Messages in this thread | | | Date | Wed, 27 Aug 2008 12:29:17 +0800 | From | Lai Jiangshan <> | Subject | Re: [PATCH] cgroup(fix critical bug): new handling for tasks file |
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Paul Menage wrote: > On Mon, Aug 25, 2008 at 10:22 PM, Lai Jiangshan <laijs@cn.fujitsu.com> wrote: >> It's complicated than necessary and change too much code IMO. > > What about the problem that maintaining a single pid array can still > fail for a really large cgroup? I guess we could just say "don't > create such large cgroups" but someone's bound to want to do that. > Perhaps use an array of pages rather than a single large kmalloc? >
Actually, I had a plan to write such a patch: [RFC PATCH] cgroup,cpuset: use alternative malloc instead of kmalloc
The main idea is: when allocate size >= PAGE_SIZE, vmalloc will be used instead. This will reduce the stress when continuous pages are few. Alternative malloc is used for cgroup_tasks_open() and update_tasks_nodemask().
And vmalloc can malloc larger memory than kmalloc, is vmalloc() enough? If not, I think using an array of pages is the best choice.
[There are several subsystem who use alternative malloc. kernel/relay.c for example. relay.c is also using an array of pages for relay buffer. ]
Lai
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