From: Michael Monnerie <michael.monnerie@is.it-management.at>
To: xfs@oss.sgi.com
Subject: Re: Slab memory usage
Date: Sun, 26 Apr 2009 23:51:22 +0200 [thread overview]
Message-ID: <200904262351.22970@zmi.at> (raw)
In-Reply-To: <49F260F1.4030503@sandeen.net>
On Samstag 25 April 2009 Eric Sandeen wrote:
> *from Documentation/sysctl/vm.txt:
>
> vfs_cache_pressure
> ------------------
>
> Controls the tendency of the kernel to reclaim the memory which is
> used for caching of directory and inode objects.
>
> At the default value of vfs_cache_pressure=100 the kernel will
> attempt to reclaim dentries and inodes at a "fair" rate with respect
> to pagecache and swapcache reclaim. Decreasing vfs_cache_pressure
> causes the kernel to prefer to retain dentry and inode caches.
> Increasing vfs_cache_pressure beyond 100 causes the kernel to prefer
> to reclaim dentries and inodes.
So if I decrease it, lets say to 60, Linux prefers to remember
files/dirs over their content. An increase to 150 would mean Linux
prefers to keep file contents over dirs/files?
If so, I think for a fileserver for many users accessing many
dirs/files, I'd prefer a lower value, in order to prevent searching.
Disk contents can be read fast, with all the read-ahead caching of
disks/controllers and Linux itself, but the scattered dirs take loooong
to scan sometimes. (Example: a foto collection with 50.000 files in many
dirs). Am I right?
mfg zmi
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next prev parent reply other threads:[~2009-04-26 21:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-24 23:01 Slab memory usage Poul Petersen
2009-04-25 1:01 ` Eric Sandeen
2009-04-26 21:51 ` Michael Monnerie [this message]
2009-04-27 8:40 ` Josef 'Jeff' Sipek
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