From: Christophe Leroy <christophe.leroy@c-s.fr>
Date: Thu, 16 Mar 2017 08:55:45 +0000 (+0100)
Subject: powerpc: Handle simultaneous interrupts at once
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=45cb08f4791ce6a15c54598b4cb73db4b4b8294f;p=openwrt%2Fstaging%2Fblogic.git

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 5c291df30fe3..ab2ed9afd3c2 100644
--- 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);