From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id BBCE76B004A for ; Wed, 6 Oct 2010 20:41:14 -0400 (EDT) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o970fCKq001233 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 7 Oct 2010 09:41:12 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id F3FAD45DE54 for ; Thu, 7 Oct 2010 09:41:11 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id B1CC845DE51 for ; Thu, 7 Oct 2010 09:41:11 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 993351DB8017 for ; Thu, 7 Oct 2010 09:41:11 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 2D30AE38004 for ; Thu, 7 Oct 2010 09:41:11 +0900 (JST) Date: Thu, 7 Oct 2010 09:35:45 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 04/10] memcg: disable local interrupts in lock_page_cgroup() Message-Id: <20101007093545.429fe04a.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <1286175485-30643-1-git-send-email-gthelen@google.com> <1286175485-30643-5-git-send-email-gthelen@google.com> <20101005160332.GB9515@barrios-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Greg Thelen , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, containers@lists.osdl.org, Andrea Righi , Balbir Singh , Daisuke Nishimura List-ID: On Wed, 6 Oct 2010 09:15:34 +0900 Minchan Kim wrote: > First of all, we could add your patch as it is and I don't expect any > regression report about interrupt latency. > That's because many embedded guys doesn't use mmotm and have a > tendency to not report regression of VM. > Even they don't use memcg. Hmm... > > I pass the decision to MAINTAINER Kame and Balbir. > Thanks for the detail explanation. > Hmm. IRQ delay is a concern. So, my option is this. How do you think ? 1. remove local_irq_save()/restore() in lock/unlock_page_cgroup(). yes, I don't like it. 2. At moving charge, do this: a) lock_page()/ or trylock_page() b) wait_on_page_writeback() c) do move_account under lock_page_cgroup(). c) unlock_page() Then, Writeback updates will never come from IRQ context while lock/unlock_page_cgroup() is held by move_account(). There will be no race. Do I miss something ? Thanks, -Kame -- 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