diff options
Diffstat (limited to 'sys/kern/kern_sx.c')
| -rw-r--r-- | sys/kern/kern_sx.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c index 2d777a2..37e5d03 100644 --- a/sys/kern/kern_sx.c +++ b/sys/kern/kern_sx.c @@ -705,8 +705,12 @@ _sx_xunlock_hard(struct sx *sx, uintptr_t tid, const char *file, int line) * ideal. It gives precedence to shared waiters if they are * present. For this condition, we have to preserve the * state of the exclusive waiters flag. + * If interruptible sleeps left the shared queue empty avoid a + * starvation for the threads sleeping on the exclusive queue by giving + * them precedence and cleaning up the shared waiters bit anyway. */ - if (sx->sx_lock & SX_LOCK_SHARED_WAITERS) { + if ((sx->sx_lock & SX_LOCK_SHARED_WAITERS) != 0 && + sleepq_sleepcnt(&sx->lock_object, SQ_SHARED_QUEUE) != 0) { queue = SQ_SHARED_QUEUE; x |= (sx->sx_lock & SX_LOCK_EXCLUSIVE_WAITERS); } else |
