->s_inotify_watches))
> return;
>
What happens here if we're watching a mointpoint - the parent is on a
different fs?
next prev parent reply other threads:[~2006-02-24 0:24 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
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 [this message]
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
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