Messages in this thread | | | Date | Thu, 13 May 2010 12:26:30 +0200 | Subject | Re: [PATCH/RFC] Have sane default values for cpusets | From | Dhaval Giani <> |
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On Wed, May 12, 2010 at 9:59 PM, Dhaval Giani <dhaval.giani@gmail.com> wrote: > On Wed, May 12, 2010 at 9:36 PM, Paul Menage <menage@google.com> wrote: >> On Wed, May 12, 2010 at 12:29 PM, Dhaval Giani <dhaval.giani@gmail.com> wrote: >>>> I think the idea is reasonable - the only way that I could see it >>>> breaking someone would be code that currently does something like: >>>> >>>> mkdir A >>>> mkdir B >>>> echo 1 > A/mem_exclusive >>>> echo 1 > B/mem_exclusive >>>> echo $mems_for_a > A/mems >>>> echo $mems_for_b > B/mems >>>> >>>> The attempts to set the mem_exclusive flags would fail, since A and B >>>> would both have all of the parent's mems. >>>> >>> >>> But would this not fail otherwise? >>> >> >> Assuming that mems_for_a and mems_for_b were disjoint, it would be >> fine currently. >> > > Ah my bad. I misread mems_for_a as taking the value from the parent. > You are right, that was a case I missed. > > Hmm, so how do we fix this? Any solutions? Not fixing the kernel > pushes the problem to the userspace, making it hard for tons of more > applications to use cgroups without jumping through a lot of hoops. >
OK, how about this. Introduce a new option, nodefaults (or some such name) which would retain the existing behaviour while the default mount options would moutn cpuset with the defaults. Also, make
mount -t cpuset cpuset /cpuset
equivalent to
mount -t cgroup -onoprefix,nodefaults,cpuset cpuset /cpuset
Would that work?
Thanks, Dhaval
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