Messages in this thread | | | Date | Mon, 24 Jul 2006 19:00:30 -0700 | From | Andrew Morton <> | Subject | Re: [RFC] ps command race fix |
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On Mon, 24 Jul 2006 18:48:47 -0700 Paul Jackson <pj@sgi.com> wrote:
> Another possibility (perhaps a really stupid idea ;) would be to > snapshot the list of pids on the open, and let the readdir() just > access that fixed array.
The patch under discussion does precisely this. (Awkwardly. Using kmalloc-pre-object might be better).
> The kernel/cpuset.c cpuset_tasks_open() routine that displays the > pids of tasks in a cpuset (the per-cpuset 'tasks' file) does this.
Your faith in large kmalloc()s is touching ;) I guess the number of pids will be smaller for cpusets.
> Then the seek and read and such semantics are nice and stable and > simple. > > Throw out the snapshot on the last close.
The patch under discussion didn't do this, although it could. But it still permits rather a lot of kernel memory to be pinned.
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