From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e31.co.us.ibm.com (8.12.11/8.12.11) with ESMTP id j9CHSZrs027478 for ; Wed, 12 Oct 2005 13:28:35 -0400 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by westrelay02.boulder.ibm.com (8.12.10/NCO/VERS6.7) with ESMTP id j9CHTh8H475446 for ; Wed, 12 Oct 2005 11:29:43 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id j9CHTg3Z000789 for ; Wed, 12 Oct 2005 11:29:43 -0600 Message-ID: <434D47FF.1000602@austin.ibm.com> Date: Wed, 12 Oct 2005 12:29:35 -0500 From: Joel Schopp MIME-Version: 1.0 Subject: Re: [Lhms-devel] Re: [PATCH 5/8] Fragmentation Avoidance V17: 005_fallback References: <20051011151221.16178.67130.sendpatchset@skynet.csn.ul.ie> <20051011151246.16178.40148.sendpatchset@skynet.csn.ul.ie> <20051012164353.GA9425@w-mikek2.ibm.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Mel Gorman Cc: mike kravetz , akpm@osdl.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lhms-devel@lists.sourceforge.net List-ID: > In reality, no and it would only happen if a caller had specified both > __GFP_USER and __GFP_KERNRCLM in the call to alloc_pages() or friends. It > makes *no* sense for someone to do this, but if they did, an oops would be > thrown during an interrupt. The alternative is to get rid of this last > element and put a BUG_ON() check before the spinlock is taken. > > This way, a stupid caller will damage the fragmentation strategy (which is > bad). The alternative, the kernel will call BUG() (which is bad). The > question is, which is worse? > If in the future we hypothetically have code that damages the fragmentation strategy we want to find it sooner rather than never. I'd rather some kernels BUG() than we have bugs which go unnoticed. -- 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