On 02/13, Oleg Nesterov wrote:

On 02/13, Raghavendra K T wrote:

quoted

@@ -772,7 +773,8 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
 	 * check again make sure it didn't become free while
 	 * we weren't looking.
 	 */
-	if (ACCESS_ONCE(lock->tickets.head) == want) {
+	head = READ_ONCE(lock->tickets.head);
+	if (__tickets_equal(head, want)) {
 		add_stats(TAKEN_SLOW_PICKUP, 1);
 		goto out;

This is off-topic, but with or without this change perhaps it makes sense
to add smp_mb__after_atomic(). It is nop on x86, just to make this code
more understandable for those (for me ;) who can never remember even the
x86 rules.

Not that I think you should do this in v5, so please ignore.

Oleg.