]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
Documentation/sysctl/vm.txt: clarify vfs_cache_pressure description
authorDenys Vlasenko <dvlasenk@redhat.com>
Wed, 4 Jun 2014 23:11:03 +0000 (16:11 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 4 Jun 2014 23:54:13 +0000 (16:54 -0700)
commit4a0da71b96b9d4080c0820e9e7d02470ebe62dc6
treed5fd8eb6b6f5d8877a5f84ddffa7f3e6a33e8284
parent3ba08129e38437561df44c36b7ea9081185d5333
Documentation/sysctl/vm.txt: clarify vfs_cache_pressure description

Existing description is worded in a way which almost encourages setting of
vfs_cache_pressure above 100, possibly way above it.

Users are left in a dark what this numeric value is - an int?  a
percentage?  what the scale is?

As a result, we are getting reports about noticeable performance
degradation from users who have set vfs_cache_pressure to ridiculously
high values - because they thought there is no downside to it.

Via code inspection it's obvious that this value is treated as a
percentage.  This patch changes text to reflect this fact, and adds a
cautionary paragraph advising against setting vfs_cache_pressure sky high.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation/sysctl/vm.txt