From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 512036B00AF for ; Sat, 9 May 2009 05:24:28 -0400 (EDT) Date: Sat, 9 May 2009 11:24:31 +0200 From: Ingo Molnar Subject: Re: [patch] tracing/mm: add page frame snapshot trace Message-ID: <20090509092431.GB13784@elte.hu> References: <20090508105320.316173813@intel.com> <20090508111031.020574236@intel.com> <20090508114742.GB17129@elte.hu> <20090508124433.GB15949@localhost> <20090509062758.GB21354@elte.hu> <20090509091325.GA7994@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090509091325.GA7994@localhost> Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Steven Rostedt , Peter Zijlstra , Li Zefan , Andrew Morton , LKML , KOSAKI Motohiro , Andi Kleen , Matt Mackall , Alexey Dobriyan , "linux-mm@kvack.org" List-ID: * Wu Fengguang wrote: > Hi Ingo, > > On Sat, May 09, 2009 at 02:27:58PM +0800, Ingo Molnar wrote: > > > > * Wu Fengguang wrote: > > > > > > So this should be done in cooperation with instrumentation > > > > folks, while improving _all_ of Linux instrumentation in > > > > general. Or, if you dont have the time/interest to work with us > > > > on that, it should not be done at all. Not having the > > > > resources/interest to do something properly is not a license to > > > > introduce further instrumentation crap into Linux. > > > > > > I'd be glad to work with you on the 'object collections' ftrace > > > interfaces. Maybe next month. For now my time have been allocated > > > for the hwpoison work, sorry! > > > > No problem - our offer still stands: we are glad to help out with > > the instrumentation side bits. We'll even write all the patches for > > you, just please help us out with making it maximally useful to > > _you_ :-) > > Thank you very much! > > The good fact is, 2/3 of the code and experiences can be reused. > > > Find below a first prototype patch written by Steve yesterday and > > tidied up a bit by me today. It can also be tried on latest -tip: > > > > http://people.redhat.com/mingo/tip.git/README > > > > This patch adds the first version of the 'object collections' > > instrumentation facility under /debug/tracing/objects/mm/. It has a > > single control so far, a 'number of pages to dump' trigger file: > > > > To dump 1000 pages to the trace buffers, do: > > > > echo 1000 > /debug/tracing/objects/mm/pages/trigger > > > > To dump all pages to the trace buffers, do: > > > > echo -1 > /debug/tracing/objects/mm/pages/trigger > > That is not too intuitive, I'm afraid. This was just a first-level approximation - and it matches the usual "0xffffffff means infinite" idiom. How about changing it from 'trigger' to 'dump_range': echo "*" > /debug/tracing/objects/mm/pages/dump_range being a shortcut for 'dump all'? And: echo "1000 2000" > /debug/tracing/objects/mm/pages/dump_range ? The '1000' is the offset where the dumping starts, and 2000 is the size of the dump. 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