From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com,
rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 9/9] rcutorture: Stop right-shifting torture_random() return values
Date: Mon, 17 Jul 2023 11:20:42 -0700 [thread overview]
Message-ID: <20230717182042.1098651-9-paulmck@kernel.org> (raw)
In-Reply-To: <bca717ca-a83a-4540-80ec-732c12623d2d@paulmck-laptop>
Now that torture_random() uses swahw32(), its callers no longer see
not-so-random low-order bits, as these are now swapped up into the upper
16 bits of the torture_random() function's return value. This commit
therefore removes the right-shifting of torture_random() return values.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/rcutorture.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index d291a1438c30..ade42d6a9d9b 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1877,7 +1877,7 @@ static int
rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
{
int mask = rcutorture_extend_mask_max();
- unsigned long randmask1 = torture_random(trsp) >> 8;
+ unsigned long randmask1 = torture_random(trsp);
unsigned long randmask2 = randmask1 >> 3;
unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
@@ -1936,7 +1936,7 @@ rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
if (!((mask - 1) & mask))
return rtrsp; /* Current RCU reader not extendable. */
/* Bias towards larger numbers of loops. */
- i = (torture_random(trsp) >> 3);
+ i = torture_random(trsp);
i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
for (j = 0; j < i; j++) {
mask = rcutorture_extend_mask(*readstate, trsp);
@@ -2137,7 +2137,7 @@ static int rcu_nocb_toggle(void *arg)
toggle_fuzz = NSEC_PER_USEC;
do {
r = torture_random(&rand);
- cpu = (r >> 4) % (maxcpu + 1);
+ cpu = (r >> 1) % (maxcpu + 1);
if (r & 0x1) {
rcu_nocb_cpu_offload(cpu);
atomic_long_inc(&n_nocb_offload);
--
2.40.1
prev parent reply other threads:[~2023-07-17 18:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 18:20 [PATCH rcu 0/9] Torture-test updates for v6.6 Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 1/9] rcutorture: Dump grace-period state upon rtort_pipe_count incidents Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 2/9] torture: Support randomized shuffling for proxy exec testing Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 3/9] torture: Add lock_torture_writer_fifo module param Paul E. McKenney
2023-07-28 3:22 ` Paul E. McKenney
2023-07-28 3:22 ` [PATCH rcu 1/2] torture: Add a kthread-creation callback to _torture_create_kthread() Paul E. McKenney
2023-08-05 22:44 ` Joel Fernandes
2023-08-08 3:26 ` John Stultz
2023-07-28 3:22 ` [PATCH rcu 2/2] torture: Add lock_torture writer_fifo module parameter Paul E. McKenney
2023-08-08 3:27 ` John Stultz
2023-08-08 4:00 ` Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 4/9] torture: Make torture_hrtimeout_*() use TASK_IDLE Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 5/9] torture: Move torture_onoff() timeouts to hrtimers Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 6/9] torture: Move torture_shuffle() " Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 7/9] torture: Move stutter_wait() " Paul E. McKenney
2023-07-17 18:20 ` [PATCH rcu 8/9] torture: Stop right-shifting torture_random() return values Paul E. McKenney
2023-07-17 18:20 ` Paul E. McKenney [this message]
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