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[PATCH] x86/x86_64: deferred handling of writes to /proc/irqxx/smp_affinity

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When handling writes to /proc/irq, current code is re-programming rte
entries directly. This is not recommended and could potentially cause
chipset's to lockup, or cause missing interrupts.

CONFIG_IRQ_BALANCE does this correctly, where it re-programs only when the
interrupt is pending. The same needs to be done for /proc/irq handling as well.
Otherwise user space irq balancers are really not doing the right thing.

- Changed pending_irq_balance_cpumask to pending_irq_migrate_cpumask for
  lack of a generic name.
- added move_irq out of IRQ_BALANCE, and added this same to X86_64
- Added new proc handler for write, so we can do deferred write at irq
  handling time.
- Display of /proc/irq/XX/smp_affinity used to display CPU_MASKALL, instead
  it now shows only active cpu masks, or exactly what was set.
- Provided a common move_irq implementation, instead of duplicating
  when using generic irq framework.

Tested on i386/x86_64 and ia64 with CONFIG_PCI_MSI turned on and off.
Tested UP builds as well.

MSI testing: tbd: I have cards, need to look for a x-over cable, although I
did test an earlier version of this patch.  Will test in a couple days.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Acked-by: Zwane Mwaikambo <zwane@holomorphy.com>
Grudgingly-acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Coywolf Qi Hunt <coywolf@lovecn.org>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ashok Raj
2005-09-06 15:16:15 -07:00
committed by Linus Torvalds
parent f63ed39c57
commit 54d5d42404
13 changed files with 253 additions and 134 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
kernel/irq/manage.c
View File

@@ -18,6 +18,10 @@
cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
#if defined (CONFIG_GENERIC_PENDING_IRQ) || defined (CONFIG_IRQBALANCE)
cpumask_t __cacheline_aligned pending_irq_cpumask[NR_IRQS];
#endif
/**
* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
*

14
kernel/irq/proc.c
View File

@@ -19,12 +19,22 @@ static struct proc_dir_entry *root_irq_dir, *irq_dir[NR_IRQS];
*/
static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
void __attribute__((weak))
proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
#ifdef CONFIG_GENERIC_PENDING_IRQ
void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
{
/*
* Save these away for later use. Re-progam when the
* interrupt is pending
*/
set_pending_irq(irq, mask_val);
}
#else
void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
{
irq_affinity[irq] = mask_val;
irq_desc[irq].handler->set_affinity(irq, mask_val);
}
#endif
static int irq_affinity_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)