locktorture: Support rwlocks

Add a "rw_lock" torture test to stress kernel rwlocks and their irq
variant. Reader critical regions are 5x longer than writers. As such
a similar ratio of lock acquisitions is seen in the statistics. In the
case of massive contention, both hold the lock for 1/10 of a second.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/Documentation/locking/locktorture.txt b/Documentation/locking/locktorture.txt
index be715015e0f76db5312ae4c5c4e29bf0f63d83a6..619f2bb136a545f1932609f3b93b898145f6a5cc 100644 (file)
--- a/Documentation/locking/locktorture.txt
+++ b/Documentation/locking/locktorture.txt
@@ -45,6 +45,11 @@ torture_type   Type of lock to torture. By default, only spinlocks will
                     o "spin_lock_irq": spin_lock_irq() and spin_unlock_irq()
                                        pairs.
 
+                    o "rw_lock": read/write lock() and unlock() rwlock pairs.
+
+                    o "rw_lock_irq": read/write lock_irq() and unlock_irq()
+                                     rwlock pairs.
+
                     o "mutex_lock": mutex_lock() and mutex_unlock() pairs.
 
                     o "rwsem_lock": read/write down() and up() semaphore pairs.

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 540d5dfe11126719a98a73a18dee00192b1b0a08..0762b25b41107d6bf6f1913ddc6d7ff704a0c18e 100644 (file)
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -27,6 +27,7 @@
 #include <linux/kthread.h>
 #include <linux/err.h>
 #include <linux/spinlock.h>
+#include <linux/rwlock.h>
 #include <linux/mutex.h>
 #include <linux/smp.h>
 #include <linux/interrupt.h>
@@ -229,6 +230,110 @@ static struct lock_torture_ops spin_lock_irq_ops = {
        .name           = "spin_lock_irq"
 };
 
+static DEFINE_RWLOCK(torture_rwlock);
+
+static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
+{
+       write_lock(&torture_rwlock);
+       return 0;
+}
+
+static void torture_rwlock_write_delay(struct torture_random_state *trsp)
+{
+       const unsigned long shortdelay_us = 2;
+       const unsigned long longdelay_ms = 100;
+
+       /* We want a short delay mostly to emulate likely code, and
+        * we want a long delay occasionally to force massive contention.
+        */
+       if (!(torture_random(trsp) %
+             (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+               mdelay(longdelay_ms);
+       else
+               udelay(shortdelay_us);
+}
+
+static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
+{
+       write_unlock(&torture_rwlock);
+}
+
+static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
+{
+       read_lock(&torture_rwlock);
+       return 0;
+}
+
+static void torture_rwlock_read_delay(struct torture_random_state *trsp)
+{
+       const unsigned long shortdelay_us = 10;
+       const unsigned long longdelay_ms = 100;
+
+       /* We want a short delay mostly to emulate likely code, and
+        * we want a long delay occasionally to force massive contention.
+        */
+       if (!(torture_random(trsp) %
+             (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
+               mdelay(longdelay_ms);
+       else
+               udelay(shortdelay_us);
+}
+
+static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
+{
+       read_unlock(&torture_rwlock);
+}
+
+static struct lock_torture_ops rw_lock_ops = {
+       .writelock      = torture_rwlock_write_lock,
+       .write_delay    = torture_rwlock_write_delay,
+       .writeunlock    = torture_rwlock_write_unlock,
+       .readlock       = torture_rwlock_read_lock,
+       .read_delay     = torture_rwlock_read_delay,
+       .readunlock     = torture_rwlock_read_unlock,
+       .name           = "rw_lock"
+};
+
+static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
+{
+       unsigned long flags;
+
+       write_lock_irqsave(&torture_rwlock, flags);
+       cxt.cur_ops->flags = flags;
+       return 0;
+}
+
+static void torture_rwlock_write_unlock_irq(void)
+__releases(torture_rwlock)
+{
+       write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
+{
+       unsigned long flags;
+
+       read_lock_irqsave(&torture_rwlock, flags);
+       cxt.cur_ops->flags = flags;
+       return 0;
+}
+
+static void torture_rwlock_read_unlock_irq(void)
+__releases(torture_rwlock)
+{
+       write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops rw_lock_irq_ops = {
+       .writelock      = torture_rwlock_write_lock_irq,
+       .write_delay    = torture_rwlock_write_delay,
+       .writeunlock    = torture_rwlock_write_unlock_irq,
+       .readlock       = torture_rwlock_read_lock_irq,
+       .read_delay     = torture_rwlock_read_delay,
+       .readunlock     = torture_rwlock_read_unlock_irq,
+       .name           = "rw_lock_irq"
+};
+
 static DEFINE_MUTEX(torture_mutex);
 
 static int torture_mutex_lock(void) __acquires(torture_mutex)
@@ -535,8 +640,11 @@ static int __init lock_torture_init(void)
        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, &rwsem_lock_ops,
+               &lock_busted_ops,
+               &spin_lock_ops, &spin_lock_irq_ops,
+               &rw_lock_ops, &rw_lock_irq_ops,
+               &mutex_lock_ops,
+               &rwsem_lock_ops,
        };
 
        if (!torture_init_begin(torture_type, verbose, &torture_runnable))
@@ -571,7 +679,8 @@ static int __init lock_torture_init(void)
                cxt.debug_lock = true;
 #endif
 #ifdef CONFIG_DEBUG_SPINLOCK
-       if (strncmp(torture_type, "spin", 4) == 0)
+       if ((strncmp(torture_type, "spin", 4) == 0) ||
+           (strncmp(torture_type, "rw_lock", 7) == 0))
                cxt.debug_lock = true;
 #endif
 

diff --git a/tools/testing/selftests/rcutorture/configs/lock/CFLIST b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
index 6108137da770296dc5e9acd7a6ac412f9820cf76..6910b73707617cc2ddf855be82e488420a35bed1 100644 (file)
--- a/tools/testing/selftests/rcutorture/configs/lock/CFLIST
+++ b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
@@ -1,3 +1,4 @@
 LOCK01
 LOCK02
 LOCK03
+LOCK04
\ No newline at end of file

diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK04 b/tools/testing/selftests/rcutorture/configs/lock/LOCK04
new file mode 100644 (file)
index 0000000..1d1da14
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK04
@@ -0,0 +1,6 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=4
+CONFIG_HOTPLUG_CPU=y
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y

diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot b/tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot
new file mode 100644 (file)
index 0000000..48c04fe
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot
@@ -0,0 +1 @@
+locktorture.torture_type=rw_lock