From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48F372BA.7020505@linux-foundation.org> Date: Mon, 13 Oct 2008 09:09:30 -0700 From: Christoph Lameter MIME-Version: 1.0 Subject: Re: [PATCH] mm: use a radix-tree to make do_move_pages() complexity linear References: <48EDF9DA.7000508@inria.fr> <20081010125010.164bcbb8.akpm@linux-foundation.org> <48EFB6E6.4080708@inria.fr> <48EFBBE9.5000703@linux-foundation.org> <48F069B8.6050709@inria.fr> In-Reply-To: <48F069B8.6050709@inria.fr> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Brice Goglin Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, nathalie.furmento@labri.fr List-ID: Brice Goglin wrote: > * One thing that bothers me is move_pages() returning -ENOENT when no > page are given to migrate_pages(). I don't see why having 100/100 pages > not migrated would return a different error than having only 99/100 > pages not migrated. We have the status array to place -ENOENT for all > these pages. If the user doesn't know where his pages are allocated, he > shouldn't get a different return value depending on how many pages were > already on the right node. And actually, this convention makes > user-space application harder to write since you need to treat -ENOENT > as a success unless you already knew for sure where your pages were > allocated. And the big thing is that this convention makes the chunking > painfully/uselessly more complex. Breaking user-ABI is bad, but fixing > crazy ABI... > I do not think that move_pages() is used that frequently. Changing the API slightly as you suggest would not be that big of a deal. -- 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