From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id A10546B005A for ; Tue, 28 Apr 2009 05:38:12 -0400 (EDT) Date: Tue, 28 Apr 2009 11:38:33 +0200 From: Ingo Molnar Subject: Re: [PATCH 5/5] proc: export more page flags in /proc/kpageflags Message-ID: <20090428093833.GE21085@elte.hu> References: <84144f020904280219p197d5ceag846ae9a80a76884e@mail.gmail.com> <20090428092918.GC21085@elte.hu> <20090428183237.EBDE.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090428183237.EBDE.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Pekka Enberg , Andi Kleen , Wu Fengguang , Steven Rostedt , =?utf-8?B?RnLpppjpp7tpYw==?= Weisbecker , Larry Woodman , Peter Zijlstra , Eduard - Gabriel Munteanu , Andrew Morton , LKML , Matt Mackall , Alexey Dobriyan , "linux-mm@kvack.org" List-ID: * KOSAKI Motohiro wrote: > > > > * Pekka Enberg wrote: > > > > > I have no idea how expensive tracepoints are but I suspect they > > > don't make too much sense for this particular scenario. After all, > > > kmemtrace is mainly interested in _allocation patterns_ whereas > > > this patch seems to be more interested in "memory layout" type of > > > things. > > > > My point is that the allocation patterns can be derived from dynamic > > events. We can build a map of everything if we know all the events > > that led up to it. Doing: > > > > echo 3 > /proc/sys/vm/drop_caches > > > > will clear 99% of the memory allocations, so we can build a new map > > from scratch just about anytime. (and if boot allocations are > > interesting they can be traced too) > > > > _And_ via this angle we'll also have access to the dynamic events, > > in a different 'view' of the same tracepoints - which is obviously > > very useful for different purposes. > > I am one of most strongly want guys to MM tracepoint. but No, many > cunstomer never permit to use drop_caches. See my other mail i just sent: it would be a natural extension of tracing to also dump all current object state when tracing is turned on. That way no drop_caches is needed at all. But it has to be expressed in one framework that cares about the totality of the kernel - not just these splintered bits of instrumentation and pieces of statistics. Ingo -- 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