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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 63928C433DF for ; Wed, 12 Aug 2020 22:58:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3DB5522BF5 for ; Wed, 12 Aug 2020 22:58:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597273092; bh=p6eLETLZRYgYan2ddKnQCwn/WJxewrAyq5jfA5ROAN8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BWBTfXzm/VKgEeTKP+TGUZjg4kCxFrrY14IuBqnK1GJTgW2H8Q9S9yQEQe80YVVa2 cQ7PYqBilmYFbQD8egtVI78rMEWSqzl+emoYFz507SW+eGkg8E0H8Jiy/z0D9ZIoWg lSToqNmb6wuUv73ob/M2cjc1k8Ah+2F1Y5L1Bol4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726834AbgHLW6I (ORCPT ); Wed, 12 Aug 2020 18:58:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:48940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726578AbgHLW5f (ORCPT ); Wed, 12 Aug 2020 18:57:35 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E1C320866; Wed, 12 Aug 2020 22:57:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597273055; bh=p6eLETLZRYgYan2ddKnQCwn/WJxewrAyq5jfA5ROAN8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZFIyMDWMKGs7fkdoK0DpEhYOUUYl0iUdYsfDAv+xCGVl3tPKAVDl6Q682ZlvVM0Nu Pn8yAL9cL5KHPR7KOOCSVC4kU4PGmmCxKb17RDjqZbt40wMlKshno7HjaBXkayEjyu saV9YtusV3spYIC9CKU+4PvW0tz7ca5vuD7q4HpQ= From: paulmck@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, elver@google.com, dvyukov@google.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 04/12] rcu: Force DEFAULT_RCU_BLIMIT to 1000 for strict RCU GPs Date: Wed, 12 Aug 2020 15:57:24 -0700 Message-Id: <20200812225732.20068-4-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200812225632.GA19759@paulmck-ThinkPad-P72> References: <20200812225632.GA19759@paulmck-ThinkPad-P72> Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: "Paul E. McKenney" The value of DEFAULT_RCU_BLIMIT is normally set to 10, the idea being to avoid needless response-time degradation due to RCU callback invocation. However, when CONFIG_RCU_STRICT_GRACE_PERIOD=y it is better to avoid throttling callback execution in order to better detect pointer leaks from RCU read-side critical sections. This commit therefore sets the value of DEFAULT_RCU_BLIMIT to 1000 in kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y. Reported-by Jann Horn Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index d333f1b..08cc91c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -454,17 +454,18 @@ static int rcu_is_cpu_rrupt_from_idle(void) return __this_cpu_read(rcu_data.dynticks_nesting) == 0; } -#define DEFAULT_RCU_BLIMIT 10 /* Maximum callbacks per rcu_do_batch ... */ -#define DEFAULT_MAX_RCU_BLIMIT 10000 /* ... even during callback flood. */ +#define DEFAULT_RCU_BLIMIT (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ? 1000 : 10) + // Maximum callbacks per rcu_do_batch ... +#define DEFAULT_MAX_RCU_BLIMIT 10000 // ... even during callback flood. static long blimit = DEFAULT_RCU_BLIMIT; -#define DEFAULT_RCU_QHIMARK 10000 /* If this many pending, ignore blimit. */ +#define DEFAULT_RCU_QHIMARK 10000 // If this many pending, ignore blimit. static long qhimark = DEFAULT_RCU_QHIMARK; -#define DEFAULT_RCU_QLOMARK 100 /* Once only this many pending, use blimit. */ +#define DEFAULT_RCU_QLOMARK 100 // Once only this many pending, use blimit. static long qlowmark = DEFAULT_RCU_QLOMARK; #define DEFAULT_RCU_QOVLD_MULT 2 #define DEFAULT_RCU_QOVLD (DEFAULT_RCU_QOVLD_MULT * DEFAULT_RCU_QHIMARK) -static long qovld = DEFAULT_RCU_QOVLD; /* If this many pending, hammer QS. */ -static long qovld_calc = -1; /* No pre-initialization lock acquisitions! */ +static long qovld = DEFAULT_RCU_QOVLD; // If this many pending, hammer QS. +static long qovld_calc = -1; // No pre-initialization lock acquisitions! module_param(blimit, long, 0444); module_param(qhimark, long, 0444); -- 2.9.5