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

From: Daniel Walker
Date: Wed Jan 10 2007 - 11:13:10 EST


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

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