From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755283AbZFYJ5k (ORCPT ); Thu, 25 Jun 2009 05:57:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754000AbZFYJ5a (ORCPT ); Thu, 25 Jun 2009 05:57:30 -0400 Received: from gate.crashing.org ([63.228.1.57]:36449 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752303AbZFYJ5a (ORCPT ); Thu, 25 Jun 2009 05:57:30 -0400 Subject: Re: [PATCH v2] slab,slub: ignore __GFP_WAIT if we're booting or suspending From: Benjamin Herrenschmidt To: Nick Piggin Cc: Pavel Machek , Pekka J Enberg , linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, akpm@linux-foundation.org, cl@linux-foundation.org, torvalds@linux-foundation.org, "Rafael J. Wysocki" In-Reply-To: <20090625043432.GA23949@wotan.suse.de> References: <20090619145913.GA1389@ucw.cz> <1245450449.16880.10.camel@pasglop> <20090619232336.GA2442@elf.ucw.cz> <1245455409.16880.15.camel@pasglop> <20090620002817.GA2524@elf.ucw.cz> <1245463809.16880.18.camel@pasglop> <20090621061847.GB1474@ucw.cz> <1245576665.16880.24.camel@pasglop> <20090625043432.GA23949@wotan.suse.de> Content-Type: text/plain Date: Thu, 25 Jun 2009 19:56:33 +1000 Message-Id: <1245923793.22312.5.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Maybe so. Masking off __GFP_WAIT up in slab and page allocator > isn't really needed though (or necessarily a good idea to throw > out that information far from where it is used). > > Checking for suspend active and avoiding writeout from reclaim > for example might be a better idea. Ah ok. Yes, I agree. I'm not familiar with those code path and so masking gfp here sounded like the easier solution but you may well be right here :-) > > So yes, just applying the mask would help, but wouldn't completely fix > > it unless we also find a way to synchronize. > > You could potentially use srcu or something like that in page > reclaim in order to have a way to be able to kick everyone > out. page reclaim entry/exit from the page allocator isn't such > a fastpath though, so even a simple mutex or something may be > possible. Ok. Well, I'll leave that to the suspend/resume folks for now, as I'm way too busy at the moment to give that a serious look, but thanks for the pointer. Cheers, Ben. > -- > 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