Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751798Ab2KEPzu (ORCPT ); Mon, 5 Nov 2012 10:55:50 -0500 Received: from a193-30.smtp-out.amazonses.com ([199.255.193.30]:60545 "EHLO a193-30.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751358Ab2KEPzt (ORCPT ); Mon, 5 Nov 2012 10:55:49 -0500 Date: Mon, 5 Nov 2012 15:55:47 +0000 From: Christoph Lameter X-X-Sender: cl@gentwo.org To: =?GB2312?B?taXOwA==?= cc: paulmck@linux.vnet.ibm.com, dipankar@in.ibm.com, Kernel-Maillist Subject: Re: [PATCH v2 6/9] rcu: use __this_cpu_read helper instead of per_cpu_ptr(p, raw_smp_processor_id()) In-Reply-To: Message-ID: <0000013ad148e92a-ea123f83-e6f6-4131-8e15-8cf05cfd1e0a-000000@email.amazonses.com> References: <5093EE6B.3070906@gmail.com> <20121102181026.GY3027@linux.vnet.ibm.com> <0000013ac2c6e1f0-c10ec42d-70bb-4e24-99d6-8e70653eca83-000000@email.amazonses.com> <20121103091909.GI3027@linux.vnet.ibm.com> <509645A5.5070901@gmail.com> <0000013ad10bc571-9f707c9b-14e3-4382-a472-2a1aaa3fb384-000000@email.amazonses.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="288502408-1885430085-1352130896=:18751" X-SES-Outgoing: 199.255.193.30 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 937 Lines: 24 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --288502408-1885430085-1352130896=:18751 Content-Type: TEXT/PLAIN; charset=GB2312 Content-Transfer-Encoding: 8BIT On Mon, 5 Nov 2012, ���� wrote: > I guarantee that x86-64 don't use gs register here. run test again�� > Maybe there is some optimizations for __this_cpu_read call on x86-64�� not > sure. There is no optimization that I know of unless the compiler eliminated the __this_cpu_read completely. gs: is necessary to perform the implied relocation in this_cpu_read(). --288502408-1885430085-1352130896=:18751-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/