MFp4:

- Add flags CVWAIT_ABSTIME and CVWAIT_CLOCKID for umtx kernel based
  condition variable, this should eliminate an extra system call to get
  current time.

- Add sub-function UMTX_OP_NWAKE_PRIVATE to wake up N channels in single
  system call. Create userland sleep queue for condition variable, in most
  cases, thread will wait in the queue, the pthread_cond_signal will defer
  thread wakeup until the mutex is unlocked, it tries to avoid an extra
  system call and a extra context switch in time window of pthread_cond_signal
  and pthread_mutex_unlock.

The changes are part of process-shared mutex project.

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/sys/_umtx.h b/sys/sys/_umtx.h
index fcda974..fa0ed99 100644
--- a/sys/sys/_umtx.h
+++ b/sys/sys/_umtx.h
@@ -46,7 +46,8 @@ struct umutex {
 struct ucond {
 	volatile __uint32_t	c_has_waiters;	/* Has waiters in kernel */
 	__uint32_t		c_flags;	/* Flags of the condition variable */
-	__uint32_t		c_spare[2];	/* Spare space */
+	__uint32_t              c_clockid;	/* Clock id */
+	__uint32_t              c_spare[1];	/* Spare space */
 };
 
 struct urwlock {