* + hrtimers-clean-up-locking.patch added to -mm tree
@ 2006-12-13 22:43 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2006-12-13 22:43 UTC (permalink / raw)
To: mm-commits; +Cc: tglx, akpm, mingo
The patch titled
hrtimers: clean up locking
has been added to the -mm tree. Its filename is
hrtimers-clean-up-locking.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: hrtimers: clean up locking
From: Thomas Gleixner <tglx@linutronix.de>
Improve kernel/hrtimers.c locking: use a per-CPU base with a lock to
control locking of all clocks belonging to a CPU. This simplifies code
that needs to lock all clocks at once. This makes life easier for
high-res timers and dyntick.
No functional changes.
[ optimization change from Andrew Morton <akpm@osdl.org> ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
include/linux/hrtimer.h | 43 +++++---
kernel/hrtimer.c | 184 ++++++++++++++++++++------------------
2 files changed, 126 insertions(+), 101 deletions(-)
diff -puN include/linux/hrtimer.h~hrtimers-clean-up-locking include/linux/hrtimer.h
--- a/include/linux/hrtimer.h~hrtimers-clean-up-locking
+++ a/include/linux/hrtimer.h
@@ -21,6 +21,9 @@
#include <linux/list.h>
#include <linux/wait.h>
+struct hrtimer_clock_base;
+struct hrtimer_cpu_base;
+
/*
* Mode arguments of xxx_hrtimer functions:
*/
@@ -37,8 +40,6 @@ enum hrtimer_restart {
HRTIMER_RESTART, /* Timer must be restarted */
};
-struct hrtimer_base;
-
/**
* struct hrtimer - the basic hrtimer structure
* @node: red black tree node for time ordered insertion
@@ -51,10 +52,10 @@ struct hrtimer_base;
* The hrtimer structure must be initialized by init_hrtimer_#CLOCKTYPE()
*/
struct hrtimer {
- struct rb_node node;
- ktime_t expires;
- enum hrtimer_restart (*function)(struct hrtimer *);
- struct hrtimer_base *base;
+ struct rb_node node;
+ ktime_t expires;
+ enum hrtimer_restart (*function)(struct hrtimer *);
+ struct hrtimer_clock_base *base;
};
/**
@@ -71,29 +72,41 @@ struct hrtimer_sleeper {
/**
* struct hrtimer_base - the timer base for a specific clock
- * @index: clock type index for per_cpu support when moving a timer
- * to a base on another cpu.
- * @lock: lock protecting the base and associated timers
+ * @index: clock type index for per_cpu support when moving a
+ * timer to a base on another cpu.
* @active: red black tree root node for the active timers
* @first: pointer to the timer node which expires first
* @resolution: the resolution of the clock, in nanoseconds
* @get_time: function to retrieve the current time of the clock
* @get_softirq_time: function to retrieve the current time from the softirq
- * @curr_timer: the timer which is executing a callback right now
* @softirq_time: the time when running the hrtimer queue in the softirq
- * @lock_key: the lock_class_key for use with lockdep
*/
-struct hrtimer_base {
+struct hrtimer_clock_base {
+ struct hrtimer_cpu_base *cpu_base;
clockid_t index;
- spinlock_t lock;
struct rb_root active;
struct rb_node *first;
ktime_t resolution;
ktime_t (*get_time)(void);
ktime_t (*get_softirq_time)(void);
- struct hrtimer *curr_timer;
ktime_t softirq_time;
- struct lock_class_key lock_key;
+};
+
+#define HRTIMER_MAX_CLOCK_BASES 2
+
+/*
+ * struct hrtimer_cpu_base - the per cpu clock bases
+ * @lock: lock protecting the base and associated clock bases
+ * and timers
+ * @lock_key: the lock_class_key for use with lockdep
+ * @clock_base: array of clock bases for this cpu
+ * @curr_timer: the timer which is executing a callback right now
+ */
+struct hrtimer_cpu_base {
+ spinlock_t lock;
+ struct lock_class_key lock_key;
+ struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
+ struct hrtimer *curr_timer;
};
/*
diff -puN kernel/hrtimer.c~hrtimers-clean-up-locking kernel/hrtimer.c
--- a/kernel/hrtimer.c~hrtimers-clean-up-locking
+++ a/kernel/hrtimer.c
@@ -1,8 +1,9 @@
/*
* linux/kernel/hrtimer.c
*
- * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
- * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
*
* High-resolution kernel timers
*
@@ -79,21 +80,22 @@ EXPORT_SYMBOL_GPL(ktime_get_real);
* This ensures that we capture erroneous accesses to these clock ids
* rather than moving them into the range of valid clock id's.
*/
-
-#define MAX_HRTIMER_BASES 2
-
-static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) =
+static DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
{
+
+ .clock_base =
{
- .index = CLOCK_REALTIME,
- .get_time = &ktime_get_real,
- .resolution = KTIME_REALTIME_RES,
- },
- {
- .index = CLOCK_MONOTONIC,
- .get_time = &ktime_get,
- .resolution = KTIME_MONOTONIC_RES,
- },
+ {
+ .index = CLOCK_REALTIME,
+ .get_time = &ktime_get_real,
+ .resolution = KTIME_REALTIME_RES,
+ },
+ {
+ .index = CLOCK_MONOTONIC,
+ .get_time = &ktime_get,
+ .resolution = KTIME_MONOTONIC_RES,
+ },
+ }
};
/**
@@ -125,7 +127,7 @@ EXPORT_SYMBOL_GPL(ktime_get_ts);
* Get the coarse grained time at the softirq based on xtime and
* wall_to_monotonic.
*/
-static void hrtimer_get_softirq_time(struct hrtimer_base *base)
+static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
{
ktime_t xtim, tomono;
unsigned long seq;
@@ -137,8 +139,9 @@ static void hrtimer_get_softirq_time(str
} while (read_seqretry(&xtime_lock, seq));
- base[CLOCK_REALTIME].softirq_time = xtim;
- base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono);
+ base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
+ base->clock_base[CLOCK_MONOTONIC].softirq_time =
+ ktime_add(xtim, tomono);
}
/*
@@ -161,19 +164,20 @@ static void hrtimer_get_softirq_time(str
* possible to set timer->base = NULL and drop the lock: the timer remains
* locked.
*/
-static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer,
- unsigned long *flags)
+static
+struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
+ unsigned long *flags)
{
- struct hrtimer_base *base;
+ struct hrtimer_clock_base *base;
for (;;) {
base = timer->base;
if (likely(base != NULL)) {
- spin_lock_irqsave(&base->lock, *flags);
+ spin_lock_irqsave(&base->cpu_base->lock, *flags);
if (likely(base == timer->base))
return base;
/* The timer has migrated to another CPU: */
- spin_unlock_irqrestore(&base->lock, *flags);
+ spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
}
cpu_relax();
}
@@ -182,12 +186,14 @@ static struct hrtimer_base *lock_hrtimer
/*
* Switch the timer base to the current CPU when possible.
*/
-static inline struct hrtimer_base *
-switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base)
+static inline struct hrtimer_clock_base *
+switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base)
{
- struct hrtimer_base *new_base;
+ struct hrtimer_clock_base *new_base;
+ struct hrtimer_cpu_base *new_cpu_base;
- new_base = &__get_cpu_var(hrtimer_bases)[base->index];
+ new_cpu_base = &__get_cpu_var(hrtimer_bases);
+ new_base = &new_cpu_base->clock_base[base->index];
if (base != new_base) {
/*
@@ -199,13 +205,13 @@ switch_hrtimer_base(struct hrtimer *time
* completed. There is no conflict as we hold the lock until
* the timer is enqueued.
*/
- if (unlikely(base->curr_timer == timer))
+ if (unlikely(base->cpu_base->curr_timer == timer))
return base;
/* See the comment in lock_timer_base() */
timer->base = NULL;
- spin_unlock(&base->lock);
- spin_lock(&new_base->lock);
+ spin_unlock(&base->cpu_base->lock);
+ spin_lock(&new_base->cpu_base->lock);
timer->base = new_base;
}
return new_base;
@@ -215,12 +221,12 @@ switch_hrtimer_base(struct hrtimer *time
#define set_curr_timer(b, t) do { } while (0)
-static inline struct hrtimer_base *
+static inline struct hrtimer_clock_base *
lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
- struct hrtimer_base *base = timer->base;
+ struct hrtimer_clock_base *base = timer->base;
- spin_lock_irqsave(&base->lock, *flags);
+ spin_lock_irqsave(&base->cpu_base->lock, *flags);
return base;
}
@@ -300,7 +306,7 @@ void hrtimer_notify_resume(void)
static inline
void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
- spin_unlock_irqrestore(&timer->base->lock, *flags);
+ spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
}
/**
@@ -350,7 +356,8 @@ hrtimer_forward(struct hrtimer *timer, k
* The timer is inserted in expiry order. Insertion into the
* red black tree is O(log(n)). Must hold the base lock.
*/
-static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+static void enqueue_hrtimer(struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
{
struct rb_node **link = &base->active.rb_node;
struct rb_node *parent = NULL;
@@ -389,7 +396,8 @@ static void enqueue_hrtimer(struct hrtim
*
* Caller must hold the base lock.
*/
-static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+static void __remove_hrtimer(struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
{
/*
* Remove the timer from the rbtree and replace the
@@ -405,7 +413,7 @@ static void __remove_hrtimer(struct hrti
* remove hrtimer, called with base lock held
*/
static inline int
-remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
{
if (hrtimer_active(timer)) {
__remove_hrtimer(timer, base);
@@ -427,7 +435,7 @@ remove_hrtimer(struct hrtimer *timer, st
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
- struct hrtimer_base *base, *new_base;
+ struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
int ret;
@@ -474,13 +482,13 @@ EXPORT_SYMBOL_GPL(hrtimer_start);
*/
int hrtimer_try_to_cancel(struct hrtimer *timer)
{
- struct hrtimer_base *base;
+ struct hrtimer_clock_base *base;
unsigned long flags;
int ret = -1;
base = lock_hrtimer_base(timer, &flags);
- if (base->curr_timer != timer)
+ if (base->cpu_base->curr_timer != timer)
ret = remove_hrtimer(timer, base);
unlock_hrtimer_base(timer, &flags);
@@ -516,12 +524,12 @@ EXPORT_SYMBOL_GPL(hrtimer_cancel);
*/
ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
{
- struct hrtimer_base *base;
+ struct hrtimer_clock_base *base;
unsigned long flags;
ktime_t rem;
base = lock_hrtimer_base(timer, &flags);
- rem = ktime_sub(timer->expires, timer->base->get_time());
+ rem = ktime_sub(timer->expires, base->get_time());
unlock_hrtimer_base(timer, &flags);
return rem;
@@ -537,26 +545,29 @@ EXPORT_SYMBOL_GPL(hrtimer_get_remaining)
*/
ktime_t hrtimer_get_next_event(void)
{
- struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+ struct hrtimer_clock_base *base = cpu_base->clock_base;
ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
unsigned long flags;
int i;
- for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
+ spin_lock_irqsave(&cpu_base->lock, flags);
+
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
struct hrtimer *timer;
- spin_lock_irqsave(&base->lock, flags);
- if (!base->first) {
- spin_unlock_irqrestore(&base->lock, flags);
+ if (!base->first)
continue;
- }
+
timer = rb_entry(base->first, struct hrtimer, node);
delta.tv64 = timer->expires.tv64;
- spin_unlock_irqrestore(&base->lock, flags);
delta = ktime_sub(delta, base->get_time());
if (delta.tv64 < mindelta.tv64)
mindelta.tv64 = delta.tv64;
}
+
+ spin_unlock_irqrestore(&cpu_base->lock, flags);
+
if (mindelta.tv64 < 0)
mindelta.tv64 = 0;
return mindelta;
@@ -572,16 +583,16 @@ ktime_t hrtimer_get_next_event(void)
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
enum hrtimer_mode mode)
{
- struct hrtimer_base *bases;
+ struct hrtimer_cpu_base *cpu_base;
memset(timer, 0, sizeof(struct hrtimer));
- bases = __raw_get_cpu_var(hrtimer_bases);
+ cpu_base = &__raw_get_cpu_var(hrtimer_bases);
if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
clock_id = CLOCK_MONOTONIC;
- timer->base = &bases[clock_id];
+ timer->base = &cpu_base->clock_base[clock_id];
rb_set_parent(&timer->node, &timer->node);
}
EXPORT_SYMBOL_GPL(hrtimer_init);
@@ -596,10 +607,10 @@ EXPORT_SYMBOL_GPL(hrtimer_init);
*/
int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
{
- struct hrtimer_base *bases;
+ struct hrtimer_cpu_base *cpu_base;
- bases = __raw_get_cpu_var(hrtimer_bases);
- *tp = ktime_to_timespec(bases[which_clock].resolution);
+ cpu_base = &__raw_get_cpu_var(hrtimer_bases);
+ *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);
return 0;
}
@@ -608,9 +619,11 @@ EXPORT_SYMBOL_GPL(hrtimer_get_res);
/*
* Expire the per base hrtimer-queue:
*/
-static inline void run_hrtimer_queue(struct hrtimer_base *base)
+static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
+ int index)
{
struct rb_node *node;
+ struct hrtimer_clock_base *base = &cpu_base->clock_base[index];
if (!base->first)
return;
@@ -618,7 +631,7 @@ static inline void run_hrtimer_queue(str
if (base->get_softirq_time)
base->softirq_time = base->get_softirq_time();
- spin_lock_irq(&base->lock);
+ spin_lock_irq(&cpu_base->lock);
while ((node = base->first)) {
struct hrtimer *timer;
@@ -630,21 +643,21 @@ static inline void run_hrtimer_queue(str
break;
fn = timer->function;
- set_curr_timer(base, timer);
+ set_curr_timer(cpu_base, timer);
__remove_hrtimer(timer, base);
- spin_unlock_irq(&base->lock);
+ spin_unlock_irq(&cpu_base->lock);
restart = fn(timer);
- spin_lock_irq(&base->lock);
+ spin_lock_irq(&cpu_base->lock);
if (restart != HRTIMER_NORESTART) {
BUG_ON(hrtimer_active(timer));
enqueue_hrtimer(timer, base);
}
}
- set_curr_timer(base, NULL);
- spin_unlock_irq(&base->lock);
+ set_curr_timer(cpu_base, NULL);
+ spin_unlock_irq(&cpu_base->lock);
}
/*
@@ -652,13 +665,13 @@ static inline void run_hrtimer_queue(str
*/
void hrtimer_run_queues(void)
{
- struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
int i;
- hrtimer_get_softirq_time(base);
+ hrtimer_get_softirq_time(cpu_base);
- for (i = 0; i < MAX_HRTIMER_BASES; i++)
- run_hrtimer_queue(&base[i]);
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
+ run_hrtimer_queue(cpu_base, i);
}
/*
@@ -787,19 +800,21 @@ sys_nanosleep(struct timespec __user *rq
*/
static void __devinit init_hrtimers_cpu(int cpu)
{
- struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu);
+ struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
int i;
- for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
- spin_lock_init(&base->lock);
- lockdep_set_class(&base->lock, &base->lock_key);
- }
+ spin_lock_init(&cpu_base->lock);
+ lockdep_set_class(&cpu_base->lock, &cpu_base->lock_key);
+
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
+ cpu_base->clock_base[i].cpu_base = cpu_base;
+
}
#ifdef CONFIG_HOTPLUG_CPU
-static void migrate_hrtimer_list(struct hrtimer_base *old_base,
- struct hrtimer_base *new_base)
+static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+ struct hrtimer_clock_base *new_base)
{
struct hrtimer *timer;
struct rb_node *node;
@@ -814,29 +829,26 @@ static void migrate_hrtimer_list(struct
static void migrate_hrtimers(int cpu)
{
- struct hrtimer_base *old_base, *new_base;
+ struct hrtimer_cpu_base *old_base, *new_base;
int i;
BUG_ON(cpu_online(cpu));
- old_base = per_cpu(hrtimer_bases, cpu);
- new_base = get_cpu_var(hrtimer_bases);
+ old_base = &per_cpu(hrtimer_bases, cpu);
+ new_base = &get_cpu_var(hrtimer_bases);
local_irq_disable();
- for (i = 0; i < MAX_HRTIMER_BASES; i++) {
-
- spin_lock(&new_base->lock);
- spin_lock(&old_base->lock);
+ spin_lock(&new_base->lock);
+ spin_lock(&old_base->lock);
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
BUG_ON(old_base->curr_timer);
- migrate_hrtimer_list(old_base, new_base);
-
- spin_unlock(&old_base->lock);
- spin_unlock(&new_base->lock);
- old_base++;
- new_base++;
+ migrate_hrtimer_list(&old_base->clock_base[i],
+ &new_base->clock_base[i]);
}
+ spin_unlock(&old_base->lock);
+ spin_unlock(&new_base->lock);
local_irq_enable();
put_cpu_var(hrtimer_bases);
_
Patches currently in -mm which might be from tglx@linutronix.de are
origin.patch
git-mtd.patch
gtod-uninline-jiffiesh.patch
gtod-fix-multiple-conversion-bugs-in-msecs_to_jiffies.patch
gtod-fix-timeout-overflow.patch
gtod-persistent-clock-support-core.patch
gtod-persistent-clock-support-i386.patch
dynticks-uninline-irq_enter.patch
dynticks-extend-next_timer_interrupt-to-use-a-reference-jiffie.patch
hrtimers-namespace-and-enum-cleanup.patch
hrtimers-clean-up-locking.patch
hrtimers-add-state-tracking.patch
hrtimers-clean-up-callback-tracking.patch
hrtimers-move-and-add-documentation.patch
acpi-include-fix.patch
acpi-keep-track-of-timer-broadcast.patch
acpi-add-state-propagation-for-dynamic-broadcasting.patch
acpi-cleanups-allow-early-access-to-pmtimer.patch
i386-apic-clean-up-the-apic-code.patch
clockevents-core.patch
clockevents-i386-drivers.patch
clockevents-i386-hpet-driver.patch
i386-apic-rework-and-fix-local-apic-calibration.patch
high-res-timers-core.patch
high-res-timers-core-do-itimer-rearming-in-process-context.patch
high-res-timers-allow-tsc-clocksource-if-pmtimer-present.patch
dynticks-core.patch
dynticks-add-nohz-stats-to-proc-stat.patch
dynticks-i386-support-idle-handler-callbacks.patch
dynticks-i386-prepare-nmi-watchdog.patch
high-res-timers-dynticks-i386-support-enable-in-kconfig.patch
debugging-feature-add-proc-timer_stat.patch
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2006-12-13 22:43 + hrtimers-clean-up-locking.patch added to -mm tree akpm
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