From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id 0EE486B016A for ; Thu, 25 Aug 2011 19:01:52 -0400 (EDT) Subject: Re: [PATCH] memcg: remove unneeded preempt_disable From: Peter Zijlstra Date: Fri, 26 Aug 2011 01:01:37 +0200 In-Reply-To: <1314300546.3268.8.camel@mulgrave> 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> <1314300546.3268.8.camel@mulgrave> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID: <1314313297.26922.17.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: James Bottomley Cc: Christoph Lameter , 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 12:29 -0700, James Bottomley wrote: >=20 > Therefore from the risc point of view, most of the this_cpu_xxx > operations are things that we don't really care about except that the > result would be easier to read in C.=20 Right, so the current fallback case is pretty much the optimal case for the RISC machines, which ends up with generic code being better off not using it much and instead preferring __this_cpu if there's more than one. I mean, its absolutely awesome these things are 1 instruction on x86, but if we pessimize all other 20-odd architectures its just not cool. -- 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