From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8441FC06513 for ; Thu, 4 Jul 2019 12:15:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5288B2189E for ; Thu, 4 Jul 2019 12:15:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727752AbfGDMPS (ORCPT ); Thu, 4 Jul 2019 08:15:18 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:51415 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727615AbfGDMPR (ORCPT ); Thu, 4 Jul 2019 08:15:17 -0400 Received: by mail-wm1-f68.google.com with SMTP id 207so5548289wma.1 for ; Thu, 04 Jul 2019 05:15:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=8JdSYBAH2R4iWrp9AtOPbWAInLP5rvqtz8MW15QLPWQ=; b=e/4C/p8VgEsri8UBrfvL42COuywMwjca7YzUAzsBinb3fQs+VanVfain93vj0z05z4 RYuP6V3Tri/FV6fJfAdEL6jhI+trqRSM/vJEZME/YuRDw0mmAHAXrSrF4PAV/Um+co4g TOIYeH9G4mU7VKhG8rUlqnLeazedC66vhRX8omJaUWC70DZBZ8DUxyFpu8fXQa9j6B0s tPVA1G5UzhOpZd4dVD/uE2MmvBY4AmYPUhxd5fhvl6u0i4Xg6eIqI45w7oCOn/ilw3k7 fnxmSnzXh/ZPrmz/DzsOrSj7ypGiDH8VzkLpVOEC5kvNauMVQMdiIoqcQuyIayfwEgrv z5oQ== X-Gm-Message-State: APjAAAWt4Yvd19fcR6z5F5hETHgdPYxQS1UQm/jPw6mbm6BHPmA149zh lpoTHgvEd+wAbzAstdhyY2MK3g== X-Google-Smtp-Source: APXvYqy/XHnwIGPw3Dn1ZxQ7L3TYQ6Pb9iT7u8RaTpass6DNag8j7SGxnuaZVAoXb/QEGM7J2cMXWg== X-Received: by 2002:a7b:cb94:: with SMTP id m20mr11914655wmi.144.1562242515927; Thu, 04 Jul 2019 05:15:15 -0700 (PDT) Received: from [10.201.49.68] (nat-pool-mxp-u.redhat.com. [149.6.153.187]) by smtp.gmail.com with ESMTPSA id n14sm11624948wra.75.2019.07.04.05.15.12 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Thu, 04 Jul 2019 05:15:13 -0700 (PDT) Subject: Re: [PATCH 1/2] kvm: x86: add likely to sched_info_on() To: Yi Wang Cc: rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org, xue.zhihong@zte.com.cn, up2wing@gmail.com, wang.liang82@zte.com.cn References: <1562240775-16086-1-git-send-email-wang.yi59@zte.com.cn> <1562240775-16086-2-git-send-email-wang.yi59@zte.com.cn> From: Paolo Bonzini Message-ID: <59ce6a26-f35f-8bb9-7392-13bcce6434e3@redhat.com> Date: Thu, 4 Jul 2019 14:15:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <1562240775-16086-2-git-send-email-wang.yi59@zte.com.cn> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/07/19 13:46, Yi Wang wrote: > The condition to test is likely() to be true when make defconfig. > Add the hint. > > Signed-off-by: Yi Wang > --- > arch/x86/kvm/cpuid.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 4992e7c..64fff41 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -642,7 +642,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > (1 << KVM_FEATURE_ASYNC_PF_VMEXIT) | > (1 << KVM_FEATURE_PV_SEND_IPI); > > - if (sched_info_on()) > + if (likely(sched_info_on())) > entry->eax |= (1 << KVM_FEATURE_STEAL_TIME); This is not a fast path, so adding likely/unlikely is unnecessary. Paolo > entry->ebx = 0; >