Messages in this thread | | | From | kamezawa.hiroyu@jp ... | Date | Tue, 5 Aug 2008 12:49:25 +0900 (JST) | Subject | Re: Re: Race condition between putback_lru_page and mem_cgroup_move_list |
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>KOSAKI Motohiro wrote: >> Hi >> >>>> I think this is a race condition if mem_cgroup_move_lists's comment isn't right. >>>> I am not sure that it was already known problem. >>>> >>>> mem_cgroup_move_lists assume the appropriate zone's lru lock is already h eld. >>>> but putback_lru_page calls mem_cgroup_move_lists without holding lru_lock . >>> Hmmm, the comment on mem_cgroup_move_lists() does say this. Although, >>> reading thru' the code, I can't see why it requires this. But then it's >>> Monday, here... >> >> I also think zone's lru lock is unnecessary. >> So, I guess below "it" indicate lock_page_cgroup, not zone lru lock. >> > >We need zone LRU lock, since the reclaim paths hold them. Not sure if I >understand why you call zone's LRU lock unnecessary, could you elaborate plea se? >
I guess the comment should be against mem_cgroup_isolate_pages()...
Thanks, -Kame
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