From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrea Righi Subject: Re: [patch 0/7] cpuset writeback throttling Date: Mon, 10 Nov 2008 10:02:13 +0100 Message-ID: <4917F895.109@gmail.com> References: <20081104124753.fb1dde5a.akpm@linux-foundation.org> <1225831988.7803.1939.camel@twins> <20081104131637.68fbe055.akpm@linux-foundation.org> <1225833710.7803.1993.camel@twins> <20081104135004.f1717fcf.akpm@linux-foundation.org> <20081104143534.b5c16147.akpm@linux-foundation.org> <20081104153610.bbfd5ed8.akpm@linux-foundation.org> <20081104190505.769b93ec.akpm@linux-foundation.org> <20081105133157.db8bae72.kamezawa.hiroyu@jp.fujitsu.com> Reply-To: righi.andrea@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081105133157.db8bae72.kamezawa.hiroyu@jp.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org To: KAMEZAWA Hiroyuki , rientjes@google.com Cc: Andrew Morton , Christoph Lameter , peterz@infradead.org, npiggin@suse.de, menage@google.com, dfults@sgi.com, linux-kernel@vger.kernel.org, containers@lists.osdl.org List-Id: containers.vger.kernel.org On 2008-11-05 05:31, KAMEZAWA Hiroyuki wrote: > On Tue, 4 Nov 2008 19:05:05 -0800 > Andrew Morton wrote: >> Generally, I worry that this is a specific fix to a specific problem >> encountered on specific machines with specific setups and specific >> workloads, and that it's just all too low-level and myopic. >> >> And now we're back in the usual position where there's existing code and >> everyone says it's terribly wonderful and everyone is reluctant to step >> back and look at the big picture. Am I wrong? >> >> >> Plus: we need per-memcg dirty-memory throttling, and this is more >> important than per-cpuset, I suspect. How will the (already rather >> buggy) code look once we've stuffed both of them in there? >> >> > IIUC, Andrea Righ posted 2 patches around dirty_ratio. (added him to CC:) > in early October. > > (1) patch for adding dirty_ratio_pcm. (1/100000) > (2) per-memcg dirty ratio. (maybe this..http://lkml.org/lkml/2008/9/12/121) > > (1) should be just posted again. > > Because we have changed page_cgroup implementation, (2) should be reworked. > "rework" itself will not be very difficult. > (.... we tend to be stick to "what interface is the best" discussion ;) > > But memcg itself is not so weak against dirty_pages because we don't call > try_to_free_pages() becasue of memory shortage but because of memory limitation. > > BTW, in my current stack, followings are queued. > a. handle SwapCache in proper way in memcg. > b. handle swap_cgroup (if configured) > c. make LRU handling easier > > For making per-memcg dirty_ratio sane, (a) should go ahead. I do (a) now. > If Andrea seems to be too busy, I'll schedule dirty_ratio-for-memcg as my work. > Hi Kame, sorry for my late. If it's not too late tonight I'll rebase and test (1) to 2.6.28-rc2-mm1 and start to rework on (2), also considering the David's suggestion (split NR_UNSTABLE_NFS from NR_FILE_DIRTY). -Andrea