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bitkeeper revision 1.1691 (42a5bd892a-21ifB8kNwgNvEid-K_Q)

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Reove IRQ balancer from Xen. It is unused, and balancing will be done
by the guests themselves.
Signed-off-by: Keir Fraser <keir@xensource.com>
This commit is contained in:
kaf24@firebug.cl.cam.ac.uk committed 2005-06-07 15:30:17 +00:00
1 parent d10f7373d3
commit b9ed424f28
1 file changed
-437
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xen/arch/x86/io_apic.c
-437
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@@ -232,440 +232,6 @@ static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t cpumask)
spin_unlock_irqrestore(&ioapic_lock, flags);
}
#if defined(CONFIG_IRQBALANCE)
# include <asm/processor.h> /* kernel_thread() */
# include <xen/kernel_stat.h> /* kstat */
# include <xen/xmalloc.h> /* kmalloc() */
# include <xen/timer.h> /* time_after() */
# ifdef CONFIG_BALANCED_IRQ_DEBUG
# define TDprintk(x...) do { printk("<%ld:%s:%d>: ", jiffies, __FILE__, __LINE__); printk(x); } while (0)
# define Dprintk(x...) do { TDprintk(x); } while (0)
# else
# define TDprintk(x...)
# define Dprintk(x...)
# endif
cpumask_t __cacheline_aligned pending_irq_balance_cpumask[NR_IRQS];
#define IRQBALANCE_CHECK_ARCH -999
static int irqbalance_disabled = IRQBALANCE_CHECK_ARCH;
static int physical_balance = 0;
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) - irq_stat[(cpu)].idle_timestamp > 1))
#define IRQ_ALLOWED(cpu, allowed_mask) cpu_isset(cpu, allowed_mask)
#define CPU_TO_PACKAGEINDEX(i) (first_cpu(cpu_sibling_map[i]))
#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)
long balanced_irq_interval = MAX_BALANCED_IRQ_INTERVAL;
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, irq_affinity[irq]);
new_cpu = move(cpu, allowed_mask, now, 1);
if (cpu != new_cpu) {
irq_desc_t *desc = irq_desc + irq;
unsigned long flags;
spin_lock_irqsave(&desc->lock, flags);
pending_irq_balance_cpumask[irq] = cpumask_of_cpu(new_cpu);
spin_unlock_irqrestore(&desc->lock, flags);
}
}
static inline void rotate_irqs_among_cpus(unsigned long useful_load_threshold)
{
int i, j;
Dprintk("Rotating IRQs among CPUs.\n");
for (i = 0; i < NR_CPUS; i++) {
for (j = 0; cpu_online(i) && (j < NR_IRQS); j++) {
if (!irq_desc[j].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;
for (i = 0; i < NR_CPUS; 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? */
if (!irq_desc[j].action)
continue;
if ( package_index == i )
IRQ_DELTA(package_index,j) = 0;
/* Determine the total count per processor per IRQ */
value_now = (unsigned long) kstat_cpu(i).irqs[j];
/* 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 (i = 0; i < NR_CPUS; i++) {
if (!cpu_online(i))
continue;
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 (i = 0; i < NR_CPUS; i++) {
if (!cpu_online(i))
continue;
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;
Dprintk("max_loaded cpu = %d\n", max_loaded);
Dprintk("min_loaded cpu = %d\n", min_loaded);
Dprintk("max_cpu_irq load = %ld\n", max_cpu_irq);
Dprintk("min_cpu_irq load = %ld\n", min_cpu_irq);
Dprintk("load imbalance = %lu\n", imbalance);
/* if imbalance is less than approx 10% of max load, then
* observe diminishing returns action. - quit
*/
if (imbalance < (max_cpu_irq >> 3)) {
Dprintk("Imbalance too trivial\n");
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? */
if (!irq_desc[j].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 accumlated 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, 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, irq_affinity[selected_irq]);
target_cpu_mask = cpumask_of_cpu(min_loaded);
cpus_and(tmp, target_cpu_mask, allowed_mask);
if (!cpus_empty(tmp)) {
irq_desc_t *desc = irq_desc + selected_irq;
unsigned long flags;
Dprintk("irq = %d moved to cpu = %d\n",
selected_irq, min_loaded);
/* mark for change destination */
spin_lock_irqsave(&desc->lock, flags);
pending_irq_balance_cpumask[selected_irq] =
cpumask_of_cpu(min_loaded);
spin_unlock_irqrestore(&desc->lock, flags);
/* 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);
Dprintk("IRQ worth rotating not found\n");
return;
}
static int balanced_irq(void *unused)
{
int i;
unsigned long prev_balance_time = jiffies;
long time_remaining = balanced_irq_interval;
daemonize("kirqd");
/* push everything to CPU 0 to give us a starting point. */
for (i = 0 ; i < NR_IRQS ; i++) {
pending_irq_balance_cpumask[i] = cpumask_of_cpu(0);
}
for ( ; ; ) {
set_current_state(TASK_INTERRUPTIBLE);
time_remaining = schedule_timeout(time_remaining);
try_to_freeze(PF_FREEZE);
if (time_after(jiffies,
prev_balance_time+balanced_irq_interval)) {
do_irq_balance();
prev_balance_time = jiffies;
time_remaining = balanced_irq_interval;
}
}
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 (i = 0; i < NR_CPUS; i++) {
if (!cpu_online(i))
continue;
irq_cpu_data[i].irq_delta = kmalloc(sizeof(unsigned long) * NR_IRQS, GFP_KERNEL);
irq_cpu_data[i].last_irq = kmalloc(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;
}
memset(irq_cpu_data[i].irq_delta,0,sizeof(unsigned long) * NR_IRQS);
memset(irq_cpu_data[i].last_irq,0,sizeof(unsigned long) * NR_IRQS);
}
printk(KERN_INFO "Starting balanced_irq\n");
if (kernel_thread(balanced_irq, NULL, CLONE_KERNEL) >= 0)
return 0;
else
printk(KERN_ERR "balanced_irq_init: failed to spawn balanced_irq");
failed:
for (i = 0; i < NR_CPUS; i++) {
if(irq_cpu_data[i].irq_delta)
kfree(irq_cpu_data[i].irq_delta);
if(irq_cpu_data[i].last_irq)
kfree(irq_cpu_data[i].last_irq);
}
return 0;
}
int __init irqbalance_disable(char *str)
{
irqbalance_disabled = 1;
return 0;
}
__setup("noirqbalance", irqbalance_disable);
static inline void move_irq(int irq)
{
/* note - we hold the desc->lock */
if (unlikely(!cpus_empty(pending_irq_balance_cpumask[irq]))) {
set_ioapic_affinity_irq(irq, pending_irq_balance_cpumask[irq]);
cpus_clear(pending_irq_balance_cpumask[irq]);
}
}
late_initcall(balanced_irq_init);
#else /* !CONFIG_IRQBALANCE */
static inline void move_irq(int irq) { }
#endif /* CONFIG_IRQBALANCE */
#ifndef CONFIG_SMP
void fastcall send_IPI_self(int vector)
{
unsigned int cfg;
/*
* Wait for idle.
*/
apic_wait_icr_idle();
cfg = APIC_DM_FIXED | APIC_DEST_SELF | vector | APIC_DEST_LOGICAL;
/*
* Send the IPI. The write to APIC_ICR fires this off.
*/
apic_write_around(APIC_ICR, cfg);
}
#endif /* !CONFIG_SMP */
/*
* Find the IRQ entry number of a certain pin.
*/
@@ -1610,7 +1176,6 @@ static unsigned int startup_edge_ioapic_irq(unsigned int irq)
*/
static void ack_edge_ioapic_irq(unsigned int irq)
{
move_irq(irq);
if ((irq_desc[irq].status & (IRQ_PENDING | IRQ_DISABLED))
== (IRQ_PENDING | IRQ_DISABLED))
mask_IO_APIC_irq(irq);
@@ -1643,8 +1208,6 @@ static void mask_and_ack_level_ioapic_irq (unsigned int irq)
unsigned long v;
int i;
move_irq(irq);
mask_IO_APIC_irq(irq);
/*
* It appears there is an erratum which affects at least version 0x11
Reference in new issue
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