Update API to support process shared condvar use cases #23
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The current librtpi conditional variable API has the user pass a pointer to the associated mutex at pi_cond_init() time and it is stored in the condvar private data for later use when waiting or signaling. As described in issue dvhart#22[1] this breaks down for process shared use cases. In those cases the associated mutex is mapped at different addresses in different processes so the pointer passed by one process to pi_cond_init() will not be valid in the context of another process doing operations on the shared condvar. Change the API to pass in the associated mutex where it is needed instead of at init time: * pi_cond_wait(), pi_cond_timedwait() - mutex used in the FUTEX_WAIT_REQUEUE_PI futex call. Passing in a pointer to the associated mutex as a parameter matches the equivalent libpthread/POSIX APIs. * pi_cond_signal(), pi_cond_broadcast() - mutex used in the FUTEX_CMP_REQUEUE_PI futex call as the requeue target in order to avoid "thundering herd" wake-ups. [1] dvhart#22 Signed-off-by: Gratian Crisan <[email protected]>
Commit 6814992 ("pi_cond: Update API to support process shared condvar use cases") introduced an API change in order to address issue "dvhart#22 Current librtpi API breaks down for process shared condvars"[1]. Make the necessary changes to port all tests to the new API: - remove the mutex parameter when initializing the condvar: DEFINE_PI_COND(), pi_cond_init(). - pass a pointer to the associated mutex for pi_cond_wait(), pi_cond_timedwait(), pi_cond_signal(), and pi_cond_broadcast() calls. [1] dvhart#22 Signed-off-by: Gratian Crisan <[email protected]>
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These all look inline with what we discussed. Thank you for seeing this through Gratian. |
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As described in issue #22 the current API breaks down for for process shared condvar use cases. Fix this by changing the API to pass in the associated mutex where it is needed instead of at init time.