From: Zhang Yanmin Date: Fri, 23 Jun 2006 09:04:22 +0000 (-0700) Subject: [PATCH] x86: kernel irq balance doesn't work X-Git-Tag: v2.6.18-rc1~1081^2~121 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1b61b910e99059abdd54c93aa70e84e076e33d16;p=linux-2.6 [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c index d70f2ade5c..a62df3e764 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 /* kmalloc() */ # include /* 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); diff --git a/include/linux/irq.h b/include/linux/irq.h index 42c9cd5628..e8a07e75e4 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -164,6 +164,14 @@ static inline void set_irq_info(int irq, cpumask_t mask) #endif // CONFIG_SMP +#ifdef CONFIG_IRQBALANCE +extern void set_balance_irq_affinity(unsigned int irq, cpumask_t mask); +#else +static inline void set_balance_irq_affinity(unsigned int irq, cpumask_t mask) +{ +} +#endif + extern int no_irq_affinity; extern int noirqdebug_setup(char *str); diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index d03b5eef8c..afacd6f585 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -24,6 +24,8 @@ static struct proc_dir_entry *smp_affinity_entry[NR_IRQS]; #ifdef CONFIG_GENERIC_PENDING_IRQ void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val) { + set_balance_irq_affinity(irq, mask_val); + /* * Save these away for later use. Re-progam when the * interrupt is pending @@ -33,6 +35,7 @@ void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val) #else void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val) { + set_balance_irq_affinity(irq, mask_val); irq_affinity[irq] = mask_val; irq_desc[irq].handler->set_affinity(irq, mask_val); }