From patchwork Thu Oct 6 22:31:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Elliott, Robert \(Servers\)" X-Patchwork-Id: 613008 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 DC197C433F5 for ; Thu, 6 Oct 2022 22:37:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231834AbiJFWhW (ORCPT ); Thu, 6 Oct 2022 18:37:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229849AbiJFWhV (ORCPT ); Thu, 6 Oct 2022 18:37:21 -0400 Received: from mx0a-002e3701.pphosted.com (mx0a-002e3701.pphosted.com [148.163.147.86]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 044D592593; Thu, 6 Oct 2022 15:37:21 -0700 (PDT) Received: from pps.filterd (m0134422.ppops.net [127.0.0.1]) by mx0b-002e3701.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 296MYusK001006; Thu, 6 Oct 2022 22:37:16 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=hpe.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pps0720; bh=Duxug50hyqlUo3vJQebtcrpCMNmKwa8QfgSYdJzoNuM=; b=UhZyX7MU0w0HqSuDw3L+7n1VfgicJUNVpqT5yfol8RiGbu2SHXmcDOsDE+GDPG17WbB5 +4a0STX/LZgmBfZLHSGwLsNu9Ly3k4rn26owIePqTqDLTzLeKy280HQ3SqOeeAISp0BU v8+83FTDfuARSYr5Wl+e4Y0B/N+BvfwoLvcgKFMwcksgclqIfIWYK93WzR4SW8okQmb/ djJyx4EOfjQzkWH/zotD2XEMRn0A0wLnO5IHlQvYpZZwn0rhOH5Z+NXYQrzqAVnlHf5N oGNwTh9xPV3BMm42dCGu7cWyAvPUhLMX1s0Exp4tH4oUi3YQIfQrrhspV0V6FtI/6R/X nw== Received: from p1lg14878.it.hpe.com (p1lg14878.it.hpe.com [16.230.97.204]) by mx0b-002e3701.pphosted.com (PPS) with ESMTPS id 3k27xag0ke-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 06 Oct 2022 22:37:15 +0000 Received: from p1lg14885.dc01.its.hpecorp.net (unknown [10.119.18.236]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by p1lg14878.it.hpe.com (Postfix) with ESMTPS id 65B3313949; Thu, 6 Oct 2022 22:32:15 +0000 (UTC) Received: from adevxp033-sys.us.rdlabs.hpecorp.net (unknown [16.231.227.36]) by p1lg14885.dc01.its.hpecorp.net (Postfix) with ESMTP id 162C6803AB6; Thu, 6 Oct 2022 22:32:15 +0000 (UTC) From: Robert Elliott To: herbert@gondor.apana.org.au, davem@davemloft.net, tim.c.chen@linux.intel.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Robert Elliott Subject: [RFC PATCH 1/7] rcu: correct CONFIG_EXT_RCU_CPU_STALL_TIMEOUT descriptions Date: Thu, 6 Oct 2022 17:31:45 -0500 Message-Id: <20221006223151.22159-2-elliott@hpe.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221006223151.22159-1-elliott@hpe.com> References: <20221006223151.22159-1-elliott@hpe.com> MIME-Version: 1.0 X-Proofpoint-ORIG-GUID: 3tntthtH4ugWrwTBrPT1WkqFVy2HJArY X-Proofpoint-GUID: 3tntthtH4ugWrwTBrPT1WkqFVy2HJArY X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-10-06_05,2022-10-06_02,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 bulkscore=0 adultscore=0 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 spamscore=0 impostorscore=0 suspectscore=0 phishscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210060133 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Make the descriptions of CONFIG_EXT_RCU_CPU_STALL_TIMEOUT match the code: - there is no longer a default of 20 ms for Android since commit 1045a06724f3 ("remove CONFIG_ANDROID"), - the code includes a maximum of 21 seconds, evident when specifying 0 which means to use the CONFIG_RCU_STALL_TIMEOUT value (whose default is 60 seconds). Example .config: CONFIG_RCU_CPU_STALL_TIMEOUT=60 CONFIG_RCU_EXP_CPU_STALL_TIMEOUT=0 leads to: /sys/module/rcupdate/parameters/rcu_cpu_stall_timeout:60 /sys/module/rcupdate/parameters/rcu_exp_cpu_stall_timeout:21000 Fixes: 1045a06724f3 ("remove CONFIG_ANDROID") Signed-off-by: Robert Elliott --- Documentation/RCU/stallwarn.rst | 9 +++++---- kernel/rcu/Kconfig.debug | 2 +- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst index e38c587067fc..d86a8b47504f 100644 --- a/Documentation/RCU/stallwarn.rst +++ b/Documentation/RCU/stallwarn.rst @@ -168,10 +168,11 @@ CONFIG_RCU_EXP_CPU_STALL_TIMEOUT Same as the CONFIG_RCU_CPU_STALL_TIMEOUT parameter but only for the expedited grace period. This parameter defines the period of time that RCU will wait from the beginning of an expedited - grace period until it issues an RCU CPU stall warning. This time - period is normally 20 milliseconds on Android devices. A zero - value causes the CONFIG_RCU_CPU_STALL_TIMEOUT value to be used, - after conversion to milliseconds. + grace period until it issues an RCU CPU stall warning. + + A zero value causes the CONFIG_RCU_CPU_STALL_TIMEOUT value to be + used, after conversion to milliseconds, limited to a maximum of + 21 seconds. This configuration parameter may be changed at runtime via the /sys/module/rcupdate/parameters/rcu_exp_cpu_stall_timeout, however diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug index 1b0c41d490f0..4477eeb8a54f 100644 --- a/kernel/rcu/Kconfig.debug +++ b/kernel/rcu/Kconfig.debug @@ -93,7 +93,7 @@ config RCU_EXP_CPU_STALL_TIMEOUT If the RCU grace period persists, additional CPU stall warnings are printed at more widely spaced intervals. A value of zero says to use the RCU_CPU_STALL_TIMEOUT value converted from - seconds to milliseconds. + seconds to milliseconds, limited to a maximum of 21 seconds. config RCU_TRACE bool "Enable tracing for RCU"