From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 7A62D6B0047 for ; Sun, 17 Jan 2010 08:27:11 -0500 (EST) From: "Rafael J. Wysocki" Subject: Re: [RFC][PATCH] PM: Force GFP_NOIO during suspend/resume (was: Re: [linux-pm] Memory allocations in .suspend became very unreliable) Date: Sun, 17 Jan 2010 14:27:27 +0100 References: <1263549544.3112.10.camel@maxim-laptop> <201001170138.37283.rjw@sisk.pl> <201001170224.36267.oliver@neukum.org> In-Reply-To: <201001170224.36267.oliver@neukum.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201001171427.27954.rjw@sisk.pl> Sender: owner-linux-mm@kvack.org To: Oliver Neukum Cc: Maxim Levitsky , linux-pm@lists.linux-foundation.org, LKML , linux-mm , Andrew Morton , Benjamin Herrenschmidt List-ID: On Sunday 17 January 2010, Oliver Neukum wrote: > Am Sonntag, 17. Januar 2010 01:38:37 schrieb Rafael J. Wysocki: > > > Now having said that, we've been considering a change that will turn all > > > GFP_KERNEL allocations into GFP_NOIO during suspend/resume, so perhaps I'll > > > prepare a patch to do that and let's see what people think. > > > > If I didn't confuse anything (which is likely, because it's a bit late here > > now), the patch below should do the trick. I have only checked that it doesn't > > break compilation, so please take it with a grain of salt. > > > > Comments welcome. > > I think this is a bad idea as it makes the mm subsystem behave differently > in the runtime and in the whole system cases. s/runtime/suspend/ ? Yes it will, but why exactly shouldn't it? System suspend/resume _is_ a special situation anyway. > What's so hard about telling people that they need to use GFP_NOIO in > suspend() and resume()? Memory allocations are made for other purposes during suspend/resume too. For example, new kernel threads may be created (for async suspend/resume among other things). Besides, the fact that you tell people to do something doesn't necessary imply that they will listen. :-) I have discussed that with Ben for a couple of times and we have generally agreed that memory allocation problems during suspend/resume are not avoidable in general unless we disable __GFP_FS and __GFP_IO at the high level. Rafael -- 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