Messages in this thread | | | Date | Sun, 25 Mar 2007 19:54:07 +0400 | From | Oleg Nesterov <> | Subject | Re: [patch] queued spinlocks (i386) |
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I am sorry for being completely off-topic, but I've been wondering for the long time...
What if we replace raw_spinlock_t.slock with "struct task_struct *owner" ?
void _spin_lock(spinlock_t *lock) { struct task_struct *owner;
for (;;) { preempt_disable(); if (likely(_raw_spin_trylock(lock))) break; preempt_enable();
while (!spin_can_lock(lock)) { rcu_read_lock(); owner = lock->owner; if (owner && current->prio < owner->prio && !test_tsk_thread_flag(owner, TIF_NEED_RESCHED)) set_tsk_thread_flag(owner, TIF_NEED_RESCHED); rcu_read_unlock(); cpu_relax(); } }
lock->owner = current; }
void _spin_unlock(spinlock_t *lock) { lock->owner = NULL; _raw_spin_unlock(lock); preempt_enable(); }
Now we don't need need_lockbreak(lock), need_resched() is enough, and we take ->prio into consideration.
Makes sense? Or stupid?
Oleg.
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