The patch titled
hrtimers debug patch
has been removed from the -mm tree. Its filename was
mm-only-hrtimers-debug-patch.patch
This patch was dropped because it had testing failures
------------------------------------------------------
Subject: hrtimers debug patch
From: Ingo Molnar <mingo@xxxxxxx>
debugging helper for hrtimers. Keep a lookout for WARN_ON messages. Saves
a stacktrace on every expires_next update, and makes that stack-trace
available in SysRq-Q (or /proc/timer_list) output.
( make sure to run this on a lockdep-enabled kernel, so that
CONFIG_STACKTRACE=y. )
NOT-Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/i386/kernel/apic.c | 2 +
include/linux/hrtimer.h | 7 ++++
kernel/hrtimer.c | 53 +++++++++++++++++++++++++++--------
kernel/time/tick-oneshot.c | 13 +++++++-
kernel/time/timer_list.c | 23 ++++++++++++++-
5 files changed, 84 insertions(+), 14 deletions(-)
diff -puN arch/i386/kernel/apic.c~mm-only-hrtimers-debug-patch arch/i386/kernel/apic.c
--- a/arch/i386/kernel/apic.c~mm-only-hrtimers-debug-patch
+++ a/arch/i386/kernel/apic.c
@@ -525,6 +525,8 @@ void __init setup_boot_APIC_clock(void)
*/
if (nmi_watchdog != NMI_IO_APIC)
lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+ else
+ printk(KERN_WARNING "APIC timer registered as dummy, due to nmi_watchdog=1!\n");
}
/* Setup the lapic or request the broadcast */
diff -puN include/linux/hrtimer.h~mm-only-hrtimers-debug-patch include/linux/hrtimer.h
--- a/include/linux/hrtimer.h~mm-only-hrtimers-debug-patch
+++ a/include/linux/hrtimer.h
@@ -15,6 +15,7 @@
#ifndef _LINUX_HRTIMER_H
#define _LINUX_HRTIMER_H
+#include <linux/stacktrace.h>
#include <linux/rbtree.h>
#include <linux/ktime.h>
#include <linux/init.h>
@@ -196,6 +197,12 @@ struct hrtimer_cpu_base {
struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
#ifdef CONFIG_HIGH_RES_TIMERS
ktime_t expires_next;
+# define HRTIMERS_STACK_TRACE_DEPTH 32
+# ifdef CONFIG_STACKTRACE
+ struct stack_trace exp_trace;
+ unsigned long exp_entries[HRTIMERS_STACK_TRACE_DEPTH];
+# endif
+ ktime_t exp_prev;
int hres_active;
struct list_head cb_pending;
unsigned long nr_events;
diff -puN kernel/hrtimer.c~mm-only-hrtimers-debug-patch kernel/hrtimer.c
--- a/kernel/hrtimer.c~mm-only-hrtimers-debug-patch
+++ a/kernel/hrtimer.c
@@ -305,6 +305,26 @@ unsigned long ktime_divns(const ktime_t
/* High resolution timer related functions */
#ifdef CONFIG_HIGH_RES_TIMERS
+static void update_cpu_base_expires_next(struct hrtimer_cpu_base *cpu_base,
+ ktime_t expires_next)
+{
+ cpu_base->exp_prev = cpu_base->expires_next;
+ cpu_base->expires_next = expires_next;
+
+#ifdef CONFIG_STACKTRACE
+ {
+ struct stack_trace *trace = &cpu_base->exp_trace;
+
+ trace->nr_entries = 0;
+ trace->entries = cpu_base->exp_entries;
+ trace->max_entries = HRTIMERS_STACK_TRACE_DEPTH;
+ trace->skip = 1;
+
+ save_stack_trace(trace);
+ }
+#endif
+}
+
/*
* High resolution timer enabled ?
*/
@@ -353,7 +373,7 @@ static void hrtimer_force_reprogram(stru
struct hrtimer_clock_base *base = cpu_base->clock_base;
ktime_t expires;
- cpu_base->expires_next.tv64 = KTIME_MAX;
+ update_cpu_base_expires_next(cpu_base, (ktime_t){ .tv64 = KTIME_MAX });
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
struct hrtimer *timer;
@@ -363,7 +383,7 @@ static void hrtimer_force_reprogram(stru
timer = rb_entry(base->first, struct hrtimer, node);
expires = ktime_sub(timer->expires, base->offset);
if (expires.tv64 < cpu_base->expires_next.tv64)
- cpu_base->expires_next = expires;
+ update_cpu_base_expires_next(cpu_base, expires);
}
if (cpu_base->expires_next.tv64 != KTIME_MAX)
@@ -382,7 +402,7 @@ static void hrtimer_force_reprogram(stru
static int hrtimer_reprogram(struct hrtimer *timer,
struct hrtimer_clock_base *base)
{
- ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
ktime_t expires = ktime_sub(timer->expires, base->offset);
int res;
@@ -396,7 +416,7 @@ static int hrtimer_reprogram(struct hrti
if (hrtimer_callback_running(timer))
return 0;
- if (expires.tv64 >= expires_next->tv64)
+ if (expires.tv64 >= cpu_base->expires_next.tv64)
return 0;
/*
@@ -404,7 +424,7 @@ static int hrtimer_reprogram(struct hrti
*/
res = tick_program_event(expires, 0);
if (!IS_ERR_VALUE(res))
- *expires_next = expires;
+ update_cpu_base_expires_next(cpu_base, expires);
return res;
}
@@ -479,7 +499,7 @@ static inline void hrtimer_remove_cb_pen
*/
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
{
- base->expires_next.tv64 = KTIME_MAX;
+ update_cpu_base_expires_next(base, (ktime_t){ .tv64 = KTIME_MAX });
base->hres_active = 0;
INIT_LIST_HEAD(&base->cb_pending);
}
@@ -543,7 +563,8 @@ static inline int hrtimer_enqueue_reprog
*/
static int hrtimer_switch_to_hres(void)
{
- struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
+ int cpu = smp_processor_id();
+ struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
unsigned long flags;
if (base->hres_active)
@@ -553,6 +574,8 @@ static int hrtimer_switch_to_hres(void)
if (tick_init_highres()) {
local_irq_restore(flags);
+ printk(KERN_WARNING "Could not switch to high resolution "
+ "mode on CPU %d\n", cpu);
return 0;
}
base->hres_active = 1;
@@ -667,6 +690,7 @@ static void enqueue_hrtimer(struct hrtim
struct rb_node **link = &base->active.rb_node;
struct rb_node *parent = NULL;
struct hrtimer *entry;
+ int leftmost = 1;
/*
* Find the right place in the rbtree:
@@ -678,18 +702,19 @@ static void enqueue_hrtimer(struct hrtim
* We dont care about collisions. Nodes with
* the same expiry time stay together.
*/
- if (timer->expires.tv64 < entry->expires.tv64)
+ if (timer->expires.tv64 < entry->expires.tv64) {
link = &(*link)->rb_left;
- else
+ } else {
link = &(*link)->rb_right;
+ leftmost = 0;
+ }
}
/*
* Insert the timer to the rbtree and check whether it
* replaces the first pending timer
*/
- if (!base->first || timer->expires.tv64 <
- rb_entry(base->first, struct hrtimer, node)->expires.tv64) {
+ if (leftmost) {
/*
* Reprogram the clock event device. When the timer is already
* expired hrtimer_enqueue_reprogram has either called the
@@ -706,6 +731,9 @@ static void enqueue_hrtimer(struct hrtim
rb_link_node(&timer->node, parent, link);
rb_insert_color(&timer->node, &base->active);
+
+ WARN_ON(base->first != rb_first(&base->active));
+
/*
* HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
* state of a possibly running callback.
@@ -742,6 +770,7 @@ static void __remove_hrtimer(struct hrti
hrtimer_force_reprogram(base->cpu_base);
}
rb_erase(&timer->node, &base->active);
+ WARN_ON(base->first != rb_first(&base->active));
}
timer->state = newstate;
}
@@ -1058,7 +1087,7 @@ void hrtimer_interrupt(struct clock_even
base++;
}
- cpu_base->expires_next = expires_next;
+ update_cpu_base_expires_next(cpu_base, expires_next);
/* Reprogramming necessary ? */
if (expires_next.tv64 != KTIME_MAX) {
diff -puN kernel/time/tick-oneshot.c~mm-only-hrtimers-debug-patch kernel/time/tick-oneshot.c
--- a/kernel/time/tick-oneshot.c~mm-only-hrtimers-debug-patch
+++ a/kernel/time/tick-oneshot.c
@@ -73,8 +73,19 @@ int tick_switch_to_oneshot(void (*handle
struct clock_event_device *dev = td->evtdev;
if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
- !tick_device_is_functional(dev))
+ !tick_device_is_functional(dev)) {
+
+ printk("could not switch to one-shot clockevents mode.\n");
+ if (!dev) {
+ printk("because no tick device\n");
+ } else {
+ if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+ printk("because %s does not support one-shot mode.\n", dev->name);
+ if (!tick_device_is_functional(dev))
+ printk("because %s is not functional.\n", dev->name);
+ }
return -EINVAL;
+ }
td->mode = TICKDEV_MODE_ONESHOT;
dev->event_handler = handler;
diff -puN kernel/time/timer_list.c~mm-only-hrtimers-debug-patch kernel/time/timer_list.c
--- a/kernel/time/timer_list.c~mm-only-hrtimers-debug-patch
+++ a/kernel/time/timer_list.c
@@ -46,7 +46,7 @@ static void print_name_offset(struct seq
sym_name = kallsyms_lookup(addr, &size, &offset, &modname, namebuf);
if (sym_name)
- SEQ_printf(m, "%s", sym_name);
+ SEQ_printf(m, "%s+%lx/%lx", sym_name, offset, size);
else
SEQ_printf(m, "<%p>", sym);
}
@@ -129,6 +129,25 @@ print_base(struct seq_file *m, struct hr
print_active_timers(m, base, now);
}
+#ifdef CONFIG_HIGH_RES_TIMERS
+static void print_cpu_base_stack_trace(struct seq_file *m,
+ struct hrtimer_cpu_base *cpu_base)
+{
+#ifdef CONFIG_STACKTRACE
+ struct stack_trace *trace = &cpu_base->exp_trace;
+ int i;
+
+ SEQ_printf(m, " last expires_next stacktrace:\n");
+ for (i = 0; i < trace->nr_entries; i++) {
+ SEQ_printf(m, " ");
+ print_name_offset(m, (void *)trace->entries[i]);
+ SEQ_printf(m, "\n");
+ }
+ SEQ_printf(m, "\n");
+#endif
+}
+#endif
+
static void print_cpu(struct seq_file *m, int cpu, u64 now)
{
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
@@ -147,6 +166,8 @@ static void print_cpu(struct seq_file *m
#ifdef CONFIG_HIGH_RES_TIMERS
P_ns(expires_next);
+ P_ns(exp_prev);
+ print_cpu_base_stack_trace(m, cpu_base);
P(hres_active);
P(nr_events);
#endif
_
Patches currently in -mm which might be from mingo@xxxxxxx are
origin.patch
git-ieee1394.patch
git-kvm.patch
forcedeth-work-around-null-skb-dereference-crash.patch
revert-x86_64-mm-change-sysenter_setup-to-__cpuinit-improve-__init-__initdata.patch
spin_lock_irq-enable-interrupts-while-spinning-preparatory-patch.patch
spin_lock_irq-enable-interrupts-while-spinning-x86_64-implementation.patch
spin_lock_irq-enable-interrupts-while-spinning-i386-implementation.patch
allow-per-cpu-variables-to-be-page-aligned.patch
cpuset-remove-sched-domain-hooks-from-cpusets.patch
simplify-the-stacktrace-code.patch
freezer-task-exit_state-should-be-treated-as-bolean.patch
softlockup-trivial-s-99-max_rt_prio.patch
optimize-timespec_trunc.patch
futex-restartable-futex_wait.patch
futex-restartable-futex_wait-fix.patch
kernel-irq-procc-unprotected-iteration-over-the-irq-action-list-in-name_unique.patch
add-support-for-deferrable-timers-respun.patch
add-support-for-deferrable-timers-respun-tidy.patch
add-support-for-deferrable-timers-respun-fix.patch
irq-check-for-percpu-flag-only-when-adding-first-irqaction.patch
move-timekeeping-code-to-timekeepingc.patch
move-timekeeping-code-to-timekeepingc-fix.patch
ignore-stolen-time-in-the-softlockup-watchdog.patch
add-touch_all_softlockup_watchdogs.patch
schedule_on_each_cpu-use-preempt_disable.patch
workqueue-kill-run_scheduled_work.patch
workqueue-dont-save-interrupts-in-run_workqueue.patch
workqueue-make-cancel_rearming_delayed_workqueue-work-on-idle-dwork.patch
workqueue-introduce-cpu_singlethread_map.patch
workqueue-introduce-workqueue_struct-singlethread.patch
workqueue-make-init_workqueues-__init.patch
aio-is-unlikely.patch
sched-fix-idle-load-balancing-in-softirqd-context.patch
sched-dynticks-idle-load-balancing-v3.patch
speedup-divides-by-cpu_power-in-scheduler.patch
sched-optimize-siblings-status-check-logic-in-wake_idle.patch
sched-dont-renice-kernel-threads.patch
sched-remove-sleepavg-from-proc.patch
sched-implement-staircase-deadline-cpu-scheduler.patch
sched-implement-staircase-deadline-cpu-scheduler-misc-fixes.patch
sched-remove-noninteractive-flag.patch
sched-document-sd-cpu-scheduler.patch
sched-add-above-background-load-function.patch
mm-implement-swap-prefetching.patch
declare-struct-ktime.patch
futex-priority-based-wakeup.patch
make-futex_wait-use-an-hrtimer-for-timeout.patch
make-futex_wait-use-an-hrtimer-for-timeout-fix.patch
make-futex_wait-use-an-hrtimer-for-timeout-fix-2.patch
futex_requeue_pi-optimization.patch
sys_futex64-allows-64bit-futexes.patch
sys_futex64-allows-64bit-futexes-fix.patch
sys_futex64-allows-64bit-futexes-workaround.patch
add-irqf_irqpoll-flag-common-code.patch
add-irqf_irqpoll-flag-on-x86_64.patch
add-irqf_irqpoll-flag-on-i386.patch
add-irqf_irqpoll-flag-on-ia64.patch
add-irqf_irqpoll-flag-on-sh.patch
add-irqf_irqpoll-flag-on-arm.patch
detect-atomic-counter-underflows.patch
make-frame_pointer-default=y.patch
mutex-subsystem-synchro-test-module.patch
vdso-print-fatal-signals.patch
vdso-improve-print_fatal_signals-support-by-adding-memory-maps.patch
vdso-print-fatal-signals-use-ctl_unnumbered.patch
lockdep-show-held-locks-when-showing-a-stackdump.patch
kmap_atomic-debugging.patch
mm-only-hrtimers-debug-patch.patch
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