On Mon, Sep 26, 2011 at 3:05 PM, Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> wrote: >> The problem with a per-cpu cpumask is that you need to disable >> preemption over the whole for_each_online_cpu() scan and that's not >> really sane on very large machines as that can easily take a very long >> time indeed. > > hmm... I might be thick, but why disable the preemption with the > per-cpu cpumask at all? ... > > Does that makes sense or have I've gone over board with this concept? :-) Scratch that. The cpumask must be per cache or the patch doesn't make sense at all. So sadly the only sane place to put it is in struct kmem_cache. I think we can still update the cpumask field without caring about preemption for the reasons stated above, but the per cache memory overhead is still there I'm afraid. Gilad -- Gilad Ben-Yossef Chief Coffee Drinker gilad@xxxxxxxxxxxxx Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com "I've seen things you people wouldn't believe. Goto statements used to implement co-routines. I watched C structures being stored in registers. All those moments will be lost in time... like tears in rain... Time to die. " -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>