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-rw-r--r--Documentation/locking/locktorture.txt16
-rw-r--r--kernel/locking/locktorture.c176
2 files changed, 168 insertions, 24 deletions
diff --git a/Documentation/locking/locktorture.txt b/Documentation/locking/locktorture.txt
index f2a905b27862..7a72621b924f 100644
--- a/Documentation/locking/locktorture.txt
+++ b/Documentation/locking/locktorture.txt
@@ -29,6 +29,11 @@ nwriters_stress Number of kernel threads that will stress exclusive lock
ownership (writers). The default value is twice the number
of online CPUs.
+nreaders_stress Number of kernel threads that will stress shared lock
+ ownership (readers). The default is the same amount of writer
+ locks. If the user did not specify nwriters_stress, then
+ both readers and writers be the amount of online CPUs.
+
torture_type Type of lock to torture. By default, only spinlocks will
be tortured. This module can torture the following locks,
with string values as follows:
@@ -97,15 +102,18 @@ STATISTICS
Statistics are printed in the following format:
spin_lock-torture: Writes: Total: 93746064 Max/Min: 0/0 Fail: 0
- (A) (B) (C) (D)
+ (A) (B) (C) (D) (E)
(A): Lock type that is being tortured -- torture_type parameter.
-(B): Number of times the lock was acquired.
+(B): Number of writer lock acquisitions. If dealing with a read/write primitive
+ a second "Reads" statistics line is printed.
+
+(C): Number of times the lock was acquired.
-(C): Min and max number of times threads failed to acquire the lock.
+(D): Min and max number of times threads failed to acquire the lock.
-(D): true/false values if there were errors acquiring the lock. This should
+(E): true/false values if there were errors acquiring the lock. This should
-only- be positive if there is a bug in the locking primitive's
implementation. Otherwise a lock should never fail (i.e., spin_lock()).
Of course, the same applies for (C), above. A dummy example of this is
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 988267cc92c1..c1073d79e440 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -52,6 +52,8 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
torture_param(int, nwriters_stress, -1,
"Number of write-locking stress-test threads");
+torture_param(int, nreaders_stress, -1,
+ "Number of read-locking stress-test threads");
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0,
"Time between CPU hotplugs (s), 0=disable");
@@ -74,15 +76,19 @@ static atomic_t n_lock_torture_errors;
static struct task_struct *stats_task;
static struct task_struct **writer_tasks;
+static struct task_struct **reader_tasks;
static int nrealwriters_stress;
static bool lock_is_write_held;
+static int nrealreaders_stress;
+static bool lock_is_read_held;
struct lock_stress_stats {
long n_lock_fail;
long n_lock_acquired;
};
static struct lock_stress_stats *lwsa; /* writer statistics */
+static struct lock_stress_stats *lrsa; /* reader statistics */
#if defined(MODULE)
#define LOCKTORTURE_RUNNABLE_INIT 1
@@ -104,6 +110,9 @@ struct lock_torture_ops {
int (*writelock)(void);
void (*write_delay)(struct torture_random_state *trsp);
void (*writeunlock)(void);
+ int (*readlock)(void);
+ void (*read_delay)(struct torture_random_state *trsp);
+ void (*readunlock)(void);
unsigned long flags;
const char *name;
};
@@ -142,6 +151,9 @@ static struct lock_torture_ops lock_busted_ops = {
.writelock = torture_lock_busted_write_lock,
.write_delay = torture_lock_busted_write_delay,
.writeunlock = torture_lock_busted_write_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
.name = "lock_busted"
};
@@ -182,6 +194,9 @@ static struct lock_torture_ops spin_lock_ops = {
.writelock = torture_spin_lock_write_lock,
.write_delay = torture_spin_lock_write_delay,
.writeunlock = torture_spin_lock_write_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
.name = "spin_lock"
};
@@ -205,6 +220,9 @@ static struct lock_torture_ops spin_lock_irq_ops = {
.writelock = torture_spin_lock_write_lock_irq,
.write_delay = torture_spin_lock_write_delay,
.writeunlock = torture_lock_spin_write_unlock_irq,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
.name = "spin_lock_irq"
};
@@ -241,6 +259,9 @@ static struct lock_torture_ops mutex_lock_ops = {
.writelock = torture_mutex_lock,
.write_delay = torture_mutex_delay,
.writeunlock = torture_mutex_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
.name = "mutex_lock"
};
@@ -274,28 +295,57 @@ static int lock_torture_writer(void *arg)
}
/*
+ * Lock torture reader kthread. Repeatedly acquires and releases
+ * the reader lock.
+ */
+static int lock_torture_reader(void *arg)
+{
+ struct lock_stress_stats *lrsp = arg;
+ static DEFINE_TORTURE_RANDOM(rand);
+
+ VERBOSE_TOROUT_STRING("lock_torture_reader task started");
+ set_user_nice(current, MAX_NICE);
+
+ do {
+ if ((torture_random(&rand) & 0xfffff) == 0)
+ schedule_timeout_uninterruptible(1);
+ cur_ops->readlock();
+ lock_is_read_held = 1;
+ lrsp->n_lock_acquired++;
+ cur_ops->read_delay(&rand);
+ lock_is_read_held = 0;
+ cur_ops->readunlock();
+ stutter_wait("lock_torture_reader");
+ } while (!torture_must_stop());
+ torture_kthread_stopping("lock_torture_reader");
+ return 0;
+}
+
+/*
* Create an lock-torture-statistics message in the specified buffer.
*/
-static void lock_torture_printk(char *page)
+static void __torture_print_stats(char *page,
+ struct lock_stress_stats *statp, bool write)
{
bool fail = 0;
- int i;
+ int i, n_stress;
long max = 0;
- long min = lwsa[0].n_lock_acquired;
+ long min = statp[0].n_lock_acquired;
long long sum = 0;
- for (i = 0; i < nrealwriters_stress; i++) {
- if (lwsa[i].n_lock_fail)
+ n_stress = write ? nrealwriters_stress : nrealreaders_stress;
+ for (i = 0; i < n_stress; i++) {
+ if (statp[i].n_lock_fail)
fail = true;
- sum += lwsa[i].n_lock_acquired;
- if (max < lwsa[i].n_lock_fail)
- max = lwsa[i].n_lock_fail;
- if (min > lwsa[i].n_lock_fail)
- min = lwsa[i].n_lock_fail;
+ sum += statp[i].n_lock_acquired;
+ if (max < statp[i].n_lock_fail)
+ max = statp[i].n_lock_fail;
+ if (min > statp[i].n_lock_fail)
+ min = statp[i].n_lock_fail;
}
- page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
page += sprintf(page,
- "Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
+ "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
+ write ? "Writes" : "Reads ",
sum, max, min, max / 2 > min ? "???" : "",
fail, fail ? "!!!" : "");
if (fail)
@@ -315,15 +365,32 @@ static void lock_torture_stats_print(void)
int size = nrealwriters_stress * 200 + 8192;
char *buf;
+ if (cur_ops->readlock)
+ size += nrealreaders_stress * 200 + 8192;
+
buf = kmalloc(size, GFP_KERNEL);
if (!buf) {
pr_err("lock_torture_stats_print: Out of memory, need: %d",
size);
return;
}
- lock_torture_printk(buf);
+
+ __torture_print_stats(buf, lwsa, true);
pr_alert("%s", buf);
kfree(buf);
+
+ if (cur_ops->readlock) {
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf) {
+ pr_err("lock_torture_stats_print: Out of memory, need: %d",
+ size);
+ return;
+ }
+
+ __torture_print_stats(buf, lrsa, false);
+ pr_alert("%s", buf);
+ kfree(buf);
+ }
}
/*
@@ -350,10 +417,10 @@ lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
const char *tag)
{
pr_alert("%s" TORTURE_FLAG
- "--- %s%s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
+ "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
torture_type, tag, debug_lock ? " [debug]": "",
- nrealwriters_stress, stat_interval, verbose,
- shuffle_interval, stutter, shutdown_secs,
+ nrealwriters_stress, nrealreaders_stress, stat_interval,
+ verbose, shuffle_interval, stutter, shutdown_secs,
onoff_interval, onoff_holdoff);
}
@@ -372,6 +439,14 @@ static void lock_torture_cleanup(void)
writer_tasks = NULL;
}
+ if (reader_tasks) {
+ for (i = 0; i < nrealreaders_stress; i++)
+ torture_stop_kthread(lock_torture_reader,
+ reader_tasks[i]);
+ kfree(reader_tasks);
+ reader_tasks = NULL;
+ }
+
torture_stop_kthread(lock_torture_stats, stats_task);
lock_torture_stats_print(); /* -After- the stats thread is stopped! */
@@ -389,7 +464,7 @@ static void lock_torture_cleanup(void)
static int __init lock_torture_init(void)
{
- int i;
+ int i, j;
int firsterr = 0;
static struct lock_torture_ops *torture_ops[] = {
&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops, &mutex_lock_ops,
@@ -430,7 +505,6 @@ static int __init lock_torture_init(void)
if (strncmp(torture_type, "spin", 4) == 0)
debug_lock = true;
#endif
- lock_torture_print_module_parms(cur_ops, "Start of test");
/* Initialize the statistics so that each run gets its own numbers. */
@@ -446,8 +520,37 @@ static int __init lock_torture_init(void)
lwsa[i].n_lock_acquired = 0;
}
- /* Start up the kthreads. */
+ if (cur_ops->readlock) {
+ if (nreaders_stress >= 0)
+ nrealreaders_stress = nreaders_stress;
+ else {
+ /*
+ * By default distribute evenly the number of
+ * readers and writers. We still run the same number
+ * of threads as the writer-only locks default.
+ */
+ if (nwriters_stress < 0) /* user doesn't care */
+ nrealwriters_stress = num_online_cpus();
+ nrealreaders_stress = nrealwriters_stress;
+ }
+
+ lock_is_read_held = 0;
+ lrsa = kmalloc(sizeof(*lrsa) * nrealreaders_stress, GFP_KERNEL);
+ if (lrsa == NULL) {
+ VERBOSE_TOROUT_STRING("lrsa: Out of memory");
+ firsterr = -ENOMEM;
+ kfree(lwsa);
+ goto unwind;
+ }
+ for (i = 0; i < nrealreaders_stress; i++) {
+ lrsa[i].n_lock_fail = 0;
+ lrsa[i].n_lock_acquired = 0;
+ }
+ }
+ lock_torture_print_module_parms(cur_ops, "Start of test");
+
+ /* Prepare torture context. */
if (onoff_interval > 0) {
firsterr = torture_onoff_init(onoff_holdoff * HZ,
onoff_interval * HZ);
@@ -478,11 +581,44 @@ static int __init lock_torture_init(void)
firsterr = -ENOMEM;
goto unwind;
}
- for (i = 0; i < nrealwriters_stress; i++) {
+
+ if (cur_ops->readlock) {
+ reader_tasks = kzalloc(nrealreaders_stress * sizeof(reader_tasks[0]),
+ GFP_KERNEL);
+ if (reader_tasks == NULL) {
+ VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ }
+
+ /*
+ * Create the kthreads and start torturing (oh, those poor little locks).
+ *
+ * TODO: Note that we interleave writers with readers, giving writers a
+ * slight advantage, by creating its kthread first. This can be modified
+ * for very specific needs, or even let the user choose the policy, if
+ * ever wanted.
+ */
+ for (i = 0, j = 0; i < nrealwriters_stress ||
+ j < nrealreaders_stress; i++, j++) {
+ if (i >= nrealwriters_stress)
+ goto create_reader;
+
+ /* Create writer. */
firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
writer_tasks[i]);
if (firsterr)
goto unwind;
+
+ create_reader:
+ if (cur_ops->readlock == NULL || (j >= nrealreaders_stress))
+ continue;
+ /* Create reader. */
+ firsterr = torture_create_kthread(lock_torture_reader, &lrsa[j],
+ reader_tasks[j]);
+ if (firsterr)
+ goto unwind;
}
if (stat_interval > 0) {
firsterr = torture_create_kthread(lock_torture_stats, NULL,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.