Messages in this thread | | | Date | Sat, 4 Jul 2009 09:10:58 -0700 | Subject | Re: [PATCH 1/2] Adds a read-only "procs" file similar to "tasks" that shows only unique tgids | From | Paul Menage <> |
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2009/7/3 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>: > Anyway, above algorithm shows that it's enough to have per-cgroup bitmap > (size can be dinamically changed) rather than big table and ugly sort(). > How about adding per-cgroup taskid bitmap ? > clear/set is very easy. >
A per-cgroup bitmap of task ids would mean (assuming that it's implemented as a sparse tree like an IDA) that you'd add extra allocations and possible failure points in the fork path - right now the fork overhead imposed by the cgroups framework itself is just linking yourself into your parent's css_set and bumping its refcount. I guess there probably are workloads where doing more work at fork/exit time and less at "tasks" scan time is a win, but that has to be balanced against those where fork/exit performance is more critical, and the fact that it would be adding another way that fork could fail.
Paul
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