Module Name: src
Committed By: ad
Date: Wed Nov 20 21:49:00 UTC 2019
Modified Files:
src/sys/kern: kern_condvar.c
Log Message:
- Put back a microoptimisation that was accidentally removed.
- Comments.
To generate a diff of this commit:
cvs rdiff -u -r1.41 -r1.42 src/sys/kern/kern_condvar.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_condvar.c
diff -u src/sys/kern/kern_condvar.c:1.41 src/sys/kern/kern_condvar.c:1.42
--- src/sys/kern/kern_condvar.c:1.41 Tue Jan 30 07:52:22 2018
+++ src/sys/kern/kern_condvar.c Wed Nov 20 21:49:00 2019
@@ -1,7 +1,7 @@
-/* $NetBSD: kern_condvar.c,v 1.41 2018/01/30 07:52:22 ozaki-r Exp $ */
+/* $NetBSD: kern_condvar.c,v 1.42 2019/11/20 21:49:00 ad Exp $ */
/*-
- * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
+ * Copyright (c) 2006, 2007, 2008, 2019 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@@ -34,7 +34,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_condvar.c,v 1.41 2018/01/30 07:52:22 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_condvar.c,v 1.42 2019/11/20 21:49:00 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -210,10 +210,10 @@ cv_exit(kcondvar_t *cv, kmutex_t *mtx, l
* Remove an LWP from the condition variable and sleep queue. This
* is called when the LWP has not been awoken normally but instead
* interrupted: for example, when a signal is received. Must be
- * called with the LWP locked, and must return it unlocked.
+ * called with the LWP locked. Will unlock if "unlock" is true.
*/
static void
-cv_unsleep(lwp_t *l, bool cleanup)
+cv_unsleep(lwp_t *l, bool unlock)
{
kcondvar_t *cv __diagused;
@@ -224,7 +224,7 @@ cv_unsleep(lwp_t *l, bool cleanup)
KASSERT(cv_is_valid(cv));
KASSERT(cv_has_waiters(cv));
- sleepq_unsleep(l, cleanup);
+ sleepq_unsleep(l, unlock);
}
/*
@@ -490,7 +490,14 @@ cv_signal(kcondvar_t *cv)
cv_wakeup_one(cv);
}
-static inline void
+/*
+ * cv_wakeup_one:
+ *
+ * Slow path for cv_signal(). Deliberately marked __noinline to
+ * prevent the compiler pulling it in to cv_signal(), which adds
+ * extra prologue and epilogue code.
+ */
+static __noinline void
cv_wakeup_one(kcondvar_t *cv)
{
sleepq_t *sq;
@@ -502,7 +509,7 @@ cv_wakeup_one(kcondvar_t *cv)
mp = sleepq_hashlock(cv);
sq = CV_SLEEPQ(cv);
l = TAILQ_FIRST(sq);
- if (l == NULL) {
+ if (__predict_false(l == NULL)) {
mutex_spin_exit(mp);
return;
}
@@ -533,7 +540,14 @@ cv_broadcast(kcondvar_t *cv)
cv_wakeup_all(cv);
}
-static inline void
+/*
+ * cv_wakeup_all:
+ *
+ * Slow path for cv_broadcast(). Deliberately marked __noinline to
+ * prevent the compiler pulling it in to cv_broadcast(), which adds
+ * extra prologue and epilogue code.
+ */
+static __noinline void
cv_wakeup_all(kcondvar_t *cv)
{
sleepq_t *sq;
