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 1F3326B016C for ; Thu, 25 Aug 2011 15:05:35 -0400 (EDT) Subject: Re: [PATCH] memcg: remove unneeded preempt_disable From: Peter Zijlstra Date: Thu, 25 Aug 2011 21:05:15 +0200 In-Reply-To: References: <1313650253-21794-1-git-send-email-gthelen@google.com> <20110818144025.8e122a67.akpm@linux-foundation.org> <1314284272.27911.32.camel@twins> <1314289208.3268.4.camel@mulgrave> <986ca4ed-6810-426f-b32f-5c8687e3a10b@email.android.com> <1e295500-5d1f-45dd-aa5b-3d2da2cf1a62@email.android.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID: <1314299115.26922.2.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: James Bottomley , Andrew Morton , Greg Thelen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, KAMEZAWA Hiroyuki , Balbir Singh , Daisuke Nishimura , linux-arch@vger.kernel.org On Thu, 2011-08-25 at 13:46 -0500, Christoph Lameter wrote: >=20 > RISC cpus have instruction to construct complex atomic actions by the cpu > as I have shown before for ARM.=20 Also, I thought this_cpu thing's were at best locally atomic. If you make them full blown atomic ops then even __this_cpu ops will have to be full atomic ops, otherwise: CPU0 CPU(1) this_cpu_inc(&foo); preempt_disable(); __this_cpu_inc(&foo); preempt_enable(); might step on each other's toes. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org