From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 1 Sep 2008 15:59:30 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][PATCH] Remove cgroup member from struct page Message-Id: <20080901155930.e45a36c8.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <48BB8AE3.7070704@linux.vnet.ibm.com> References: <20080831174756.GA25790@balbir.in.ibm.com> <20080901090102.46b75141.kamezawa.hiroyu@jp.fujitsu.com> <48BB6160.4070904@linux.vnet.ibm.com> <20080901130351.f005d5b6.kamezawa.hiroyu@jp.fujitsu.com> <48BB8716.5090805@linux.vnet.ibm.com> <20080901152424.d9adfe47.kamezawa.hiroyu@jp.fujitsu.com> <48BB8AE3.7070704@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: balbir@linux.vnet.ibm.com Cc: Andrew Morton , hugh@veritas.com, menage@google.com, xemul@openvz.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "nickpiggin@yahoo.com.au" List-ID: On Mon, 01 Sep 2008 11:55:39 +0530 Balbir Singh wrote: > KAMEZAWA Hiroyuki wrote: > > On Mon, 01 Sep 2008 11:39:26 +0530 > > Balbir Singh 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. > Hmm, one concern I have now is I don't see any contention on res_counter->lock in recent lock_stat test....which was usually on the top of list in past. Did you see it ? > Please don't let my patch stop you, we'll integrate the best of both worlds and > what is good for memcg. > Thank you. To be honest, I wonder control via page_cgroup may be too rich for 32bit archs ;(. Regards, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org