From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id AD2C76B004D for ; Tue, 17 Nov 2009 03:36:51 -0500 (EST) Received: from spaceape7.eur.corp.google.com (spaceape7.eur.corp.google.com [172.28.16.141]) by smtp-out.google.com with ESMTP id nAH8al1X002208 for ; Tue, 17 Nov 2009 00:36:48 -0800 Received: from pxi2 (pxi2.prod.google.com [10.243.27.2]) by spaceape7.eur.corp.google.com with ESMTP id nAH8ai7d029070 for ; Tue, 17 Nov 2009 00:36:45 -0800 Received: by pxi2 with SMTP id 2so4731959pxi.11 for ; Tue, 17 Nov 2009 00:36:44 -0800 (PST) Date: Tue, 17 Nov 2009 00:36:38 -0800 (PST) From: David Rientjes 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: linux-mm , LKML , Andrew Morton List-ID: 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, 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