From patchwork Fri Feb 5 14:01:45 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 61271 Delivered-To: patch@linaro.org Received: by 10.112.43.199 with SMTP id y7csp1110296lbl; Fri, 5 Feb 2016 06:04:40 -0800 (PST) X-Received: by 10.66.253.137 with SMTP id aa9mr19972745pad.139.1454681080366; Fri, 05 Feb 2016 06:04:40 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id ln6si24130431pab.182.2016.02.05.06.04.36; Fri, 05 Feb 2016 06:04:40 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754056AbcBEOEf (ORCPT + 30 others); Fri, 5 Feb 2016 09:04:35 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:13309 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753449AbcBEOE2 (ORCPT ); Fri, 5 Feb 2016 09:04:28 -0500 Received: from 172.24.1.47 (EHLO SZXEML429-HUB.china.huawei.com) ([172.24.1.47]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DEF55828; Fri, 05 Feb 2016 22:03:14 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by SZXEML429-HUB.china.huawei.com (10.82.67.184) with Microsoft SMTP Server id 14.3.235.1; Fri, 5 Feb 2016 22:03:06 +0800 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Brendan Gregg CC: Adrian Hunter , Cody P Schafer , "David S. Miller" , He Kuang , =?UTF-8?q?J=C3=A9r=C3=A9mie=20Galarneau?= , Jiri Olsa , Kirill Smelkov , Li Zefan , Masami Hiramatsu , Namhyung Kim , Peter Zijlstra , , Wang Nan , Subject: [PATCH 20/54] perf core: Set event's default overflow_handler Date: Fri, 5 Feb 2016 14:01:45 +0000 Message-ID: <1454680939-24963-21-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1454680939-24963-1-git-send-email-wangnan0@huawei.com> References: <1454680939-24963-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.56B4ABA3.00DD, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 1df6681b572edf2ad91b792f9eb37e98 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Set a default event->overflow_handler in perf_event_alloc() so don't need checking event->overflow_handler in __perf_event_overflow(). Following commits can give a different default overflow_handler. No extra performance introduced into hot path because in the original code we still need reading this handler from memory. A conditional branch is avoided so actually we remove some instructions. Initial idea comes from Peter at [1]. [1] http://lkml.kernel.org/r/20130708121557.GA17211@twins.programming.kicks-ass.net Signed-off-by: Wang Nan Cc: He Kuang Cc: Alexei Starovoitov Cc: Arnaldo Carvalho de Melo Cc: Brendan Gregg Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com --- kernel/events/core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) -- 1.8.3.4 diff --git a/kernel/events/core.c b/kernel/events/core.c index 3e6a3ad..77a6475 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6392,10 +6392,7 @@ static int __perf_event_overflow(struct perf_event *event, irq_work_queue(&event->pending); } - if (event->overflow_handler) - event->overflow_handler(event, data, regs); - else - perf_event_output(event, data, regs); + event->overflow_handler(event, data, regs); if (*perf_event_fasync(event) && event->pending_kill) { event->pending_wakeup = 1; @@ -7869,8 +7866,13 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, context = parent_event->overflow_handler_context; } - event->overflow_handler = overflow_handler; - event->overflow_handler_context = context; + if (overflow_handler) { + event->overflow_handler = overflow_handler; + event->overflow_handler_context = context; + } else { + event->overflow_handler = perf_event_output; + event->overflow_handler_context = NULL; + } perf_event__state_init(event);