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| author | Josh Triplett <josh@joshtriplett.org> | 2009-09-08 15:54:35 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-18 00:05:34 +0200 |
| commit | b8d57a76d9f92aa63b4f12990da5697b17000b0c (patch) | |
| tree | a3be4dafddde67043deaf9a9dbf2a26bc7b7c80a | |
| parent | b835db1f9cadaf008750a32664e35a207782c95e (diff) | |
| download | blackbird-op-linux-b8d57a76d9f92aa63b4f12990da5697b17000b0c.tar.gz blackbird-op-linux-b8d57a76d9f92aa63b4f12990da5697b17000b0c.zip | |
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>
| -rw-r--r-- | kernel/rcutorture.c | 15 |
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) |
