From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752223AbXDMCTH (ORCPT ); Thu, 12 Apr 2007 22:19:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752921AbXDMCTH (ORCPT ); Thu, 12 Apr 2007 22:19:07 -0400 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:26963 "HELO smtp107.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752223AbXDMCTF (ORCPT ); Thu, 12 Apr 2007 22:19:05 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=pAOGTz1x1VM9pShWPdgEJAHAPzYCEvQ5pbaVQBUC43Ca81L8gH96y4czglk0Dk1E+B77Vk9WcJ+N+unVusWmhjDnQtgBEw689cL0rIWA5bESmiX0WtfNhPAmQSasaYgWALuDL5bRQrSn4Tl80hGQpLs4CYC+ZDCanXw6RUYp7vM= ; X-YMail-OSG: N_aNdmAVM1nvsNTxlfICJOmM7wH87k3p_nMMahinlZT_ftaQSZCTrSrt2Vf63v8Ga9Gu.RmZ0A-- Message-ID: <461EE890.2040601@yahoo.com.au> Date: Fri, 13 Apr 2007 12:18:56 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Andrew Morton CC: William Lee Irwin III , Matt Mackall , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/13] maps: pagemap, kpagemap, and related cleanups References: <1.486631555@selenic.com> <20070412231050.GN2986@holomorphy.com> <20070412163235.dd030637.akpm@linux-foundation.org> <461ECB9C.8060000@yahoo.com.au> <20070412174201.065068b2.akpm@linux-foundation.org> <461ED96C.5030606@yahoo.com.au> <20070412182213.a18cc4a7.akpm@linux-foundation.org> <461EE005.6070605@yahoo.com.au> <20070412185723.5a5f0443.akpm@linux-foundation.org> In-Reply-To: <20070412185723.5a5f0443.akpm@linux-foundation.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Fri, 13 Apr 2007 11:42:29 +1000 Nick Piggin wrote: >>Maybe. How about LRU? Reclaim performance is bad, and you want to work out >>which pages keep going off the end of it, or which pages keep getting >>written out via it, or who's pages are on the active list, forcing mine >>out. > > > I guess we have static analysis versus dynamic. The interfaces which Matt > is proposing are suited to answering the question "what is my memory being > used for" (static). They're unlikely to be useful for answering the question > "what's happening in the VM" (dynamic). Systemtap is probably better for the > dynamic analysis. "what is my memory being used for *now*" ;) > I guess one could generate an answer to the static question with systemtap, > by accumulating running counts across the application lifetime and then > snapshotting them. Sounds hard though. Can't you just traverse arbitrary kernel data structures at a given point in time, exactly like the /proc/ call is doing? -- SUSE Labs, Novell Inc.