Re: [RFC] Mount point suggestions for cgroup

From: Jan Safranek
Date: Wed Nov 04 2009 - 11:25:36 EST


On 11/04/2009 05:11 PM, Serge E. Hallyn wrote:
Quoting Dave Hansen (dave@xxxxxxxxxxxxxxxxxx):
On Wed, 2009-11-04 at 13:46 +0530, Balbir Singh wrote:
The reason I liked /dev/cgroup was because cpusets could be
mounted at /dev/cpuset or /dev/cgroup/cpuset. My concern with /cgroup
is that a ls "/" now becomes larger in size. But I'll take your vote
for it as +1 for /cgroup.

/dev/pts is a decent precedent for doing it under /dev, although it does
deal with actual devices. cgroups do not.

Hmm, on whose behalf are you making this decision?

LSB people will want to avoid using /cgroup,

LSB (and FHS) IMHO does not specify any place for such stuff:

/dev - for devices only, cgroups are not devices
/mnt - for admin temporary mounts and "should not affect the manner in which any program is run"
/var - for "any unsorted variable data", cgroups are not "unsorted variable data", it's interface to kernel

FHS does not specify either /sys and /selinux and it seems to me nobody complains about them.

/sys/cgroup would be the best, if sysfs supported mkdir(). But it does not :(. Our kernel guys told me it's relatively easy to create new empty directory /sys/cgroup (or /sys/kernel/cgroup), but it must be compiled into kernel or a module. Then I could mount some tmpfs to it, create /sys/cgroup/cpu, /sys/cgroup/memory etc. and mount the control group hierarchies there... but as you can see, it's really really ugly thing to do.

Jan
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