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Complete the device polling support by adding a thread in charge

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of polling interfaces at the lowest possible priority
(this might result in softnetisr being scheduled, but there is
no risk of livelock because they have a higher priority than
this thread).
This commit is contained in:
Luigi Rizzo 2001-12-19 00:53:24 +00:00
parent 885ccc61f2
commit d105c784d5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=88156
1 changed files with 55 additions and 0 deletions
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55
sys/kern/kern_poll.c
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@ -34,6 +34,10 @@
#include <net/if.h> /* for IFF_* flags */
#include <net/netisr.h> /* for NETISR_POLL */
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/kthread.h>
#ifdef SMP
#error DEVICE_POLLING is not compatible with SMP
#endif
@ -132,6 +136,14 @@ static u_int32_t poll_handlers; /* next free entry in pr[]. */
SYSCTL_ULONG(_kern_polling, OID_AUTO, handlers, CTLFLAG_RD,
&poll_handlers, 0, "Number of registered poll handlers");
static u_int32_t poll_in_idle=1; /* boolean */
SYSCTL_ULONG(_kern_polling, OID_AUTO, poll_in_idle, CTLFLAG_RW,
&poll_in_idle, 0, "Poll during idle loop");
static u_int32_t idlepoll_sleeping; /* idlepoll is sleeping */
SYSCTL_ULONG(_kern_polling, OID_AUTO, idlepoll_sleeping, CTLFLAG_RD,
&idlepoll_sleeping, 0, "idlepoll is sleeping");
static int polling = 0; /* global polling enable */
SYSCTL_ULONG(_kern_polling, OID_AUTO, enable, CTLFLAG_RW,
&polling, 0, "Polling enabled");
@ -382,6 +394,8 @@ ether_poll_register(poll_handler_t *h, struct ifnet *ifp)
poll_handlers++;
ifp->if_ipending |= IFF_POLLING;
splx(s);
if (idlepoll_sleeping)
wakeup(&idlepoll_sleeping);
return 1; /* polling enabled in next call */
}
@ -420,3 +434,44 @@ ether_poll_deregister(struct ifnet *ifp)
mtx_unlock(&Giant);
return 1;
}
static void
poll_idle(void)
{
struct thread *td = curthread;
struct rtprio rtp;
int pri;
rtp.prio = RTP_PRIO_MAX; /* lowest priority */
rtp.type = RTP_PRIO_IDLE;
mtx_lock_spin(&sched_lock);
rtp_to_pri(&rtp, &td->td_ksegrp->kg_pri);
pri = td->td_ksegrp->kg_pri.pri_level;
mtx_unlock_spin(&sched_lock);
for (;;) {
if (poll_in_idle && poll_handlers > 0) {
idlepoll_sleeping = 0;
mtx_lock(&Giant);
ether_poll(poll_each_burst);
mtx_unlock(&Giant);
mtx_assert(&Giant, MA_NOTOWNED);
mtx_lock_spin(&sched_lock);
setrunqueue(td);
td->td_proc->p_stats->p_ru.ru_nvcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
} else {
idlepoll_sleeping = 1;
tsleep(&idlepoll_sleeping, pri, "pollid", hz * 3);
}
}
}
static struct proc *idlepoll;
static struct kproc_desc idlepoll_kp = {
"idlepoll",
poll_idle,
&idlepoll
};
SYSINIT(idlepoll, SI_SUB_KTHREAD_VM, SI_ORDER_ANY, kproc_start, &idlepoll_kp)