Author: kib
Date: Thu May 16 13:17:57 2019
New Revision: 347694
URL: https://svnweb.freebsd.org/changeset/base/347694
Log:
subr_turnstile: Extract some common code to a helper.
Code walks the list of contested turnstiles to calculate the priority
to unlend.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/sys/kern/subr_turnstile.c
Modified: head/sys/kern/subr_turnstile.c
==============================================================================
--- head/sys/kern/subr_turnstile.c Thu May 16 13:13:33 2019
(r347693)
+++ head/sys/kern/subr_turnstile.c Thu May 16 13:17:57 2019
(r347694)
@@ -897,6 +897,24 @@ turnstile_broadcast(struct turnstile *ts, int queue)
}
}
+static u_char
+turnstile_calc_unlend_prio_locked(struct thread *td)
+{
+ struct turnstile *nts;
+ u_char cp, pri;
+
+ THREAD_LOCK_ASSERT(td, MA_OWNED);
+ mtx_assert(&td_contested_lock, MA_OWNED);
+
+ pri = PRI_MAX;
+ LIST_FOREACH(nts, &td->td_contested, ts_link) {
+ cp = turnstile_first_waiter(nts)->td_priority;
+ if (cp < pri)
+ pri = cp;
+ }
+ return (pri);
+}
+
/*
* Wakeup all threads on the pending list and adjust the priority of the
* current thread appropriately. This must be called with the turnstile
@@ -906,9 +924,8 @@ void
turnstile_unpend(struct turnstile *ts)
{
TAILQ_HEAD( ,thread) pending_threads;
- struct turnstile *nts;
struct thread *td;
- u_char cp, pri;
+ u_char pri;
MPASS(ts != NULL);
mtx_assert(&ts->ts_lock, MA_OWNED);
@@ -932,7 +949,6 @@ turnstile_unpend(struct turnstile *ts)
* priority however.
*/
td = curthread;
- pri = PRI_MAX;
thread_lock(td);
mtx_lock_spin(&td_contested_lock);
/*
@@ -946,11 +962,7 @@ turnstile_unpend(struct turnstile *ts)
ts->ts_owner = NULL;
LIST_REMOVE(ts, ts_link);
}
- LIST_FOREACH(nts, &td->td_contested, ts_link) {
- cp = turnstile_first_waiter(nts)->td_priority;
- if (cp < pri)
- pri = cp;
- }
+ pri = turnstile_calc_unlend_prio_locked(td);
mtx_unlock_spin(&td_contested_lock);
sched_unlend_prio(td, pri);
thread_unlock(td);
@@ -991,7 +1003,7 @@ void
turnstile_disown(struct turnstile *ts)
{
struct thread *td;
- u_char cp, pri;
+ u_char pri;
MPASS(ts != NULL);
mtx_assert(&ts->ts_lock, MA_OWNED);
@@ -1017,15 +1029,10 @@ turnstile_disown(struct turnstile *ts)
* priority however.
*/
td = curthread;
- pri = PRI_MAX;
thread_lock(td);
mtx_unlock_spin(&ts->ts_lock);
mtx_lock_spin(&td_contested_lock);
- LIST_FOREACH(ts, &td->td_contested, ts_link) {
- cp = turnstile_first_waiter(ts)->td_priority;
- if (cp < pri)
- pri = cp;
- }
+ pri = turnstile_calc_unlend_prio_locked(td);
mtx_unlock_spin(&td_contested_lock);
sched_unlend_prio(td, pri);
thread_unlock(td);
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