spin_unlock_irqrestore(&ioapic_lock, flags);
}
-#if defined(CONFIG_IRQBALANCE)
-# include <asm/processor.h> /* kernel_thread() */
-# include <linux/kernel_stat.h> /* kstat */
-# include <linux/slab.h> /* kmalloc() */
-# include <linux/timer.h>
-
-#define IRQBALANCE_CHECK_ARCH -999
-#define MAX_BALANCED_IRQ_INTERVAL (5*HZ)
-#define MIN_BALANCED_IRQ_INTERVAL (HZ/2)
-#define BALANCED_IRQ_MORE_DELTA (HZ/10)
-#define BALANCED_IRQ_LESS_DELTA (HZ)
-
-static int irqbalance_disabled __read_mostly = IRQBALANCE_CHECK_ARCH;
-static int physical_balance __read_mostly;
-static long balanced_irq_interval __read_mostly = MAX_BALANCED_IRQ_INTERVAL;
-
-static struct irq_cpu_info {
- unsigned long *last_irq;
- unsigned long *irq_delta;
- unsigned long irq;
-} irq_cpu_data[NR_CPUS];
-
-#define CPU_IRQ(cpu) (irq_cpu_data[cpu].irq)
-#define LAST_CPU_IRQ(cpu, irq) (irq_cpu_data[cpu].last_irq[irq])
-#define IRQ_DELTA(cpu, irq) (irq_cpu_data[cpu].irq_delta[irq])
-
-#define IDLE_ENOUGH(cpu,now) \
- (idle_cpu(cpu) && ((now) - per_cpu(irq_stat, (cpu)).idle_timestamp > 1))
-
-#define IRQ_ALLOWED(cpu, allowed_mask) cpu_isset(cpu, allowed_mask)
-
-#define CPU_TO_PACKAGEINDEX(i) (first_cpu(per_cpu(cpu_sibling_map, i)))
-
-static cpumask_t balance_irq_affinity_init __initdata = CPU_MASK_ALL;
-
-static cpumask_t *balance_irq_affinity;
-
-
-static void __init irq_affinity_init_work(void *data)
-{
- struct dyn_array *da = data;
-
- int i;
- struct balance_irq_affinity *affinity;
-
- affinity = *da->name;
-
- for (i = 0; i < *da->nr; i++)
- memcpy(&affinity[i], &balance_irq_affinity_init,
- sizeof(struct balance_irq_affinity));
-
-}
-
-DEFINE_DYN_ARRAY(balance_irq_affinity, sizeof(struct balance_irq_affinity), nr_irqs, PAGE_SIZE, irq_affinity_init_work);
-
-
-void set_balance_irq_affinity(unsigned int irq, cpumask_t mask)
-{
- balance_irq_affinity[irq] = mask;
-}
-
-static unsigned long move(int curr_cpu, cpumask_t allowed_mask,
- unsigned long now, int direction)
-{
- int search_idle = 1;
- int cpu = curr_cpu;
-
- goto inside;
-
- do {
- if (unlikely(cpu == curr_cpu))
- search_idle = 0;
-inside:
- if (direction == 1) {
- cpu++;
- if (cpu >= NR_CPUS)
- cpu = 0;
- } else {
- cpu--;
- if (cpu == -1)
- cpu = NR_CPUS-1;
- }
- } while (!cpu_online(cpu) || !IRQ_ALLOWED(cpu, allowed_mask) ||
- (search_idle && !IDLE_ENOUGH(cpu, now)));
-
- return cpu;
-}
-
-static inline void balance_irq(int cpu, int irq)
-{
- unsigned long now = jiffies;
- cpumask_t allowed_mask;
- unsigned int new_cpu;
-
- if (irqbalance_disabled)
- return;
-
- cpus_and(allowed_mask, cpu_online_map, balance_irq_affinity[irq]);
- new_cpu = move(cpu, allowed_mask, now, 1);
- if (cpu != new_cpu)
- set_pending_irq(irq, cpumask_of_cpu(new_cpu));
-}
-
-static inline void rotate_irqs_among_cpus(unsigned long useful_load_threshold)
-{
- int i, j;
- struct irq_desc *desc;
-
- for_each_online_cpu(i) {
- for (j = 0; j < nr_irqs; j++) {
- desc = irq_to_desc(j);
- if (!desc->action)
- continue;
- /* Is it a significant load ? */
- if (IRQ_DELTA(CPU_TO_PACKAGEINDEX(i), j) <
- useful_load_threshold)
- continue;
- balance_irq(i, j);
- }
- }
- balanced_irq_interval = max((long)MIN_BALANCED_IRQ_INTERVAL,
- balanced_irq_interval - BALANCED_IRQ_LESS_DELTA);
- return;
-}
-
-static void do_irq_balance(void)
-{
- int i, j;
- unsigned long max_cpu_irq = 0, min_cpu_irq = (~0);
- unsigned long move_this_load = 0;
- int max_loaded = 0, min_loaded = 0;
- int load;
- unsigned long useful_load_threshold = balanced_irq_interval + 10;
- int selected_irq;
- int tmp_loaded, first_attempt = 1;
- unsigned long tmp_cpu_irq;
- unsigned long imbalance = 0;
- cpumask_t allowed_mask, target_cpu_mask, tmp;
- struct irq_desc *desc;
-
- for_each_possible_cpu(i) {
- int package_index;
- CPU_IRQ(i) = 0;
- if (!cpu_online(i))
- continue;
- package_index = CPU_TO_PACKAGEINDEX(i);
- for (j = 0; j < nr_irqs; j++) {
- unsigned long value_now, delta;
- /* Is this an active IRQ or balancing disabled ? */
- desc = irq_to_desc(j);
- if (!desc->action || irq_balancing_disabled(j))
- continue;
- if (package_index == i)
- IRQ_DELTA(package_index, j) = 0;
- /* Determine the total count per processor per IRQ */
- value_now = (unsigned long) kstat_irqs_cpu(j, i);
-
- /* Determine the activity per processor per IRQ */
- delta = value_now - LAST_CPU_IRQ(i, j);
-
- /* Update last_cpu_irq[][] for the next time */
- LAST_CPU_IRQ(i, j) = value_now;
-
- /* Ignore IRQs whose rate is less than the clock */
- if (delta < useful_load_threshold)
- continue;
- /* update the load for the processor or package total */
- IRQ_DELTA(package_index, j) += delta;
-
- /* Keep track of the higher numbered sibling as well */
- if (i != package_index)
- CPU_IRQ(i) += delta;
- /*
- * We have sibling A and sibling B in the package
- *
- * cpu_irq[A] = load for cpu A + load for cpu B
- * cpu_irq[B] = load for cpu B
- */
- CPU_IRQ(package_index) += delta;
- }
- }
- /* Find the least loaded processor package */
- for_each_online_cpu(i) {
- if (i != CPU_TO_PACKAGEINDEX(i))
- continue;
- if (min_cpu_irq > CPU_IRQ(i)) {
- min_cpu_irq = CPU_IRQ(i);
- min_loaded = i;
- }
- }
- max_cpu_irq = ULONG_MAX;
-
-tryanothercpu:
- /*
- * Look for heaviest loaded processor.
- * We may come back to get the next heaviest loaded processor.
- * Skip processors with trivial loads.
- */
- tmp_cpu_irq = 0;
- tmp_loaded = -1;
- for_each_online_cpu(i) {
- if (i != CPU_TO_PACKAGEINDEX(i))
- continue;
- if (max_cpu_irq <= CPU_IRQ(i))
- continue;
- if (tmp_cpu_irq < CPU_IRQ(i)) {
- tmp_cpu_irq = CPU_IRQ(i);
- tmp_loaded = i;
- }
- }
-
- if (tmp_loaded == -1) {
- /*
- * In the case of small number of heavy interrupt sources,
- * loading some of the cpus too much. We use Ingo's original
- * approach to rotate them around.
- */
- if (!first_attempt && imbalance >= useful_load_threshold) {
- rotate_irqs_among_cpus(useful_load_threshold);
- return;
- }
- goto not_worth_the_effort;
- }
-
- first_attempt = 0; /* heaviest search */
- max_cpu_irq = tmp_cpu_irq; /* load */
- max_loaded = tmp_loaded; /* processor */
- imbalance = (max_cpu_irq - min_cpu_irq) / 2;
-
- /*
- * if imbalance is less than approx 10% of max load, then
- * observe diminishing returns action. - quit
- */
- if (imbalance < (max_cpu_irq >> 3))
- goto not_worth_the_effort;
-
-tryanotherirq:
- /* if we select an IRQ to move that can't go where we want, then
- * see if there is another one to try.
- */
- move_this_load = 0;
- selected_irq = -1;
- for (j = 0; j < nr_irqs; j++) {
- /* Is this an active IRQ? */
- desc = irq_to_desc(j);
- if (!desc->action)
- continue;
- if (imbalance <= IRQ_DELTA(max_loaded, j))
- continue;
- /* Try to find the IRQ that is closest to the imbalance
- * without going over.
- */
- if (move_this_load < IRQ_DELTA(max_loaded, j)) {
- move_this_load = IRQ_DELTA(max_loaded, j);
- selected_irq = j;
- }
- }
- if (selected_irq == -1)
- goto tryanothercpu;
-
- imbalance = move_this_load;
-
- /* For physical_balance case, we accumulated both load
- * values in the one of the siblings cpu_irq[],
- * to use the same code for physical and logical processors
- * as much as possible.
- *
- * NOTE: the cpu_irq[] array holds the sum of the load for
- * sibling A and sibling B in the slot for the lowest numbered
- * sibling (A), _AND_ the load for sibling B in the slot for
- * the higher numbered sibling.
- *
- * We seek the least loaded sibling by making the comparison
- * (A+B)/2 vs B
- */
- load = CPU_IRQ(min_loaded) >> 1;
- for_each_cpu_mask(j, per_cpu(cpu_sibling_map, min_loaded)) {
- if (load > CPU_IRQ(j)) {
- /* This won't change cpu_sibling_map[min_loaded] */
- load = CPU_IRQ(j);
- min_loaded = j;
- }
- }
-
- cpus_and(allowed_mask,
- cpu_online_map,
- balance_irq_affinity[selected_irq]);
- target_cpu_mask = cpumask_of_cpu(min_loaded);
- cpus_and(tmp, target_cpu_mask, allowed_mask);
-
- if (!cpus_empty(tmp)) {
- /* mark for change destination */
- set_pending_irq(selected_irq, cpumask_of_cpu(min_loaded));
-
- /* Since we made a change, come back sooner to
- * check for more variation.
- */
- balanced_irq_interval = max((long)MIN_BALANCED_IRQ_INTERVAL,
- balanced_irq_interval - BALANCED_IRQ_LESS_DELTA);
- return;
- }
- goto tryanotherirq;
-
-not_worth_the_effort:
- /*
- * if we did not find an IRQ to move, then adjust the time interval
- * upward
- */
- balanced_irq_interval = min((long)MAX_BALANCED_IRQ_INTERVAL,
- balanced_irq_interval + BALANCED_IRQ_MORE_DELTA);
- return;
-}
-
-static int balanced_irq(void *unused)
-{
- int i;
- unsigned long prev_balance_time = jiffies;
- long time_remaining = balanced_irq_interval;
- struct irq_desc *desc;
-
- /* push everything to CPU 0 to give us a starting point. */
- for (i = 0 ; i < nr_irqs ; i++) {
- desc = irq_to_desc(i);
- desc->pending_mask = cpumask_of_cpu(0);
- set_pending_irq(i, cpumask_of_cpu(0));
- }
-
- set_freezable();
- for ( ; ; ) {
- time_remaining = schedule_timeout_interruptible(time_remaining);
- try_to_freeze();
- if (time_after(jiffies,
- prev_balance_time+balanced_irq_interval)) {
- preempt_disable();
- do_irq_balance();
- prev_balance_time = jiffies;
- time_remaining = balanced_irq_interval;
- preempt_enable();
- }
- }
- return 0;
-}
-
-static int __init balanced_irq_init(void)
-{
- int i;
- struct cpuinfo_x86 *c;
- cpumask_t tmp;
-
- cpus_shift_right(tmp, cpu_online_map, 2);
- c = &boot_cpu_data;
- /* When not overwritten by the command line ask subarchitecture. */
- if (irqbalance_disabled == IRQBALANCE_CHECK_ARCH)
- irqbalance_disabled = NO_BALANCE_IRQ;
- if (irqbalance_disabled)
- return 0;
-
- /* disable irqbalance completely if there is only one processor online */
- if (num_online_cpus() < 2) {
- irqbalance_disabled = 1;
- return 0;
- }
- /*
- * Enable physical balance only if more than 1 physical processor
- * is present
- */
- if (smp_num_siblings > 1 && !cpus_empty(tmp))
- physical_balance = 1;
-
- for_each_online_cpu(i) {
- irq_cpu_data[i].irq_delta = kzalloc(sizeof(unsigned long) * nr_irqs, GFP_KERNEL);
- irq_cpu_data[i].last_irq = kzalloc(sizeof(unsigned long) * nr_irqs, GFP_KERNEL);
- if (irq_cpu_data[i].irq_delta == NULL || irq_cpu_data[i].last_irq == NULL) {
- printk(KERN_ERR "balanced_irq_init: out of memory");
- goto failed;
- }
- }
-
- printk(KERN_INFO "Starting balanced_irq\n");
- if (!IS_ERR(kthread_run(balanced_irq, NULL, "kirqd")))
- return 0;
- printk(KERN_ERR "balanced_irq_init: failed to spawn balanced_irq");
-failed:
- for_each_possible_cpu(i) {
- kfree(irq_cpu_data[i].irq_delta);
- irq_cpu_data[i].irq_delta = NULL;
- kfree(irq_cpu_data[i].last_irq);
- irq_cpu_data[i].last_irq = NULL;
- }
- return 0;
-}
-
-int __devinit irqbalance_disable(char *str)
-{
- irqbalance_disabled = 1;
- return 1;
-}
-
-__setup("noirqbalance", irqbalance_disable);
-
-late_initcall(balanced_irq_init);
-#endif /* CONFIG_IRQBALANCE */
#endif /* CONFIG_SMP */
#ifndef CONFIG_SMP
projects / linux-beck.git / commitdiff