linux_old1/include/linux/nmi.h

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/*
* linux/include/linux/nmi.h
*/
#ifndef LINUX_NMI_H
#define LINUX_NMI_H
#include <linux/sched.h>
#include <asm/irq.h>
/**
* touch_nmi_watchdog - restart NMI watchdog timeout.
*
* If the architecture supports the NMI watchdog, touch_nmi_watchdog()
* may be used to reset the timeout - for code which intentionally
* disables interrupts for a long time. This call is stateless.
*/
#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
#include <asm/nmi.h>
extern void touch_nmi_watchdog(void);
#else
[PATCH] x86: fix laptop bootup hang in init_acpi() During kernel bootup, a new T60 laptop (CoreDuo, 32-bit) hangs about 10%-20% of the time in acpi_init(): Calling initcall 0xc055ce1a: topology_init+0x0/0x2f() Calling initcall 0xc055d75e: mtrr_init_finialize+0x0/0x2c() Calling initcall 0xc05664f3: param_sysfs_init+0x0/0x175() Calling initcall 0xc014cb65: pm_sysrq_init+0x0/0x17() Calling initcall 0xc0569f99: init_bio+0x0/0xf4() Calling initcall 0xc056b865: genhd_device_init+0x0/0x50() Calling initcall 0xc056c4bd: fbmem_init+0x0/0x87() Calling initcall 0xc056dd74: acpi_init+0x0/0x1ee() It's a hard hang that not even an NMI could punch through! Frustratingly, adding printks or function tracing to the ACPI code made the hangs go away ... After some time an additional detail emerged: disabling the NMI watchdog made these occasional hangs go away. So i spent the better part of today trying to debug this and trying out various theories when i finally found the likely reason for the hang: if acpi_ns_initialize_devices() executes an _INI AML method and an NMI happens to hit that AML execution in the wrong moment, the machine would hang. (my theory is that this must be some sort of chipset setup method doing stores to chipset mmio registers?) Unfortunately given the characteristics of the hang it was sheer impossible to figure out which of the numerous AML methods is impacted by this problem. As a workaround i wrote an interface to disable chipset-based NMIs while executing _INI sections - and indeed this fixed the hang. I did a boot-loop of 100 separate reboots and none hung - while without the patch it would hang every 5-10 attempts. Out of caution i did not touch the nmi_watchdog=2 case (it's not related to the chipset anyway and didnt hang). I implemented this for both x86_64 and i686, tested the i686 laptop both with nmi_watchdog=1 [which triggered the hangs] and nmi_watchdog=2, and tested an Athlon64 box with the 64-bit kernel as well. Everything builds and works with the patch applied. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-02-13 20:26:24 +08:00
static inline void touch_nmi_watchdog(void)
{
touch_softlockup_watchdog();
}
#endif
/*
* Create trigger_all_cpu_backtrace() out of the arch-provided
* base function. Return whether such support was available,
* to allow calling code to fall back to some other mechanism:
*/
#ifdef arch_trigger_all_cpu_backtrace
static inline bool trigger_all_cpu_backtrace(void)
{
arch_trigger_all_cpu_backtrace();
return true;
}
#else
static inline bool trigger_all_cpu_backtrace(void)
{
return false;
}
#endif
lockup_detector: Combine nmi_watchdog and softlockup detector The new nmi_watchdog (which uses the perf event subsystem) is very similar in structure to the softlockup detector. Using Ingo's suggestion, I combined the two functionalities into one file: kernel/watchdog.c. Now both the nmi_watchdog (or hardlockup detector) and softlockup detector sit on top of the perf event subsystem, which is run every 60 seconds or so to see if there are any lockups. To detect hardlockups, cpus not responding to interrupts, I implemented an hrtimer that runs 5 times for every perf event overflow event. If that stops counting on a cpu, then the cpu is most likely in trouble. To detect softlockups, tasks not yielding to the scheduler, I used the previous kthread idea that now gets kicked every time the hrtimer fires. If the kthread isn't being scheduled neither is anyone else and the warning is printed to the console. I tested this on x86_64 and both the softlockup and hardlockup paths work. V2: - cleaned up the Kconfig and softlockup combination - surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI - seperated out the softlockup case from perf event subsystem - re-arranged the enabling/disabling nmi watchdog from proc space - added cpumasks for hardlockup failure cases - removed fallback to soft events if no PMU exists for hard events V3: - comment cleanups - drop support for older softlockup code - per_cpu cleanups - completely remove software clock base hardlockup detector - use per_cpu masking on hard/soft lockup detection - #ifdef cleanups - rename config option NMI_WATCHDOG to LOCKUP_DETECTOR - documentation additions V4: - documentation fixes - convert per_cpu to __get_cpu_var - powerpc compile fixes V5: - split apart warn flags for hard and soft lockups TODO: - figure out how to make an arch-agnostic clock2cycles call (if possible) to feed into perf events as a sample period [fweisbec: merged conflict patch] Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-08 05:11:44 +08:00
#ifdef CONFIG_LOCKUP_DETECTOR
int hw_nmi_is_cpu_stuck(struct pt_regs *);
u64 hw_nmi_get_sample_period(int watchdog_thresh);
extern int watchdog_user_enabled;
extern int watchdog_thresh;
struct ctl_table;
extern int proc_dowatchdog(struct ctl_table *, int ,
void __user *, size_t *, loff_t *);
#endif
#endif