Messages in this thread |  | | | Date | Mon, 25 Feb 2008 00:20:14 -0500 | | From | Gregory Haskins <> | | Subject | Re: [PATCH [RT] 11/14] optimize the !printk fastpath through the lock acquisition | |
Bill Huey (hui) wrote:
>
> The might_sleep is annotation and well as a conditional preemption
> point for the regular kernel. You might want to do a schedule check
> there, but it's the wrong function if memory serves me correctly. It's
> reserved for things that actually are design to sleep.
Note that might_sleep() already does a cond_resched() on the
configurations that need it, so I am not sure what you are getting at
here. Is that not enough?
> The rt_spin*()
> function are really a method of preserving BKL semantics across real
> schedule() calls. You'd have to use something else instead for that
> purpose like cond_reschedule() instead.
I dont quite understand this part either. From my perspective,
rt_spin*() functions are locking constructs that might sleep (or might
spin with the new patches), and they happen to be BKL and wakeup
transparent. To me, either the might_sleep() is correct for all paths
that don't fit the in_atomic-printk exception, or none of them are.
Are you saying that the modified logic that I introduced is broken? Or
that the original use of the might_sleep() annotation inside this
function is broken?
-Greg
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