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From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
	jiangshanlai@gmail.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
	"Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: [PATCH tip/core/rcu 7/9] rcutorture: Make in-kernel-loop testing more brutal
Date: Wed,  2 Oct 2019 18:47:26 -0700
Message-ID: <20191003014728.13496-7-paulmck@kernel.org> (raw)
In-Reply-To: <20191003014710.GA13323@paulmck-ThinkPad-P72>

From: "Paul E. McKenney" <paulmck@linux.ibm.com>

The rcu_torture_fwd_prog_nr() tests the ability of RCU to tolerate
in-kernel busy loops.  It invokes rcu_torture_fwd_prog_cond_resched()
within its delay loop, which, in PREEMPT && NO_HZ_FULL kernels results
in the occasional direct call to schedule().  Now, this direct call to
schedule() is appropriate for call_rcu() flood testing, in which either
the kernel should restrain itself or userspace transitions will supply
the needed restraint.  But in pure in-kernel loops, the occasional
cond_resched() should do the job.

This commit therefore makes rcu_torture_fwd_prog_nr() use cond_resched()
instead of rcu_torture_fwd_prog_cond_resched() in order to increase the
brutality of this aspect of rcutorture testing.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
 kernel/rcu/rcutorture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index a9e97c3..f1339ee 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1811,7 +1811,7 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
 		if (!fwd_progress_need_resched || need_resched())
-			rcu_torture_fwd_prog_cond_resched(1);
+			cond_resched();
 	if (!time_before(jiffies, stopat) &&

  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-03  1:47 [PATCH tip/core/rcu 0/9] Torture-test updates Paul E. McKenney
2019-10-03  1:47 ` [PATCH tip/core/rcu 1/9] rcu: Remove unused function rcutorture_record_progress() paulmck
2019-10-03  1:47 ` [PATCH tip/core/rcu 2/9] locktorture: Replace strncmp() with str_has_prefix() paulmck
2019-10-03  1:47 ` [PATCH tip/core/rcu 3/9] rcutorture: Remove CONFIG_HOTPLUG_CPU=n from scenarios paulmck
2019-10-03  1:47 ` [PATCH tip/core/rcu 4/9] rcutorture: Emulate dyntick aspect of userspace nohz_full sojourn paulmck
2019-10-03  1:47 ` [PATCH tip/core/rcu 5/9] rcu: Remove unused variable rcu_perf_writer_state paulmck
2019-10-03  1:47 ` [PATCH tip/core/rcu 6/9] rcutorture: Separate warnings for each failure type paulmck
2019-10-03  1:47 ` paulmck [this message]
2019-10-03  1:47 ` [PATCH tip/core/rcu 8/9] locking: locktorture: Do not include rwlock.h directly paulmck
2019-10-03  1:47 ` [PATCH tip/core/rcu 9/9] rcu: Suppress levelspread uninitialized messages paulmck
2019-10-03  8:53   ` Geert Uytterhoeven
2019-10-05 16:16     ` Paul E. McKenney

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