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[IA64] smp_flush_tlb_mm() should only send IPI's to cpus in cpu_vm_mask 

Having flush_tlb_mm->smp_flush_tlb_mm() send an IPI to every cpu
on the system is occasionally triggering spin_lock contention in
generic_smp_call_function_interrupt().

Follow x86 arch's lead and only sends IPIs to the cpus in mm->cpu_vm_mask.

Experiments with this change have shown significant improvement in this
contention issue.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Dimitri Sivanich 2009-04-15 10:56:25 -05:00 committed by Tony Luck
parent c4cb768f02
commit edb91dc01a
1 changed files with 5 additions and 8 deletions
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13
arch/ia64/kernel/smp.c
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@ -301,15 +301,12 @@ smp_flush_tlb_mm (struct mm_struct *mm)
return;
}
smp_call_function_mask(mm->cpu_vm_mask,
(void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
local_irq_disable();
local_finish_flush_tlb_mm(mm);
local_irq_enable();
preempt_enable();
/*
* We could optimize this further by using mm->cpu_vm_mask to track which CPUs
* have been running in the address space. It's not clear that this is worth the
* trouble though: to avoid races, we have to raise the IPI on the target CPU
* anyhow, and once a CPU is interrupted, the cost of local_flush_tlb_all() is
* rather trivial.
*/
on_each_cpu((void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
}
void arch_send_call_function_single_ipi(int cpu)