diff options
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_timeout.c | 38 |
1 files changed, 35 insertions, 3 deletions
diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c index e3441c2..2e67ece1f 100644 --- a/sys/kern/kern_timeout.c +++ b/sys/kern/kern_timeout.c @@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$"); #include <sys/lock.h> #include <sys/mutex.h> #include <sys/proc.h> +#include <sys/sleepqueue.h> #include <sys/sysctl.h> static int avg_depth; @@ -308,8 +309,10 @@ softclock(void *dummy) * There is someone waiting * for the callout to complete. */ - wakeup(&callout_wait); callout_wait = 0; + mtx_unlock_spin(&callout_lock); + wakeup(&callout_wait); + mtx_lock_spin(&callout_lock); } steps = 0; c = nextsoftcheck; @@ -529,9 +532,38 @@ _callout_stop_safe(c, safe) * finish. */ while (c == curr_callout) { + + /* + * Use direct calls to sleepqueue interface + * instead of cv/msleep in order to avoid + * a LOR between callout_lock and sleepqueue + * chain spinlocks. This piece of code + * emulates a msleep_spin() call actually. + */ + mtx_unlock_spin(&callout_lock); + sleepq_lock(&callout_wait); + + /* + * Check again the state of curr_callout + * because curthread could have lost the + * race previously won. + */ + mtx_lock_spin(&callout_lock); + if (c != curr_callout) { + sleepq_release(&callout_wait); + break; + } callout_wait = 1; - msleep_spin(&callout_wait, &callout_lock, - "codrain", 0); + DROP_GIANT(); + mtx_unlock_spin(&callout_lock); + sleepq_add(&callout_wait, + &callout_lock.lock_object, "codrain", + SLEEPQ_SLEEP, 0); + sleepq_wait(&callout_wait); + + /* Reacquire locks previously released. */ + PICKUP_GIANT(); + mtx_lock_spin(&callout_lock); } } else if (use_mtx && !curr_cancelled) { /* |
