Messages in this thread | | | Date | Thu, 7 Jan 2010 12:45:54 +0530 | From | Balbir Singh <> | Subject | Re: [RFC] Shared page accounting for memory cgroup |
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* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-01-06 16:12:11]:
> On Wed, 6 Jan 2010 12:31:50 +0530 > Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > > > No. If it takes long time, locking fork()/exit() for such long time is the bigger > > > issue. > > > I recommend you to add memacct subsystem to sum up RSS of all processes's RSS counting > > > under a cgroup. Althoght it may add huge costs in page fault path but implementation > > > will be very simple and will not hurt realtime ops. > > > There will be no terrible race, I guess. > > > > > > > But others hold that lock as well, simple thing like listing tasks and > > moving tasks, etc. I expect the usage of shared to be in the same > > range. > > > > And piles up costs ? I think cgroup guys should pay attention to fork/exit > costs more. Now, it gets slower and slower. > In that point, I never like migrate-at-task-move work in cpuset and memcg. > > My 1st objection to this patch is this "shared" doesn't mean "shared between > cgroup" but means "shared between processes". > I think it's of no use and no help to users. >
So what in your opinion would help end users? My concern is that as we make progress with memcg, we account only for privately used pages with no hint/data about the real usage (shared within or with other cgroups). How do we decide if one cgroup is really heavy?
> And implementation is 2nd thing. >
More details on your concern, please!
-- Balbir
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