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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F0EDEE645C for ; Fri, 15 Sep 2023 12:54:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235138AbjIOMyJ (ORCPT ); Fri, 15 Sep 2023 08:54:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235034AbjIOMyI (ORCPT ); Fri, 15 Sep 2023 08:54:08 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DDACE19AE; Fri, 15 Sep 2023 05:53:59 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 02C4E1FB; Fri, 15 Sep 2023 05:54:37 -0700 (PDT) Received: from [10.1.197.1] (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 29E353F5A1; Fri, 15 Sep 2023 05:53:58 -0700 (PDT) Message-ID: <73655f9b-9ea4-cb46-d712-20f1c4ac7c95@arm.com> Date: Fri, 15 Sep 2023 13:53:56 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v2 5/5] hwtracing: hisi_ptt: Add dummy callback pmu::read() Content-Language: en-US To: Yicong Yang , mathieu.poirier@linaro.org, jonathan.cameron@huawei.com, linux-kernel@vger.kernel.org Cc: alexander.shishkin@linux.intel.com, helgaas@kernel.org, linux-pci@vger.kernel.org, prime.zeng@hisilicon.com, linuxarm@huawei.com, yangyicong@hisilicon.com, hejunhao3@huawei.com References: <20230914112223.27165-1-yangyicong@huawei.com> <20230914112223.27165-6-yangyicong@huawei.com> From: Suzuki K Poulose In-Reply-To: <20230914112223.27165-6-yangyicong@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/09/2023 12:22, Yicong Yang wrote: > From: Junhao He > > When start trace with perf option "-C $cpu" and immediately stop it > with SIGTERM or others, the perf core will invoke pmu::read() while > the driver doesn't implement it. Add a dummy pmu::read() to avoid > any issues. What issues are we talking about here ? Shouldn't the core perf skip the call, if pmu::read() is not available ? Suzuki > > Signed-off-by: Junhao He > Signed-off-by: Yicong Yang > Acked-by: Jonathan Cameron > --- > drivers/hwtracing/ptt/hisi_ptt.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c > index 62a444f5228e..c1b5fd2b8974 100644 > --- a/drivers/hwtracing/ptt/hisi_ptt.c > +++ b/drivers/hwtracing/ptt/hisi_ptt.c > @@ -1184,6 +1184,10 @@ static void hisi_ptt_pmu_del(struct perf_event *event, int flags) > hisi_ptt_pmu_stop(event, PERF_EF_UPDATE); > } > > +static void hisi_ptt_pmu_read(struct perf_event *event) > +{ > +} > + > static void hisi_ptt_remove_cpuhp_instance(void *hotplug_node) > { > cpuhp_state_remove_instance_nocalls(hisi_ptt_pmu_online, hotplug_node); > @@ -1227,6 +1231,7 @@ static int hisi_ptt_register_pmu(struct hisi_ptt *hisi_ptt) > .stop = hisi_ptt_pmu_stop, > .add = hisi_ptt_pmu_add, > .del = hisi_ptt_pmu_del, > + .read = hisi_ptt_pmu_read, > }; > > reg = readl(hisi_ptt->iobase + HISI_PTT_LOCATION);