[dpdk-dev] [PATCH v7 3/5] eal: use wait event scheme for mcslock

[Feifei Wang]

Instead of polling for mcslock to be updated, use wait event scheme
for this case.

Furthermore, use 'uintptr_t *' is for different size of pointer in 32/64
bits architecture.

And define a new pointer 'next' for the compilation error:
-------------------------------------------------------------------
'dereferencing type-punned pointer will break strict-aliasing rules'
-------------------------------------------------------------------

Signed-off-by: Feifei Wang <feifei.wang2 at arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
---
 lib/eal/include/generic/rte_mcslock.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/eal/include/generic/rte_mcslock.h b/lib/eal/include/generic/rte_mcslock.h
index 34f33c64a5..d5b9b293cd 100644
--- a/lib/eal/include/generic/rte_mcslock.h
+++ b/lib/eal/include/generic/rte_mcslock.h
@@ -116,8 +116,9 @@ rte_mcslock_unlock(rte_mcslock_t **msl, rte_mcslock_t *me)
 		/* More nodes added to the queue by other CPUs.
 		 * Wait until the next pointer is set.
 		 */
-		while (__atomic_load_n(&me->next, __ATOMIC_RELAXED) == NULL)
-			rte_pause();
+		uintptr_t *next = NULL;
+		next = (uintptr_t *)&me->next;
+		rte_wait_event(next, UINTPTR_MAX, ==, 0, __ATOMIC_RELAXED);
 	}
 
 	/* Pass lock to next waiter. */
-- 
2.25.1