Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux...
authorIngo Molnar <mingo@elte.hu>
Thu, 5 Aug 2010 06:46:15 +0000 (08:46 +0200)
committerIngo Molnar <mingo@elte.hu>
Thu, 5 Aug 2010 06:46:15 +0000 (08:46 +0200)
16 files changed:
Documentation/kernel-parameters.txt
arch/Kconfig
arch/x86/Kconfig
arch/x86/include/asm/nmi.h
arch/x86/kernel/apic/Makefile
arch/x86/kernel/apic/hw_nmi.c [new file with mode: 0644]
arch/x86/kernel/apic/nmi.c
arch/x86/kernel/traps.c
include/linux/nmi.h
include/linux/sched.h
kernel/Makefile
kernel/softlockup.c [deleted file]
kernel/sysctl.c
kernel/timer.c
kernel/watchdog.c [new file with mode: 0644]
lib/Kconfig.debug

index 2b2407d9a6d025a8451605b104a35daa7da59b47..c45a3548537a9e23b326e5d529fbd2ab5adaabca 100644 (file)
@@ -1812,6 +1812,8 @@ and is between 256 and 4096 characters. It is defined in the file
 
        nousb           [USB] Disable the USB subsystem
 
+       nowatchdog      [KNL] Disable the lockup detector.
+
        nowb            [ARM]
 
        nox2apic        [X86-64,APIC] Do not enable x2APIC mode.
index acda512da2e21b52a972bb4255404fab3fce7015..4877a8c8ee1697599289f35107824f95ba8daf84 100644 (file)
@@ -151,4 +151,11 @@ config HAVE_MIXED_BREAKPOINTS_REGS
 config HAVE_USER_RETURN_NOTIFIER
        bool
 
+config HAVE_PERF_EVENTS_NMI
+       bool
+       help
+         System hardware can generate an NMI using the perf event
+         subsystem.  Also has support for calculating CPU cycle events
+         to determine how many clock cycles in a given period.
+
 source "kernel/gcov/Kconfig"
index dcb0593b4a66348a204a44fee3366c5da0848ad1..6f77afa6bca92203a338badf7e25a3fe01ab4e57 100644 (file)
@@ -55,6 +55,7 @@ config X86
        select HAVE_HW_BREAKPOINT
        select HAVE_MIXED_BREAKPOINTS_REGS
        select PERF_EVENTS
+       select HAVE_PERF_EVENTS_NMI
        select ANON_INODES
        select HAVE_ARCH_KMEMCHECK
        select HAVE_USER_RETURN_NOTIFIER
index 93da9c3f334120b64165a8124b79b09e71365bf4..932f0f86b4b76252e6e6434ab9c15d81c3b17004 100644 (file)
@@ -17,7 +17,9 @@ int do_nmi_callback(struct pt_regs *regs, int cpu);
 
 extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
 extern int check_nmi_watchdog(void);
+#if !defined(CONFIG_LOCKUP_DETECTOR)
 extern int nmi_watchdog_enabled;
+#endif
 extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
 extern int reserve_perfctr_nmi(unsigned int);
 extern void release_perfctr_nmi(unsigned int);
index 565c1bfc507d41b8387eea7cc7e6ffd22f3f114a..910f20b457c464d34f1e9874269d652ea0da325e 100644 (file)
@@ -2,7 +2,12 @@
 # Makefile for local APIC drivers and for the IO-APIC code
 #
 
-obj-$(CONFIG_X86_LOCAL_APIC)   += apic.o apic_noop.o probe_$(BITS).o ipi.o nmi.o
+obj-$(CONFIG_X86_LOCAL_APIC)   += apic.o apic_noop.o probe_$(BITS).o ipi.o
+ifneq ($(CONFIG_HARDLOCKUP_DETECTOR),y)
+obj-$(CONFIG_X86_LOCAL_APIC)   += nmi.o
+endif
+obj-$(CONFIG_HARDLOCKUP_DETECTOR)      += hw_nmi.o
+
 obj-$(CONFIG_X86_IO_APIC)      += io_apic.o
 obj-$(CONFIG_SMP)              += ipi.o
 
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
new file mode 100644 (file)
index 0000000..cefd694
--- /dev/null
@@ -0,0 +1,107 @@
+/*
+ *  HW NMI watchdog support
+ *
+ *  started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ *  Arch specific calls to support NMI watchdog
+ *
+ *  Bits copied from original nmi.c file
+ *
+ */
+#include <asm/apic.h>
+
+#include <linux/cpumask.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/nmi.h>
+#include <linux/module.h>
+
+/* For reliability, we're prepared to waste bits here. */
+static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+
+u64 hw_nmi_get_sample_period(void)
+{
+       return (u64)(cpu_khz) * 1000 * 60;
+}
+
+#ifdef ARCH_HAS_NMI_WATCHDOG
+void arch_trigger_all_cpu_backtrace(void)
+{
+       int i;
+
+       cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
+
+       printk(KERN_INFO "sending NMI to all CPUs:\n");
+       apic->send_IPI_all(NMI_VECTOR);
+
+       /* Wait for up to 10 seconds for all CPUs to do the backtrace */
+       for (i = 0; i < 10 * 1000; i++) {
+               if (cpumask_empty(to_cpumask(backtrace_mask)))
+                       break;
+               mdelay(1);
+       }
+}
+
+static int __kprobes
+arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
+                        unsigned long cmd, void *__args)
+{
+       struct die_args *args = __args;
+       struct pt_regs *regs;
+       int cpu = smp_processor_id();
+
+       switch (cmd) {
+       case DIE_NMI:
+       case DIE_NMI_IPI:
+               break;
+
+       default:
+               return NOTIFY_DONE;
+       }
+
+       regs = args->regs;
+
+       if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
+               static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+               arch_spin_lock(&lock);
+               printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
+               show_regs(regs);
+               dump_stack();
+               arch_spin_unlock(&lock);
+               cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
+               return NOTIFY_STOP;
+       }
+
+       return NOTIFY_DONE;
+}
+
+static __read_mostly struct notifier_block backtrace_notifier = {
+       .notifier_call          = arch_trigger_all_cpu_backtrace_handler,
+       .next                   = NULL,
+       .priority               = 1
+};
+
+static int __init register_trigger_all_cpu_backtrace(void)
+{
+       register_die_notifier(&backtrace_notifier);
+       return 0;
+}
+early_initcall(register_trigger_all_cpu_backtrace);
+#endif
+
+/* STUB calls to mimic old nmi_watchdog behaviour */
+#if defined(CONFIG_X86_LOCAL_APIC)
+unsigned int nmi_watchdog = NMI_NONE;
+EXPORT_SYMBOL(nmi_watchdog);
+void acpi_nmi_enable(void) { return; }
+void acpi_nmi_disable(void) { return; }
+#endif
+atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
+EXPORT_SYMBOL(nmi_active);
+int unknown_nmi_panic;
+void cpu_nmi_set_wd_enabled(void) { return; }
+void stop_apic_nmi_watchdog(void *unused) { return; }
+void setup_apic_nmi_watchdog(void *unused) { return; }
+int __init check_nmi_watchdog(void) { return 0; }
index 1edaf15c0b8eef05b36653a0ed9087a9b3717f9e..a43f71cb30f8709595fe77c80be19d36c24aae29 100644 (file)
@@ -401,13 +401,6 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
        int cpu = smp_processor_id();
        int rc = 0;
 
-       /* check for other users first */
-       if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
-                       == NOTIFY_STOP) {
-               rc = 1;
-               touched = 1;
-       }
-
        sum = get_timer_irqs(cpu);
 
        if (__get_cpu_var(nmi_touch)) {
index 725ef4d17cd5922289b24e515c8b030e86cf6c18..60788dee0f8a74f53d547c462d5694201b6d609d 100644 (file)
@@ -392,7 +392,13 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
                if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
                                                                == NOTIFY_STOP)
                        return;
+
 #ifdef CONFIG_X86_LOCAL_APIC
+               if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
+                                                       == NOTIFY_STOP)
+                       return;
+
+#ifndef CONFIG_LOCKUP_DETECTOR
                /*
                 * Ok, so this is none of the documented NMI sources,
                 * so it must be the NMI watchdog.
@@ -400,6 +406,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
                if (nmi_watchdog_tick(regs, reason))
                        return;
                if (!do_nmi_callback(regs, cpu))
+#endif /* !CONFIG_LOCKUP_DETECTOR */
                        unknown_nmi_error(reason, regs);
 #else
                unknown_nmi_error(reason, regs);
index b752e807addece22ec9210f0d109d2818505d34d..06aab5eee134cd56c4bade9005912fa3a785a327 100644 (file)
@@ -20,10 +20,14 @@ extern void touch_nmi_watchdog(void);
 extern void acpi_nmi_disable(void);
 extern void acpi_nmi_enable(void);
 #else
+#ifndef CONFIG_HARDLOCKUP_DETECTOR
 static inline void touch_nmi_watchdog(void)
 {
        touch_softlockup_watchdog();
 }
+#else
+extern void touch_nmi_watchdog(void);
+#endif
 static inline void acpi_nmi_disable(void) { }
 static inline void acpi_nmi_enable(void) { }
 #endif
@@ -47,4 +51,13 @@ static inline bool trigger_all_cpu_backtrace(void)
 }
 #endif
 
+#ifdef CONFIG_LOCKUP_DETECTOR
+int hw_nmi_is_cpu_stuck(struct pt_regs *);
+u64 hw_nmi_get_sample_period(void);
+extern int watchdog_enabled;
+struct ctl_table;
+extern int proc_dowatchdog_enabled(struct ctl_table *, int ,
+                       void __user *, size_t *, loff_t *);
+#endif
+
 #endif
index 7b6ec63cb74fa7f7d83520b2712b772a09c89ecf..3992f50de6145927a39f72c46dcf8279a16f57ab 100644 (file)
@@ -316,20 +316,16 @@ extern void scheduler_tick(void);
 
 extern void sched_show_task(struct task_struct *p);
 
-#ifdef CONFIG_DETECT_SOFTLOCKUP
-extern void softlockup_tick(void);
+#ifdef CONFIG_LOCKUP_DETECTOR
 extern void touch_softlockup_watchdog(void);
 extern void touch_softlockup_watchdog_sync(void);
 extern void touch_all_softlockup_watchdogs(void);
-extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
-                                   void __user *buffer,
-                                   size_t *lenp, loff_t *ppos);
+extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
+                                 void __user *buffer,
+                                 size_t *lenp, loff_t *ppos);
 extern unsigned int  softlockup_panic;
 extern int softlockup_thresh;
 #else
-static inline void softlockup_tick(void)
-{
-}
 static inline void touch_softlockup_watchdog(void)
 {
 }
index 057472fbc272eed8b64f23c16f55b49217aa9043..ce53fb2bd1d90669caab50084cfac710c620c946 100644 (file)
@@ -76,8 +76,8 @@ obj-$(CONFIG_GCOV_KERNEL) += gcov/
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_KGDB) += debug/
-obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
+obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
deleted file mode 100644 (file)
index 4b493f6..0000000
+++ /dev/null
@@ -1,293 +0,0 @@
-/*
- * Detect Soft Lockups
- *
- * started by Ingo Molnar, Copyright (C) 2005, 2006 Red Hat, Inc.
- *
- * this code detects soft lockups: incidents in where on a CPU
- * the kernel does not reschedule for 10 seconds or more.
- */
-#include <linux/mm.h>
-#include <linux/cpu.h>
-#include <linux/nmi.h>
-#include <linux/init.h>
-#include <linux/delay.h>
-#include <linux/freezer.h>
-#include <linux/kthread.h>
-#include <linux/lockdep.h>
-#include <linux/notifier.h>
-#include <linux/module.h>
-#include <linux/sysctl.h>
-
-#include <asm/irq_regs.h>
-
-static DEFINE_SPINLOCK(print_lock);
-
-static DEFINE_PER_CPU(unsigned long, softlockup_touch_ts); /* touch timestamp */
-static DEFINE_PER_CPU(unsigned long, softlockup_print_ts); /* print timestamp */
-static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
-static DEFINE_PER_CPU(bool, softlock_touch_sync);
-
-static int __read_mostly did_panic;
-int __read_mostly softlockup_thresh = 60;
-
-/*
- * Should we panic (and reboot, if panic_timeout= is set) when a
- * soft-lockup occurs:
- */
-unsigned int __read_mostly softlockup_panic =
-                               CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
-
-static int __init softlockup_panic_setup(char *str)
-{
-       softlockup_panic = simple_strtoul(str, NULL, 0);
-
-       return 1;
-}
-__setup("softlockup_panic=", softlockup_panic_setup);
-
-static int
-softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)
-{
-       did_panic = 1;
-
-       return NOTIFY_DONE;
-}
-
-static struct notifier_block panic_block = {
-       .notifier_call = softlock_panic,
-};
-
-/*
- * Returns seconds, approximately.  We don't need nanosecond
- * resolution, and we don't need to waste time with a big divide when
- * 2^30ns == 1.074s.
- */
-static unsigned long get_timestamp(int this_cpu)
-{
-       return cpu_clock(this_cpu) >> 30LL;  /* 2^30 ~= 10^9 */
-}
-
-static void __touch_softlockup_watchdog(void)
-{
-       int this_cpu = raw_smp_processor_id();
-
-       __raw_get_cpu_var(softlockup_touch_ts) = get_timestamp(this_cpu);
-}
-
-void touch_softlockup_watchdog(void)
-{
-       __raw_get_cpu_var(softlockup_touch_ts) = 0;
-}
-EXPORT_SYMBOL(touch_softlockup_watchdog);
-
-void touch_softlockup_watchdog_sync(void)
-{
-       __raw_get_cpu_var(softlock_touch_sync) = true;
-       __raw_get_cpu_var(softlockup_touch_ts) = 0;
-}
-
-void touch_all_softlockup_watchdogs(void)
-{
-       int cpu;
-
-       /* Cause each CPU to re-update its timestamp rather than complain */
-       for_each_online_cpu(cpu)
-               per_cpu(softlockup_touch_ts, cpu) = 0;
-}
-EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
-
-int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
-                            void __user *buffer,
-                            size_t *lenp, loff_t *ppos)
-{
-       touch_all_softlockup_watchdogs();
-       return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-}
-
-/*
- * This callback runs from the timer interrupt, and checks
- * whether the watchdog thread has hung or not:
- */
-void softlockup_tick(void)
-{
-       int this_cpu = smp_processor_id();
-       unsigned long touch_ts = per_cpu(softlockup_touch_ts, this_cpu);
-       unsigned long print_ts;
-       struct pt_regs *regs = get_irq_regs();
-       unsigned long now;
-
-       /* Is detection switched off? */
-       if (!per_cpu(softlockup_watchdog, this_cpu) || softlockup_thresh <= 0) {
-               /* Be sure we don't false trigger if switched back on */
-               if (touch_ts)
-                       per_cpu(softlockup_touch_ts, this_cpu) = 0;
-               return;
-       }
-
-       if (touch_ts == 0) {
-               if (unlikely(per_cpu(softlock_touch_sync, this_cpu))) {
-                       /*
-                        * If the time stamp was touched atomically
-                        * make sure the scheduler tick is up to date.
-                        */
-                       per_cpu(softlock_touch_sync, this_cpu) = false;
-                       sched_clock_tick();
-               }
-               __touch_softlockup_watchdog();
-               return;
-       }
-
-       print_ts = per_cpu(softlockup_print_ts, this_cpu);
-
-       /* report at most once a second */
-       if (print_ts == touch_ts || did_panic)
-               return;
-
-       /* do not print during early bootup: */
-       if (unlikely(system_state != SYSTEM_RUNNING)) {
-               __touch_softlockup_watchdog();
-               return;
-       }
-
-       now = get_timestamp(this_cpu);
-
-       /*
-        * Wake up the high-prio watchdog task twice per
-        * threshold timespan.
-        */
-       if (time_after(now - softlockup_thresh/2, touch_ts))
-               wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
-
-       /* Warn about unreasonable delays: */
-       if (time_before_eq(now - softlockup_thresh, touch_ts))
-               return;
-
-       per_cpu(softlockup_print_ts, this_cpu) = touch_ts;
-
-       spin_lock(&print_lock);
-       printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n",
-                       this_cpu, now - touch_ts,
-                       current->comm, task_pid_nr(current));
-       print_modules();
-       print_irqtrace_events(current);
-       if (regs)
-               show_regs(regs);
-       else
-               dump_stack();
-       spin_unlock(&print_lock);
-
-       if (softlockup_panic)
-               panic("softlockup: hung tasks");
-}
-
-/*
- * The watchdog thread - runs every second and touches the timestamp.
- */
-static int watchdog(void *__bind_cpu)
-{
-       struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
-
-       sched_setscheduler(current, SCHED_FIFO, &param);
-
-       /* initialize timestamp */
-       __touch_softlockup_watchdog();
-
-       set_current_state(TASK_INTERRUPTIBLE);
-       /*
-        * Run briefly once per second to reset the softlockup timestamp.
-        * If this gets delayed for more than 60 seconds then the
-        * debug-printout triggers in softlockup_tick().
-        */
-       while (!kthread_should_stop()) {
-               __touch_softlockup_watchdog();
-               schedule();
-
-               if (kthread_should_stop())
-                       break;
-
-               set_current_state(TASK_INTERRUPTIBLE);
-       }
-       __set_current_state(TASK_RUNNING);
-
-       return 0;
-}
-
-/*
- * Create/destroy watchdog threads as CPUs come and go:
- */
-static int __cpuinit
-cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
-       int hotcpu = (unsigned long)hcpu;
-       struct task_struct *p;
-
-       switch (action) {
-       case CPU_UP_PREPARE:
-       case CPU_UP_PREPARE_FROZEN:
-               BUG_ON(per_cpu(softlockup_watchdog, hotcpu));
-               p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);
-               if (IS_ERR(p)) {
-                       printk(KERN_ERR "watchdog for %i failed\n", hotcpu);
-                       return NOTIFY_BAD;
-               }
-               per_cpu(softlockup_touch_ts, hotcpu) = 0;
-               per_cpu(softlockup_watchdog, hotcpu) = p;
-               kthread_bind(p, hotcpu);
-               break;
-       case CPU_ONLINE:
-       case CPU_ONLINE_FROZEN:
-               wake_up_process(per_cpu(softlockup_watchdog, hotcpu));
-               break;
-#ifdef CONFIG_HOTPLUG_CPU
-       case CPU_UP_CANCELED:
-       case CPU_UP_CANCELED_FROZEN:
-               if (!per_cpu(softlockup_watchdog, hotcpu))
-                       break;
-               /* Unbind so it can run.  Fall thru. */
-               kthread_bind(per_cpu(softlockup_watchdog, hotcpu),
-                            cpumask_any(cpu_online_mask));
-       case CPU_DEAD:
-       case CPU_DEAD_FROZEN:
-               p = per_cpu(softlockup_watchdog, hotcpu);
-               per_cpu(softlockup_watchdog, hotcpu) = NULL;
-               kthread_stop(p);
-               break;
-#endif /* CONFIG_HOTPLUG_CPU */
-       }
-       return NOTIFY_OK;
-}
-
-static struct notifier_block __cpuinitdata cpu_nfb = {
-       .notifier_call = cpu_callback
-};
-
-static int __initdata nosoftlockup;
-
-static int __init nosoftlockup_setup(char *str)
-{
-       nosoftlockup = 1;
-       return 1;
-}
-__setup("nosoftlockup", nosoftlockup_setup);
-
-static int __init spawn_softlockup_task(void)
-{
-       void *cpu = (void *)(long)smp_processor_id();
-       int err;
-
-       if (nosoftlockup)
-               return 0;
-
-       err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
-       if (err == NOTIFY_BAD) {
-               BUG();
-               return 1;
-       }
-       cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
-       register_cpu_notifier(&cpu_nfb);
-
-       atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
-
-       return 0;
-}
-early_initcall(spawn_softlockup_task);
index d24f761f48769d925692efcbb233a276dad01905..6f79c7f81c960a3da9d6b3832a92f4deaad9c7d0 100644 (file)
 #include <scsi/sg.h>
 #endif
 
+#ifdef CONFIG_LOCKUP_DETECTOR
+#include <linux/nmi.h>
+#endif
+
 
 #if defined(CONFIG_SYSCTL)
 
@@ -106,7 +110,7 @@ extern int blk_iopoll_enabled;
 #endif
 
 /* Constants used for minimum and  maximum */
-#ifdef CONFIG_DETECT_SOFTLOCKUP
+#ifdef CONFIG_LOCKUP_DETECTOR
 static int sixty = 60;
 static int neg_one = -1;
 #endif
@@ -710,7 +714,34 @@ static struct ctl_table kern_table[] = {
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
-#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
+#if defined(CONFIG_LOCKUP_DETECTOR)
+       {
+               .procname       = "watchdog",
+               .data           = &watchdog_enabled,
+               .maxlen         = sizeof (int),
+               .mode           = 0644,
+               .proc_handler   = proc_dowatchdog_enabled,
+       },
+       {
+               .procname       = "watchdog_thresh",
+               .data           = &softlockup_thresh,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dowatchdog_thresh,
+               .extra1         = &neg_one,
+               .extra2         = &sixty,
+       },
+       {
+               .procname       = "softlockup_panic",
+               .data           = &softlockup_panic,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &zero,
+               .extra2         = &one,
+       },
+#endif
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
        {
                .procname       = "unknown_nmi_panic",
                .data           = &unknown_nmi_panic,
@@ -813,26 +844,6 @@ static struct ctl_table kern_table[] = {
                .proc_handler   = proc_dointvec,
        },
 #endif
-#ifdef CONFIG_DETECT_SOFTLOCKUP
-       {
-               .procname       = "softlockup_panic",
-               .data           = &softlockup_panic,
-               .maxlen         = sizeof(int),
-               .mode           = 0644,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = &zero,
-               .extra2         = &one,
-       },
-       {
-               .procname       = "softlockup_thresh",
-               .data           = &softlockup_thresh,
-               .maxlen         = sizeof(int),
-               .mode           = 0644,
-               .proc_handler   = proc_dosoftlockup_thresh,
-               .extra1         = &neg_one,
-               .extra2         = &sixty,
-       },
-#endif
 #ifdef CONFIG_DETECT_HUNG_TASK
        {
                .procname       = "hung_task_panic",
index ee305c8d4e18eb038a54f0f9aea8eb2f353b1f44..c29e2d4d2a665f921b3c3b5bf1177462962770e3 100644 (file)
@@ -1289,7 +1289,6 @@ void run_local_timers(void)
 {
        hrtimer_run_queues();
        raise_softirq(TIMER_SOFTIRQ);
-       softlockup_tick();
 }
 
 /*
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
new file mode 100644 (file)
index 0000000..613bc1f
--- /dev/null
@@ -0,0 +1,567 @@
+/*
+ * Detect hard and soft lockups on a system
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * this code detects hard lockups: incidents in where on a CPU
+ * the kernel does not respond to anything except NMI.
+ *
+ * Note: Most of this code is borrowed heavily from softlockup.c,
+ * so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks
+ * to those contributors as well.
+ */
+
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/nmi.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/lockdep.h>
+#include <linux/notifier.h>
+#include <linux/module.h>
+#include <linux/sysctl.h>
+
+#include <asm/irq_regs.h>
+#include <linux/perf_event.h>
+
+int watchdog_enabled;
+int __read_mostly softlockup_thresh = 60;
+
+static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
+static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
+static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
+static DEFINE_PER_CPU(bool, softlockup_touch_sync);
+static DEFINE_PER_CPU(bool, soft_watchdog_warn);
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static DEFINE_PER_CPU(bool, hard_watchdog_warn);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
+static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
+#endif
+
+static int __read_mostly did_panic;
+static int __initdata no_watchdog;
+
+
+/* boot commands */
+/*
+ * Should we panic when a soft-lockup or hard-lockup occurs:
+ */
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static int hardlockup_panic;
+
+static int __init hardlockup_panic_setup(char *str)
+{
+       if (!strncmp(str, "panic", 5))
+               hardlockup_panic = 1;
+       return 1;
+}
+__setup("nmi_watchdog=", hardlockup_panic_setup);
+#endif
+
+unsigned int __read_mostly softlockup_panic =
+                       CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
+
+static int __init softlockup_panic_setup(char *str)
+{
+       softlockup_panic = simple_strtoul(str, NULL, 0);
+
+       return 1;
+}
+__setup("softlockup_panic=", softlockup_panic_setup);
+
+static int __init nowatchdog_setup(char *str)
+{
+       no_watchdog = 1;
+       return 1;
+}
+__setup("nowatchdog", nowatchdog_setup);
+
+/* deprecated */
+static int __init nosoftlockup_setup(char *str)
+{
+       no_watchdog = 1;
+       return 1;
+}
+__setup("nosoftlockup", nosoftlockup_setup);
+/*  */
+
+
+/*
+ * Returns seconds, approximately.  We don't need nanosecond
+ * resolution, and we don't need to waste time with a big divide when
+ * 2^30ns == 1.074s.
+ */
+static unsigned long get_timestamp(int this_cpu)
+{
+       return cpu_clock(this_cpu) >> 30LL;  /* 2^30 ~= 10^9 */
+}
+
+static unsigned long get_sample_period(void)
+{
+       /*
+        * convert softlockup_thresh from seconds to ns
+        * the divide by 5 is to give hrtimer 5 chances to
+        * increment before the hardlockup detector generates
+        * a warning
+        */
+       return softlockup_thresh / 5 * NSEC_PER_SEC;
+}
+
+/* Commands for resetting the watchdog */
+static void __touch_watchdog(void)
+{
+       int this_cpu = smp_processor_id();
+
+       __get_cpu_var(watchdog_touch_ts) = get_timestamp(this_cpu);
+}
+
+void touch_softlockup_watchdog(void)
+{
+       __get_cpu_var(watchdog_touch_ts) = 0;
+}
+EXPORT_SYMBOL(touch_softlockup_watchdog);
+
+void touch_all_softlockup_watchdogs(void)
+{
+       int cpu;
+
+       /*
+        * this is done lockless
+        * do we care if a 0 races with a timestamp?
+        * all it means is the softlock check starts one cycle later
+        */
+       for_each_online_cpu(cpu)
+               per_cpu(watchdog_touch_ts, cpu) = 0;
+}
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+void touch_nmi_watchdog(void)
+{
+       __get_cpu_var(watchdog_nmi_touch) = true;
+       touch_softlockup_watchdog();
+}
+EXPORT_SYMBOL(touch_nmi_watchdog);
+
+#endif
+
+void touch_softlockup_watchdog_sync(void)
+{
+       __raw_get_cpu_var(softlockup_touch_sync) = true;
+       __raw_get_cpu_var(watchdog_touch_ts) = 0;
+}
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+/* watchdog detector functions */
+static int is_hardlockup(void)
+{
+       unsigned long hrint = __get_cpu_var(hrtimer_interrupts);
+
+       if (__get_cpu_var(hrtimer_interrupts_saved) == hrint)
+               return 1;
+
+       __get_cpu_var(hrtimer_interrupts_saved) = hrint;
+       return 0;
+}
+#endif
+
+static int is_softlockup(unsigned long touch_ts)
+{
+       unsigned long now = get_timestamp(smp_processor_id());
+
+       /* Warn about unreasonable delays: */
+       if (time_after(now, touch_ts + softlockup_thresh))
+               return now - touch_ts;
+
+       return 0;
+}
+
+static int
+watchdog_panic(struct notifier_block *this, unsigned long event, void *ptr)
+{
+       did_panic = 1;
+
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block panic_block = {
+       .notifier_call = watchdog_panic,
+};
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static struct perf_event_attr wd_hw_attr = {
+       .type           = PERF_TYPE_HARDWARE,
+       .config         = PERF_COUNT_HW_CPU_CYCLES,
+       .size           = sizeof(struct perf_event_attr),
+       .pinned         = 1,
+       .disabled       = 1,
+};
+
+/* Callback function for perf event subsystem */
+void watchdog_overflow_callback(struct perf_event *event, int nmi,
+                struct perf_sample_data *data,
+                struct pt_regs *regs)
+{
+       if (__get_cpu_var(watchdog_nmi_touch) == true) {
+               __get_cpu_var(watchdog_nmi_touch) = false;
+               return;
+       }
+
+       /* check for a hardlockup
+        * This is done by making sure our timer interrupt
+        * is incrementing.  The timer interrupt should have
+        * fired multiple times before we overflow'd.  If it hasn't
+        * then this is a good indication the cpu is stuck
+        */
+       if (is_hardlockup()) {
+               int this_cpu = smp_processor_id();
+
+               /* only print hardlockups once */
+               if (__get_cpu_var(hard_watchdog_warn) == true)
+                       return;
+
+               if (hardlockup_panic)
+                       panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu);
+               else
+                       WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu);
+
+               __get_cpu_var(hard_watchdog_warn) = true;
+               return;
+       }
+
+       __get_cpu_var(hard_watchdog_warn) = false;
+       return;
+}
+static void watchdog_interrupt_count(void)
+{
+       __get_cpu_var(hrtimer_interrupts)++;
+}
+#else
+static inline void watchdog_interrupt_count(void) { return; }
+#endif /* CONFIG_HARDLOCKUP_DETECTOR */
+
+/* watchdog kicker functions */
+static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
+{
+       unsigned long touch_ts = __get_cpu_var(watchdog_touch_ts);
+       struct pt_regs *regs = get_irq_regs();
+       int duration;
+
+       /* kick the hardlockup detector */
+       watchdog_interrupt_count();
+
+       /* kick the softlockup detector */
+       wake_up_process(__get_cpu_var(softlockup_watchdog));
+
+       /* .. and repeat */
+       hrtimer_forward_now(hrtimer, ns_to_ktime(get_sample_period()));
+
+       if (touch_ts == 0) {
+               if (unlikely(__get_cpu_var(softlockup_touch_sync))) {
+                       /*
+                        * If the time stamp was touched atomically
+                        * make sure the scheduler tick is up to date.
+                        */
+                       __get_cpu_var(softlockup_touch_sync) = false;
+                       sched_clock_tick();
+               }
+               __touch_watchdog();
+               return HRTIMER_RESTART;
+       }
+
+       /* check for a softlockup
+        * This is done by making sure a high priority task is
+        * being scheduled.  The task touches the watchdog to
+        * indicate it is getting cpu time.  If it hasn't then
+        * this is a good indication some task is hogging the cpu
+        */
+       duration = is_softlockup(touch_ts);
+       if (unlikely(duration)) {
+               /* only warn once */
+               if (__get_cpu_var(soft_watchdog_warn) == true)
+                       return HRTIMER_RESTART;
+
+               printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
+                       smp_processor_id(), duration,
+                       current->comm, task_pid_nr(current));
+               print_modules();
+               print_irqtrace_events(current);
+               if (regs)
+                       show_regs(regs);
+               else
+                       dump_stack();
+
+               if (softlockup_panic)
+                       panic("softlockup: hung tasks");
+               __get_cpu_var(soft_watchdog_warn) = true;
+       } else
+               __get_cpu_var(soft_watchdog_warn) = false;
+
+       return HRTIMER_RESTART;
+}
+
+
+/*
+ * The watchdog thread - touches the timestamp.
+ */
+static int watchdog(void *unused)
+{
+       struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+       struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
+
+       sched_setscheduler(current, SCHED_FIFO, &param);
+
+       /* initialize timestamp */
+       __touch_watchdog();
+
+       /* kick off the timer for the hardlockup detector */
+       /* done here because hrtimer_start can only pin to smp_processor_id() */
+       hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()),
+                     HRTIMER_MODE_REL_PINNED);
+
+       set_current_state(TASK_INTERRUPTIBLE);
+       /*
+        * Run briefly once per second to reset the softlockup timestamp.
+        * If this gets delayed for more than 60 seconds then the
+        * debug-printout triggers in watchdog_timer_fn().
+        */
+       while (!kthread_should_stop()) {
+               __touch_watchdog();
+               schedule();
+
+               if (kthread_should_stop())
+                       break;
+
+               set_current_state(TASK_INTERRUPTIBLE);
+       }
+       __set_current_state(TASK_RUNNING);
+
+       return 0;
+}
+
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static int watchdog_nmi_enable(int cpu)
+{
+       struct perf_event_attr *wd_attr;
+       struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+       /* is it already setup and enabled? */
+       if (event && event->state > PERF_EVENT_STATE_OFF)
+               goto out;
+
+       /* it is setup but not enabled */
+       if (event != NULL)
+               goto out_enable;
+
+       /* Try to register using hardware perf events */
+       wd_attr = &wd_hw_attr;
+       wd_attr->sample_period = hw_nmi_get_sample_period();
+       event = perf_event_create_kernel_counter(wd_attr, cpu, -1, watchdog_overflow_callback);
+       if (!IS_ERR(event)) {
+               printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
+               goto out_save;
+       }
+
+       printk(KERN_ERR "NMI watchdog failed to create perf event on cpu%i: %p\n", cpu, event);
+       return -1;
+
+       /* success path */
+out_save:
+       per_cpu(watchdog_ev, cpu) = event;
+out_enable:
+       perf_event_enable(per_cpu(watchdog_ev, cpu));
+out:
+       return 0;
+}
+
+static void watchdog_nmi_disable(int cpu)
+{
+       struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+       if (event) {
+               perf_event_disable(event);
+               per_cpu(watchdog_ev, cpu) = NULL;
+
+               /* should be in cleanup, but blocks oprofile */
+               perf_event_release_kernel(event);
+       }
+       return;
+}
+#else
+static int watchdog_nmi_enable(int cpu) { return 0; }
+static void watchdog_nmi_disable(int cpu) { return; }
+#endif /* CONFIG_HARDLOCKUP_DETECTOR */
+
+/* prepare/enable/disable routines */
+static int watchdog_prepare_cpu(int cpu)
+{
+       struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
+
+       WARN_ON(per_cpu(softlockup_watchdog, cpu));
+       hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+       hrtimer->function = watchdog_timer_fn;
+
+       return 0;
+}
+
+static int watchdog_enable(int cpu)
+{
+       struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
+
+       /* enable the perf event */
+       if (watchdog_nmi_enable(cpu) != 0)
+               return -1;
+
+       /* create the watchdog thread */
+       if (!p) {
+               p = kthread_create(watchdog, (void *)(unsigned long)cpu, "watchdog/%d", cpu);
+               if (IS_ERR(p)) {
+                       printk(KERN_ERR "softlockup watchdog for %i failed\n", cpu);
+                       return -1;
+               }
+               kthread_bind(p, cpu);
+               per_cpu(watchdog_touch_ts, cpu) = 0;
+               per_cpu(softlockup_watchdog, cpu) = p;
+               wake_up_process(p);
+       }
+
+       return 0;
+}
+
+static void watchdog_disable(int cpu)
+{
+       struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
+       struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
+
+       /*
+        * cancel the timer first to stop incrementing the stats
+        * and waking up the kthread
+        */
+       hrtimer_cancel(hrtimer);
+
+       /* disable the perf event */
+       watchdog_nmi_disable(cpu);
+
+       /* stop the watchdog thread */
+       if (p) {
+               per_cpu(softlockup_watchdog, cpu) = NULL;
+               kthread_stop(p);
+       }
+
+       /* if any cpu succeeds, watchdog is considered enabled for the system */
+       watchdog_enabled = 1;
+}
+
+static void watchdog_enable_all_cpus(void)
+{
+       int cpu;
+       int result = 0;
+
+       for_each_online_cpu(cpu)
+               result += watchdog_enable(cpu);
+
+       if (result)
+               printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n");
+
+}
+
+static void watchdog_disable_all_cpus(void)
+{
+       int cpu;
+
+       for_each_online_cpu(cpu)
+               watchdog_disable(cpu);
+
+       /* if all watchdogs are disabled, then they are disabled for the system */
+       watchdog_enabled = 0;
+}
+
+
+/* sysctl functions */
+#ifdef CONFIG_SYSCTL
+/*
+ * proc handler for /proc/sys/kernel/nmi_watchdog
+ */
+
+int proc_dowatchdog_enabled(struct ctl_table *table, int write,
+                    void __user *buffer, size_t *length, loff_t *ppos)
+{
+       proc_dointvec(table, write, buffer, length, ppos);
+
+       if (watchdog_enabled)
+               watchdog_enable_all_cpus();
+       else
+               watchdog_disable_all_cpus();
+       return 0;
+}
+
+int proc_dowatchdog_thresh(struct ctl_table *table, int write,
+                            void __user *buffer,
+                            size_t *lenp, loff_t *ppos)
+{
+       return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+}
+#endif /* CONFIG_SYSCTL */
+
+
+/*
+ * Create/destroy watchdog threads as CPUs come and go:
+ */
+static int __cpuinit
+cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+       int hotcpu = (unsigned long)hcpu;
+
+       switch (action) {
+       case CPU_UP_PREPARE:
+       case CPU_UP_PREPARE_FROZEN:
+               if (watchdog_prepare_cpu(hotcpu))
+                       return NOTIFY_BAD;
+               break;
+       case CPU_ONLINE:
+       case CPU_ONLINE_FROZEN:
+               if (watchdog_enable(hotcpu))
+                       return NOTIFY_BAD;
+               break;
+#ifdef CONFIG_HOTPLUG_CPU
+       case CPU_UP_CANCELED:
+       case CPU_UP_CANCELED_FROZEN:
+               watchdog_disable(hotcpu);
+               break;
+       case CPU_DEAD:
+       case CPU_DEAD_FROZEN:
+               watchdog_disable(hotcpu);
+               break;
+#endif /* CONFIG_HOTPLUG_CPU */
+       }
+       return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata cpu_nfb = {
+       .notifier_call = cpu_callback
+};
+
+static int __init spawn_watchdog_task(void)
+{
+       void *cpu = (void *)(long)smp_processor_id();
+       int err;
+
+       if (no_watchdog)
+               return 0;
+
+       err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
+       WARN_ON(err == NOTIFY_BAD);
+
+       cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
+       register_cpu_notifier(&cpu_nfb);
+
+       atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+
+       return 0;
+}
+early_initcall(spawn_watchdog_task);
index e722e9d62221d40560176b5f8d2cabdcf74a5e2d..e2cd7fbf31c05cf6e6bed6a54781e2ad1c99c70b 100644 (file)
@@ -152,28 +152,33 @@ config DEBUG_SHIRQ
          Drivers ought to be able to handle interrupts coming in at those
          points; some don't and need to be caught.
 
-config DETECT_SOFTLOCKUP
-       bool "Detect Soft Lockups"
+config LOCKUP_DETECTOR
+       bool "Detect Hard and Soft Lockups"
        depends on DEBUG_KERNEL && !S390
-       default y
        help
-         Say Y here to enable the kernel to detect "soft lockups",
-         which are bugs that cause the kernel to loop in kernel
+         Say Y here to enable the kernel to act as a watchdog to detect
+         hard and soft lockups.
+
+         Softlockups are bugs that cause the kernel to loop in kernel
          mode for more than 60 seconds, without giving other tasks a
-         chance to run.
+         chance to run.  The current stack trace is displayed upon
+         detection and the system will stay locked up.
 
-         When a soft-lockup is detected, the kernel will print the
-         current stack trace (which you should report), but the
-         system will stay locked up. This feature has negligible
-         overhead.
+         Hardlockups are bugs that cause the CPU to loop in kernel mode
+         for more than 60 seconds, without letting other interrupts have a
+         chance to run.  The current stack trace is displayed upon detection
+         and the system will stay locked up.
+
+         The overhead should be minimal.  A periodic hrtimer runs to
+         generate interrupts and kick the watchdog task every 10-12 seconds.
+         An NMI is generated every 60 seconds or so to check for hardlockups.
 
-         (Note that "hard lockups" are separate type of bugs that
-          can be detected via the NMI-watchdog, on platforms that
-          support it.)
+config HARDLOCKUP_DETECTOR
+       def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
 
 config BOOTPARAM_SOFTLOCKUP_PANIC
        bool "Panic (Reboot) On Soft Lockups"
-       depends on DETECT_SOFTLOCKUP
+       depends on LOCKUP_DETECTOR
        help
          Say Y here to enable the kernel to panic on "soft lockups",
          which are bugs that cause the kernel to loop in kernel
@@ -190,7 +195,7 @@ config BOOTPARAM_SOFTLOCKUP_PANIC
 
 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
        int
-       depends on DETECT_SOFTLOCKUP
+       depends on LOCKUP_DETECTOR
        range 0 1
        default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
        default 1 if BOOTPARAM_SOFTLOCKUP_PANIC