From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753175AbZILH4X (ORCPT ); Sat, 12 Sep 2009 03:56:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753108AbZILH4W (ORCPT ); Sat, 12 Sep 2009 03:56:22 -0400 Received: from hera.kernel.org ([140.211.167.34]:39038 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752568AbZILH4V (ORCPT ); Sat, 12 Sep 2009 03:56:21 -0400 Date: Sat, 12 Sep 2009 07:55:41 GMT From: tip-bot for Josh Triplett Cc: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com, hpa@zytor.com, mingo@redhat.com, rostedt@goodmis.org, josh@joshtriplett.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, tglx@linutronix.de, josh@joshtriplett.org, mingo@elte.hu In-Reply-To: <12524504772607-git-send-email-> References: <12524504772607-git-send-email-> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/urgent] rcutorture: Occasionally delay readers enough to make RCU force_quiescent_state Message-ID: Git-Commit-ID: f4a82a059aea43947d4f37dba9da1782d11caece X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Sat, 12 Sep 2009 07:55:42 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f4a82a059aea43947d4f37dba9da1782d11caece Gitweb: http://git.kernel.org/tip/f4a82a059aea43947d4f37dba9da1782d11caece Author: Josh Triplett AuthorDate: Tue, 8 Sep 2009 15:54:35 -0700 Committer: Ingo Molnar CommitDate: Sat, 12 Sep 2009 09:47:07 +0200 rcutorture: Occasionally delay readers enough to make RCU force_quiescent_state rcutorture already delays readers, but never for long enough to make RCU force a quiescent state. Add an occasional delay of 50ms. Signed-off-by: Josh Triplett Signed-off-by: Paul E. McKenney Acked-by: Steven Rostedt Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org LKML-Reference: <12524504772607-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutorture.c | 15 +++++++++------ 1 files changed, 9 insertions(+), 6 deletions(-) diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index b33db53..328a825 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -281,14 +281,17 @@ static int rcu_torture_read_lock(void) __acquires(RCU) static void rcu_read_delay(struct rcu_random_state *rrsp) { - long delay; - const long longdelay = 200; + const unsigned long shortdelay_us = 200; + const unsigned long longdelay_ms = 50; - /* We want there to be long-running readers, but not all the time. */ + /* We want a short delay sometimes to make a reader delay the grace + * period, and we want a long delay occasionally to trigger + * force_quiescent_state. */ - delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay); - if (!delay) - udelay(longdelay); + if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) + mdelay(longdelay_ms); + if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) + udelay(shortdelay_us); } static void rcu_torture_read_unlock(int idx) __releases(RCU)