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| author | Zhang Yanmin <yanmin.zhang@intel.com> | 2006-06-23 02:04:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-23 07:42:57 -0700 |
| commit | 1b61b910e99059abdd54c93aa70e84e076e33d16 (patch) | |
| tree | fe2cd431dc39521a0f2d30e22c9bd3eb3e1bc317 /arch | |
| parent | afa024c3dbccf026e45121f4b9de54cda48edbea (diff) | |
| download | linux-3.10-1b61b910e99059abdd54c93aa70e84e076e33d16.tar.gz linux-3.10-1b61b910e99059abdd54c93aa70e84e076e33d16.tar.bz2 linux-3.10-1b61b910e99059abdd54c93aa70e84e076e33d16.zip | |
[PATCH] x86: kernel irq balance doesn't work
On i386, kernel irq balance doesn't work.
1) In function do_irq_balance, after kernel finds the min_loaded cpu but
before calling set_pending_irq to really pin the selected_irq to the
target cpu, kernel does a cpus_and with irq_affinity[selected_irq].
Later on, when the irq is acked, kernel would calls
move_native_irq=>desc->handler->set_affinity to change the irq affinity.
However, every function pointed by
hw_interrupt_type->set_affinity(unsigned int irq, cpumask_t cpumask)
always changes irq_affinity[irq] to cpumask. Next time when recalling
do_irq_balance, it has to do cpu_ands again with
irq_affinity[selected_irq], but irq_affinity[selected_irq] already
becomes one cpu selected by the first irq balance.
2) Function balance_irq in file arch/i386/kernel/io_apic.c has the same
issue.
[akpm@osdl.org: cleanups]
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/i386/kernel/io_apic.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c index d70f2ade5cd..a62df3e764c 100644 --- a/arch/i386/kernel/io_apic.c +++ b/arch/i386/kernel/io_apic.c @@ -267,7 +267,7 @@ static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t cpumask) # include <linux/slab.h> /* kmalloc() */ # include <linux/timer.h> /* time_after() */ -# ifdef CONFIG_BALANCED_IRQ_DEBUG +#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 @@ -275,10 +275,15 @@ static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t cpumask) # define Dprintk(x...) # endif - #define IRQBALANCE_CHECK_ARCH -999 -static int irqbalance_disabled = IRQBALANCE_CHECK_ARCH; -static int physical_balance = 0; +#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; @@ -297,12 +302,14 @@ static struct irq_cpu_info { #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) +static cpumask_t balance_irq_affinity[NR_IRQS] = { + [0 ... NR_IRQS-1] = CPU_MASK_ALL +}; -static long balanced_irq_interval = MAX_BALANCED_IRQ_INTERVAL; +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) @@ -340,7 +347,7 @@ static inline void balance_irq(int cpu, int irq) if (irqbalance_disabled) return; - cpus_and(allowed_mask, cpu_online_map, irq_affinity[irq]); + 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)); @@ -529,7 +536,9 @@ tryanotherirq: } } - cpus_and(allowed_mask, cpu_online_map, irq_affinity[selected_irq]); + 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); |