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Add a lock for the callwheel (callout facility), and only go to 

splclock() while holding it.
This commit is contained in:
thorpej 2000-08-21 23:40:56 +00:00
parent ebc99afce8
commit 012500bf1f
1 changed files with 48 additions and 21 deletions
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69
sys/kern/kern_clock.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern_clock.c,v 1.63 2000/08/01 04:57:29 thorpej Exp $ */
/* $NetBSD: kern_clock.c,v 1.64 2000/08/21 23:40:56 thorpej Exp $ */
/*-
* Copyright (c) 2000 The NetBSD Foundation, Inc.
@ -373,6 +373,22 @@ u_int64_t callwheel_softempty; /* # empty buckets seen */
#define MAX_SOFTCLOCK_STEPS 100
#endif
struct simplelock callwheel_slock;
#define CALLWHEEL_LOCK(s) \
do { \
s = splclock(); \
simple_lock(&callwheel_slock); \
} while (0)
#define CALLWHEEL_UNLOCK(s) \
do { \
simple_unlock(&callwheel_slock); \
splx(s); \
} while (0)
static void callout_stop_locked(struct callout *);
/*
* Initialize clock frequencies and start both clocks running.
*/
@ -874,7 +890,8 @@ softclock(void)
int s, idx;
int steps = 0;
s = splhigh();
CALLWHEEL_LOCK(s);
softclock_running = 1;
#ifdef CALLWHEEL_STATS
@ -899,8 +916,8 @@ softclock(void)
if (++steps >= MAX_SOFTCLOCK_STEPS) {
nextsoftcheck = c;
/* Give interrupts a chance. */
splx(s);
(void) splhigh();
CALLWHEEL_UNLOCK(s);
CALLWHEEL_LOCK(s);
c = nextsoftcheck;
steps = 0;
}
@ -916,9 +933,9 @@ softclock(void)
arg = c->c_arg;
c->c_func = NULL;
c->c_flags &= ~CALLOUT_PENDING;
splx(s);
CALLWHEEL_UNLOCK(s);
(*func)(arg);
(void) splhigh();
CALLWHEEL_LOCK(s);
steps = 0;
c = nextsoftcheck;
}
@ -926,7 +943,7 @@ softclock(void)
}
nextsoftcheck = NULL;
softclock_running = 0;
splx(s);
CALLWHEEL_UNLOCK(s);
}
/*
@ -956,6 +973,8 @@ callout_startup(void)
for (i = 0; i < callwheelsize; i++)
TAILQ_INIT(&callwheel[i]);
simple_lock_init(&callwheel_slock);
}
/*
@ -985,15 +1004,14 @@ callout_reset(struct callout *c, int ticks, void (*func)(void *), void *arg)
if (ticks <= 0)
ticks = 1;
/* Lock out the clock. */
s = splhigh();
CALLWHEEL_LOCK(s);
/*
* If this callout's timer is already running, cancel it
* before we modify it.
*/
if (c->c_flags & CALLOUT_PENDING) {
callout_stop(c);
callout_stop_locked(c); /* Already locked */
#ifdef CALLWHEEL_STATS
callwheel_changed++;
#endif
@ -1021,28 +1039,23 @@ callout_reset(struct callout *c, int ticks, void (*func)(void *), void *arg)
callwheel_sizes[c->c_time & callwheelmask];
#endif
splx(s);
CALLWHEEL_UNLOCK(s);
}
/*
* callout_stop:
* callout_stop_locked:
*
* Disestablish a timeout.
* Disestablish a timeout. Callwheel is locked.
*/
void
callout_stop(struct callout *c)
static void
callout_stop_locked(struct callout *c)
{
int s;
/* Lock out the clock. */
s = splhigh();
/*
* Don't attempt to delete a callout that's not on the queue.
*/
if ((c->c_flags & CALLOUT_PENDING) == 0) {
c->c_flags &= ~CALLOUT_ACTIVE;
splx(s);
return;
}
@ -1059,8 +1072,22 @@ callout_stop(struct callout *c)
#endif
c->c_func = NULL;
}
splx(s);
/*
* callout_stop:
*
* Disestablish a timeout. Callwheel is unlocked. This is
* the standard entry point.
*/
void
callout_stop(struct callout *c)
{
int s;
CALLWHEEL_LOCK(s);
callout_stop_locked(c);
CALLWHEEL_UNLOCK(s);
}
#ifdef CALLWHEEL_STATS