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Move the loadav() callout into its own kthread since it uses allproc_lock

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which is a sleepable lock and thus is not safe to acquire from a callout
routine.
This commit is contained in:
John Baldwin 2004-01-28 20:44:41 +00:00
parent 5352136a25
commit d5b75694e7
1 changed files with 31 additions and 12 deletions
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43
sys/kern/kern_synch.c
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@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
#include <sys/condvar.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
@ -76,7 +77,6 @@ SYSINIT(synch_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, synch_setup, NULL)
int hogticks;
int lbolt;
static struct callout loadav_callout;
static struct callout lbolt_callout;
struct loadavg averunnable =
@ -96,7 +96,8 @@ static int fscale __unused = FSCALE;
SYSCTL_INT(_kern, OID_AUTO, fscale, CTLFLAG_RD, 0, FSCALE, "");
static void endtsleep(void *);
static void loadav(void *arg);
static void loadav(void);
static void loadav_thread(void *dummy);
static void lboltcb(void *arg);
/*
@ -581,7 +582,7 @@ setrunnable(struct thread *td)
* Completely Bogus.. only works with 1:1 (but compiles ok now :-)
*/
static void
loadav(void *arg)
loadav(void)
{
int i, nrun;
struct loadavg *avg;
@ -610,14 +611,31 @@ nextproc:
for (i = 0; i < 3; i++)
avg->ldavg[i] = (cexp[i] * avg->ldavg[i] +
nrun * FSCALE * (FSCALE - cexp[i])) >> FSHIFT;
}
/*
* Schedule the next update to occur after 5 seconds, but add a
* random variation to avoid synchronisation with processes that
* run at regular intervals.
*/
callout_reset(&loadav_callout, hz * 4 + (int)(random() % (hz * 2 + 1)),
loadav, NULL);
/*
* Main loop for a kthread that executes loadav() periodically.
*/
static void
loadav_thread(void *dummy)
{
struct proc *p;
int nowake;
p = curthread->td_proc;
PROC_LOCK(p);
p->p_flag |= P_NOLOAD;
PROC_UNLOCK(p);
for (;;) {
loadav();
/*
* Schedule the next update to occur after 5 seconds, but
* add a random variation to avoid synchronisation with
* processes that run at regular intervals.
*/
tsleep(&nowake, curthread->td_priority, "-", hz * 4 +
(int)(random() % (hz * 2 + 1)));
}
}
static void
@ -632,12 +650,13 @@ static void
synch_setup(dummy)
void *dummy;
{
callout_init(&loadav_callout, 0);
callout_init(&lbolt_callout, CALLOUT_MPSAFE);
/* Kick off timeout driven events by calling first time. */
loadav(NULL);
lboltcb(NULL);
/* Kick off loadav kernel process. */
kthread_create(loadav_thread, NULL, NULL, 0, 0, "loadav");
}
/*