/*
* Gets called when softcall queue is not moving forward. We choose
* a CPU and poke except the ones which are already poked.
*/
static int
softcall_choose_cpu()
{
cpu_t *cplist = CPU;
cpu_t *cp;
int intr_load = INT_MAX;
int cpuid = -1;
cpuset_t poke;
int s;
ASSERT(getpil() >= DISP_LEVEL);
ASSERT(ncpus > 1);
ASSERT(MUTEX_HELD(&softcall_lock));
CPUSET_ZERO(poke);
/*
* The hint is to start from current CPU.
*/
cp = cplist;
do {
if (CPU_IN_SET(*softcall_cpuset, cp->cpu_id) ||
(cp->cpu_flags & CPU_ENABLE) == 0)
continue;
/* if CPU is not busy */
if (cp->cpu_intrload == 0) {
cpuid = cp->cpu_id;
break;
}
if (cp->cpu_intrload < intr_load) {
cpuid = cp->cpu_id;
intr_load = cp->cpu_intrload;
} else if (cp->cpu_intrload == intr_load) {
/*
* We want to poke CPUs having similar
* load because we don't know which CPU is
* can acknowledge level1 interrupt. The
* list of such CPUs should not be large.
*/
if (cpuid != -1) {
/*
* Put the last CPU chosen because
* it also has same interrupt load.
*/
CPUSET_ADD(poke, cpuid);
cpuid = -1;
}
CPUSET_ADD(poke, cp->cpu_id);
}
} while ((cp = cp->cpu_next_onln) != cplist);
/* if we found a CPU which suits best to poke */
if (cpuid != -1) {
CPUSET_ZERO(poke);
CPUSET_ADD(poke, cpuid);
}
if (CPUSET_ISNULL(poke)) {
mutex_exit(&softcall_lock);
return (0);
}
/*
* We first set the bit in cpuset and then poke.
*/
CPUSET_XOR(*softcall_cpuset, poke);
mutex_exit(&softcall_lock);
/*
* If softcall() was called at low pil then we may
* get preempted before we raise PIL. It should be okay
* because we are just going to poke CPUs now or at most
* another thread may start choosing CPUs in this routine.
*/
s = splhigh();
siron_poke_cpu(poke);
splx(s);
return (1);
}
/*
* Gets called when softcall queue is not moving forward. We choose
* a CPU and poke except the ones which are already poked.
*/
static int
softcall_choose_cpu()
{
cpu_t *cplist = CPU;
cpu_t *cp;
int intr_load = INT_MAX;
int cpuid = -1;
cpuset_t poke;
int s;
ASSERT(getpil() >= DISP_LEVEL);
ASSERT(ncpus > 1);
ASSERT(MUTEX_HELD(&softcall_lock));
CPUSET_ZERO(poke);
/*
* The hint is to start from current CPU.
*/
cp = cplist;
do {
/*
* Don't select this CPU if :
* - in cpuset already
* - CPU is not accepting interrupts
* - CPU is being offlined
*/
if (CPU_IN_SET(*softcall_cpuset, cp->cpu_id) ||
(cp->cpu_flags & CPU_ENABLE) == 0 ||
(cp == cpu_inmotion))
continue;
#if defined(__x86)
/*
* Don't select this CPU if a hypervisor indicates it
* isn't currently scheduled onto a physical cpu. We are
* looking for a cpu that can respond quickly and the time
* to get the virtual cpu scheduled and switched to running
* state is likely to be relatively lengthy.
*/
if (vcpu_on_pcpu(cp->cpu_id) == VCPU_NOT_ON_PCPU)
continue;
#endif /* __x86 */
/* if CPU is not busy */
if (cp->cpu_intrload == 0) {
cpuid = cp->cpu_id;
break;
}
if (cp->cpu_intrload < intr_load) {
cpuid = cp->cpu_id;
intr_load = cp->cpu_intrload;
} else if (cp->cpu_intrload == intr_load) {
/*
* We want to poke CPUs having similar
* load because we don't know which CPU is
* can acknowledge level1 interrupt. The
* list of such CPUs should not be large.
*/
if (cpuid != -1) {
/*
* Put the last CPU chosen because
* it also has same interrupt load.
*/
CPUSET_ADD(poke, cpuid);
cpuid = -1;
}
CPUSET_ADD(poke, cp->cpu_id);
}
} while ((cp = cp->cpu_next_onln) != cplist);
/* if we found a CPU which suits best to poke */
if (cpuid != -1) {
CPUSET_ZERO(poke);
CPUSET_ADD(poke, cpuid);
}
if (CPUSET_ISNULL(poke)) {
mutex_exit(&softcall_lock);
return (0);
}
/*
* We first set the bit in cpuset and then poke.
*/
CPUSET_XOR(*softcall_cpuset, poke);
mutex_exit(&softcall_lock);
/*
* If softcall() was called at low pil then we may
* get preempted before we raise PIL. It should be okay
* because we are just going to poke CPUs now or at most
* another thread may start choosing CPUs in this routine.
*/
s = splhigh();
siron_poke_cpu(poke);
splx(s);
return (1);
}
