From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id EED665F0001 for ; Wed, 15 Apr 2009 08:48:18 -0400 (EDT) Received: from localhost (smtp.ultrahosting.com [127.0.0.1]) by smtp.ultrahosting.com (Postfix) with ESMTP id DECE182C371 for ; Wed, 15 Apr 2009 08:58:44 -0400 (EDT) Received: from smtp.ultrahosting.com ([74.213.174.254]) by localhost (smtp.ultrahosting.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TDJuiuac-qgV for ; Wed, 15 Apr 2009 08:58:44 -0400 (EDT) Received: from qirst.com (unknown [74.213.171.31]) by smtp.ultrahosting.com (Postfix) with ESMTP id 3651982C3E0 for ; Wed, 15 Apr 2009 08:58:40 -0400 (EDT) Date: Wed, 15 Apr 2009 08:41:38 -0400 (EDT) From: Christoph Lameter Subject: Re: [PATCH] migration: only migrate_prep() once per move_pages() In-Reply-To: <49E5A9DC.2050309@inria.fr> Message-ID: References: <49E58D7A.4010708@ens-lyon.org> <20090415164955.41746866.kamezawa.hiroyu@jp.fujitsu.com> <49E5A9DC.2050309@inria.fr> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Brice Goglin Cc: KAMEZAWA Hiroyuki , linux-mm@kvack.org, LKML List-ID: On Wed, 15 Apr 2009, Brice Goglin wrote: > But lru_add_drain_all() touches some code that I am far from > understanding :/ Can we imagine using IPI instead of a deferred > work_struct for this kind of things? Or maybe, for each processor, check > whether drain_cpu_pagevecs() would have something to do before actually > scheduling the local work_struct? It's racy, but migrate_prep() doesn't > guarantee anyway that pages won't be moved out of the LRU before the > actual migration, so... IPI means that code must run with interrupts disabled. > > BTW, current users of sys_move_pages() does retry when it gets -EBUSY ? > > > > I'd say they ignore it since it doesn't happen often :) Right. -- 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