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    Subject[PATCH 3/6] [watchdog] remove old softlockup code
    Date
    Now that is no longer compiled or used, just remove it.

    Also moves some of the code wrapped with DETECT_SOFTLOCKUP to the
    LOCKUP_DETECTOR wrappers because that is the code that uses it now.

    Signed-off-by: Don Zickus <dzickus@redhat.com>
    ---
    kernel/softlockup.c | 278 ---------------------------------------------------
    kernel/sysctl.c | 22 ++--
    2 files changed, 10 insertions(+), 290 deletions(-)
    delete mode 100644 kernel/softlockup.c

    diff --git a/kernel/softlockup.c b/kernel/softlockup.c
    deleted file mode 100644
    index d225790..0000000
    --- a/kernel/softlockup.c
    +++ /dev/null
    @@ -1,278 +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 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_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) {
    - __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 (now > touch_ts + softlockup_thresh/2)
    - wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
    -
    - /* Warn about unreasonable delays: */
    - if (now <= (touch_ts + softlockup_thresh))
    - 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);
    diff --git a/kernel/sysctl.c b/kernel/sysctl.c
    index 1fec781..494e9a2 100644
    --- a/kernel/sysctl.c
    +++ b/kernel/sysctl.c
    @@ -99,7 +99,7 @@ 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
    @@ -713,6 +713,15 @@ static struct ctl_table kern_table[] = {
    .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)
    {
    @@ -817,17 +826,6 @@ 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,
    - },
    -#endif
    #ifdef CONFIG_DETECT_HUNG_TASK
    {
    .procname = "hung_task_panic",
    --
    1.6.5.2


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