Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754877AbZKQIgo (ORCPT ); Tue, 17 Nov 2009 03:36:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754591AbZKQIgn (ORCPT ); Tue, 17 Nov 2009 03:36:43 -0500 Received: from smtp-out.google.com ([216.239.45.13]:23736 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753666AbZKQIgm (ORCPT ); Tue, 17 Nov 2009 03:36:42 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=ojLMoEHp5jBVN9ODo8VfrN2zXLZk0cDj2sC/pFtKfYz7ihBAqauA+CLskQEdlavU8 dFObOsrp8GT9U4A6W0H+w== Date: Tue, 17 Nov 2009 00:36:38 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: KOSAKI Motohiro cc: linux-mm , LKML , Andrew Morton Subject: Re: [PATCH 0/7] Kill PF_MEMALLOC abuse In-Reply-To: <20091117172802.3DF4.A69D9226@jp.fujitsu.com> Message-ID: References: <20091117161551.3DD4.A69D9226@jp.fujitsu.com> <20091117172802.3DF4.A69D9226@jp.fujitsu.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1471 Lines: 27 On Tue, 17 Nov 2009, KOSAKI Motohiro wrote: > > I agree in principle with removing non-VM users of PF_MEMALLOC, but I > > think it should be left to the individual subsystem maintainers to apply > > or ack since the allocations may depend on the __GFP_NORETRY | ~__GFP_WAIT > > behavior of PF_MEMALLOC. This could be potentially dangerous for a > > PF_MEMALLOC user if allocations made by the kthread, for example, should > > never retry for orders smaller than PAGE_ALLOC_COSTLY_ORDER or block on > > direct reclaim. > > if there is so such reason. we might need to implement another MM trick. > but keeping this strage usage is not a option. All memory freeing activity > (e.g. page out, task killing) need some memory. we need to protect its > emergency memory. otherwise linux reliability decrease dramatically when > the system face to memory stress. > Right, that's why I agree with trying to remove non-VM use of PF_MEMALLOC, but I think this patchset needs to go through the individual subsystem maintainers so they can ensure the conversion doesn't cause undesirable results if their kthreads' memory allocations depend on the __GFP_NORETRY behavior that PF_MEMALLOC ensures. Otherwise it looks good. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/