[PATCH 6/7] workqueue: Remove the cacheline_aligned for nr_running

From: Lai Jiangshan
Date: Tue Dec 07 2021 - 02:36:16 EST


From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>

nr_running is never modified remotely after the schedule callback in
wakeup path is removed.

Rather nr_running is often accessed with other fields in the pool
together, so the cacheline_aligned for nr_running isn't needed.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 256f552e9513..33f1106b4f99 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -154,6 +154,9 @@ struct worker_pool {

unsigned long watchdog_ts; /* L: watchdog timestamp */

+ /* The current concurrency level. */
+ atomic_t nr_running;
+
struct list_head worklist; /* L: list of pending works */

int nr_workers; /* L: total number of workers */
@@ -177,19 +180,12 @@ struct worker_pool {
struct hlist_node hash_node; /* PL: unbound_pool_hash node */
int refcnt; /* PL: refcnt for unbound pools */

- /*
- * The current concurrency level. As it's likely to be accessed
- * from other CPUs during try_to_wake_up(), put it in a separate
- * cacheline.
- */
- atomic_t nr_running ____cacheline_aligned_in_smp;
-
/*
* Destruction of pool is RCU protected to allow dereferences
* from get_work_pool().
*/
struct rcu_head rcu;
-} ____cacheline_aligned_in_smp;
+};

/*
* The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS
--
2.19.1.6.gb485710b