From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43977A92.3090206@yahoo.com.au> Date: Thu, 08 Dec 2005 11:13:06 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [RFC 1/3] Framework for accurate node based statistics References: <20051206182843.19188.82045.sendpatchset@schroedinger.engr.sgi.com> <439619F9.4030905@yahoo.com.au> <439684C0.9090107@yahoo.com.au> <43976949.8010205@yahoo.com.au> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: linux-kernel@vger.kernel.org, Hugh Dickins , linux-mm@kvack.org, Andi Kleen , Marcelo Tosatti List-ID: Christoph Lameter wrote: > On Thu, 8 Dec 2005, Nick Piggin wrote: > > >>Christoph Lameter wrote: >> >>>On Wed, 7 Dec 2005, Nick Piggin wrote: >>> >>>>Sorry, I think I meant: why don't you just use the "add all counters >>>>from all per-cpu of the node" in order to find the node-statistic? >>> >>>which function is that? >>> >> >>I'm thinking of get_page_state_node... but that's not quite the same >>thing. I guess sum all per-CPU counters from all zones in the node, >>but that's going to be costly on big machines. > > > The per cpu counters count when a cpu did an allocation. They do not count > on which node the allocation was done and are thereofre not useful to > determine the memory use on one node. > Yes, not that exact function of course. > >>So I'm not sure, I guess I don't have any bright ideas... there is the >>batching approach used by current pagecache_acct - is something like >>that not sufficient either? > > > The framework provides a similar approach by keeping differential > counters for each processor. > But the accounting delay has the unbounded error problem that the batching approach does not. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com -- 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