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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 AA7E8C31E40 for ; Fri, 9 Aug 2019 09:22:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 759212171F for ; Fri, 9 Aug 2019 09:22:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="A8vjojex" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 759212171F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=dh772mSfj2t4fVxQwZEp1IrkYksM3KU1v38nv7F5kec=; b=A8vjojexViyENPLEt8+1n+Lbh yRj4Re+gBsg93fUTXB5NESCDK7HyaIUoVCagzdn6gulKGWVH/I36Kws3DffWoNDt/0jdT8Lu31x/N OkO5SfqOvbeJSuncj3uPvHiotNG6DO4j5ifqf7YSB95ODKjtTKXa8uu4kZMr05GlO1cM4WBzSf7fW 9GIOytDuUFq/JE9vTdeFiQcpylgYRqXYquiSl1uheziK34QoBgRumN0ZerdlQow07mSv1Bi/UKL1h C8/TrfTarCWT5oika5MCiyqTYTdBZg+AX9N2w4dyjaFo4JXSC4YkCDuWpGRnN3ZrITIAo5OUK/tF/ 2rg0/BjyQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hw16B-0007WI-QT; Fri, 09 Aug 2019 09:22:11 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hw169-0007Vy-NI for linux-arm-kernel@lists.infradead.org; Fri, 09 Aug 2019 09:22:10 +0000 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 2483B15A2; Fri, 9 Aug 2019 02:22:09 -0700 (PDT) Received: from dawn-kernel.cambridge.arm.com (unknown [10.1.197.116]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6D8F53F575; Fri, 9 Aug 2019 02:22:08 -0700 (PDT) Subject: Re: [PATCH] coresight: tmc-etr: Remove perf_data check. To: yabinc@google.com, mathieu.poirier@linaro.org, alexander.shishkin@linux.intel.com References: <20190808193122.76679-1-yabinc@google.com> From: Suzuki K Poulose Message-ID: <84df6071-ef7e-c3d6-6ffa-fcfcbab0c8e6@arm.com> Date: Fri, 9 Aug 2019 10:22:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190808193122.76679-1-yabinc@google.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190809_022209_806455_01DCC63A X-CRM114-Status: GOOD ( 18.52 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Yabin, Thank you for the analysis and the patch. On 08/08/2019 20:31, Yabin Cui wrote: > When tracing etm data of multiple threads on multiple cpus through > perf interface, each cpu has a unique etr_perf_buffer while sharing > the same etr device. There is no guarantee that the last cpu starts > etm tracing also stops last. So the perf_data check is no longer valid. > > Signed-off-by: Yabin Cui > --- > drivers/hwtracing/coresight/coresight-tmc-etr.c | 9 --------- > drivers/hwtracing/coresight/coresight-tmc.h | 2 -- > 2 files changed, 11 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c > index 17006705287a..0418440e0141 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c > @@ -1484,20 +1484,12 @@ tmc_update_etr_buffer(struct coresight_device *csdev, > goto out; > } > > - if (WARN_ON(drvdata->perf_data != etr_perf)) { > - lost = true; > - spin_unlock_irqrestore(&drvdata->spinlock, flags); > - goto out; > - } > - I think some sort of sanity check is a good idea to make sure we don't loose the context. Even when different CPUs have different etr_perf buffer, the underlying etr_buf should be the same. So, we should be able to simply convert the check to, something like : struct etr_perf_buffer *perf_buf = drvdata->perf_data; ... if (WARN_ON(perf_buf->etr_buf != etr_perf->buf)) { .... } Does that solve the problem for you ? Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel