Messages in this thread Patch in this message | | | Date | Thu, 7 Dec 2006 21:47:45 +0100 | From | Ingo Molnar <> | Subject | Re: [patch] x86_64: do not enable the NMI watchdog by default |
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* Andrew Morton <akpm@osdl.org> wrote:
> (the patch doesn't vaguely apply btw).
patch below should apply to tail of current-ish -mm. Build and boot tested on x86_64.
Ingo
----------------------> Subject: [patch] x86_64: do not enable the NMI watchdog by default From: Ingo Molnar <mingo@elte.hu>
do not enable the NMI watchdog by default. Now that we have lockdep i cannot remember the last time it caught a real bug, but the NMI watchdog can /cause/ problems. Furthermore, to the typical user, an NMI watchdog assert results in a total lockup anyway (if under X). In that sense, all that the NMI watchdog does is that it makes the system /less/ stable and /less/ debuggable.
people can still enable it either after bootup via:
echo 1 > /proc/sys/kernel/nmi
or via the nmi_watchdog=1 or nmi_watchdog=2 boot options.
build and boot tested on an Athlon64 box.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86_64/kernel/apic.c | 1 - arch/x86_64/kernel/io_apic.c | 1 - arch/x86_64/kernel/nmi.c | 2 +- arch/x86_64/kernel/smpboot.c | 1 - include/asm-x86_64/nmi.h | 1 - 5 files changed, 1 insertion(+), 5 deletions(-)
Index: linux-mm-genapic.q/arch/x86_64/kernel/apic.c =================================================================== --- linux-mm-genapic.q.orig/arch/x86_64/kernel/apic.c +++ linux-mm-genapic.q/arch/x86_64/kernel/apic.c @@ -427,7 +427,6 @@ void __cpuinit setup_local_APIC (void) oldvalue, value); } - nmi_watchdog_default(); setup_apic_nmi_watchdog(NULL); apic_pm_activate(); } Index: linux-mm-genapic.q/arch/x86_64/kernel/io_apic.c =================================================================== --- linux-mm-genapic.q.orig/arch/x86_64/kernel/io_apic.c +++ linux-mm-genapic.q/arch/x86_64/kernel/io_apic.c @@ -1580,7 +1580,6 @@ static int try_apic_pin(int apic, int pi * Ok, does IRQ0 through the IOAPIC work? */ if (!no_timer_check && timer_irq_works()) { - nmi_watchdog_default(); if (nmi_watchdog == NMI_IO_APIC) { disable_8259A_irq(0); setup_nmi(); Index: linux-mm-genapic.q/arch/x86_64/kernel/nmi.c =================================================================== --- linux-mm-genapic.q.orig/arch/x86_64/kernel/nmi.c +++ linux-mm-genapic.q/arch/x86_64/kernel/nmi.c @@ -183,7 +183,7 @@ static __cpuinit inline int nmi_known_cp } /* Run after command line and cpu_init init, but before all other checks */ -void nmi_watchdog_default(void) +static inline void nmi_watchdog_default(void) { if (nmi_watchdog != NMI_DEFAULT) return; Index: linux-mm-genapic.q/arch/x86_64/kernel/smpboot.c =================================================================== --- linux-mm-genapic.q.orig/arch/x86_64/kernel/smpboot.c +++ linux-mm-genapic.q/arch/x86_64/kernel/smpboot.c @@ -1080,7 +1080,6 @@ static int __init smp_sanity_check(unsig */ void __init smp_prepare_cpus(unsigned int max_cpus) { - nmi_watchdog_default(); current_cpu_data = boot_cpu_data; current_thread_info()->cpu = 0; /* needed? */ set_cpu_sibling_map(0); Index: linux-mm-genapic.q/include/asm-x86_64/nmi.h =================================================================== --- linux-mm-genapic.q.orig/include/asm-x86_64/nmi.h +++ linux-mm-genapic.q/include/asm-x86_64/nmi.h @@ -59,7 +59,6 @@ extern void disable_timer_nmi_watchdog(v extern void enable_timer_nmi_watchdog(void); extern int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason); -extern void nmi_watchdog_default(void); extern int setup_nmi_watchdog(char *); extern atomic_t nmi_active; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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