From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Landley Subject: Re: OOM killer gripe (was Re: What still uses the block layer?) Date: Mon, 15 Oct 2007 04:52:30 -0500 Message-ID: <200710150452.30939.rob@landley.net> References: <200710112011.22000.rob@landley.net> <200710150304.00901.rob@landley.net> <200710152337.45252.nickpiggin@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from static-71-162-243-5.phlapa.fios.verizon.net ([71.162.243.5]:51356 "EHLO grelber.thyrsus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758235AbXJOJwf (ORCPT ); Mon, 15 Oct 2007 05:52:35 -0400 In-Reply-To: <200710152337.45252.nickpiggin@yahoo.com.au> Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Nick Piggin Cc: Theodore Tso , James Bottomley , Matthew Wilcox , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Suparna Bhattacharya , Nick Piggin On Monday 15 October 2007 8:37:44 am Nick Piggin wrote: > > Virtual memory isn't perfect. I've _always_ been able to come up with > > examples where it just doesn't work for me. This doesn't mean VM > > overcommit should be abolished, because it's useful more often than not. > > I hate to go completely offtopic here, but disks are so incredibly > slow when compared to RAM that there is really nothing the kernel > can do about this. I know. > Presumably the job will finish, given infinite > time. I gave it about half an hour, then it locked solid and stopped writing to the disk at all. (I gave it another 5 minutes at that point, then held down the power button.) Lost about 50 open konqueror tabs... > How much swap do you have configured? 2 gigs, same as ram. > You really shouldn't configure > so much unless you do want the kernel to actually use it all, right? Two words: "Software suspend". I've actually been thinking of increasing it on the next install... > Because if we're not really conservative about OOM killing, then the > user who actually really did want to use all the swap they configured > gets angry when we kill their jobs without using it all. I tend to lower "swappiness" and when that happens all sorts of stuff goes weird. Software suspend used to say says it can't free enough memory if I put swappiness at 0 (dunno if it still does). This time the OOM killer never triggered before hard deadlock. (I think I had it around 20 or 40 or some such.) > Would an oom-kill-someone-now sysrq be of help, I wonder? *shrug* It might. I was a letting it run hoping it would complete itself when it locked solid. (The keyboard LEDs weren't flashing, so I don't _think_ it paniced. I was in X so I wouldn't have seen a message...) (To be honest, I can never remember how to trigger sysrq on a laptop keyboard. Presumably X won't intercept it the way it does alt-f1 and ctrl-alt-del...) Rob -- "One of my most productive days was throwing away 1000 lines of code." - Ken Thompson.