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authorJosh Triplett <josh@joshtriplett.org>2009-09-08 15:54:35 -0700
committerIngo Molnar <mingo@elte.hu>2009-09-18 00:05:34 +0200
commitb8d57a76d9f92aa63b4f12990da5697b17000b0c (patch)
treea3be4dafddde67043deaf9a9dbf2a26bc7b7c80a /kernel
parentb835db1f9cadaf008750a32664e35a207782c95e (diff)
downloadlinux-b8d57a76d9f92aa63b4f12990da5697b17000b0c.tar.bz2
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 <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> 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 <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcutorture.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index b33db539a8ad..328a8257c885 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)