From: Wu Zhangjin <wuzhangjin@gmail.com>
Date: Tue, 9 Mar 2010 16:27:28 +0000 (+0800)
Subject: MIPS: Trace: Don't trace irqsoff for the idle process
X-Git-Tag: v2.6.34-rc4~6^2~30
X-Git-Url: http://bbs.cooldavid.org/git/?a=commitdiff_plain;h=7a7ac952d5217b2f568e5ef91ac39b572e166f24;p=net-next-2.6.git

MIPS: Trace: Don't trace irqsoff for the idle process

Like x86 did in arch/x86/kernel/{process_32.c,process_64.c}, also don't
trace irqsoff for idle.

If there's no useful work to be done, we don't care about the irqsoff
duration. If we trace the idle process, the max duration of irqsoff will
be the idle time and make the irqsoff tracer useless.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Patchwork: http://patchwork.linux-mips.org/patch/1044/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 463b71b90a0..99960940d4a 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -63,8 +63,13 @@ void __noreturn cpu_idle(void)
 
 			smtc_idle_loop_hook();
 #endif
-			if (cpu_wait)
+
+			if (cpu_wait) {
+				/* Don't trace irqs off for idle */
+				stop_critical_timings();
 				(*cpu_wait)();
+				start_critical_timings();
+			}
 		}
 #ifdef CONFIG_HOTPLUG_CPU
 		if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) &&