From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id AD5D94402ED for ; Wed, 25 Nov 2015 10:46:10 -0500 (EST) Received: by wmec201 with SMTP id c201so262396667wme.0 for ; Wed, 25 Nov 2015 07:46:10 -0800 (PST) Received: from mail-wm0-f49.google.com (mail-wm0-f49.google.com. [74.125.82.49]) by mx.google.com with ESMTPS id m197si6647843wmd.63.2015.11.25.07.46.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Nov 2015 07:46:09 -0800 (PST) Received: by wmvv187 with SMTP id v187so263125476wmv.1 for ; Wed, 25 Nov 2015 07:46:09 -0800 (PST) Date: Wed, 25 Nov 2015 16:46:07 +0100 From: Michal Hocko Subject: Re: [PATCH v2 3/9] mm, page_owner: convert page_owner_inited to static key Message-ID: <20151125154607.GO27283@dhcp22.suse.cz> References: <1448368581-6923-1-git-send-email-vbabka@suse.cz> <1448368581-6923-4-git-send-email-vbabka@suse.cz> <20151125145202.GL27283@dhcp22.suse.cz> <5655CEDB.3040205@suse.cz> <20151125152533.GC17308@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151125152533.GC17308@twins.programming.kicks-ass.net> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Joonsoo Kim , Minchan Kim , Sasha Levin , "Kirill A. Shutemov" , Mel Gorman On Wed 25-11-15 16:25:33, Peter Zijlstra wrote: > On Wed, Nov 25, 2015 at 04:08:11PM +0100, Vlastimil Babka wrote: > > Now I admit I have no idea if there are architectures that don't support jump > > labels *and* have an expensive atomic read, and whether we care? > > atomic_read() is basically always READ_ONCE(), there's a few archs that > implement it in asm with a 'weird' load instruction, but its still a > load. The worst is I think an uncached load for blackfin or somesuch. > > There's plenty archs that do not support the jump label bits, but > typically you don't care much about those. I'm not aware of an arch that > cannot fundamentally implement jump_label support if they wanted to. OK, I see. Thanks for the clarification! Then I do not have any objections. -- Michal Hocko SUSE Labs -- 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