From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree Date: Fri, 21 Sep 2012 13:16:02 -0700 Message-ID: <20120921201602.GN7264@google.com> References: <1347977530-29755-1-git-send-email-glommer@parallels.com> <1347977530-29755-10-git-send-email-glommer@parallels.com> <00000139d9fe8595-8905906d-18ed-4d41-afdb-f4c632c2d50a-000000@email.amazonses.com> <5059777E.8060906@parallels.com> <505C33D3.5000202@parallels.com> <20120921200733.GM7264@google.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=awTSgynr58EnOeWqHI2C9/wDajgV/xYbg7EJTirp4uU=; b=1HbvDMizB1zZi1VL/9DoW739EjwpNfdXil9iwamhAmG9ojbZjdT7GiVNoTFIC+KdkR CGcJo5tgImdhJUsA5pwsZJUtbg1KU0PudBzjji0JrOGYe6XrTAiioVoP5EN7tNDzg8DZ VB/83LiqFkr2fNjP0izmbPPzywpIVTpWxJQyq77tmXPTlokKBE7sN7lpfR9T9KcoTES7 K1//GftykGL3/yHIAwbFH5UDE2Gakyi7Hje9rfoe9bMKASPRdVBfL425Gm2JEfgS8313 U9i6DOdadDPDoFy7bJLxiH5qa55fjQViiQj8Infkn4LHndznxycJQK4QGMAQ0WCYBh0/ bCaw== Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Pekka Enberg Cc: Glauber Costa , Christoph Lameter , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, devel@openvz.org, linux-mm@kvack.org, Suleiman Souhlal , Frederic Weisbecker , Mel Gorman , David Rientjes , Ingo Molnar , Steven Rostedt On Fri, Sep 21, 2012 at 11:14:45PM +0300, Pekka Enberg wrote: > On Fri, Sep 21, 2012 at 11:07 PM, Tejun Heo wrote: > > Not necessarily disagreeing, but I don't think it's helpful to set the > > bar impossibly high. Even static_key doesn't have "exactly *zero*" > > impact. Let's stick to as minimal as possible when not in use and > > reasonable in use. > > For !CONFIG_MEMCG_KMEM, it should be exactly zero. No need to play > games with static_key. Ah, misread, though you were talking about MEMCG_KMEM && not in use. Yeap, if turned off in Kconfig, it shouldn't have any performance overhead. Thanks. -- tejun -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757930Ab2IUUQJ (ORCPT ); Fri, 21 Sep 2012 16:16:09 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:57886 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752725Ab2IUUQH (ORCPT ); Fri, 21 Sep 2012 16:16:07 -0400 Date: Fri, 21 Sep 2012 13:16:02 -0700 From: Tejun Heo To: Pekka Enberg Cc: Glauber Costa , Christoph Lameter , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, devel@openvz.org, linux-mm@kvack.org, Suleiman Souhlal , Frederic Weisbecker , Mel Gorman , David Rientjes , Ingo Molnar , Steven Rostedt Subject: Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree Message-ID: <20120921201602.GN7264@google.com> References: <1347977530-29755-1-git-send-email-glommer@parallels.com> <1347977530-29755-10-git-send-email-glommer@parallels.com> <00000139d9fe8595-8905906d-18ed-4d41-afdb-f4c632c2d50a-000000@email.amazonses.com> <5059777E.8060906@parallels.com> <505C33D3.5000202@parallels.com> <20120921200733.GM7264@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 21, 2012 at 11:14:45PM +0300, Pekka Enberg wrote: > On Fri, Sep 21, 2012 at 11:07 PM, Tejun Heo wrote: > > Not necessarily disagreeing, but I don't think it's helpful to set the > > bar impossibly high. Even static_key doesn't have "exactly *zero*" > > impact. Let's stick to as minimal as possible when not in use and > > reasonable in use. > > For !CONFIG_MEMCG_KMEM, it should be exactly zero. No need to play > games with static_key. Ah, misread, though you were talking about MEMCG_KMEM && not in use. Yeap, if turned off in Kconfig, it shouldn't have any performance overhead. Thanks. -- tejun