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[23.128.96.33]) by mx.google.com with ESMTPS id n14-20020a170903110e00b001bbcb3d9265si10189925plh.68.2023.09.25.03.27.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Sep 2023 03:27:06 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by lipwig.vger.email (Postfix) with ESMTP id DF52D81CEB35; Mon, 25 Sep 2023 03:14:12 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at lipwig.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231132AbjIYKNw (ORCPT + 29 others); Mon, 25 Sep 2023 06:13:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231548AbjIYKNc (ORCPT ); Mon, 25 Sep 2023 06:13:32 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D76DC2697; Mon, 25 Sep 2023 03:02:07 -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 C943ADA7; Mon, 25 Sep 2023 03:02:45 -0700 (PDT) Received: from [10.57.36.242] (unknown [10.57.36.242]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C39193F59C; Mon, 25 Sep 2023 03:02:06 -0700 (PDT) Message-ID: Date: Mon, 25 Sep 2023 11:02:11 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Content-Language: en-US To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, zhengyejian1@huawei.com From: Christian Loehle Subject: [PATCH] tracing: document buffer_size_kb more precisely X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (lipwig.vger.email [0.0.0.0]); Mon, 25 Sep 2023 03:14:12 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778004919930628232 X-GMAIL-MSGID: 1778004919930628232 buffer_size_kb no longer shows the requested amount, but the one that is actually used internally for the ring buffer. commit 6d98a0f2ac3c ("tracing: Set actual size after ring buffer resize") changed the sysfs behavior such that value read will always show the actual size, while previously it showed the size that was requested through the sysfs interface, even if it was rounded up to fulfill the request. So the documentation can state that more precisely now. Signed-off-by: Christian Loehle --- Documentation/trace/ftrace.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 23572f6697c0..2e066b3b6edc 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -191,7 +191,7 @@ of ftrace. Here is a list of some of the key files: A few extra pages may be allocated to accommodate buffer management meta-data. If the last page allocated has room for more bytes than requested, the rest of the page will be used, - making the actual allocation bigger than requested or shown. + making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management meta-data. )