From patchwork Tue Jun 4 14:30:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Clark X-Patchwork-Id: 13685413 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 65C5FC25B78 for ; Tue, 4 Jun 2024 14:32:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jl+9meVgUi/jX8w7qrPYAO3XNDn7wkCL0NevBSfW/Uk=; b=wDSkXA3sjxUnzC HAoJ67L35z+ZsC5VH00YYVfuea+Br0PZbT+NvMXBip1K+izl5gJHn2wvUI9+eFUmtqakfJadLhO7B 5NCy4H0kNgUGluEFy7/I10vMguN1GmijO3Sc/xyFM/u5kWnsBaFUKbMEDCen23MX+wjHUg95WbGTx 87gO+U2Ucij+9uKZokadOjsfEnqSZ6iFI4Q/REv1Swa/2+RXbkrjsoPSTtCM2kkr08YtRZxR3Va1W OUva31VnJyxCevv6YOCIVtky58XMd2QsLjvEGijXCKEpz2uPFQt/sTM5nR1cbwEd022x38Y1RQDd+ 3/ZOI3pcCj8VZfB4GEwA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sEVDH-00000002iHG-0Xd7; Tue, 04 Jun 2024 14:32:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sEVDC-00000002iE3-2wi2 for linux-arm-kernel@lists.infradead.org; Tue, 04 Jun 2024 14:32:33 +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 3383F1042; Tue, 4 Jun 2024 07:32:54 -0700 (PDT) Received: from e127643.broadband (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CCA3A3F64C; Tue, 4 Jun 2024 07:32:26 -0700 (PDT) From: James Clark To: coresight@lists.linaro.org, suzuki.poulose@arm.com, gankulkarni@os.amperecomputing.com, mike.leach@linaro.org, leo.yan@linux.dev, anshuman.khandual@arm.com Cc: James Clark , Alexander Shishkin , Maxime Coquelin , Alexandre Torgue , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Jiri Olsa , Ian Rogers , Adrian Hunter , John Garry , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-perf-users@vger.kernel.org Subject: [PATCH v2 09/16] coresight: Clarify comments around the PID of the sink owner Date: Tue, 4 Jun 2024 15:30:18 +0100 Message-Id: <20240604143030.519906-10-james.clark@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240604143030.519906-1-james.clark@arm.com> References: <20240604143030.519906-1-james.clark@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240604_073231_135688_B35A9876 X-CRM114-Status: GOOD ( 16.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org "Process being monitored" and "pid of the process to monitor" imply that this would be the same PID if there were two sessions targeting the same process. But this is actually the PID of the process that did the Perf event open call, rather than the target of the session. So update the comments to make this clearer. Reviewed-by: Anshuman Khandual Reviewed-by: Mike Leach Signed-off-by: James Clark --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++-- drivers/hwtracing/coresight/coresight-tmc.h | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index e75428fa1592..8962fc27d04f 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -36,7 +36,8 @@ struct etr_buf_hw { * etr_perf_buffer - Perf buffer used for ETR * @drvdata - The ETR drvdaga this buffer has been allocated for. * @etr_buf - Actual buffer used by the ETR - * @pid - The PID this etr_perf_buffer belongs to. + * @pid - The PID of the session owner that etr_perf_buffer + * belongs to. * @snaphost - Perf session mode * @nr_pages - Number of pages in the ring buffer. * @pages - Array of Pages in the ring buffer. @@ -1662,7 +1663,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data) goto unlock_out; } - /* Get a handle on the pid of the process to monitor */ + /* Get a handle on the pid of the session owner */ pid = etr_perf->pid; /* Do not proceed if this device is associated with another session */ diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index c77763b49de0..2671926be62a 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -171,8 +171,9 @@ struct etr_buf { * @csdev: component vitals needed by the framework. * @miscdev: specifics to handle "/dev/xyz.tmc" entry. * @spinlock: only one at a time pls. - * @pid: Process ID of the process being monitored by the session - * that is using this component. + * @pid: Process ID of the process that owns the session that is using + * this component. For example this would be the pid of the Perf + * process. * @buf: Snapshot of the trace data for ETF/ETB. * @etr_buf: details of buffer used in TMC-ETR * @len: size of the available trace for ETF/ETB.