diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 516527d4bc5546e4b20b321f1bedffdcc67c404f..a342b6e1cc10e900dcc9453f65f193065fe8ef42 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -30,10 +30,10 @@ MODULE PARAMETERS
This module has the following parameters:
-nreaders This is the number of RCU reading threads supported.
- The default is twice the number of CPUs. Why twice?
- To properly exercise RCU implementations with preemptible
- read-side critical sections.
+irqreaders Says to invoke RCU readers from irq level. This is currently
+ done via timers. Defaults to "1" for variants of RCU that
+ permit this. (Or, more accurately, variants of RCU that do
+ -not- permit this know to ignore this variable.)
nfakewriters This is the number of RCU fake writer threads to run. Fake
writer threads repeatedly use the synchronous "wait for
@@ -44,6 +44,16 @@ nfakewriters This is the number of RCU fake writer threads to run. Fake
to trigger special cases caused by multiple writers, such as
the synchronize_srcu() early return optimization.
+nreaders This is the number of RCU reading threads supported.
+ The default is twice the number of CPUs. Why twice?
+ To properly exercise RCU implementations with preemptible
+ read-side critical sections.
+
+shuffle_interval
+ The number of seconds to keep the test threads affinitied
+ to a particular subset of the CPUs, defaults to 3 seconds.
+ Used in conjunction with test_no_idle_hz.
+
stat_interval The number of seconds between output of torture
statistics (via printk()). Regardless of the interval,
statistics are printed when the module is unloaded.
@@ -51,11 +61,6 @@ stat_interval The number of seconds between output of torture
be printed -only- when the module is unloaded, and this
is the default.
-shuffle_interval
- The number of seconds to keep the test threads affinitied
- to a particular subset of the CPUs, defaults to 3 seconds.
- Used in conjunction with test_no_idle_hz.
-
stutter The length of time to run the test before pausing for this
same period of time. Defaults to "stutter=5", so as
to run and pause for (roughly) five-second intervals.
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 5e954edf0ed55a3f246c1f8994e2907d9e5f0ad8..90b5b123f7a1ee2814686ed791a4d1e45c95935b 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -59,6 +59,7 @@ static int verbose; /* Print more debug info. */
static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
static int stutter = 5; /* Start/stop testing interval (in sec) */
+static int irqreader = 1; /* RCU readers from irq (timers). */
static char *torture_type = "rcu"; /* What RCU implementation to torture. */
module_param(nreaders, int, 0444);
@@ -75,6 +76,8 @@ module_param(shuffle_interval, int, 0444);
MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
module_param(stutter, int, 0444);
MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
+module_param(irqreader, int, 0444);
+MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
module_param(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
@@ -121,6 +124,7 @@ static atomic_t n_rcu_torture_alloc_fail;
static atomic_t n_rcu_torture_free;
static atomic_t n_rcu_torture_mberror;
static atomic_t n_rcu_torture_error;
+static long n_rcu_torture_timers = 0;
static struct list_head rcu_torture_removed;
static int stutter_pause_test = 0;
@@ -217,6 +221,7 @@ struct rcu_torture_ops {
void (*sync)(void);
void (*cb_barrier)(void);
int (*stats)(char *page);
+ int irqcapable;
char *name;
};
static struct rcu_torture_ops *cur_ops = NULL;
@@ -291,6 +296,7 @@ static struct rcu_torture_ops rcu_ops = {
.sync = synchronize_rcu,
.cb_barrier = rcu_barrier,
.stats = NULL,
+ .irqcapable = 1,
.name = "rcu"
};
@@ -331,6 +337,7 @@ static struct rcu_torture_ops rcu_sync_ops = {
.sync = synchronize_rcu,
.cb_barrier = NULL,
.stats = NULL,
+ .irqcapable = 1,
.name = "rcu_sync"
};
@@ -392,6 +399,7 @@ static struct rcu_torture_ops rcu_bh_ops = {
.sync = rcu_bh_torture_synchronize,
.cb_barrier = rcu_barrier_bh,
.stats = NULL,
+ .irqcapable = 1,
.name = "rcu_bh"
};
@@ -406,6 +414,7 @@ static struct rcu_torture_ops rcu_bh_sync_ops = {
.sync = rcu_bh_torture_synchronize,
.cb_barrier = NULL,
.stats = NULL,
+ .irqcapable = 1,
.name = "rcu_bh_sync"
};
@@ -532,6 +541,7 @@ static struct rcu_torture_ops sched_ops = {
.sync = sched_torture_synchronize,
.cb_barrier = rcu_barrier_sched,
.stats = NULL,
+ .irqcapable = 1,
.name = "sched"
};
@@ -619,6 +629,52 @@ rcu_torture_fakewriter(void *arg)
return 0;
}
+/*
+ * RCU torture reader from timer handler. Dereferences rcu_torture_current,
+ * incrementing the corresponding element of the pipeline array. The
+ * counter in the element should never be greater than 1, otherwise, the
+ * RCU implementation is broken.
+ */
+static void rcu_torture_timer(unsigned long unused)
+{
+ int idx;
+ int completed;
+ static DEFINE_RCU_RANDOM(rand);
+ static DEFINE_SPINLOCK(rand_lock);
+ struct rcu_torture *p;
+ int pipe_count;
+
+ idx = cur_ops->readlock();
+ completed = cur_ops->completed();
+ p = rcu_dereference(rcu_torture_current);
+ if (p == NULL) {
+ /* Leave because rcu_torture_writer is not yet underway */
+ cur_ops->readunlock(idx);
+ return;
+ }
+ if (p->rtort_mbtest == 0)
+ atomic_inc(&n_rcu_torture_mberror);
+ spin_lock(&rand_lock);
+ cur_ops->readdelay(&rand);
+ n_rcu_torture_timers++;
+ spin_unlock(&rand_lock);
+ preempt_disable();
+ pipe_count = p->rtort_pipe_count;
+ if (pipe_count > RCU_TORTURE_PIPE_LEN) {
+ /* Should not happen, but... */
+ pipe_count = RCU_TORTURE_PIPE_LEN;
+ }
+ ++__get_cpu_var(rcu_torture_count)[pipe_count];
+ completed = cur_ops->completed() - completed;
+ if (completed > RCU_TORTURE_PIPE_LEN) {
+ /* Should not happen, but... */
+ completed = RCU_TORTURE_PIPE_LEN;
+ }
+ ++__get_cpu_var(rcu_torture_batch)[completed];
+ preempt_enable();
+ cur_ops->readunlock(idx);
+}
+
/*
* RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
* incrementing the corresponding element of the pipeline array. The
@@ -633,11 +689,18 @@ rcu_torture_reader(void *arg)
DEFINE_RCU_RANDOM(rand);
struct rcu_torture *p;
int pipe_count;
+ struct timer_list t;
VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
set_user_nice(current, 19);
+ if (irqreader && cur_ops->irqcapable)
+ setup_timer_on_stack(&t, rcu_torture_timer, 0);
do {
+ if (irqreader && cur_ops->irqcapable) {
+ if (!timer_pending(&t))
+ mod_timer(&t, 1);
+ }
idx = cur_ops->readlock();
completed = cur_ops->completed();
p = rcu_dereference(rcu_torture_current);
@@ -669,6 +732,8 @@ rcu_torture_reader(void *arg)
rcu_stutter_wait();
} while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
+ if (irqreader && cur_ops->irqcapable)
+ del_timer_sync(&t);
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
@@ -699,14 +764,15 @@ rcu_torture_printk(char *page)
cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
cnt += sprintf(&page[cnt],
"rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
- "rtmbe: %d",
+ "rtmbe: %d nt: %ld",
rcu_torture_current,
rcu_torture_current_version,
list_empty(&rcu_torture_freelist),
atomic_read(&n_rcu_torture_alloc),
atomic_read(&n_rcu_torture_alloc_fail),
atomic_read(&n_rcu_torture_free),
- atomic_read(&n_rcu_torture_mberror));
+ atomic_read(&n_rcu_torture_mberror),
+ n_rcu_torture_timers);
if (atomic_read(&n_rcu_torture_mberror) != 0)
cnt += sprintf(&page[cnt], " !!!");
cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
@@ -862,10 +928,10 @@ rcu_torture_print_module_parms(char *tag)
printk(KERN_ALERT "%s" TORTURE_FLAG
"--- %s: nreaders=%d nfakewriters=%d "
"stat_interval=%d verbose=%d test_no_idle_hz=%d "
- "shuffle_interval=%d stutter=%d\n",
+ "shuffle_interval=%d stutter=%d irqreader=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
- stutter);
+ stutter, irqreader);
}
static void