>>> On Mon, Feb 25, 2008 at 4:54 PM, in message
<[EMAIL PROTECTED]>, Pavel Machek <[EMAIL PROTECTED]> wrote:
> Hi!
>
>> @@ -720,7 +728,8 @@ rt_spin_lock_slowlock(struct rt_mutex *lock)
>> * saved_state accordingly. If we did not get a real wakeup
>> * then we return with the saved state.
>> */
>> - saved_state = xchg(¤t->state, TASK_UNINTERRUPTIBLE);
>> + saved_state = current->state;
>> + smp_mb();
>>
>> for (;;) {
>> unsigned long saved_flags;
>
> Please document what the barrier is good for.
Yeah, I think you are right that this isn't needed. I think that is a relic
from back when I was debugging some other problems. Let me wrap my head around
the implications of removing it, and either remove it or document appropriately.
>
> Plus, you are replacing atomic operation with nonatomic; is that ok?
Yeah, I think so. We are substituting a write with a read, and word reads are
always atomic anyway IIUC (or is that only true on certain architectures)?
Note that we are moving the atomic-write to be done later in the
update_current() calls.
-Greg
-
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