From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from toip5.srvr.bell.ca ([209.226.175.88]) by tomts5-srv.bellnexxia.net (InterMail vM.5.01.06.13 201-253-122-130-113-20050324) with ESMTP id <20071204193037.TODX17217.tomts5-srv.bellnexxia.net@toip5.srvr.bell.ca> for ; Tue, 4 Dec 2007 14:30:37 -0500 Date: Tue, 4 Dec 2007 14:25:37 -0500 From: Mathieu Desnoyers Subject: Re: [RFC PATCH] LTTng instrumentation mm (updated) Message-ID: <20071204192537.GC31752@Krystal> References: <20071128140953.GA8018@Krystal> <1196268856.18851.20.camel@localhost> <20071129023421.GA711@Krystal> <1196317552.18851.47.camel@localhost> <20071130161155.GA29634@Krystal> <1196444801.18851.127.camel@localhost> <20071130170516.GA31586@Krystal> <1196448122.19681.16.camel@localhost> <20071130191006.GB3955@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: "Frank Ch. Eigler" Cc: Dave Hansen , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mbligh@google.com List-ID: * Frank Ch. Eigler (fche@redhat.com) wrote: > Mathieu Desnoyers writes: > > > [...] > >> > We would like to be able to tell which swap file the information has > >> > been written to/read from at any given time during the trace. > >> > >> Oh, tracing is expected to be on at all times? I figured someone would > >> encounter a problem, then turn it on to dig down a little deeper, then > >> turn it off. > > > > Yep, it can be expected to be on at all times, especially on production > > systems using "flight recorder" tracing to record information in a > > circular buffer [...] > > Considering how early in the boot sequence swap partitions are > activated, it seems optimistic to assume that the monitoring equipment > will always start up in time to catch the initial swapons. It would > be more useful if a marker parameter was included in the swap events > to let a tool/user map to /proc/swaps or a file name. > > - FChE Not early at all ? We have userspace processes running.. this is _late_ in the boot sequence! ;) Anyhow, that I have now is a combination including your proposal : - I dump the swapon/swapoff events. - I also dump the equivalent of /proc/swaps (with kernel internal information) at trace start to know what swap files are currently used. Does it sound fair ? Mathieu -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- 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