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Date: Sun, 11 Nov 2018 12:20:13 -0800
From: "Paul E. McKenney" <paulmck@...ux.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 03/17] rcutorture: Remove cbflood facility
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Now that the forward-progress code does a full-bore continuous callback
flood lasting multiple seconds, there is little point in also posting a
mere 60,000 callbacks every second or so. This commit therefore removes
the old cbflood testing. Over time, it may be desirable to concurrently
do full-bore continuous callback floods on all CPUs simultaneously, but
one dragon at a time.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
.../admin-guide/kernel-parameters.txt | 18 ----
kernel/rcu/rcutorture.c | 86 +------------------
2 files changed, 1 insertion(+), 103 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 81d1d5a74728..6c53d6eb4594 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3743,24 +3743,6 @@
in microseconds. The default of zero says
no holdoff.
- rcutorture.cbflood_inter_holdoff= [KNL]
- Set holdoff time (jiffies) between successive
- callback-flood tests.
-
- rcutorture.cbflood_intra_holdoff= [KNL]
- Set holdoff time (jiffies) between successive
- bursts of callbacks within a given callback-flood
- test.
-
- rcutorture.cbflood_n_burst= [KNL]
- Set the number of bursts making up a given
- callback-flood test. Set this to zero to
- disable callback-flood testing.
-
- rcutorture.cbflood_n_per_burst= [KNL]
- Set the number of callbacks to be registered
- in a given burst of a callback-flood test.
-
rcutorture.fqs_duration= [KNL]
Set duration of force_quiescent_state bursts
in microseconds.
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 8cf700ca7845..17f480129a78 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -80,13 +80,6 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@...ibm.com> and Josh Triplett <josh@jos
/* Must be power of two minus one. */
#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
-torture_param(int, cbflood_inter_holdoff, HZ,
- "Holdoff between floods (jiffies)");
-torture_param(int, cbflood_intra_holdoff, 1,
- "Holdoff between bursts (jiffies)");
-torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
-torture_param(int, cbflood_n_per_burst, 20000,
- "# callbacks per burst in flood");
torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
"Extend readers by disabling bh (1), irqs (2), or preempt (4)");
torture_param(int, fqs_duration, 0,
@@ -138,12 +131,10 @@ module_param(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
static int nrealreaders;
-static int ncbflooders;
static struct task_struct *writer_task;
static struct task_struct **fakewriter_tasks;
static struct task_struct **reader_tasks;
static struct task_struct *stats_task;
-static struct task_struct **cbflood_task;
static struct task_struct *fqs_task;
static struct task_struct *boost_tasks[NR_CPUS];
static struct task_struct *stall_task;
@@ -181,7 +172,6 @@ static long n_rcu_torture_boosts;
static atomic_long_t n_rcu_torture_timers;
static long n_barrier_attempts;
static long n_barrier_successes; /* did rcu_barrier test succeed? */
-static atomic_long_t n_cbfloods;
static struct list_head rcu_torture_removed;
static int rcu_torture_writer_state;
@@ -873,59 +863,6 @@ checkwait: stutter_wait("rcu_torture_boost");
return 0;
}
-static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
-{
-}
-
-/*
- * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
- * to call_rcu() or analogous, increasing the probability of occurrence
- * of callback-overflow corner cases.
- */
-static int
-rcu_torture_cbflood(void *arg)
-{
- int err = 1;
- int i;
- int j;
- struct rcu_head *rhp;
-
- if (cbflood_n_per_burst > 0 &&
- cbflood_inter_holdoff > 0 &&
- cbflood_intra_holdoff > 0 &&
- cur_ops->call &&
- cur_ops->cb_barrier) {
- rhp = vmalloc(array3_size(cbflood_n_burst,
- cbflood_n_per_burst,
- sizeof(*rhp)));
- err = !rhp;
- }
- if (err) {
- VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
- goto wait_for_stop;
- }
- VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
- do {
- schedule_timeout_interruptible(cbflood_inter_holdoff);
- atomic_long_inc(&n_cbfloods);
- WARN_ON(signal_pending(current));
- for (i = 0; i < cbflood_n_burst; i++) {
- for (j = 0; j < cbflood_n_per_burst; j++) {
- cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
- rcu_torture_cbflood_cb);
- }
- schedule_timeout_interruptible(cbflood_intra_holdoff);
- WARN_ON(signal_pending(current));
- }
- cur_ops->cb_barrier();
- stutter_wait("rcu_torture_cbflood");
- } while (!torture_must_stop());
- vfree(rhp);
-wait_for_stop:
- torture_kthread_stopping("rcu_torture_cbflood");
- return 0;
-}
-
/*
* RCU torture force-quiescent-state kthread. Repeatedly induces
* bursts of calls to force_quiescent_state(), increasing the probability
@@ -1460,11 +1397,10 @@ rcu_torture_stats_print(void)
n_rcu_torture_boosts,
atomic_long_read(&n_rcu_torture_timers));
torture_onoff_stats();
- pr_cont("barrier: %ld/%ld:%ld ",
+ pr_cont("barrier: %ld/%ld:%ld\n",
n_barrier_successes,
n_barrier_attempts,
n_rcu_torture_barrier_error);
- pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
pr_alert("%s%s ", torture_type, TORTURE_FLAG);
if (atomic_read(&n_rcu_torture_mberror) != 0 ||
@@ -2093,8 +2029,6 @@ rcu_torture_cleanup(void)
cur_ops->name, gp_seq, flags);
torture_stop_kthread(rcu_torture_stats, stats_task);
torture_stop_kthread(rcu_torture_fqs, fqs_task);
- for (i = 0; i < ncbflooders; i++)
- torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
if (rcu_torture_can_boost())
cpuhp_remove_state(rcutor_hp);
@@ -2377,24 +2311,6 @@ rcu_torture_init(void)
goto unwind;
if (object_debug)
rcu_test_debug_objects();
- if (cbflood_n_burst > 0) {
- /* Create the cbflood threads */
- ncbflooders = (num_online_cpus() + 3) / 4;
- cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
- GFP_KERNEL);
- if (!cbflood_task) {
- VERBOSE_TOROUT_ERRSTRING("out of memory");
- firsterr = -ENOMEM;
- goto unwind;
- }
- for (i = 0; i < ncbflooders; i++) {
- firsterr = torture_create_kthread(rcu_torture_cbflood,
- NULL,
- cbflood_task[i]);
- if (firsterr)
- goto unwind;
- }
- }
torture_init_end();
return 0;
--
2.17.1
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