powerpc: Handle simultaneous interrupts at once

It often happens to have simultaneous interrupts, for instance
when having double Ethernet attachment. With the current
implementation, we suffer the cost of kernel entry/exit for each
interrupt.

This patch introduces a loop in __do_irq() to handle all interrupts
at once before returning.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 5c291df30fe34328d64b7bc0985843a7d9dfe73a..ab2ed9afd3c23f8c121c30c906c22ed7365c9f29 100644 (file)
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -481,7 +481,11 @@ void __do_irq(struct pt_regs *regs)
        if (unlikely(!irq))
                __this_cpu_inc(irq_stat.spurious_irqs);
        else
-               generic_handle_irq(irq);
+               do {
+                       generic_handle_irq(irq);
+
+                       irq = ppc_md.get_irq();
+               } while (irq);
 
        trace_irq_exit(regs);