[PATCH] x86: Add abilty to enable/disable nmi watchdog from procfs (update)
Adds a new /proc/sys/kernel/nmi_watchdog call that will enable/disable the nmi watchdog. By entering a non-zero value here, a user can enable the nmi watchdog to monitor the online cpus in the system. By entering a zero value here, a user can disable the nmi watchdog and free up a performance counter which could then be utilized by the oprofile subsystem, otherwise oprofile may be short a counter when in use. Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
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@ -1124,11 +1124,15 @@ debugging information is displayed on console.
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NMI switch that most IA32 servers have fires unknown NMI up, for example.
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If a system hangs up, try pressing the NMI switch.
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[NOTE]
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This function and oprofile share a NMI callback. Therefore this function
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cannot be enabled when oprofile is activated.
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And NMI watchdog will be disabled when the value in this file is set to
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non-zero.
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nmi_watchdog
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------------
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Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero
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the NMI watchdog is enabled and will continuously test all online cpus to
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determine whether or not they are still functioning properly.
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Because the NMI watchdog shares registers with oprofile, by disabling the NMI
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watchdog, oprofile may have more registers to utilize.
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2.4 /proc/sys/vm - The virtual memory subsystem
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@ -847,7 +847,7 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
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}
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/*
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* proc handler for /proc/sys/kernel/nmi_watchdog
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* proc handler for /proc/sys/kernel/nmi
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*/
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int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
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void __user *buffer, size_t *length, loff_t *ppos)
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@ -861,8 +861,8 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
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return 0;
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if (atomic_read(&nmi_active) < 0) {
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printk(KERN_WARNING "NMI watchdog is permanently disabled\n");
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return -EINVAL;
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printk( KERN_WARNING "NMI watchdog is permanently disabled\n");
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return -EIO;
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}
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if (nmi_watchdog == NMI_DEFAULT) {
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@ -872,24 +872,11 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
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nmi_watchdog = NMI_IO_APIC;
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}
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if (nmi_watchdog == NMI_LOCAL_APIC)
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{
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if (nmi_watchdog == NMI_LOCAL_APIC) {
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if (nmi_watchdog_enabled)
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enable_lapic_nmi_watchdog();
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else
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disable_lapic_nmi_watchdog();
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} else if (nmi_watchdog == NMI_IO_APIC) {
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/* FIXME
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* for some reason these functions don't work
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*/
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printk("Can not enable/disable NMI on IO APIC\n");
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return -EINVAL;
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#if 0
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if (nmi_watchdog_enabled)
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enable_timer_nmi_watchdog();
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else
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disable_timer_nmi_watchdog();
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#endif
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} else {
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printk( KERN_WARNING
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"NMI watchdog doesn't know what hardware to touch\n");
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@ -167,7 +167,7 @@ static __cpuinit inline int nmi_known_cpu(void)
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}
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/* Run after command line and cpu_init init, but before all other checks */
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void __cpuinit nmi_watchdog_default(void)
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void nmi_watchdog_default(void)
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{
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if (nmi_watchdog != NMI_DEFAULT)
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return;
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@ -766,32 +766,19 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
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if (atomic_read(&nmi_active) < 0) {
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printk( KERN_WARNING "NMI watchdog is permanently disabled\n");
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return -EINVAL;
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return -EIO;
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}
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/* if nmi_watchdog is not set yet, then set it */
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nmi_watchdog_default();
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if (nmi_watchdog == NMI_LOCAL_APIC)
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{
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if (nmi_watchdog == NMI_LOCAL_APIC) {
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if (nmi_watchdog_enabled)
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enable_lapic_nmi_watchdog();
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else
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disable_lapic_nmi_watchdog();
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} else if (nmi_watchdog == NMI_IO_APIC) {
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/* FIXME
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* for some reason these functions don't work
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*/
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printk("Can not enable/disable NMI on IO APIC\n");
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return -EIO;
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#if 0
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if (nmi_watchdog_enabled)
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enable_timer_nmi_watchdog();
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else
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disable_timer_nmi_watchdog();
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#endif
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} else {
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printk(KERN_WARNING
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printk( KERN_WARNING
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"NMI watchdog doesn't know what hardware to touch\n");
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return -EIO;
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}
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