Messages in this thread Patch in this message | | | Date | Tue, 6 Jan 2009 15:00:47 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [PATCH][RFC]: mutex: adaptive spin |
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On Tue, 6 Jan 2009, Peter Zijlstra wrote: > > Indeed, the below does boot -- which means I get to sleep now ;-)
Well, if you didn't go to sleep, a few more questions..
> int __sched > mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass) > { > + int ret; > + > might_sleep(); > - return __mutex_lock_common(lock, TASK_KILLABLE, subclass, _RET_IP_); > + ret = __mutex_lock_common(lock, TASK_KILLABLE, subclass, _RET_IP_); > + if (!ret) > + lock->owner = current; > + > + return ret;
This looks ugly. Why doesn't __mutex_lock_common() just set the lock owner? Hate seeing it done in the caller that has to re-compute common (yeah, yeah, it's cheap) and just looks ugly.
IOW, why didn't this just get done with something like
--- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -186,6 +186,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, done: lock_acquired(&lock->dep_map, ip); /* got the lock - rejoice! */ + lock->owner = task; mutex_remove_waiter(lock, &waiter, task_thread_info(task)); debug_mutex_set_owner(lock, task_thread_info(task));
instead? That takes care of all callers, including the conditional thing (since the error case is a totally different path).
Linus
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