From: Dave Chinner <david@fromorbit.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andreas Dilger <adilger@dilger.ca>,
Waiman Long <longman@redhat.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jonathan Corbet <corbet@lwn.net>,
Luis Chamberlain <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
Iurii Zaikin <yzaikin@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
linux-doc@vger.kernel.org,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Eric Biggers <ebiggers@google.com>,
Eric Sandeen <sandeen@redhat.com>
Subject: Re: [PATCH 00/11] fs/dcache: Limit # of negative dentries
Date: Thu, 27 Feb 2020 19:07:03 +1100 [thread overview]
Message-ID: <20200227080703.GK10737@dread.disaster.area> (raw)
In-Reply-To: <20200226214507.GE24185@bombadil.infradead.org>
On Wed, Feb 26, 2020 at 01:45:07PM -0800, Matthew Wilcox wrote:
> had twice as many entries in it, would that significantly reduce the
> thrash of new entries being created". In the page cache, we end up
> with a double LRU where once-used entries fall off the list quickly
> but twice-or-more used entries get to stay around for a bit longer.
> Maybe we could do something like that; keep a victim cache for recently
> evicted dentries, and if we get a large hit rate in the victim cache,
> expand the size of the primary cache.
You know, I've been saying exactly the same thing about the inode
LRU in response to people trying to hack behaviour out of the
shrinker that is triggered by the working set getting trashed by
excessive creation of single use inodes (i.e. large scale directory
traversal).
IOWs, both have the same problem with working set retention in the
face of excessive growth pressure.
So, you know, perhaps two caches with the same problem, that use the
same LRU implementation, could solve the same problem by enhancing
the generic LRU code they use to an active/inactive style clocking
LRU like the page LRUs?
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-02-27 8:07 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 16:13 [PATCH 00/11] fs/dcache: Limit # of negative dentries Waiman Long
2020-02-26 16:13 ` [PATCH 01/11] fs/dcache: Fix incorrect accounting " Waiman Long
2020-02-26 16:13 ` [PATCH 02/11] fs/dcache: Simplify __dentry_kill() Waiman Long
2020-02-26 16:13 ` [PATCH 03/11] fs/dcache: Add a counter to track number of children Waiman Long
2020-02-26 16:13 ` [PATCH 04/11] fs/dcache: Add sysctl parameter dentry-dir-max Waiman Long
2020-02-26 16:13 ` [PATCH 05/11] fs/dcache: Reclaim excessive negative dentries in directories Waiman Long
2020-02-26 16:13 ` [PATCH 06/11] fs/dcache: directory opportunistically stores # of positive dentries Waiman Long
2020-02-26 16:14 ` [PATCH 07/11] fs/dcache: Add static key negative_reclaim_enable Waiman Long
2020-02-26 16:14 ` [PATCH 08/11] fs/dcache: Limit dentry reclaim count in negative_reclaim_workfn() Waiman Long
2020-02-26 16:14 ` [PATCH 09/11] fs/dcache: Don't allow small values for dentry-dir-max Waiman Long
2020-02-26 16:14 ` [PATCH 10/11] fs/dcache: Kill off dentry as last resort Waiman Long
2020-02-26 16:14 ` [PATCH 11/11] fs/dcache: Track # of negative dentries reclaimed & killed Waiman Long
2020-02-26 16:29 ` [PATCH 00/11] fs/dcache: Limit # of negative dentries Matthew Wilcox
2020-02-26 19:19 ` Waiman Long
2020-02-26 21:28 ` Matthew Wilcox
2020-02-26 21:28 ` Andreas Dilger
2020-02-26 21:45 ` Matthew Wilcox
2020-02-27 8:07 ` Dave Chinner [this message]
2020-02-27 9:55 ` Ian Kent
2020-02-28 3:34 ` Matthew Wilcox
2020-02-28 4:16 ` Ian Kent
2020-02-28 4:36 ` Ian Kent
2020-02-28 4:52 ` Al Viro
2020-02-28 4:22 ` Al Viro
2020-02-28 4:52 ` Ian Kent
2020-02-28 15:32 ` Waiman Long
2020-02-28 15:39 ` Matthew Wilcox
2020-02-28 19:32 ` Theodore Y. Ts'o
2020-02-27 19:04 ` Eric Sandeen
2020-02-27 22:39 ` Dave Chinner
2020-02-27 8:30 ` Dave Chinner
2020-02-28 15:47 ` Waiman Long
2020-03-15 3:46 ` Matthew Wilcox
2020-03-21 10:17 ` Konstantin Khlebnikov
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