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Message-ID: <20160715114803.GA11606@linutronix.de>
Date: Fri, 15 Jul 2016 13:48:04 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
linux-rt-users <linux-rt-users@...r.kernel.org>,
Steven Rostedt <rostedt@...dmis.org>
Subject: [ANNOUNCE] 4.6.4-rt8
Dear RT folks!
I'm pleased to announce the v4.6.4-rt8 patch set.
Changes since v4.6.4-rt8:
- Import Thomas' timer rework known as "timer: Refactor the timer
wheel" patch set which made its way into the -TIP tree. With this
changes we get NOHZ_FULL working. Finally.
- Avoid warning of an unused symbol in the !RT case
(preemptible_lazy())
- Replace the "trace event preempt count" fixup with Steven's version.
Known issues
- CPU hotplug got a little better but can deadlock.
The delta patch against 4.6.4-rt8 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.6/incr/patch-4.6.4-rt7-rt8.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 v4.6.4-rt8
The RT patch against 4.6.4 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.6/patch-4.6.4-rt8.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.6/patches-4.6.4-rt8.tar.xz
Sebastian
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 57773fd02253..cd97771f61d6 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -755,7 +755,7 @@ static void uv_heartbeat(unsigned long ignored)
uv_set_scir_bits(bits);
/* enable next timer period */
- mod_timer_pinned(timer, jiffies + SCIR_CPU_HB_INTERVAL);
+ mod_timer(timer, jiffies + SCIR_CPU_HB_INTERVAL);
}
static void uv_heartbeat_enable(int cpu)
@@ -764,7 +764,7 @@ static void uv_heartbeat_enable(int cpu)
struct timer_list *timer = &uv_cpu_hub_info(cpu)->scir.timer;
uv_set_cpu_scir_bits(cpu, SCIR_CPU_HEARTBEAT|SCIR_CPU_ACTIVITY);
- setup_timer(timer, uv_heartbeat, cpu);
+ setup_pinned_timer(timer, uv_heartbeat, cpu);
timer->expires = jiffies + SCIR_CPU_HB_INTERVAL;
add_timer_on(timer, cpu);
uv_cpu_hub_info(cpu)->scir.enabled = 1;
diff --git a/block/genhd.c b/block/genhd.c
index 9f42526b4d62..f06d7f3b075b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1523,12 +1523,7 @@ static void __disk_unblock_events(struct gendisk *disk, bool check_now)
if (--ev->block)
goto out_unlock;
- /*
- * Not exactly a latency critical operation, set poll timer
- * slack to 25% and kick event check.
- */
intv = disk_events_poll_jiffies(disk);
- set_timer_slack(&ev->dwork.timer, intv / 4);
if (check_now)
queue_delayed_work(system_freezable_power_efficient_wq,
&ev->dwork, 0);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index daba7ebb9699..18d58f136628 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -714,7 +714,7 @@ struct intel_uncore {
struct drm_i915_private *i915;
enum forcewake_domain_id id;
unsigned wake_count;
- struct timer_list timer;
+ struct hrtimer timer;
i915_reg_t reg_set;
u32 val_set;
u32 val_clear;
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 68b6f69aa682..49aefb097c15 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -60,7 +60,11 @@ fw_domain_reset(const struct intel_uncore_forcewake_domain *d)
static inline void
fw_domain_arm_timer(struct intel_uncore_forcewake_domain *d)
{
- mod_timer_pinned(&d->timer, jiffies + 1);
+ d->wake_count++;
+ hrtimer_start_range_ns(&d->timer,
+ ktime_set(0, NSEC_PER_MSEC),
+ NSEC_PER_MSEC,
+ HRTIMER_MODE_REL);
}
static inline void
@@ -224,9 +228,11 @@ static int __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
return ret;
}
-static void intel_uncore_fw_release_timer(unsigned long arg)
+static enum hrtimer_restart
+intel_uncore_fw_release_timer(struct hrtimer *timer)
{
- struct intel_uncore_forcewake_domain *domain = (void *)arg;
+ struct intel_uncore_forcewake_domain *domain =
+ container_of(timer, struct intel_uncore_forcewake_domain, timer);
unsigned long irqflags;
assert_rpm_device_not_suspended(domain->i915);
@@ -240,6 +246,8 @@ static void intel_uncore_fw_release_timer(unsigned long arg)
1 << domain->id);
spin_unlock_irqrestore(&domain->i915->uncore.lock, irqflags);
+
+ return HRTIMER_NORESTART;
}
void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
@@ -259,16 +267,16 @@ void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
active_domains = 0;
for_each_fw_domain(domain, dev_priv, id) {
- if (del_timer_sync(&domain->timer) == 0)
+ if (hrtimer_cancel(&domain->timer) == 0)
continue;
- intel_uncore_fw_release_timer((unsigned long)domain);
+ intel_uncore_fw_release_timer(&domain->timer);
}
spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
for_each_fw_domain(domain, dev_priv, id) {
- if (timer_pending(&domain->timer))
+ if (hrtimer_active(&domain->timer))
active_domains |= (1 << id);
}
@@ -491,7 +499,6 @@ static void __intel_uncore_forcewake_put(struct drm_i915_private *dev_priv,
if (--domain->wake_count)
continue;
- domain->wake_count++;
fw_domain_arm_timer(domain);
}
}
@@ -732,7 +739,6 @@ static inline void __force_wake_get(struct drm_i915_private *dev_priv,
continue;
}
- domain->wake_count++;
fw_domain_arm_timer(domain);
}
@@ -1150,7 +1156,8 @@ static void fw_domain_init(struct drm_i915_private *dev_priv,
d->i915 = dev_priv;
d->id = domain_id;
- setup_timer(&d->timer, intel_uncore_fw_release_timer, (unsigned long)d);
+ hrtimer_init(&d->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ d->timer.function = intel_uncore_fw_release_timer;
dev_priv->uncore.fw_domains |= (1 << domain_id);
diff --git a/drivers/mmc/host/jz4740_mmc.c b/drivers/mmc/host/jz4740_mmc.c
index 03ddf0ecf402..684087db170b 100644
--- a/drivers/mmc/host/jz4740_mmc.c
+++ b/drivers/mmc/host/jz4740_mmc.c
@@ -1068,8 +1068,6 @@ static int jz4740_mmc_probe(struct platform_device* pdev)
jz4740_mmc_clock_disable(host);
setup_timer(&host->timeout_timer, jz4740_mmc_timeout,
(unsigned long)host);
- /* It is not important when it times out, it just needs to timeout. */
- set_timer_slack(&host->timeout_timer, HZ);
host->use_dma = true;
if (host->use_dma && jz4740_mmc_acquire_dma_channels(host) != 0)
diff --git a/drivers/net/ethernet/tile/tilepro.c b/drivers/net/ethernet/tile/tilepro.c
index 298e059d0498..ea5d774fc89b 100644
--- a/drivers/net/ethernet/tile/tilepro.c
+++ b/drivers/net/ethernet/tile/tilepro.c
@@ -588,7 +588,7 @@ static bool tile_net_lepp_free_comps(struct net_device *dev, bool all)
static void tile_net_schedule_egress_timer(struct tile_net_cpu *info)
{
if (!info->egress_timer_scheduled) {
- mod_timer_pinned(&info->egress_timer, jiffies + 1);
+ mod_timer(&info->egress_timer, jiffies + 1);
info->egress_timer_scheduled = true;
}
}
@@ -1004,7 +1004,7 @@ static void tile_net_register(void *dev_ptr)
BUG();
/* Initialize the egress timer. */
- init_timer(&info->egress_timer);
+ init_timer_pinned(&info->egress_timer);
info->egress_timer.data = (long)info;
info->egress_timer.function = tile_net_handle_egress_timer;
diff --git a/drivers/power/bq27xxx_battery.c b/drivers/power/bq27xxx_battery.c
index 45f6ebf88df6..e90b3f307e0f 100644
--- a/drivers/power/bq27xxx_battery.c
+++ b/drivers/power/bq27xxx_battery.c
@@ -735,11 +735,8 @@ static void bq27xxx_battery_poll(struct work_struct *work)
bq27xxx_battery_update(di);
- if (poll_interval > 0) {
- /* The timer does not have to be accurate. */
- set_timer_slack(&di->work.timer, poll_interval * HZ / 4);
+ if (poll_interval > 0)
schedule_delayed_work(&di->work, poll_interval * HZ);
- }
}
/*
diff --git a/drivers/tty/metag_da.c b/drivers/tty/metag_da.c
index 9325262289f9..25ccef2fe748 100644
--- a/drivers/tty/metag_da.c
+++ b/drivers/tty/metag_da.c
@@ -323,12 +323,12 @@ static void dashtty_timer(unsigned long ignored)
if (channel >= 0)
fetch_data(channel);
- mod_timer_pinned(&poll_timer, jiffies + DA_TTY_POLL);
+ mod_timer(&poll_timer, jiffies + DA_TTY_POLL);
}
static void add_poll_timer(struct timer_list *poll_timer)
{
- setup_timer(poll_timer, dashtty_timer, 0);
+ setup_pinned_timer(poll_timer, dashtty_timer, 0);
poll_timer->expires = jiffies + DA_TTY_POLL;
/*
diff --git a/drivers/tty/mips_ejtag_fdc.c b/drivers/tty/mips_ejtag_fdc.c
index a119176a1855..234123b0c642 100644
--- a/drivers/tty/mips_ejtag_fdc.c
+++ b/drivers/tty/mips_ejtag_fdc.c
@@ -689,7 +689,7 @@ static void mips_ejtag_fdc_tty_timer(unsigned long opaque)
mips_ejtag_fdc_handle(priv);
if (!priv->removing)
- mod_timer_pinned(&priv->poll_timer, jiffies + FDC_TTY_POLL);
+ mod_timer(&priv->poll_timer, jiffies + FDC_TTY_POLL);
}
/* TTY Port operations */
@@ -1002,7 +1002,7 @@ static int mips_ejtag_fdc_tty_probe(struct mips_cdmm_device *dev)
raw_spin_unlock_irq(&priv->lock);
} else {
/* If we didn't get an usable IRQ, poll instead */
- setup_timer(&priv->poll_timer, mips_ejtag_fdc_tty_timer,
+ setup_pinned_timer(&priv->poll_timer, mips_ejtag_fdc_tty_timer,
(unsigned long)priv);
priv->poll_timer.expires = jiffies + FDC_TTY_POLL;
/*
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 04dcedfdebf8..86919ec47163 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -500,7 +500,6 @@ static int ohci_init (struct ohci_hcd *ohci)
setup_timer(&ohci->io_watchdog, io_watchdog_func,
(unsigned long) ohci);
- set_timer_slack(&ohci->io_watchdog, msecs_to_jiffies(20));
ohci->hcca = dma_alloc_coherent (hcd->self.controller,
sizeof(*ohci->hcca), &ohci->hcca_dma, GFP_KERNEL);
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 327280535848..7901a685b8de 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -490,8 +490,6 @@ static void compliance_mode_recovery_timer_init(struct xhci_hcd *xhci)
xhci->comp_mode_recovery_timer.expires = jiffies +
msecs_to_jiffies(COMP_MODE_RCVRY_MSECS);
- set_timer_slack(&xhci->comp_mode_recovery_timer,
- msecs_to_jiffies(COMP_MODE_RCVRY_MSECS));
add_timer(&xhci->comp_mode_recovery_timer);
xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
"Compliance mode recovery timer initialized");
diff --git a/include/linux/list.h b/include/linux/list.h
index 5356f4d661a7..3df0783a25e4 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -679,6 +679,16 @@ static inline bool hlist_fake(struct hlist_node *h)
}
/*
+ * Check whether the node is the only node of the head without
+ * accessing head.
+ */
+static inline bool hlist_is_singular_node(struct hlist_node *n,
+ struct hlist_head *h)
+{
+ return !n->next && n->pprev == &h->first;
+}
+
+/*
* Move a list from one list head to another. Fixup the pprev
* reference of the first entry if it exists.
*/
diff --git a/include/linux/timer.h b/include/linux/timer.h
index 299d2b78591f..a915acbd0072 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -19,7 +19,6 @@ struct timer_list {
void (*function)(unsigned long);
unsigned long data;
u32 flags;
- int slack;
#ifdef CONFIG_TIMER_STATS
int start_pid;
@@ -58,11 +57,14 @@ struct timer_list {
* workqueue locking issues. It's not meant for executing random crap
* with interrupts disabled. Abuse is monitored!
*/
-#define TIMER_CPUMASK 0x0007FFFF
-#define TIMER_MIGRATING 0x00080000
+#define TIMER_CPUMASK 0x0003FFFF
+#define TIMER_MIGRATING 0x00040000
#define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
-#define TIMER_DEFERRABLE 0x00100000
+#define TIMER_DEFERRABLE 0x00080000
+#define TIMER_PINNED 0x00100000
#define TIMER_IRQSAFE 0x00200000
+#define TIMER_ARRAYSHIFT 22
+#define TIMER_ARRAYMASK 0xFFC00000
#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
.entry = { .next = TIMER_ENTRY_STATIC }, \
@@ -70,7 +72,6 @@ struct timer_list {
.expires = (_expires), \
.data = (_data), \
.flags = (_flags), \
- .slack = -1, \
__TIMER_LOCKDEP_MAP_INITIALIZER( \
__FILE__ ":" __stringify(__LINE__)) \
}
@@ -78,9 +79,15 @@ struct timer_list {
#define TIMER_INITIALIZER(_function, _expires, _data) \
__TIMER_INITIALIZER((_function), (_expires), (_data), 0)
+#define TIMER_PINNED_INITIALIZER(_function, _expires, _data) \
+ __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_PINNED)
+
#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data) \
__TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE)
+#define TIMER_PINNED_DEFERRED_INITIALIZER(_function, _expires, _data) \
+ __TIMER_INITIALIZER((_function), (_expires), (_data), TIMER_DEFERRABLE | TIMER_PINNED)
+
#define DEFINE_TIMER(_name, _function, _expires, _data) \
struct timer_list _name = \
TIMER_INITIALIZER(_function, _expires, _data)
@@ -124,8 +131,12 @@ static inline void init_timer_on_stack_key(struct timer_list *timer,
#define init_timer(timer) \
__init_timer((timer), 0)
+#define init_timer_pinned(timer) \
+ __init_timer((timer), TIMER_PINNED)
#define init_timer_deferrable(timer) \
__init_timer((timer), TIMER_DEFERRABLE)
+#define init_timer_pinned_deferrable(timer) \
+ __init_timer((timer), TIMER_DEFERRABLE | TIMER_PINNED)
#define init_timer_on_stack(timer) \
__init_timer_on_stack((timer), 0)
@@ -145,10 +156,20 @@ static inline void init_timer_on_stack_key(struct timer_list *timer,
#define setup_timer(timer, fn, data) \
__setup_timer((timer), (fn), (data), 0)
+#define setup_pinned_timer(timer, fn, data) \
+ __setup_timer((timer), (fn), (data), TIMER_PINNED)
+#define setup_deferrable_timer(timer, fn, data) \
+ __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE)
+#define setup_pinned_deferrable_timer(timer, fn, data) \
+ __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
#define setup_timer_on_stack(timer, fn, data) \
__setup_timer_on_stack((timer), (fn), (data), 0)
+#define setup_pinned_timer_on_stack(timer, fn, data) \
+ __setup_timer_on_stack((timer), (fn), (data), TIMER_PINNED)
#define setup_deferrable_timer_on_stack(timer, fn, data) \
__setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
+#define setup_pinned_deferrable_timer_on_stack(timer, fn, data) \
+ __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
/**
* timer_pending - is a timer pending?
@@ -169,12 +190,7 @@ extern void add_timer_on(struct timer_list *timer, int cpu);
extern int del_timer(struct timer_list * timer);
extern int mod_timer(struct timer_list *timer, unsigned long expires);
extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
-extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
-extern void set_timer_slack(struct timer_list *time, int slack_hz);
-
-#define TIMER_NOT_PINNED 0
-#define TIMER_PINNED 1
/*
* The jiffies value which is added to now, when there is no timer
* in the timer wheel:
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 12cb3bb40c1c..be586c632a0c 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -33,19 +33,6 @@ struct trace_enum_map {
#define TRACEPOINT_DEFAULT_PRIO 10
-/*
- * The preempt count recorded in trace_event_raw_event_# are off by one due to
- * rcu_read_lock_sched_notrace() in __DO_TRACE. This is corrected here.
- */
-static inline int event_preempt_count(void)
-{
-#ifdef CONFIG_PREEMPT
- return preempt_count() - 1;
-#else
- return 0;
-#endif
-}
-
extern int
tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
extern int
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 58040375efe3..140ee06079b6 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3521,7 +3521,7 @@ static __always_inline int preemptible_lazy(void)
#else
-static int preemptible_lazy(void)
+static inline int preemptible_lazy(void)
{
return 1;
}
diff --git a/kernel/signal.c b/kernel/signal.c
index cacc654a243c..0a625c7b8792 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2837,23 +2837,18 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
* @ts: upper bound on process time suspension
*/
int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
- const struct timespec *ts)
+ const struct timespec *ts)
{
+ ktime_t *to = NULL, timeout = { .tv64 = KTIME_MAX };
struct task_struct *tsk = current;
- long timeout = MAX_SCHEDULE_TIMEOUT;
sigset_t mask = *which;
- int sig;
+ int sig, ret = 0;
if (ts) {
if (!timespec_valid(ts))
return -EINVAL;
- timeout = timespec_to_jiffies(ts);
- /*
- * We can be close to the next tick, add another one
- * to ensure we will wait at least the time asked for.
- */
- if (ts->tv_sec || ts->tv_nsec)
- timeout++;
+ timeout = timespec_to_ktime(*ts);
+ to = &timeout;
}
/*
@@ -2864,7 +2859,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
spin_lock_irq(&tsk->sighand->siglock);
sig = dequeue_signal(tsk, &mask, info);
- if (!sig && timeout) {
+ if (!sig && timeout.tv64) {
/*
* None ready, temporarily unblock those we're interested
* while we are sleeping in so that we'll be awakened when
@@ -2876,8 +2871,9 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
- timeout = freezable_schedule_timeout_interruptible(timeout);
-
+ __set_current_state(TASK_INTERRUPTIBLE);
+ ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
+ HRTIMER_MODE_REL);
spin_lock_irq(&tsk->sighand->siglock);
__set_task_blocked(tsk, &tsk->real_blocked);
sigemptyset(&tsk->real_blocked);
@@ -2887,7 +2883,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
if (sig)
return sig;
- return timeout ? -EINTR : -EAGAIN;
+ return ret ? -EINTR : -EAGAIN;
}
/**
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 966a5a6fdd0a..f738251000fe 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -164,3 +164,4 @@ static inline void timers_update_migration(bool update_nohz) { }
DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);
+void timer_clear_idle(void);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 8b005db22760..6fc9a5fdd5f4 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -706,6 +706,12 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
delta = next_tick - basemono;
if (delta <= (u64)TICK_NSEC) {
tick.tv64 = 0;
+
+ /*
+ * Tell the timer code that the base is not idle, i.e. undo
+ * the effect of get_next_timer_interrupt().
+ */
+ timer_clear_idle();
/*
* We've not stopped the tick yet, and there's a timer in the
* next period, so no point in stopping it either, bail.
@@ -814,6 +820,12 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now, int
tick_do_update_jiffies64(now);
update_cpu_load_nohz(active);
+ /*
+ * Clear the timer idle flag, so we avoid IPIs on remote queueing and
+ * the clock forward checks in the enqueue path.
+ */
+ timer_clear_idle();
+
calc_load_exit_idle();
touch_softlockup_watchdog_sched();
/*
@@ -1090,35 +1102,6 @@ static void tick_nohz_switch_to_nohz(void)
tick_nohz_activate(ts, NOHZ_MODE_LOWRES);
}
-/*
- * When NOHZ is enabled and the tick is stopped, we need to kick the
- * tick timer from irq_enter() so that the jiffies update is kept
- * alive during long running softirqs. That's ugly as hell, but
- * correctness is key even if we need to fix the offending softirq in
- * the first place.
- *
- * Note, this is different to tick_nohz_restart. We just kick the
- * timer and do not touch the other magic bits which need to be done
- * when idle is left.
- */
-static void tick_nohz_kick_tick(struct tick_sched *ts, ktime_t now)
-{
-#if 0
- /* Switch back to 2.6.27 behaviour */
- ktime_t delta;
-
- /*
- * Do not touch the tick device, when the next expiry is either
- * already reached or less/equal than the tick period.
- */
- delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now);
- if (delta.tv64 <= tick_period.tv64)
- return;
-
- tick_nohz_restart(ts, now);
-#endif
-}
-
static inline void tick_nohz_irq_enter(void)
{
struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
@@ -1129,10 +1112,8 @@ static inline void tick_nohz_irq_enter(void)
now = ktime_get();
if (ts->idle_active)
tick_nohz_stop_idle(ts, now);
- if (ts->tick_stopped) {
+ if (ts->tick_stopped)
tick_nohz_update_jiffies(now);
- tick_nohz_kick_tick(ts, now);
- }
}
#else
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 716ef84a5d87..b1d2d4026cfe 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -59,46 +59,156 @@ __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
/*
- * per-CPU timer vector definitions:
+ * The timer wheel has LVL_DEPTH array levels. Each level provides an array of
+ * LVL_SIZE buckets. Each level is driven by its own clock and therefor each
+ * level has a different granularity.
+ *
+ * The level granularity is: LVL_CLK_DIV ^ lvl
+ * The level clock frequency is: HZ / (LVL_CLK_DIV ^ level)
+ *
+ * The array level of a newly armed timer depends on the relative expiry
+ * time. The farther the expiry time is away the higher the array level and
+ * therefor the granularity becomes.
+ *
+ * Contrary to the original timer wheel implementation, which aims for 'exact'
+ * expiry of the timers, this implementation removes the need for recascading
+ * the timers into the lower array levels. The previous 'classic' timer wheel
+ * implementation of the kernel already violated the 'exact' expiry by adding
+ * slack to the expiry time to provide batched expiration. The granularity
+ * levels provide implicit batching.
+ *
+ * This is an optimization of the original timer wheel implementation for the
+ * majority of the timer wheel use cases: timeouts. The vast majority of
+ * timeout timers (networking, disk I/O ...) are canceled before expiry. If
+ * the timeout expires it indicates that normal operation is disturbed, so it
+ * does not matter much whether the timeout comes with a slight delay.
+ *
+ * The only exception to this are networking timers with a small expiry
+ * time. They rely on the granularity. Those fit into the first wheel level,
+ * which has HZ granularity.
+ *
+ * We don't have cascading anymore. timers with a expiry time above the
+ * capacity of the last wheel level are force expired at the maximum timeout
+ * value of the last wheel level. From data sampling we know that the maximum
+ * value observed is 5 days (network connection tracking), so this should not
+ * be an issue.
+ *
+ * The currently chosen array constants values are a good compromise between
+ * array size and granularity.
+ *
+ * This results in the following granularity and range levels:
+ *
+ * HZ 1000 steps
+ * Level Offset Granularity Range
+ * 0 0 1 ms 0 ms - 63 ms
+ * 1 64 8 ms 64 ms - 511 ms
+ * 2 128 64 ms 512 ms - 4095 ms (512ms - ~4s)
+ * 3 192 512 ms 4096 ms - 32767 ms (~4s - ~32s)
+ * 4 256 4096 ms (~4s) 32768 ms - 262143 ms (~32s - ~4m)
+ * 5 320 32768 ms (~32s) 262144 ms - 2097151 ms (~4m - ~34m)
+ * 6 384 262144 ms (~4m) 2097152 ms - 16777215 ms (~34m - ~4h)
+ * 7 448 2097152 ms (~34m) 16777216 ms - 134217727 ms (~4h - ~1d)
+ * 8 512 16777216 ms (~4h) 134217728 ms - 1073741822 ms (~1d - ~12d)
+ *
+ * HZ 300
+ * Level Offset Granularity Range
+ * 0 0 3 ms 0 ms - 210 ms
+ * 1 64 26 ms 213 ms - 1703 ms (213ms - ~1s)
+ * 2 128 213 ms 1706 ms - 13650 ms (~1s - ~13s)
+ * 3 192 1706 ms (~1s) 13653 ms - 109223 ms (~13s - ~1m)
+ * 4 256 13653 ms (~13s) 109226 ms - 873810 ms (~1m - ~14m)
+ * 5 320 109226 ms (~1m) 873813 ms - 6990503 ms (~14m - ~1h)
+ * 6 384 873813 ms (~14m) 6990506 ms - 55924050 ms (~1h - ~15h)
+ * 7 448 6990506 ms (~1h) 55924053 ms - 447392423 ms (~15h - ~5d)
+ * 8 512 55924053 ms (~15h) 447392426 ms - 3579139406 ms (~5d - ~41d)
+ *
+ * HZ 250
+ * Level Offset Granularity Range
+ * 0 0 4 ms 0 ms - 255 ms
+ * 1 64 32 ms 256 ms - 2047 ms (256ms - ~2s)
+ * 2 128 256 ms 2048 ms - 16383 ms (~2s - ~16s)
+ * 3 192 2048 ms (~2s) 16384 ms - 131071 ms (~16s - ~2m)
+ * 4 256 16384 ms (~16s) 131072 ms - 1048575 ms (~2m - ~17m)
+ * 5 320 131072 ms (~2m) 1048576 ms - 8388607 ms (~17m - ~2h)
+ * 6 384 1048576 ms (~17m) 8388608 ms - 67108863 ms (~2h - ~18h)
+ * 7 448 8388608 ms (~2h) 67108864 ms - 536870911 ms (~18h - ~6d)
+ * 8 512 67108864 ms (~18h) 536870912 ms - 4294967288 ms (~6d - ~49d)
+ *
+ * HZ 100
+ * Level Offset Granularity Range
+ * 0 0 10 ms 0 ms - 630 ms
+ * 1 64 80 ms 640 ms - 5110 ms (640ms - ~5s)
+ * 2 128 640 ms 5120 ms - 40950 ms (~5s - ~40s)
+ * 3 192 5120 ms (~5s) 40960 ms - 327670 ms (~40s - ~5m)
+ * 4 256 40960 ms (~40s) 327680 ms - 2621430 ms (~5m - ~43m)
+ * 5 320 327680 ms (~5m) 2621440 ms - 20971510 ms (~43m - ~5h)
+ * 6 384 2621440 ms (~43m) 20971520 ms - 167772150 ms (~5h - ~1d)
+ * 7 448 20971520 ms (~5h) 167772160 ms - 1342177270 ms (~1d - ~15d)
*/
-#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
-#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
-#define TVN_SIZE (1 << TVN_BITS)
-#define TVR_SIZE (1 << TVR_BITS)
-#define TVN_MASK (TVN_SIZE - 1)
-#define TVR_MASK (TVR_SIZE - 1)
-#define MAX_TVAL ((unsigned long)((1ULL << (TVR_BITS + 4*TVN_BITS)) - 1))
-struct tvec {
- struct hlist_head vec[TVN_SIZE];
-};
+/* Clock divisor for the next level */
+#define LVL_CLK_SHIFT 3
+#define LVL_CLK_DIV (1UL << LVL_CLK_SHIFT)
+#define LVL_CLK_MASK (LVL_CLK_DIV - 1)
+#define LVL_SHIFT(n) ((n) * LVL_CLK_SHIFT)
+#define LVL_GRAN(n) (1UL << LVL_SHIFT(n))
-struct tvec_root {
- struct hlist_head vec[TVR_SIZE];
-};
+/*
+ * The time start value for each level to select the bucket at enqueue
+ * time.
+ */
+#define LVL_START(n) ((LVL_SIZE - 1) << (((n) - 1) * LVL_CLK_SHIFT))
-struct tvec_base {
- spinlock_t lock;
- struct timer_list *running_timer;
-#ifdef CONFIG_PREEMPT_RT_FULL
- wait_queue_head_t wait_for_running_timer;
+/* Size of each clock level */
+#define LVL_BITS 6
+#define LVL_SIZE (1UL << LVL_BITS)
+#define LVL_MASK (LVL_SIZE - 1)
+#define LVL_OFFS(n) ((n) * LVL_SIZE)
+
+/* Level depth */
+#if HZ > 100
+# define LVL_DEPTH 9
+# else
+# define LVL_DEPTH 8
#endif
- unsigned long timer_jiffies;
- unsigned long next_timer;
- unsigned long active_timers;
- unsigned long all_timers;
- int cpu;
- bool migration_enabled;
- bool nohz_active;
- struct tvec_root tv1;
- struct tvec tv2;
- struct tvec tv3;
- struct tvec tv4;
- struct tvec tv5;
+
+/* The cutoff (max. capacity of the wheel) */
+#define WHEEL_TIMEOUT_CUTOFF (LVL_START(LVL_DEPTH))
+#define WHEEL_TIMEOUT_MAX (WHEEL_TIMEOUT_CUTOFF - LVL_GRAN(LVL_DEPTH - 1))
+
+/*
+ * The resulting wheel size. If NOHZ is configured we allocate two
+ * wheels so we have a separate storage for the deferrable timers.
+ */
+#define WHEEL_SIZE (LVL_SIZE * LVL_DEPTH)
+
+#ifdef CONFIG_NO_HZ_COMMON
+# define NR_BASES 2
+# define BASE_STD 0
+# define BASE_DEF 1
+#else
+# define NR_BASES 1
+# define BASE_STD 0
+# define BASE_DEF 0
+#endif
+
+struct timer_base {
+ raw_spinlock_t lock;
+ struct timer_list *running_timer;
+#ifdef CONFIG_PREEMPT_RT_FULL
+ struct swait_queue_head wait_for_running_timer;
+#endif
+ unsigned long clk;
+ unsigned long next_expiry;
+ unsigned int cpu;
+ bool migration_enabled;
+ bool nohz_active;
+ bool is_idle;
+ DECLARE_BITMAP(pending_map, WHEEL_SIZE);
+ struct hlist_head vectors[WHEEL_SIZE];
} ____cacheline_aligned;
-
-static DEFINE_PER_CPU(struct tvec_base, tvec_bases);
+static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]);
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
unsigned int sysctl_timer_migration = 1;
@@ -109,15 +219,17 @@ void timers_update_migration(bool update_nohz)
unsigned int cpu;
/* Avoid the loop, if nothing to update */
- if (this_cpu_read(tvec_bases.migration_enabled) == on)
+ if (this_cpu_read(timer_bases[BASE_STD].migration_enabled) == on)
return;
for_each_possible_cpu(cpu) {
- per_cpu(tvec_bases.migration_enabled, cpu) = on;
+ per_cpu(timer_bases[BASE_STD].migration_enabled, cpu) = on;
+ per_cpu(timer_bases[BASE_DEF].migration_enabled, cpu) = on;
per_cpu(hrtimer_bases.migration_enabled, cpu) = on;
if (!update_nohz)
continue;
- per_cpu(tvec_bases.nohz_active, cpu) = true;
+ per_cpu(timer_bases[BASE_STD].nohz_active, cpu) = true;
+ per_cpu(timer_bases[BASE_DEF].nohz_active, cpu) = true;
per_cpu(hrtimer_bases.nohz_active, cpu) = true;
}
}
@@ -136,20 +248,6 @@ int timer_migration_handler(struct ctl_table *table, int write,
mutex_unlock(&mutex);
return ret;
}
-
-static inline struct tvec_base *get_target_base(struct tvec_base *base,
- int pinned)
-{
- if (pinned || !base->migration_enabled)
- return this_cpu_ptr(&tvec_bases);
- return per_cpu_ptr(&tvec_bases, get_nohz_timer_target());
-}
-#else
-static inline struct tvec_base *get_target_base(struct tvec_base *base,
- int pinned)
-{
- return this_cpu_ptr(&tvec_bases);
-}
#endif
static unsigned long round_jiffies_common(unsigned long j, int cpu,
@@ -354,101 +452,126 @@ unsigned long round_jiffies_up_relative(unsigned long j)
}
EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
-/**
- * set_timer_slack - set the allowed slack for a timer
- * @timer: the timer to be modified
- * @slack_hz: the amount of time (in jiffies) allowed for rounding
- *
- * Set the amount of time, in jiffies, that a certain timer has
- * in terms of slack. By setting this value, the timer subsystem
- * will schedule the actual timer somewhere between
- * the time mod_timer() asks for, and that time plus the slack.
- *
- * By setting the slack to -1, a percentage of the delay is used
- * instead.
- */
-void set_timer_slack(struct timer_list *timer, int slack_hz)
+
+static inline unsigned int timer_get_idx(struct timer_list *timer)
{
- timer->slack = slack_hz;
+ return (timer->flags & TIMER_ARRAYMASK) >> TIMER_ARRAYSHIFT;
+}
+
+static inline void timer_set_idx(struct timer_list *timer, unsigned int idx)
+{
+ timer->flags = (timer->flags & ~TIMER_ARRAYMASK) |
+ idx << TIMER_ARRAYSHIFT;
+}
+
+/*
+ * Helper function to calculate the array index for a given expiry
+ * time.
+ */
+static inline unsigned calc_index(unsigned expires, unsigned lvl)
+{
+ expires = (expires + LVL_GRAN(lvl)) >> LVL_SHIFT(lvl);
+ return LVL_OFFS(lvl) + (expires & LVL_MASK);
+}
+
+static int calc_wheel_index(unsigned long expires, unsigned long clk)
+{
+ unsigned long delta = expires - clk;
+ unsigned int idx;
+
+ if (delta < LVL_START(1)) {
+ idx = calc_index(expires, 0);
+ } else if (delta < LVL_START(2)) {
+ idx = calc_index(expires, 1);
+ } else if (delta < LVL_START(3)) {
+ idx = calc_index(expires, 2);
+ } else if (delta < LVL_START(4)) {
+ idx = calc_index(expires, 3);
+ } else if (delta < LVL_START(5)) {
+ idx = calc_index(expires, 4);
+ } else if (delta < LVL_START(6)) {
+ idx = calc_index(expires, 5);
+ } else if (delta < LVL_START(7)) {
+ idx = calc_index(expires, 6);
+ } else if (LVL_DEPTH > 8 && delta < LVL_START(8)) {
+ idx = calc_index(expires, 7);
+ } else if ((long) delta < 0) {
+ idx = clk & LVL_MASK;
+ } else {
+ /*
+ * Force expire obscene large timeouts to expire at the
+ * capacity limit of the wheel.
+ */
+ if (expires >= WHEEL_TIMEOUT_CUTOFF)
+ expires = WHEEL_TIMEOUT_MAX;
+
+ idx = calc_index(expires, LVL_DEPTH - 1);
+ }
+ return idx;
+}
+
+/*
+ * Enqueue the timer into the hash bucket, mark it pending in
+ * the bitmap and store the index in the timer flags.
+ */
+static void enqueue_timer(struct timer_base *base, struct timer_list *timer,
+ unsigned int idx)
+{
+ hlist_add_head(&timer->entry, base->vectors + idx);
+ __set_bit(idx, base->pending_map);
+ timer_set_idx(timer, idx);
}
-EXPORT_SYMBOL_GPL(set_timer_slack);
static void
-__internal_add_timer(struct tvec_base *base, struct timer_list *timer)
+__internal_add_timer(struct timer_base *base, struct timer_list *timer)
{
- unsigned long expires = timer->expires;
- unsigned long idx = expires - base->timer_jiffies;
- struct hlist_head *vec;
+ unsigned int idx;
- if (idx < TVR_SIZE) {
- int i = expires & TVR_MASK;
- vec = base->tv1.vec + i;
- } else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
- int i = (expires >> TVR_BITS) & TVN_MASK;
- vec = base->tv2.vec + i;
- } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
- int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
- vec = base->tv3.vec + i;
- } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
- int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
- vec = base->tv4.vec + i;
- } else if ((signed long) idx < 0) {
- /*
- * Can happen if you add a timer with expires == jiffies,
- * or you set a timer to go off in the past
- */
- vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
- } else {
- int i;
- /* If the timeout is larger than MAX_TVAL (on 64-bit
- * architectures or with CONFIG_BASE_SMALL=1) then we
- * use the maximum timeout.
- */
- if (idx > MAX_TVAL) {
- idx = MAX_TVAL;
- expires = idx + base->timer_jiffies;
- }
- i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
- vec = base->tv5.vec + i;
- }
-
- hlist_add_head(&timer->entry, vec);
+ idx = calc_wheel_index(timer->expires, base->clk);
+ enqueue_timer(base, timer, idx);
}
-static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
+static void
+trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer)
{
- /* Advance base->jiffies, if the base is empty */
- if (!base->all_timers++)
- base->timer_jiffies = jiffies;
-
- __internal_add_timer(base, timer);
- /*
- * Update base->active_timers and base->next_timer
- */
- if (!(timer->flags & TIMER_DEFERRABLE)) {
- if (!base->active_timers++ ||
- time_before(timer->expires, base->next_timer))
- base->next_timer = timer->expires;
- }
+ if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active)
+ return;
/*
- * Check whether the other CPU is in dynticks mode and needs
- * to be triggered to reevaluate the timer wheel.
- * We are protected against the other CPU fiddling
- * with the timer by holding the timer base lock. This also
- * makes sure that a CPU on the way to stop its tick can not
- * evaluate the timer wheel.
- *
- * Spare the IPI for deferrable timers on idle targets though.
- * The next busy ticks will take care of it. Except full dynticks
- * require special care against races with idle_cpu(), lets deal
- * with that later.
+ * This wants some optimizing similar to the below, but we do that
+ * when we switch from push to pull for deferrable timers.
*/
- if (base->nohz_active) {
- if (!(timer->flags & TIMER_DEFERRABLE) ||
- tick_nohz_full_cpu(base->cpu))
+ if (timer->flags & TIMER_DEFERRABLE) {
+ if (tick_nohz_full_cpu(base->cpu))
wake_up_nohz_cpu(base->cpu);
+ return;
}
+
+ /*
+ * We might have to IPI the remote CPU if the base is idle and the
+ * timer is not deferrable. If the other cpu is on the way to idle
+ * then it can't set base->is_idle as we hold base lock.
+ */
+ if (!base->is_idle)
+ return;
+
+ /* Check whether this is the new first expiring timer */
+ if (time_after_eq(timer->expires, base->next_expiry))
+ return;
+
+ /*
+ * Set the next expiry time and kick the cpu so it can reevaluate the
+ * wheel
+ */
+ base->next_expiry = timer->expires;
+ wake_up_nohz_cpu(base->cpu);
+}
+
+static void
+internal_add_timer(struct timer_base *base, struct timer_list *timer)
+{
+ __internal_add_timer(base, timer);
+ trigger_dyntick_cpu(base, timer);
}
#ifdef CONFIG_TIMER_STATS
@@ -684,7 +807,6 @@ static void do_init_timer(struct timer_list *timer, unsigned int flags,
{
timer->entry.pprev = NULL;
timer->flags = flags | raw_smp_processor_id();
- timer->slack = -1;
#ifdef CONFIG_TIMER_STATS
timer->start_site = NULL;
timer->start_pid = -1;
@@ -724,104 +846,170 @@ static inline void detach_timer(struct timer_list *timer, bool clear_pending)
entry->next = LIST_POISON2;
}
-static inline void
-detach_expired_timer(struct timer_list *timer, struct tvec_base *base)
-{
- detach_timer(timer, true);
- if (!(timer->flags & TIMER_DEFERRABLE))
- base->active_timers--;
- base->all_timers--;
-}
-
-static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
+static int detach_if_pending(struct timer_list *timer, struct timer_base *base,
bool clear_pending)
{
+ unsigned idx = timer_get_idx(timer);
+
if (!timer_pending(timer))
return 0;
+ if (hlist_is_singular_node(&timer->entry, base->vectors + idx))
+ __clear_bit(idx, base->pending_map);
+
detach_timer(timer, clear_pending);
- if (!(timer->flags & TIMER_DEFERRABLE)) {
- base->active_timers--;
- if (timer->expires == base->next_timer)
- base->next_timer = base->timer_jiffies;
- }
- /* If this was the last timer, advance base->jiffies */
- if (!--base->all_timers)
- base->timer_jiffies = jiffies;
return 1;
}
+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 (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active &&
+ (tflags & TIMER_DEFERRABLE))
+ base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu);
+ return base;
+}
+
+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 (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active &&
+ (tflags & TIMER_DEFERRABLE))
+ base = this_cpu_ptr(&timer_bases[BASE_DEF]);
+ return base;
+}
+
+static inline struct timer_base *get_timer_base(u32 tflags)
+{
+ return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+static inline struct timer_base *__get_target_base(struct timer_base *base,
+ unsigned tflags)
+{
+#ifdef CONFIG_SMP
+ if ((tflags & TIMER_PINNED) || !base->migration_enabled)
+ return get_timer_this_cpu_base(tflags);
+ return get_timer_cpu_base(tflags, get_nohz_timer_target());
+#else
+ return get_timer_this_cpu_base(tflags);
+#endif
+}
+
+static inline void forward_timer_base(struct timer_base *base)
+{
+ /*
+ * We only forward the base when it's idle and we have a delta between
+ * base clock and jiffies.
+ */
+ if (!base->is_idle || (long) (jiffies - base->clk) < 2)
+ return;
+
+ /*
+ * If the next expiry value is > jiffies, then we fast forward to
+ * jiffies otherwise we forward to the next expiry value.
+ */
+ if (time_after(base->next_expiry, jiffies))
+ base->clk = jiffies;
+ else
+ base->clk = base->next_expiry;
+}
+#else
+static inline struct timer_base *__get_target_base(struct timer_base *base,
+ unsigned tflags)
+{
+ return get_timer_this_cpu_base(tflags);
+}
+
+static inline void forward_timer_base(struct timer_base *base) { }
+#endif
+
+static inline struct timer_base *get_target_base(struct timer_base *base,
+ unsigned tflags)
+{
+ struct timer_base *target = __get_target_base(base, tflags);
+
+ forward_timer_base(target);
+ return target;
+}
+
/*
- * We are using hashed locking: holding per_cpu(tvec_bases).lock
- * means that all timers which are tied to this base via timer->base are
- * locked, and the base itself is locked too.
+ * We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means
+ * that all timers which are tied to this base are locked, and the base itself
+ * is locked too.
*
* So __run_timers/migrate_timers can safely modify all timers which could
- * be found on ->tvX lists.
+ * be found in the base->vectors array.
*
- * When the timer's base is locked and removed from the list, the
- * TIMER_MIGRATING flag is set, FIXME
+ * When a timer is migrating then the TIMER_MIGRATING flag is set and we need
+ * to wait until the migration is done.
*/
-static struct tvec_base *lock_timer_base(struct timer_list *timer,
- unsigned long *flags)
+static struct timer_base *lock_timer_base(struct timer_list *timer,
+ unsigned long *flags)
__acquires(timer->base->lock)
{
for (;;) {
+ struct timer_base *base;
u32 tf = timer->flags;
- struct tvec_base *base;
if (!(tf & TIMER_MIGRATING)) {
- base = per_cpu_ptr(&tvec_bases, tf & TIMER_CPUMASK);
- spin_lock_irqsave(&base->lock, *flags);
+ base = get_timer_base(tf);
+ raw_spin_lock_irqsave(&base->lock, *flags);
if (timer->flags == tf)
return base;
- spin_unlock_irqrestore(&base->lock, *flags);
+ raw_spin_unlock_irqrestore(&base->lock, *flags);
}
cpu_relax();
}
}
-#ifdef CONFIG_PREEMPT_RT_FULL
-static inline struct tvec_base *switch_timer_base(struct timer_list *timer,
- struct tvec_base *old,
- struct tvec_base *new)
-{
- /*
- * We cannot do the below because we might be preempted and
- * then the preempter would see NULL and loop forever.
- */
- if (spin_trylock(&new->lock)) {
- WRITE_ONCE(timer->flags,
- (timer->flags & ~TIMER_BASEMASK) | new->cpu);
- spin_unlock(&old->lock);
- return new;
- }
- return old;
-}
-
-#else
-static inline struct tvec_base *switch_timer_base(struct timer_list *timer,
- struct tvec_base *old,
- struct tvec_base *new)
-{
- /* See the comment in lock_timer_base() */
- timer->flags |= TIMER_MIGRATING;
-
- spin_unlock(&old->lock);
- spin_lock(&new->lock);
- WRITE_ONCE(timer->flags,
- (timer->flags & ~TIMER_BASEMASK) | new->cpu);
- return new;
-}
-#endif
static inline int
-__mod_timer(struct timer_list *timer, unsigned long expires,
- bool pending_only, int pinned)
+__mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
{
- struct tvec_base *base, *new_base;
- unsigned long flags;
+ struct timer_base *base, *new_base;
+ unsigned int idx = UINT_MAX;
+ unsigned long clk = 0, flags;
int ret = 0;
+ /*
+ * This is a common optimization triggered by the networking code - if
+ * the timer is re-modified to be the same thing or ends up in the
+ * same array bucket then just return:
+ */
+ if (timer_pending(timer)) {
+ if (timer->expires == expires)
+ return 1;
+ /*
+ * Take the current timer_jiffies of base, but without holding
+ * the lock!
+ */
+ base = get_timer_base(timer->flags);
+ clk = base->clk;
+
+ idx = calc_wheel_index(expires, clk);
+
+ /*
+ * Retrieve and compare the array index of the pending
+ * timer. If it matches set the expiry to the new value so a
+ * subsequent call will exit in the expires check above.
+ */
+ if (idx == timer_get_idx(timer)) {
+ timer->expires = expires;
+ return 1;
+ }
+ }
+
timer_stats_timer_set_start_info(timer);
BUG_ON(!timer->function);
@@ -833,25 +1021,44 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
debug_activate(timer, expires);
- new_base = get_target_base(base, pinned);
+ new_base = get_target_base(base, timer->flags);
if (base != new_base) {
/*
- * We are trying to schedule the timer on the local CPU.
+ * We are trying to schedule the timer on the new base.
* However we can't change timer's base while it is running,
* otherwise del_timer_sync() can't detect that the timer's
- * handler yet has not finished. This also guarantees that
- * the timer is serialized wrt itself.
+ * handler yet has not finished. This also guarantees that the
+ * timer is serialized wrt itself.
*/
- if (likely(base->running_timer != timer))
- base = switch_timer_base(timer, base, new_base);
+ if (likely(base->running_timer != timer)) {
+ /* See the comment in lock_timer_base() */
+ timer->flags |= TIMER_MIGRATING;
+
+ raw_spin_unlock(&base->lock);
+ base = new_base;
+ raw_spin_lock(&base->lock);
+ WRITE_ONCE(timer->flags,
+ (timer->flags & ~TIMER_BASEMASK) | base->cpu);
+ }
}
timer->expires = expires;
- internal_add_timer(base, timer);
+ /*
+ * If idx was calculated above and the base time did not advance
+ * between calculating idx and taking the lock, only enqueue_timer()
+ * and trigger_dyntick_cpu() is required. Otherwise we need to
+ * (re)calculate the wheel index via internal_add_timer().
+ */
+ if (idx != UINT_MAX && clk == base->clk) {
+ enqueue_timer(base, timer, idx);
+ trigger_dyntick_cpu(base, timer);
+ } else {
+ internal_add_timer(base, timer);
+ }
out_unlock:
- spin_unlock_irqrestore(&base->lock, flags);
+ raw_spin_unlock_irqrestore(&base->lock, flags);
return ret;
}
@@ -868,49 +1075,10 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
*/
int mod_timer_pending(struct timer_list *timer, unsigned long expires)
{
- return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
+ return __mod_timer(timer, expires, true);
}
EXPORT_SYMBOL(mod_timer_pending);
-/*
- * Decide where to put the timer while taking the slack into account
- *
- * Algorithm:
- * 1) calculate the maximum (absolute) time
- * 2) calculate the highest bit where the expires and new max are different
- * 3) use this bit to make a mask
- * 4) use the bitmask to round down the maximum time, so that all last
- * bits are zeros
- */
-static inline
-unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
-{
- unsigned long expires_limit, mask;
- int bit;
-
- if (timer->slack >= 0) {
- expires_limit = expires + timer->slack;
- } else {
- long delta = expires - jiffies;
-
- if (delta < 256)
- return expires;
-
- expires_limit = expires + delta / 256;
- }
- mask = expires ^ expires_limit;
- if (mask == 0)
- return expires;
-
- bit = __fls(mask);
-
- mask = (1UL << bit) - 1;
-
- expires_limit = expires_limit & ~(mask);
-
- return expires_limit;
-}
-
/**
* mod_timer - modify a timer's timeout
* @timer: the timer to be modified
@@ -933,49 +1101,11 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
*/
int mod_timer(struct timer_list *timer, unsigned long expires)
{
- expires = apply_slack(timer, expires);
-
- /*
- * This is a common optimization triggered by the
- * networking code - if the timer is re-modified
- * to be the same thing then just return:
- */
- if (timer_pending(timer) && timer->expires == expires)
- return 1;
-
- return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
+ return __mod_timer(timer, expires, false);
}
EXPORT_SYMBOL(mod_timer);
/**
- * mod_timer_pinned - modify a timer's timeout
- * @timer: the timer to be modified
- * @expires: new timeout in jiffies
- *
- * mod_timer_pinned() is a way to update the expire field of an
- * active timer (if the timer is inactive it will be activated)
- * and to ensure that the timer is scheduled on the current CPU.
- *
- * Note that this does not prevent the timer from being migrated
- * when the current CPU goes offline. If this is a problem for
- * you, use CPU-hotplug notifiers to handle it correctly, for
- * example, cancelling the timer when the corresponding CPU goes
- * offline.
- *
- * mod_timer_pinned(timer, expires) is equivalent to:
- *
- * del_timer(timer); timer->expires = expires; add_timer(timer);
- */
-int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
-{
- if (timer->expires == expires && timer_pending(timer))
- return 1;
-
- return __mod_timer(timer, expires, false, TIMER_PINNED);
-}
-EXPORT_SYMBOL(mod_timer_pinned);
-
-/**
* add_timer - start a timer
* @timer: the timer to be added
*
@@ -1005,13 +1135,14 @@ EXPORT_SYMBOL(add_timer);
*/
void add_timer_on(struct timer_list *timer, int cpu)
{
- struct tvec_base *new_base = per_cpu_ptr(&tvec_bases, cpu);
- struct tvec_base *base;
+ struct timer_base *new_base, *base;
unsigned long flags;
timer_stats_timer_set_start_info(timer);
BUG_ON(timer_pending(timer) || !timer->function);
+ new_base = get_timer_cpu_base(timer->flags, cpu);
+
/*
* If @timer was on a different CPU, it should be migrated with the
* old base locked to prevent other operations proceeding with the
@@ -1021,16 +1152,16 @@ void add_timer_on(struct timer_list *timer, int cpu)
if (base != new_base) {
timer->flags |= TIMER_MIGRATING;
- spin_unlock(&base->lock);
+ raw_spin_unlock(&base->lock);
base = new_base;
- spin_lock(&base->lock);
+ raw_spin_lock(&base->lock);
WRITE_ONCE(timer->flags,
(timer->flags & ~TIMER_BASEMASK) | cpu);
}
debug_activate(timer, timer->expires);
internal_add_timer(base, timer);
- spin_unlock_irqrestore(&base->lock, flags);
+ raw_spin_unlock_irqrestore(&base->lock, flags);
}
EXPORT_SYMBOL_GPL(add_timer_on);
@@ -1040,18 +1171,18 @@ EXPORT_SYMBOL_GPL(add_timer_on);
*/
static void wait_for_running_timer(struct timer_list *timer)
{
- struct tvec_base *base;
+ struct timer_base *base;
u32 tf = timer->flags;
if (tf & TIMER_MIGRATING)
return;
- base = per_cpu_ptr(&tvec_bases, tf & TIMER_CPUMASK);
- wait_event(base->wait_for_running_timer,
+ base = get_timer_base(tf);
+ swait_event(base->wait_for_running_timer,
base->running_timer != timer);
}
-# define wakeup_timer_waiters(b) wake_up_all(&(b)->wait_for_running_timer)
+# define wakeup_timer_waiters(b) swake_up_all(&(b)->wait_for_running_timer)
#else
static inline void wait_for_running_timer(struct timer_list *timer)
{
@@ -1074,7 +1205,7 @@ static inline void wait_for_running_timer(struct timer_list *timer)
*/
int del_timer(struct timer_list *timer)
{
- struct tvec_base *base;
+ struct timer_base *base;
unsigned long flags;
int ret = 0;
@@ -1084,7 +1215,7 @@ int del_timer(struct timer_list *timer)
if (timer_pending(timer)) {
base = lock_timer_base(timer, &flags);
ret = detach_if_pending(timer, base, true);
- spin_unlock_irqrestore(&base->lock, flags);
+ raw_spin_unlock_irqrestore(&base->lock, flags);
}
return ret;
@@ -1100,7 +1231,7 @@ EXPORT_SYMBOL(del_timer);
*/
int try_to_del_timer_sync(struct timer_list *timer)
{
- struct tvec_base *base;
+ struct timer_base *base;
unsigned long flags;
int ret = -1;
@@ -1112,7 +1243,7 @@ int try_to_del_timer_sync(struct timer_list *timer)
timer_stats_timer_clear_start_info(timer);
ret = detach_if_pending(timer, base, true);
}
- spin_unlock_irqrestore(&base->lock, flags);
+ raw_spin_unlock_irqrestore(&base->lock, flags);
return ret;
}
@@ -1184,27 +1315,6 @@ int del_timer_sync(struct timer_list *timer)
EXPORT_SYMBOL(del_timer_sync);
#endif
-static int cascade(struct tvec_base *base, struct tvec *tv, int index)
-{
- /* cascade all the timers from tv up one level */
- struct timer_list *timer;
- struct hlist_node *tmp;
- struct hlist_head tv_list;
-
- hlist_move_list(tv->vec + index, &tv_list);
-
- /*
- * We are removing _all_ timers from the list, so we
- * don't have to detach them individually.
- */
- hlist_for_each_entry_safe(timer, tmp, &tv_list, entry) {
- /* No accounting, while moving them */
- __internal_add_timer(base, timer);
- }
-
- return index;
-}
-
static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
unsigned long data)
{
@@ -1248,149 +1358,144 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
}
}
-#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
-
-/**
- * __run_timers - run all expired timers (if any) on this CPU.
- * @base: the timer vector to be processed.
- *
- * This function cascades all vectors and executes all expired timer
- * vectors.
- */
-static inline void __run_timers(struct tvec_base *base)
+static void expire_timers(struct timer_base *base, struct hlist_head *head)
{
- struct timer_list *timer;
+ while (!hlist_empty(head)) {
+ struct timer_list *timer;
+ void (*fn)(unsigned long);
+ unsigned long data;
- spin_lock_irq(&base->lock);
+ timer = hlist_entry(head->first, struct timer_list, entry);
+ timer_stats_account_timer(timer);
- while (time_after_eq(jiffies, base->timer_jiffies)) {
- struct hlist_head work_list;
- struct hlist_head *head = &work_list;
- int index;
+ base->running_timer = timer;
+ detach_timer(timer, true);
- if (!base->all_timers) {
- base->timer_jiffies = jiffies;
- break;
- }
+ fn = timer->function;
+ data = timer->data;
- index = base->timer_jiffies & TVR_MASK;
-
- /*
- * Cascade timers:
- */
- if (!index &&
- (!cascade(base, &base->tv2, INDEX(0))) &&
- (!cascade(base, &base->tv3, INDEX(1))) &&
- !cascade(base, &base->tv4, INDEX(2)))
- cascade(base, &base->tv5, INDEX(3));
- ++base->timer_jiffies;
- hlist_move_list(base->tv1.vec + index, head);
- while (!hlist_empty(head)) {
- void (*fn)(unsigned long);
- unsigned long data;
- bool irqsafe;
-
- timer = hlist_entry(head->first, struct timer_list, entry);
- fn = timer->function;
- data = timer->data;
- irqsafe = timer->flags & TIMER_IRQSAFE;
-
- timer_stats_account_timer(timer);
-
- base->running_timer = timer;
- detach_expired_timer(timer, base);
-
- if (irqsafe) {
- spin_unlock(&base->lock);
- call_timer_fn(timer, fn, data);
- base->running_timer = NULL;
- spin_lock(&base->lock);
- } else {
- spin_unlock_irq(&base->lock);
- call_timer_fn(timer, fn, data);
- base->running_timer = NULL;
- spin_lock_irq(&base->lock);
- }
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT_FULL) &&
+ timer->flags & TIMER_IRQSAFE) {
+ raw_spin_unlock(&base->lock);
+ call_timer_fn(timer, fn, data);
+ base->running_timer = NULL;
+ raw_spin_lock(&base->lock);
+ } else {
+ raw_spin_unlock_irq(&base->lock);
+ call_timer_fn(timer, fn, data);
+ base->running_timer = NULL;
+ raw_spin_lock_irq(&base->lock);
}
}
- spin_unlock_irq(&base->lock);
- wakeup_timer_waiters(base);
+}
+
+static int __collect_expired_timers(struct timer_base *base,
+ struct hlist_head *heads)
+{
+ unsigned long clk = base->clk;
+ struct hlist_head *vec;
+ int i, levels = 0;
+ unsigned int idx;
+
+ for (i = 0; i < LVL_DEPTH; i++) {
+ idx = (clk & LVL_MASK) + i * LVL_SIZE;
+
+ if (__test_and_clear_bit(idx, base->pending_map)) {
+ vec = base->vectors + idx;
+ hlist_move_list(vec, heads++);
+ levels++;
+ }
+ /* Is it time to look at the next level? */
+ if (clk & LVL_CLK_MASK)
+ break;
+ /* Shift clock for the next level granularity */
+ clk >>= LVL_CLK_SHIFT;
+ }
+ return levels;
}
#ifdef CONFIG_NO_HZ_COMMON
/*
- * Find out when the next timer event is due to happen. This
- * is used on S/390 to stop all activity when a CPU is idle.
- * This function needs to be called with interrupts disabled.
+ * Find the next pending bucket of a level. Search from level start (@offset)
+ * + @clk upwards and if nothing there, search from start of the level
+ * (@offset) up to @offset + clk.
*/
-static unsigned long __next_timer_interrupt(struct tvec_base *base)
+static int next_pending_bucket(struct timer_base *base, unsigned offset,
+ unsigned clk)
{
- unsigned long timer_jiffies = base->timer_jiffies;
- unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
- int index, slot, array, found = 0;
- struct timer_list *nte;
- struct tvec *varray[4];
+ unsigned pos, start = offset + clk;
+ unsigned end = offset + LVL_SIZE;
- /* Look for timer events in tv1. */
- index = slot = timer_jiffies & TVR_MASK;
- do {
- hlist_for_each_entry(nte, base->tv1.vec + slot, entry) {
- if (nte->flags & TIMER_DEFERRABLE)
- continue;
+ pos = find_next_bit(base->pending_map, end, start);
+ if (pos < end)
+ return pos - start;
- found = 1;
- expires = nte->expires;
- /* Look at the cascade bucket(s)? */
- if (!index || slot < index)
- goto cascade;
- return expires;
+ pos = find_next_bit(base->pending_map, start, offset);
+ return pos < start ? pos + LVL_SIZE - start : -1;
+}
+
+/*
+ * Search the first expiring timer in the various clock levels. Caller must
+ * hold base->lock.
+ */
+static unsigned long __next_timer_interrupt(struct timer_base *base)
+{
+ unsigned long clk, next, adj;
+ unsigned lvl, offset = 0;
+
+ next = base->clk + NEXT_TIMER_MAX_DELTA;
+ clk = base->clk;
+ for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) {
+ int pos = next_pending_bucket(base, offset, clk & LVL_MASK);
+
+ if (pos >= 0) {
+ unsigned long tmp = clk + (unsigned long) pos;
+
+ tmp <<= LVL_SHIFT(lvl);
+ if (time_before(tmp, next))
+ next = tmp;
}
- slot = (slot + 1) & TVR_MASK;
- } while (slot != index);
-
-cascade:
- /* Calculate the next cascade event */
- if (index)
- timer_jiffies += TVR_SIZE - index;
- timer_jiffies >>= TVR_BITS;
-
- /* Check tv2-tv5. */
- varray[0] = &base->tv2;
- varray[1] = &base->tv3;
- varray[2] = &base->tv4;
- varray[3] = &base->tv5;
-
- for (array = 0; array < 4; array++) {
- struct tvec *varp = varray[array];
-
- index = slot = timer_jiffies & TVN_MASK;
- do {
- hlist_for_each_entry(nte, varp->vec + slot, entry) {
- if (nte->flags & TIMER_DEFERRABLE)
- continue;
-
- found = 1;
- if (time_before(nte->expires, expires))
- expires = nte->expires;
- }
- /*
- * Do we still search for the first timer or are
- * we looking up the cascade buckets ?
- */
- if (found) {
- /* Look at the cascade bucket(s)? */
- if (!index || slot < index)
- break;
- return expires;
- }
- slot = (slot + 1) & TVN_MASK;
- } while (slot != index);
-
- if (index)
- timer_jiffies += TVN_SIZE - index;
- timer_jiffies >>= TVN_BITS;
+ /*
+ * Clock for the next level. If the current level clock lower
+ * bits are zero, we look at the next level as is. If not we
+ * need to advance it by one because that's going to be the
+ * next expiring bucket in that level. base->clk is the next
+ * expiring jiffie. So in case of:
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+ * 0 0 0 0 0 0
+ *
+ * we have to look at all levels @index 0. With
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+ * 0 0 0 0 0 2
+ *
+ * LVL0 has the next expiring bucket @index 2. The upper
+ * levels have the next expiring bucket @index 1.
+ *
+ * In case that the propagation wraps the next level the same
+ * rules apply:
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+ * 0 0 0 0 F 2
+ *
+ * So after looking at LVL0 we get:
+ *
+ * LVL5 LVL4 LVL3 LVL2 LVL1
+ * 0 0 0 1 0
+ *
+ * So no propagation from LVL1 to LVL2 because that happened
+ * with the add already, but then we need to propagate further
+ * from LVL2 to LVL3.
+ *
+ * So the simple check whether the lower bits of the current
+ * level are 0 or not is sufficient for all cases.
+ */
+ adj = clk & LVL_CLK_MASK ? 1 : 0;
+ clk >>= LVL_CLK_SHIFT;
+ clk += adj;
}
- return expires;
+ return next;
}
/*
@@ -1436,7 +1541,7 @@ static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
*/
u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
{
- struct tvec_base *base = this_cpu_ptr(&tvec_bases);
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
u64 expires = KTIME_MAX;
unsigned long nextevt;
@@ -1447,28 +1552,81 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
if (cpu_is_offline(smp_processor_id()))
return expires;
-#ifdef CONFIG_PREEMPT_RT_FULL
+ raw_spin_lock(&base->lock);
+ nextevt = __next_timer_interrupt(base);
+ base->next_expiry = nextevt;
/*
- * On PREEMPT_RT we cannot sleep here. As a result we can't take
- * the base lock to check when the next timer is pending and so
- * we assume the next jiffy.
+ * We have a fresh next event. Check whether we can forward the base.
*/
- return basem + TICK_NSEC;
-#endif
- spin_lock(&base->lock);
- if (base->active_timers) {
- if (time_before_eq(base->next_timer, base->timer_jiffies))
- base->next_timer = __next_timer_interrupt(base);
- nextevt = base->next_timer;
- if (time_before_eq(nextevt, basej))
- expires = basem;
- else
- expires = basem + (nextevt - basej) * TICK_NSEC;
+ if (time_after(nextevt, jiffies))
+ base->clk = jiffies;
+ else if (time_after(nextevt, base->clk))
+ base->clk = nextevt;
+
+ if (time_before_eq(nextevt, basej)) {
+ expires = basem;
+ base->is_idle = false;
+ } else {
+ expires = basem + (nextevt - basej) * TICK_NSEC;
+ /*
+ * If we expect to sleep more than a tick, mark the base idle.
+ */
+ if ((expires - basem) > TICK_NSEC)
+ base->is_idle = true;
}
- spin_unlock(&base->lock);
+ raw_spin_unlock(&base->lock);
return cmp_next_hrtimer_event(basem, expires);
}
+
+/**
+ * timer_clear_idle - Clear the idle state of the timer base
+ *
+ * Called with interrupts disabled
+ */
+void timer_clear_idle(void)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+ /*
+ * We do this unlocked. The worst outcome is a remote enqueue sending
+ * a pointless IPI, but taking the lock would just make the window for
+ * sending the IPI a few instructions smaller for the cost of taking
+ * the lock in the exit from idle path.
+ */
+ base->is_idle = false;
+}
+
+static int collect_expired_timers(struct timer_base *base,
+ struct hlist_head *heads)
+{
+ /*
+ * NOHZ optimization. After a long idle sleep we need to forward the
+ * base to current jiffies. Avoid a loop by searching the bitfield for
+ * the next expiring timer.
+ */
+ if ((long)(jiffies - base->clk) > 2) {
+ unsigned long next = __next_timer_interrupt(base);
+
+ /*
+ * If the next timer is ahead of time forward to current
+ * jiffies, otherwise forward to the next expiry time.
+ */
+ if (time_after(next, jiffies)) {
+ /* The call site will increment clock! */
+ base->clk = jiffies - 1;
+ return 0;
+ }
+ base->clk = next;
+ }
+ return __collect_expired_timers(base, heads);
+}
+#else
+static inline int collect_expired_timers(struct timer_base *base,
+ struct hlist_head *heads)
+{
+ return __collect_expired_timers(base, heads);
+}
#endif
/*
@@ -1491,17 +1649,44 @@ void update_process_times(int user_tick)
run_posix_cpu_timers(p);
}
+/**
+ * __run_timers - run all expired timers (if any) on this CPU.
+ * @base: the timer vector to be processed.
+ */
+static inline void __run_timers(struct timer_base *base)
+{
+ struct hlist_head heads[LVL_DEPTH];
+ int levels;
+
+ if (!time_after_eq(jiffies, base->clk))
+ return;
+
+ raw_spin_lock_irq(&base->lock);
+
+ while (time_after_eq(jiffies, base->clk)) {
+
+ levels = collect_expired_timers(base, heads);
+ base->clk++;
+
+ while (levels--)
+ expire_timers(base, heads + levels);
+ }
+ raw_spin_unlock_irq(&base->lock);
+ wakeup_timer_waiters(base);
+}
+
/*
* This function runs timers and the timer-tq in bottom half context.
*/
static void run_timer_softirq(struct softirq_action *h)
{
- struct tvec_base *base = this_cpu_ptr(&tvec_bases);
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
irq_work_tick_soft();
- if (time_after_eq(jiffies, base->timer_jiffies))
- __run_timers(base);
+ __run_timers(base);
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active)
+ __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
}
/*
@@ -1509,7 +1694,18 @@ static void run_timer_softirq(struct softirq_action *h)
*/
void run_local_timers(void)
{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
hrtimer_run_queues();
+ /* Raise the softirq only if required. */
+ if (time_before(jiffies, base->clk)) {
+ if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active)
+ return;
+ /* CPU is awake, so check the deferrable base. */
+ base++;
+ if (time_before(jiffies, base->clk))
+ return;
+ }
raise_softirq(TIMER_SOFTIRQ);
}
@@ -1594,7 +1790,7 @@ signed long __sched schedule_timeout(signed long timeout)
expire = timeout + jiffies;
setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
- __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
+ __mod_timer(&timer, expire, false);
schedule();
del_singleshot_timer_sync(&timer);
@@ -1645,14 +1841,13 @@ signed long __sched schedule_timeout_idle(signed long timeout)
EXPORT_SYMBOL(schedule_timeout_idle);
#ifdef CONFIG_HOTPLUG_CPU
-static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *head)
+static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *head)
{
struct timer_list *timer;
int cpu = new_base->cpu;
while (!hlist_empty(head)) {
timer = hlist_entry(head->first, struct timer_list, entry);
- /* We ignore the accounting on the dying cpu */
detach_timer(timer, false);
timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu;
internal_add_timer(new_base, timer);
@@ -1661,37 +1856,31 @@ static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *he
static void migrate_timers(int cpu)
{
- struct tvec_base *old_base;
- struct tvec_base *new_base;
- int i;
+ struct timer_base *old_base;
+ struct timer_base *new_base;
+ int b, i;
BUG_ON(cpu_online(cpu));
- old_base = per_cpu_ptr(&tvec_bases, cpu);
- new_base = get_local_ptr(&tvec_bases);
- /*
- * The caller is globally serialized and nobody else
- * takes two locks at once, deadlock is not possible.
- */
- spin_lock_irq(&new_base->lock);
- spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
- BUG_ON(old_base->running_timer);
+ for (b = 0; b < NR_BASES; b++) {
+ old_base = per_cpu_ptr(&timer_bases[b], cpu);
+ new_base = get_cpu_ptr(&timer_bases[b]);
+ /*
+ * The caller is globally serialized and nobody else
+ * takes two locks at once, deadlock is not possible.
+ */
+ raw_spin_lock_irq(&new_base->lock);
+ raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
- for (i = 0; i < TVR_SIZE; i++)
- migrate_timer_list(new_base, old_base->tv1.vec + i);
- for (i = 0; i < TVN_SIZE; i++) {
- migrate_timer_list(new_base, old_base->tv2.vec + i);
- migrate_timer_list(new_base, old_base->tv3.vec + i);
- migrate_timer_list(new_base, old_base->tv4.vec + i);
- migrate_timer_list(new_base, old_base->tv5.vec + i);
+ BUG_ON(old_base->running_timer);
+
+ for (i = 0; i < WHEEL_SIZE; i++)
+ migrate_timer_list(new_base, old_base->vectors + i);
+
+ raw_spin_unlock(&old_base->lock);
+ raw_spin_unlock_irq(&new_base->lock);
+ put_cpu_ptr(&timer_bases);
}
-
- old_base->active_timers = 0;
- old_base->all_timers = 0;
-
- spin_unlock(&old_base->lock);
- spin_unlock_irq(&new_base->lock);
- put_local_ptr(&tvec_bases);
}
static int timer_cpu_notify(struct notifier_block *self,
@@ -1719,16 +1908,18 @@ static inline void timer_register_cpu_notifier(void) { }
static void __init init_timer_cpu(int cpu)
{
- struct tvec_base *base = per_cpu_ptr(&tvec_bases, cpu);
+ struct timer_base *base;
+ int i;
- base->cpu = cpu;
- spin_lock_init(&base->lock);
+ for (i = 0; i < NR_BASES; i++) {
+ base = per_cpu_ptr(&timer_bases[i], cpu);
+ base->cpu = cpu;
+ raw_spin_lock_init(&base->lock);
+ base->clk = jiffies;
#ifdef CONFIG_PREEMPT_RT_FULL
- init_waitqueue_head(&base->wait_for_running_timer);
+ init_swait_queue_head(&base->wait_for_running_timer);
#endif
-
- base->timer_jiffies = jiffies;
- base->next_timer = base->timer_jiffies;
+ }
}
static void __init init_timer_cpus(void)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 90b40cf6ec98..72a4cf8dbef5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -245,7 +245,15 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
return NULL;
local_save_flags(fbuffer->flags);
- fbuffer->pc = event_preempt_count();
+ fbuffer->pc = preempt_count();
+ /*
+ * If CONFIG_PREEMPT is enabled, then the tracepoint itself disables
+ * preemption (adding one to the preempt_count). Since we are
+ * interested in the preempt_count at the time the tracepoint was
+ * hit, we need to subtract one to offset the increment.
+ */
+ if (IS_ENABLED(CONFIG_PREEMPT))
+ fbuffer->pc--;
fbuffer->trace_file = trace_file;
fbuffer->event =
diff --git a/lib/random32.c b/lib/random32.c
index 510d1ce7d4d2..69ed593aab07 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -233,7 +233,6 @@ static void __prandom_timer(unsigned long dontcare)
static void __init __prandom_start_seed_timer(void)
{
- set_timer_slack(&seed_timer, HZ);
seed_timer.expires = jiffies + msecs_to_jiffies(40 * MSEC_PER_SEC);
add_timer(&seed_timer);
}
diff --git a/localversion-rt b/localversion-rt
index 045478966e9f..700c857efd9b 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt7
+-rt8
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index bc5196ea1bdf..fc646aa7fad7 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -603,7 +603,7 @@ static void reqsk_timer_handler(unsigned long data)
if (req->num_timeout++ == 0)
atomic_dec(&queue->young);
timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
- mod_timer_pinned(&req->rsk_timer, jiffies + timeo);
+ mod_timer(&req->rsk_timer, jiffies + timeo);
return;
}
drop:
@@ -617,8 +617,9 @@ static void reqsk_queue_hash_req(struct request_sock *req,
req->num_timeout = 0;
req->sk = NULL;
- setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req);
- mod_timer_pinned(&req->rsk_timer, jiffies + timeout);
+ setup_pinned_timer(&req->rsk_timer, reqsk_timer_handler,
+ (unsigned long)req);
+ mod_timer(&req->rsk_timer, jiffies + timeout);
inet_ehash_insert(req_to_sk(req), NULL);
/* before letting lookups find us, make sure all req fields
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index c67f9bd7699c..dfb6286f2e49 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -188,7 +188,8 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
tw->tw_prot = sk->sk_prot_creator;
atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));
twsk_net_set(tw, sock_net(sk));
- setup_timer(&tw->tw_timer, tw_timer_handler, (unsigned long)tw);
+ setup_pinned_timer(&tw->tw_timer, tw_timer_handler,
+ (unsigned long)tw);
/*
* Because we use RCU lookups, we should not set tw_refcnt
* to a non null value before everything is setup for this
@@ -248,7 +249,7 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
tw->tw_kill = timeo <= 4*HZ;
if (!rearm) {
- BUG_ON(mod_timer_pinned(&tw->tw_timer, jiffies + timeo));
+ BUG_ON(mod_timer(&tw->tw_timer, jiffies + timeo));
atomic_inc(&tw->tw_dr->tw_count);
} else {
mod_timer_pending(&tw->tw_timer, jiffies + timeo);
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