From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646AbZIHWyj (ORCPT ); Tue, 8 Sep 2009 18:54:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752549AbZIHWyi (ORCPT ); Tue, 8 Sep 2009 18:54:38 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:41969 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752538AbZIHWyg (ORCPT ); Tue, 8 Sep 2009 18:54:36 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josht@linux.vnet.ibm.com, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Josh Triplett Subject: [PATCH tip/core/rcu 1/3] rcutorture: Occasionally delay readers enough to make RCU force_quiescent_state Date: Tue, 8 Sep 2009 15:54:35 -0700 Message-Id: <12524504772607-git-send-email-> X-Mailer: git-send-email 1.5.2.5 In-Reply-To: <20090908225349.GA19524@linux.vnet.ibm.com> References: <20090908225349.GA19524@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josh Triplett 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 --- 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) -- 1.5.2.5