Re: [PATCH 2.6.20-rc4 1/4] futex priority based wakeup

[Daniel Walker <dwalker@mvista.com>]

On Tue, 2007-01-09 at 17:16 +0100, Pierre Peiffer wrote:
> @@ -1358,7 +1366,7 @@ static int futex_unlock_pi(u32 __user *u
>         struct futex_hash_bucket *hb;
>         struct futex_q *this, *next;
>         u32 uval;
> -       struct list_head *head;
> +       struct plist_head *head;
>         union futex_key key;
>         int ret, attempt = 0;
> 
> @@ -1409,7 +1417,7 @@ retry_locked:
>          */
>         head = &hb->chain;
> 
> -       list_for_each_entry_safe(this, next, head, list) {
> +       plist_for_each_entry_safe(this, next, head, list) {
>                 if (!match_futex (&this->key, &key))
>                         continue;
>                 ret = wake_futex_pi(uaddr, uval, this);


Is this really necessary? The rtmutex will priority sort the waiters
when you enable priority inheritance. Inside the wake_futex_pi() it
actually just pulls the new owner off another plist inside the the
rtmutex structure.

Daniel