[PATCH 09/10] workqueue: single pass rebind_workers

From: Lai Jiangshan
Date: Sat Sep 01 2012 - 13:46:40 EST


busy_worker_rebind_fn() can't return until all idle workers are rebound,
the code of busy_worker_rebind_fn() ensure this.

So we can change the order of the code of rebind_workers(),
and make it is a single pass to do the rebind_workers().

It makes the code much clean and better readability(still need later patch
to improve the readability)

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
---
kernel/workqueue.c | 23 ++++++++---------------
1 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 16bcd84..6d68571 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1458,16 +1458,11 @@ static void rebind_workers(struct global_cwq *gcwq)
init_completion(&idle_rebind.ref_done);
idle_rebind.ref_cnt = 1;
gcwq->idle_rebind = &idle_rebind;
-retry:
idle_rebind.idle_cnt = 1;
- INIT_COMPLETION(idle_rebind.idle_done);

/* set REBIND and kick idle ones, we'll wait for these later */
for_each_worker_pool(pool, gcwq) {
list_for_each_entry(worker, &pool->idle_list, entry) {
- if (!(worker->flags & WORKER_UNBOUND))
- continue;
-
/* morph UNBOUND to REBIND */
worker->flags &= ~WORKER_UNBOUND;
worker->flags |= WORKER_REBIND;
@@ -1479,16 +1474,6 @@ retry:
}
}

- if (--idle_rebind.idle_cnt) {
- spin_unlock_irq(&gcwq->lock);
- wait_for_completion(&idle_rebind.idle_done);
- spin_lock_irq(&gcwq->lock);
- /* busy ones might have become idle while waiting, retry */
- goto retry;
- }
-
- complete_all(&idle_rebind.rebind_hold);
-
/* rebind busy workers */
for_each_busy_worker(worker, i, pos, gcwq) {
struct work_struct *rebind_work = &worker->rebind_work;
@@ -1515,6 +1500,14 @@ retry:
* we will leave rebind_workers(), have to wait until no worker
* has ref to this idle_rebind.
*/
+ if (--idle_rebind.idle_cnt) {
+ spin_unlock_irq(&gcwq->lock);
+ wait_for_completion(&idle_rebind.idle_done);
+ spin_lock_irq(&gcwq->lock);
+ }
+
+ complete_all(&idle_rebind.rebind_hold);
+
if (--idle_rebind.ref_cnt) {
spin_unlock_irq(&gcwq->lock);
wait_for_completion(&idle_rebind.ref_done);
--
1.7.4.4

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