Dear RT folks!
I'm pleased to announce the v4.14.8-rt9 patch set.
Changes since v4.14.8-rt8:
- Tom Zanussi's "tracing: Inter-event (e.g. latency) support" patch
has been updated to v8.
- The hrtimer-softirq rewrite by Anna-Maria has been updated to v4
(last I claimed I updated to v4 I updated to v3). This update includes
the following fix:
- Add bh_disable/enable() with a comment in hrtimers_dead_cpu().
Lockdep complained about a possible deadlock, reported by Grygorii
Strashko.
- Merge the series "timer/nohz: Fix timer/nohz woes" with NOHZ / timer
related fixes by Anna-Maria and Thomas Gleixner.
- The known issue "crash on UP system with a SMP kernel" reported last
time has been resolved by a patch in from Steven Rostedt which is
part of v4.14.8.
Known issues
- A warning triggered in "rcu_note_context_switch" originated from
SyS_timer_gettime(). The issue was always there, it is now
visible. Reported by Grygorii Strashko and Daniel Wagner.
The delta patch against v4.14.8-rt8 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.14/incr/patch-4.14.8-rt8-rt9.patch.xz
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.14.8-rt9
The RT patch against v4.14.8 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patch-4.14.8-rt9.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14.8-rt9.tar.xz
Sebastian
diff --git a/kernel/softirq.c b/kernel/softirq.c
index d9fbc5ff378f..5c9ecaed3645 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -838,7 +838,8 @@ static inline void tick_irq_exit(void)
int cpu = smp_processor_id();
/* Make sure that timer wheel updates are propagated */
- if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu)) {
+ if ((idle_cpu(cpu) || tick_nohz_full_cpu(cpu)) &&
+ !need_resched() && !local_softirq_pending()) {
if (!in_interrupt())
tick_nohz_irq_exit();
}
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index c2c344fda487..fb3413d2b738 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -68,9 +68,6 @@
#define HRTIMER_ACTIVE_SOFT (HRTIMER_ACTIVE_HARD << MASK_SHIFT)
#define HRTIMER_ACTIVE_ALL (HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
-/* Define for debug mode check */
-#define HRTIMER_MODECHECK true
-
/*
* The timer bases:
*
@@ -415,18 +412,8 @@ static inline void debug_hrtimer_init(struct hrtimer *timer)
}
static inline void debug_hrtimer_activate(struct hrtimer *timer,
- enum hrtimer_mode mode,
- bool modecheck)
+ enum hrtimer_mode mode)
{
- /*
- * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
- * match, when a timer is started via__hrtimer_start_range_ns().
- */
-#ifndef CONFIG_PREEMPT_RT_BASE
- if (modecheck)
- WARN_ON_ONCE(!(mode & HRTIMER_MODE_SOFT) ^ !timer->is_soft);
-#endif
-
debug_object_activate(timer, &hrtimer_debug_descr);
}
@@ -461,8 +448,7 @@ EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);
static inline void debug_hrtimer_init(struct hrtimer *timer) { }
static inline void debug_hrtimer_activate(struct hrtimer *timer,
- enum hrtimer_mode mode,
- bool modecheck) { }
+ enum hrtimer_mode mode) { }
static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
#endif
@@ -475,10 +461,9 @@ debug_init(struct hrtimer *timer, clockid_t clockid,
}
static inline void debug_activate(struct hrtimer *timer,
- enum hrtimer_mode mode,
- bool modecheck)
+ enum hrtimer_mode mode)
{
- debug_hrtimer_activate(timer, mode, modecheck);
+ debug_hrtimer_activate(timer, mode);
trace_hrtimer_start(timer, mode);
}
@@ -491,15 +476,15 @@ static inline void debug_deactivate(struct hrtimer *timer)
static struct hrtimer_clock_base *
__next_base(struct hrtimer_cpu_base *cpu_base, unsigned int *active)
{
- struct hrtimer_clock_base *base = NULL;
+ unsigned int idx;
- if (*active) {
- unsigned int idx = __ffs(*active);
- *active &= ~(1U << idx);
- base = &cpu_base->clock_base[idx];
- }
+ if (!*active)
+ return NULL;
- return base;
+ idx = __ffs(*active);
+ *active &= ~(1U << idx);
+
+ return &cpu_base->clock_base[idx];
}
#define for_each_active_base(base, cpu_base, active) \
@@ -546,11 +531,11 @@ static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
* hrtimer_run_softirq(), hrtimer_update_softirq_timer() will re-add these bases.
*
* Therefore softirq values are those from the HRTIMER_ACTIVE_SOFT clock bases.
- * The !softirq values are the minima across HRTIMER_ACTIVE, unless an actual
+ * The !softirq values are the minima across HRTIMER_ACTIVE_ALL, unless an actual
* softirq is pending, in which case they're the minima of HRTIMER_ACTIVE_HARD.
*
* @active_mask must be one of:
- * - HRTIMER_ACTIVE,
+ * - HRTIMER_ACTIVE_ALL,
* - HRTIMER_ACTIVE_SOFT, or
* - HRTIMER_ACTIVE_HARD.
*/
@@ -801,6 +786,13 @@ static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)
expires = 0;
if (timer->is_soft) {
+ /*
+ * soft hrtimer could be started on a remote CPU. In this
+ * case softirq_expires_next needs to be updated on the
+ * remote CPU. The soft hrtimer will not expire before the
+ * first hard hrtimer on the remote CPU -
+ * hrtimer_check_target() prevents this case.
+ */
struct hrtimer_cpu_base *timer_cpu_base = base->cpu_base;
if (timer_cpu_base->softirq_activated)
@@ -995,10 +987,9 @@ void hrtimer_wait_for_timer(const struct hrtimer *timer)
*/
static int enqueue_hrtimer(struct hrtimer *timer,
struct hrtimer_clock_base *base,
- enum hrtimer_mode mode,
- bool modecheck)
+ enum hrtimer_mode mode)
{
- debug_activate(timer, mode, modecheck);
+ debug_activate(timer, mode);
base->cpu_base->active_bases |= 1 << base->index;
@@ -1104,7 +1095,7 @@ hrtimer_update_softirq_timer(struct hrtimer_cpu_base *cpu_base, bool reprogram)
* hrtimer expires at the same time than the next hard
* hrtimer. cpu_base->softirq_expires_next needs to be updated!
*/
- if (!reprogram || expires == KTIME_MAX)
+ if (expires == KTIME_MAX)
return;
/*
@@ -1133,8 +1124,9 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
- return enqueue_hrtimer(timer, new_base, mode, HRTIMER_MODECHECK);
+ return enqueue_hrtimer(timer, new_base, mode);
}
+
/**
* hrtimer_start_range_ns - (re)start an hrtimer
* @timer: the timer to be added
@@ -1150,6 +1142,14 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
struct hrtimer_clock_base *base;
unsigned long flags;
+ /*
+ * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
+ * match.
+ */
+#ifndef CONFIG_PREEMPT_RT_BASE
+ WARN_ON_ONCE(!(mode & HRTIMER_MODE_SOFT) ^ !timer->is_soft);
+#endif
+
base = lock_hrtimer_base(timer, &flags);
if (__hrtimer_start_range_ns(timer, tim, delta_ns, mode, base))
@@ -1424,8 +1424,7 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
*/
if (restart != HRTIMER_NORESTART &&
!(timer->state & HRTIMER_STATE_ENQUEUED))
- enqueue_hrtimer(timer, base, HRTIMER_MODE_ABS,
- !HRTIMER_MODECHECK);
+ enqueue_hrtimer(timer, base, HRTIMER_MODE_ABS);
/*
* Separate the ->running assignment from the ->state assignment.
@@ -1939,8 +1938,7 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
* sort out already expired timers and reprogram the
* event device.
*/
- enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS,
- !HRTIMER_MODECHECK);
+ enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);
}
}
@@ -1952,6 +1950,12 @@ int hrtimers_dead_cpu(unsigned int scpu)
BUG_ON(cpu_online(scpu));
tick_cancel_sched_timer(scpu);
+ /*
+ * this BH disable ensures that raise_softirq_irqoff() does
+ * not wakeup ksoftirqd (and acquire the pi-lock) while
+ * holding the cpu_base lock
+ */
+ local_bh_disable();
local_irq_disable();
old_base = &per_cpu(hrtimer_bases, scpu);
new_base = this_cpu_ptr(&hrtimer_bases);
@@ -1979,6 +1983,7 @@ int hrtimers_dead_cpu(unsigned int scpu)
/* Check, if we got expired work to do */
__hrtimer_peek_ahead_timers();
local_irq_enable();
+ local_bh_enable();
return 0;
}
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 40ac38728b7a..26210086c562 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -844,11 +844,10 @@ static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu)
struct timer_base *base = per_cpu_ptr(&timer_bases[BASE_STD], cpu);
/*
- * If the timer is deferrable and nohz is active then we need to use
- * the deferrable base.
+ * If the timer is deferrable and NO_HZ_COMMON is set then we need
+ * to use the deferrable base.
*/
- if (is_timers_nohz_active() &&
- (tflags & TIMER_DEFERRABLE))
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE))
base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu);
return base;
}
@@ -858,11 +857,10 @@ static inline struct timer_base *get_timer_this_cpu_base(u32 tflags)
struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
/*
- * If the timer is deferrable and nohz is active then we need to use
- * the deferrable base.
+ * If the timer is deferrable and NO_HZ_COMMON is set then we need
+ * to use the deferrable base.
*/
- if (is_timers_nohz_active() &&
- (tflags & TIMER_DEFERRABLE))
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE))
base = this_cpu_ptr(&timer_bases[BASE_DEF]);
return base;
}
@@ -1005,8 +1003,6 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
if (!ret && pending_only)
goto out_unlock;
- debug_activate(timer, expires);
-
new_base = get_target_base(base, timer->flags);
if (base != new_base) {
@@ -1030,6 +1026,8 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
}
}
+ debug_activate(timer, expires);
+
timer->expires = expires;
/*
* If 'idx' was calculated above and the base time did not advance
@@ -1696,7 +1694,7 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h)
base->must_forward_clk = false;
__run_timers(base);
- if (is_timers_nohz_active())
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON))
__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
}
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index e244f26d4761..8a00d4da91f2 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -613,7 +613,7 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter,
/* parameter values */
if (se->fields[i]->is_string) {
trace_seq_printf(s, print_fmt, se->fields[i]->name,
- (char *)(long)entry->fields[n_u64],
+ (char *)&entry->fields[n_u64],
i == se->n_fields - 1 ? "" : " ");
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
} else {
@@ -1500,37 +1500,25 @@ static struct trace_event_file *find_var_file(struct trace_array *tr,
{
struct hist_trigger_data *var_hist_data;
struct hist_var_data *var_data;
- struct trace_event_call *call;
struct trace_event_file *file, *found = NULL;
- const char *name;
+
+ if (system)
+ return find_event_file(tr, system, event_name);
list_for_each_entry(var_data, &tr->hist_vars, list) {
var_hist_data = var_data->hist_data;
file = var_hist_data->event_file;
if (file == found)
continue;
- call = file->event_call;
- name = trace_event_name(call);
- if (!system || !event_name) {
- if (find_var(var_hist_data, file, var_name)) {
- if (found) {
- hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
- return NULL;
- }
-
- found = file;
+ if (find_var_field(var_hist_data, var_name)) {
+ if (found) {
+ hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
+ return NULL;
}
- continue;
+
+ found = file;
}
-
- if (strcmp(event_name, name) != 0)
- continue;
- if (strcmp(system, call->class->system) != 0)
- continue;
-
- found = file;
- break;
}
return found;
@@ -1977,7 +1965,7 @@ static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
{
struct hist_trigger_data *hist_data = elt->map->private_data;
- unsigned int size = TASK_COMM_LEN + 1;
+ unsigned int size = TASK_COMM_LEN;
struct hist_elt_data *elt_data;
struct hist_field *key_field;
unsigned int i, n_str;
diff --git a/lib/timerqueue.c b/lib/timerqueue.c
index 4a720ed4fdaf..0d54bcbc8170 100644
--- a/lib/timerqueue.c
+++ b/lib/timerqueue.c
@@ -33,8 +33,9 @@
* @head: head of timerqueue
* @node: timer node to be added
*
- * Adds the timer node to the timerqueue, sorted by the
- * node's expires value.
+ * Adds the timer node to the timerqueue, sorted by the node's expires
+ * value. Returns true if the newly added timer is the first expiring timer in
+ * the queue.
*/
bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
{
@@ -70,7 +71,8 @@ EXPORT_SYMBOL_GPL(timerqueue_add);
* @head: head of timerqueue
* @node: timer node to be removed
*
- * Removes the timer node from the timerqueue.
+ * Removes the timer node from the timerqueue. Returns true if the queue is
+ * not empty after the remove.
*/
bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
{
diff --git a/localversion-rt b/localversion-rt
index 700c857efd9b..22746d6390a4 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt8
+-rt9
--
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