locking/ww_mutex: Improve test to cover acquire context changes

Currently each thread starts an acquire context only once, and
performs all its loop iterations under it.

This means that the Wound/Wait relations between threads are fixed.

To make things a little more realistic and cover more of the
functionality with the test, open a new acquire context for each loop.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
index 6b7abb334ca6..90d8d8879969 100644
--- a/kernel/locking/test-ww_mutex.c
+++ b/kernel/locking/test-ww_mutex.c
@@ -398,12 +398,11 @@ static void stress_inorder_work(struct work_struct *work)
         if (!order)
                 return;
 
-        ww_acquire_init(&ctx, &ww_class);
-
         do {
                 int contended = -1;
                 int n, err;
 
+                ww_acquire_init(&ctx, &ww_class);
 retry:
                 err = 0;
                 for (n = 0; n < nlocks; n++) {
@@ -433,9 +432,9 @@ retry:
                                     __func__, err);
                         break;
                 }
-        } while (--stress->nloops);
 
-        ww_acquire_fini(&ctx);
+                ww_acquire_fini(&ctx);
+        } while (--stress->nloops);
 
         kfree(order);
         kfree(stress);
@@ -470,9 +469,9 @@ static void stress_reorder_work(struct work_struct *work)
         kfree(order);
         order = NULL;
 
-        ww_acquire_init(&ctx, &ww_class);
-
         do {
+                ww_acquire_init(&ctx, &ww_class);
+
                 list_for_each_entry(ll, &locks, link) {
                         err = ww_mutex_lock(ll->lock, &ctx);
                         if (!err)
@@ -495,9 +494,9 @@ static void stress_reorder_work(struct work_struct *work)
                 dummy_load(stress);
                 list_for_each_entry(ll, &locks, link)
                         ww_mutex_unlock(ll->lock);
-        } while (--stress->nloops);
 
-        ww_acquire_fini(&ctx);
+                ww_acquire_fini(&ctx);
+        } while (--stress->nloops);
 
 out:
         list_for_each_entry_safe(ll, ln, &locks, link)