Messages in this thread | | | Date | Tue, 16 Sep 2008 11:30:43 +0800 | From | Lai Jiangshan <> | Subject | Re: [PATCH -mm 2/2] cgroup: use multibuf for tasks file |
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Li Zefan wrote: > Lai Jiangshan wrote: >> Paul Menage wrote: >>> On Fri, Sep 12, 2008 at 4:55 AM, Lai Jiangshan <laijs@cn.fujitsu.com> wrote: >>>> when we open a really large cgroup for read, we may failed >>>> for kmalloc() is not reliable for allocate a big buffer. >>> This still depends on an answer to whether using plain vmalloc is too >>> much overhead. >>> >>> Balbir pointed out to me that most cgroups are likely to be pretty >>> small - so the solution of just doing a kmalloc() for 8K or less, and >>> a vmalloc() for more than 8K (which is >2000 threads) will avoid the >>> vmalloc overhead in almost all cases; the question is whether >>> eliminating the remaining overhead is worth the extra complexity. >>> >> I think open cgroup.tasks to read is not a critical path. >> so using plain vmalloc(even more overhead functions) is worth. >> > > This patch does not only add runtime overhead, but also make code much more > complex, so the code is harder to read and harder to maintain, and object size > is increased, which means increased memory footprint. > > And is there any reason not using plain vmalloc? Don't bloat the kernel without > good reasons IMO... >
I said that vmalloc is worth. vmalloc was the fist choice of my opinion. ^_^
> >
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