Messages in this thread | | | Date | Mon, 01 Sep 2008 11:55:39 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][PATCH] Remove cgroup member from struct page |
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KAMEZAWA Hiroyuki wrote: > On Mon, 01 Sep 2008 11:39:26 +0530 > Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > > >>> The development of lockless-page_cgroup is not stalled. I'm just waiting for >>> my 8cpu box comes back from maintainance... >>> If you want to see, I'll post v3 with brief result on small (2cpu) box. >>> >> I understand and I am not pushing you to completing it, but at the same time I >> don't want to queue up behind it for long. I suspect the cost of porting >> lockless page cache on top of my patches should not be high, but I'll never know >> till I try :) >> > My point is, your patch adds big lock. Then, I don't have to do meaningless effort > to reduce lock.
My patch does not add a big lock, it moves the lock from struct page->page_cgroup to struct page_cgroup. The other locking added is the locking overhead associated with inserting entries into the radix tree, true. I ran oprofile along with lockdep and lockstats enabled on my patches. I don't see the radix_tree or page_cgroup->lock showing up, I see __slab_free and __slab_alloc showing up. I'll poke a little further.
Please don't let my patch stop you, we'll integrate the best of both worlds and what is good for memcg.
-- Balbir
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