On 08/22, Paul E. McKenney wrote:
>
> Queued for testing, thank you, Oleg!
Thanks Paul!
> Right now, this is mostly relying on 0day and -next testing. Any thoughts
> for a useful torture test for this?
Right now I do not have any idea how to write the meaningful test for
rcu_sync... Perhaps something like
struct rcu_sync_struct rss;
spinlock_t lock;
int A, B;
void read(void)
{
rcu_read_lock();
bool need_lock = !rcu_sync_is_idle(&rss);
if (need_lock)
spin_lock(&lock);
BUG_ON(A != B);
if (need_lock)
spin_unlock(&lock);
rcu_read_unlock();
}
void modify(void)
{
rcu_sync_enter(&rss);
spin_lock(&lock);
A++; B++;
spin_unlock(&lock);
rcu_sync_exit(&rss);
}
makes sense... I'll try to think.
> One approach would be to treat it
> like a reader-writer lock. Other thoughts?
I booted the kernel with the additional patch below, and nothing bad has
happened, it continues to print
Writes: Total: 2 Max/Min: 0/0 Fail: 0
Reads : Total: 2 Max/Min: 0/0 Fail: 0
However, I do not know what this code actually does, so currently I have
no idea if this test makes any sense for percpu_rw_semaphore.
Oleg.
---
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index ec8cce2..62561ec 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -55,7 +55,7 @@ torture_param(int, stutter, 5, "Number of jiffies to run/halt
test, 0=disable");
torture_param(bool, verbose, true,
"Enable verbose debugging printk()s");
-static char *torture_type = "spin_lock";
+static char *torture_type = "rwsem_lock";
module_param(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type,
"Type of lock to torture (spin_lock, spin_lock_irq,
mutex_lock, ...)");
@@ -361,10 +361,12 @@ static struct lock_torture_ops mutex_lock_ops = {
.name = "mutex_lock"
};
-static DECLARE_RWSEM(torture_rwsem);
-static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
+#include <linux/percpu-rwsem.h>
+static struct percpu_rw_semaphore pcpu_rwsem;
+
+static int torture_rwsem_down_write(void) __acquires(pcpu_rwsem)
{
- down_write(&torture_rwsem);
+ percpu_down_write(&pcpu_rwsem);
return 0;
}
@@ -384,14 +386,14 @@ static void torture_rwsem_write_delay(struct
torture_random_state *trsp)
#endif
}
-static void torture_rwsem_up_write(void) __releases(torture_rwsem)
+static void torture_rwsem_up_write(void) __releases(pcpu_rwsem)
{
- up_write(&torture_rwsem);
+ percpu_up_write(&pcpu_rwsem);
}
-static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
+static int torture_rwsem_down_read(void) __acquires(pcpu_rwsem)
{
- down_read(&torture_rwsem);
+ percpu_down_read(&pcpu_rwsem);
return 0;
}
@@ -411,9 +413,9 @@ static void torture_rwsem_read_delay(struct
torture_random_state *trsp)
#endif
}
-static void torture_rwsem_up_read(void) __releases(torture_rwsem)
+static void torture_rwsem_up_read(void) __releases(pcpu_rwsem)
{
- up_read(&torture_rwsem);
+ percpu_up_read(&pcpu_rwsem);
}
static struct lock_torture_ops rwsem_lock_ops = {
@@ -645,6 +647,11 @@ static int __init lock_torture_init(void)
&rwsem_lock_ops,
};
+ /*
+ * TODO: DECLARE_PERCPU_RWSEM(). The patch already exists.
+ */
+ BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
+
if (!torture_init_begin(torture_type, verbose, &torture_runnable))
return -EBUSY;
--
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