From 802c64b310e5b9dfda6cb50b850b962ed96a9e81 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 2 Feb 2009 21:57:48 -0800 Subject: [PATCH] sparc64: On non-Niagara, need to touch NMI watchdog in NOHZ mode. When we're idling in NOHZ mode, timer interrupts are not running. Evidence of processing timer interrupts is what the NMI watchdog uses to determine if the CPU is stuck. On Niagara, we'll yield the cpu. This will make the cpu, at worst, hang out in the hypervisor until an interrupt arrives. This will prevent the NMI watchdog timer from firing. However on non-Niagara we just loop executing instructions which will cause the NMI watchdog to keep firing. It won't see timer interrupts happening so it will think the cpu is stuck. Fix this by touching the NMI watchdog in the cpu idle loop on non-Niagara machines. Signed-off-by: David S. Miller --- arch/sparc/kernel/process_64.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index cc8b5604442c..a73954b87f0a 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -52,8 +53,10 @@ static void sparc64_yield(int cpu) { - if (tlb_type != hypervisor) + if (tlb_type != hypervisor) { + touch_nmi_watchdog(); return; + } clear_thread_flag(TIF_POLLING_NRFLAG); smp_mb__after_clear_bit(); -- 2.20.1