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From: "J. Bruce Fields" <bfields@fieldses.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
	"J. Bruce Fields" <bfields@redhat.com>,
	linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 4/4] dcache: don't clear DCACHE_DISCONNECTED too early
Date: Tue, 15 Oct 2013 15:29:09 -0400	[thread overview]
Message-ID: <20131015192908.GB10128@fieldses.org> (raw)
In-Reply-To: <20131012084235.GB5649@infradead.org>

On Sat, Oct 12, 2013 at 01:42:35AM -0700, Christoph Hellwig wrote:
> On Fri, Oct 11, 2013 at 12:02:37PM -0400, J. Bruce Fields wrote:
> > But just for fun--I did some cleanup and fixed some other quadratic
> > behavior here and can notice a difference on lookups of very deep
> > subdirectories.
> > 
> > For example I'm seeing an uncached lookup of an 8000-deep directory
> > taking about 6 seconds, and can get that down to a tenth of a second.
> > 
> > I'm not sure yet if the difference on less extreme examples is really
> > significant, I need to experiment some more.
> > 
> > I'll do some more review and post patches and results.
> 
> This sounds like and awesome improvement.

Nobody should be nesting that deep, but maybe it's useful to have the
insurance against bad behavior anyway.

> How much code do you have to
> add for it?

 fs/exportfs/expfs.c | 224 ++++++++++++++++++++++++++--------------------------
 1 file changed, 112 insertions(+), 112 deletions(-)

But maybe I removed some necessary complication.  I'll post the
patches....

--b.

  reply	other threads:[~2013-10-15 19:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-07 18:45 4 DCACHE_DISCONNECTED patches J. Bruce Fields
2013-09-07 18:45 ` [PATCH 1/4] dcache: use IS_ROOT to decide where dentry is hashed J. Bruce Fields
2013-09-07 18:45 ` [PATCH 2/4] dcache: make __d_shrink callers check d_unhashed() J. Bruce Fields
2013-09-07 18:46 ` [PATCH 3/4] dcache: Don't set DISCONNECTED on "pseudo filesystem" dentries J. Bruce Fields
2013-09-07 18:46 ` [PATCH 4/4] dcache: don't clear DCACHE_DISCONNECTED too early J. Bruce Fields
2013-09-09  0:46   ` Al Viro
2013-09-09  7:45     ` Christoph Hellwig
2013-09-09 20:46     ` J. Bruce Fields
2013-10-11 16:02       ` J. Bruce Fields
2013-10-12  8:42         ` Christoph Hellwig
2013-10-15 19:29           ` J. Bruce Fields [this message]
2013-09-08  9:16 ` 4 DCACHE_DISCONNECTED patches Christoph Hellwig

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