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Commit b8d57a76 authored by Josh Triplett's avatar Josh Triplett Committed by Ingo Molnar
Browse files

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: default avatarJosh Triplett <josh@joshtriplett.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: default avatarSteven 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: default avatarIngo Molnar <mingo@elte.hu>
parent b835db1f

kernel/rcutorture.c

+9 −6
Original line number Diff line number Diff line
@@ -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)