Changeset 31d8e10 in mainline for kernel/generic/src/synch/waitq.c

Timestamp:

2007-04-05T16:09:49Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

547fa39

Parents:

879585a3

Message:

Continue to de-oversynchronize the kernel.

• replace as→refcount with an atomic counter; accesses to this

reference counter are not to be done when the as→lock mutex is held;
this gets us rid of mutex_lock_active();

Remove the possibility of a deadlock between TLB shootdown and asidlock.

• get rid of mutex_lock_active() on as→lock
• when locking the asidlock spinlock, always do it conditionally and with

preemption disabled; in the unsuccessful case, enable interrupts and try again

• there should be no deadlock between TLB shootdown and the as→lock mutexes
• PLEASE REVIEW !!!

Add DEADLOCK_PROBE's to places where we have spinlock_trylock() loops.

File:

• kernel/generic/src/synch/waitq.c (modified) (4 diffs)

kernel/generic/src/synch/waitq.c

@@ -87 +87 @@
         waitq_t *wq;
         bool do_wakeup = false;
+        DEADLOCK_PROBE_INIT(p_wqlock);
 
         spinlock_lock(&threads_lock);
@@ -97 +98 @@
                 if (!spinlock_trylock(&wq->lock)) {
                         spinlock_unlock(&t->lock);
+                        DEADLOCK_PROBE(p_wqlock, DEADLOCK_THRESHOLD);
                         goto grab_locks;        /* avoid deadlock */
                 }
@@ -129 +131 @@
         bool do_wakeup = false;
         ipl_t ipl;
+        DEADLOCK_PROBE_INIT(p_wqlock);
 
         ipl = interrupts_disable();
@@ -148 +151 @@
                 if (!spinlock_trylock(&wq->lock)) {
                         spinlock_unlock(&t->lock);
+                        DEADLOCK_PROBE(p_wqlock, DEADLOCK_THRESHOLD);
                         goto grab_locks;        /* avoid deadlock */
                 }