Re: [PATCH 2/3] locking/percpu-rwsem: Replace bulky wait-queues with swait

From: Davidlohr Bueso
Date: Mon Nov 21 2016 - 12:27:00 EST

On Mon, 21 Nov 2016, Oleg Nesterov wrote:

On 11/18, Davidlohr Bueso wrote:

@@ -12,7 +12,7 @@ struct percpu_rw_semaphore {
struct rcu_sync rss;
unsigned int __percpu *read_count;
struct rw_semaphore rw_sem;
- wait_queue_head_t writer;
+ struct swait_queue_head writer;

I won't argue, but even swait_queue_head is overkill in this case.

We can just add "struct task_struct *writer" into percpu_rw_semaphore,

Given that this is how all things locking/ work, I very much agree with
you, lemme send a v2.