From: Dave Chinner <david@fromorbit.com>
To: Waiman Long <longman@redhat.com>
Cc: 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@vger.kernel.org, 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 19:30:29 +1100 [thread overview]
Message-ID: <20200227083029.GL10737@dread.disaster.area> (raw)
In-Reply-To: <20200226161404.14136-1-longman@redhat.com>
On Wed, Feb 26, 2020 at 11:13:53AM -0500, Waiman Long wrote:
> As there is no limit for negative dentries, it is possible that a sizeable
> portion of system memory can be tied up in dentry cache slabs. Dentry slabs
> are generally recalimable if the dentries are in the LRUs. Still having
> too much memory used up by dentries can be problematic:
I don't get it.
Why isn't the solution simply "constrain the application generating
unbound numbers of dentries to a memcg"?
Then when the memcg runs out of memory, it will start reclaiming the
dentries that were allocated inside the memcg that are using all
it's resources, thereby preventing unbound growth of the dentry
cache.
I mean, this sort of resource control is exactly what memcgs are
supposed to be used for and are already used for. I don't see why we
need all this complexity for global dentry resource management when
memcgs should already provide an effective means of managing and
placing bounds on the amount of memory any specific application can
use...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-02-27 8:30 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
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 [this message]
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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