Re: [PATCH RT] rt: add rwsem_is_contended() definition to rwsem_rt.h

From: Sebastian Andrzej Siewior
Date: Tue Feb 17 2015 - 05:09:20 EST

* Clark Williams | 2014-08-27 16:09:28 [-0500]:

>The latest btrfs code uses rwsem_is_contended() in the function
>caching_thread(). On RT systems, include/linux/rwsem.h is replaced with
>include/linux/rwsem_rt.h which does not provide a definition for
>rwsem_is_contended(). This commit provides a definition that should
>work on RT (where the lock is actually an rt_mutex).

I see that I added rwsem_is_contended() in v3.14-rt1 which does:
|static inline int rwsem_is_contended(struct rw_semaphore *sem)
| /* rt_mutex_has_waiters() */
| return !RB_EMPTY_ROOT(&sem->lock.waiters);

Do you lack this in kernel prior to v3.14?

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