Messages in this thread Patch in this message | | | Subject | [PATCH -rt] clean up pi_lock in rtmutex | From | Steven Rostedt <> | Date | Tue, 01 Aug 2006 09:56:46 -0400 |
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Ingo,
This is pretty much the same patch that I sent to mainline to clean up the rtmutex code. I gave the reasons why in that patch, so I'm not going to repeat them here. This is for 2.6.17-rt7
-- Steve
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Index: linux-2.6.17-rt7/kernel/rtmutex.c =================================================================== --- linux-2.6.17-rt7.orig/kernel/rtmutex.c 2006-08-01 09:40:36.000000000 -0400 +++ linux-2.6.17-rt7/kernel/rtmutex.c 2006-08-01 09:53:41.000000000 -0400 @@ -419,7 +419,7 @@ static int task_blocks_on_rt_mutex(struc { struct rt_mutex_waiter *top_waiter = waiter; task_t *owner = rt_mutex_owner(lock); - int boost = 0, res; + int chain_walk = 0, res; unsigned long flags; spin_lock_irqsave(¤t->pi_lock, flags); @@ -444,23 +444,24 @@ static int task_blocks_on_rt_mutex(struc plist_add(&waiter->pi_list_entry, &owner->pi_waiters); __rt_mutex_adjust_prio(owner); - if (owner->pi_blocked_on) { - boost = 1; - get_task_struct(owner); - } - spin_unlock_irqrestore(&owner->pi_lock, flags); - } - else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) { - spin_lock_irqsave(&owner->pi_lock, flags); - if (owner->pi_blocked_on) { - boost = 1; - get_task_struct(owner); - } + if (owner->pi_blocked_on) + chain_walk = 1; + spin_unlock_irqrestore(&owner->pi_lock, flags); } - if (!boost) + else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) + chain_walk = 1; + + if (!chain_walk) return 0; + /* + * The owner can't disappear while holding a lock, + * so the owner struct is protected by wait_lock. + * Gets dropped in rt_mutex_adjust_prio_chain()! + */ + get_task_struct(owner); + spin_unlock(&lock->wait_lock); res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, @@ -542,7 +543,7 @@ static void remove_waiter(struct rt_mute struct rt_mutex_waiter *waiter __IP_DECL__) { int first = (waiter == rt_mutex_top_waiter(lock)); - int boost = 0; + int chain_walk = 0; task_t *owner = rt_mutex_owner(lock); unsigned long flags; @@ -566,18 +567,20 @@ static void remove_waiter(struct rt_mute } __rt_mutex_adjust_prio(owner); - if (owner->pi_blocked_on) { - boost = 1; - get_task_struct(owner); - } + if (owner->pi_blocked_on) + chain_walk = 1; + spin_unlock_irqrestore(&owner->pi_lock, flags); } WARN_ON(!plist_node_empty(&waiter->pi_list_entry)); - if (!boost) + if (!chain_walk) return; + /* gets dropped in rt_mutex_adjust_prio_chain()! */ + get_task_struct(owner); + spin_unlock(&lock->wait_lock); rt_mutex_adjust_prio_chain(owner, 0, lock, NULL __IP__);
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