[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>
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index c2d9823..5230eaa 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -301,15 +301,12 @@
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)