[PATCH] kill __init_timer_base in favor of boot_tvec_bases

From: Oleg Nesterov
Date: Fri Mar 24 2006 - 15:22:19 EST

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This patch
[PATCH] tvec_bases too large for per-cpu data
http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=a4a6198b80cf82eb8160603c98da218d1bd5e104

introduced "struct tvec_t_base_s boot_tvec_bases" which is visible
at compile time. This means we can kill __init_timer_base and move
timer_base_s's content into tvec_t_base_s.

include/linux/timer.h | 8 ++--
kernel/timer.c | 84 ++++++++++++++++++++------------------------------
2 files changed, 39 insertions(+), 53 deletions(-)

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

--- MM/include/linux/timer.h~TIMER 2006-03-23 22:48:10.000000000 +0300
+++ MM/include/linux/timer.h 2006-03-25 01:23:14.000000000 +0300
@@ -6,7 +6,7 @@
#include <linux/spinlock.h>
#include <linux/stddef.h>

-struct timer_base_s;
+struct tvec_t_base_s;

struct timer_list {
struct list_head entry;
@@ -15,16 +15,16 @@ struct timer_list {
void (*function)(unsigned long);
unsigned long data;

- struct timer_base_s *base;
+ struct tvec_t_base_s *base;
};

-extern struct timer_base_s __init_timer_base;
+extern struct tvec_t_base_s boot_tvec_bases;

#define TIMER_INITIALIZER(_function, _expires, _data) { \
.function = (_function), \
.expires = (_expires), \
.data = (_data), \
- .base = &__init_timer_base, \
+ .base = &boot_tvec_bases, \
}

#define DEFINE_TIMER(_name, _function, _expires, _data) \
--- MM/kernel/timer.c~TIMER 2006-03-23 22:48:10.000000000 +0300
+++ MM/kernel/timer.c 2006-03-25 01:37:29.000000000 +0300
@@ -54,7 +54,6 @@ EXPORT_SYMBOL(jiffies_64);
/*
* per-CPU timer vector definitions:
*/
-
#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
#define TVN_SIZE (1 << TVN_BITS)
@@ -62,11 +61,6 @@ EXPORT_SYMBOL(jiffies_64);
#define TVN_MASK (TVN_SIZE - 1)
#define TVR_MASK (TVR_SIZE - 1)

-struct timer_base_s {
- spinlock_t lock;
- struct timer_list *running_timer;
-};
-
typedef struct tvec_s {
struct list_head vec[TVN_SIZE];
} tvec_t;
@@ -76,7 +70,8 @@ typedef struct tvec_root_s {
} tvec_root_t;

struct tvec_t_base_s {
- struct timer_base_s t_base;
+ spinlock_t lock;
+ struct timer_list *running_timer;
unsigned long timer_jiffies;
tvec_root_t tv1;
tvec_t tv2;
@@ -87,13 +82,14 @@ struct tvec_t_base_s {

typedef struct tvec_t_base_s tvec_base_t;
static DEFINE_PER_CPU(tvec_base_t *, tvec_bases);
-static tvec_base_t boot_tvec_bases;
+tvec_base_t boot_tvec_bases;
+EXPORT_SYMBOL(boot_tvec_bases);

static inline void set_running_timer(tvec_base_t *base,
struct timer_list *timer)
{
#ifdef CONFIG_SMP
- base->t_base.running_timer = timer;
+ base->running_timer = timer;
#endif
}

@@ -139,15 +135,6 @@ static void internal_add_timer(tvec_base
list_add_tail(&timer->entry, vec);
}

-typedef struct timer_base_s timer_base_t;
-/*
- * Used by TIMER_INITIALIZER, we can't use per_cpu(tvec_bases)
- * at compile time, and we need timer->base to lock the timer.
- */
-timer_base_t __init_timer_base
- ____cacheline_aligned_in_smp = { .lock = SPIN_LOCK_UNLOCKED };
-EXPORT_SYMBOL(__init_timer_base);
-
/***
* init_timer - initialize a timer.
* @timer: the timer to be initialized
@@ -158,7 +145,7 @@ EXPORT_SYMBOL(__init_timer_base);
void fastcall init_timer(struct timer_list *timer)
{
timer->entry.next = NULL;
- timer->base = &per_cpu(tvec_bases, raw_smp_processor_id())->t_base;
+ timer->base = per_cpu(tvec_bases, raw_smp_processor_id());
}
EXPORT_SYMBOL(init_timer);

@@ -174,7 +161,7 @@ static inline void detach_timer(struct t
}

/*
- * We are using hashed locking: holding per_cpu(tvec_bases).t_base.lock
+ * 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.
*
@@ -185,10 +172,10 @@ static inline void detach_timer(struct t
* possible to set timer->base = NULL and drop the lock: the timer remains
* locked.
*/
-static timer_base_t *lock_timer_base(struct timer_list *timer,
+static tvec_base_t *lock_timer_base(struct timer_list *timer,
unsigned long *flags)
{
- timer_base_t *base;
+ tvec_base_t *base;

for (;;) {
base = timer->base;
@@ -205,8 +192,7 @@ static timer_base_t *lock_timer_base(str

int __mod_timer(struct timer_list *timer, unsigned long expires)
{
- timer_base_t *base;
- tvec_base_t *new_base;
+ tvec_base_t *base, *new_base;
unsigned long flags;
int ret = 0;

@@ -221,7 +207,7 @@ int __mod_timer(struct timer_list *timer

new_base = __get_cpu_var(tvec_bases);

- if (base != &new_base->t_base) {
+ if (base != new_base) {
/*
* We are trying to schedule the timer on the local CPU.
* However we can't change timer's base while it is running,
@@ -231,19 +217,19 @@ int __mod_timer(struct timer_list *timer
*/
if (unlikely(base->running_timer == timer)) {
/* The timer remains on a former base */
- new_base = container_of(base, tvec_base_t, t_base);
+ new_base = base;
} else {
/* See the comment in lock_timer_base() */
timer->base = NULL;
spin_unlock(&base->lock);
- spin_lock(&new_base->t_base.lock);
- timer->base = &new_base->t_base;
+ spin_lock(&new_base->lock);
+ timer->base = new_base;
}
}

timer->expires = expires;
internal_add_timer(new_base, timer);
- spin_unlock_irqrestore(&new_base->t_base.lock, flags);
+ spin_unlock_irqrestore(&new_base->lock, flags);

return ret;
}
@@ -263,10 +249,10 @@ void add_timer_on(struct timer_list *tim
unsigned long flags;

BUG_ON(timer_pending(timer) || !timer->function);
- spin_lock_irqsave(&base->t_base.lock, flags);
- timer->base = &base->t_base;
+ spin_lock_irqsave(&base->lock, flags);
+ timer->base = base;
internal_add_timer(base, timer);
- spin_unlock_irqrestore(&base->t_base.lock, flags);
+ spin_unlock_irqrestore(&base->lock, flags);
}

@@ -319,7 +305,7 @@ EXPORT_SYMBOL(mod_timer);
*/
int del_timer(struct timer_list *timer)
{
- timer_base_t *base;
+ tvec_base_t *base;
unsigned long flags;
int ret = 0;

@@ -346,7 +332,7 @@ EXPORT_SYMBOL(del_timer);
*/
int try_to_del_timer_sync(struct timer_list *timer)
{
- timer_base_t *base;
+ tvec_base_t *base;
unsigned long flags;
int ret = -1;

@@ -410,7 +396,7 @@ static int cascade(tvec_base_t *base, tv
struct timer_list *tmp;

tmp = list_entry(curr, struct timer_list, entry);
- BUG_ON(tmp->base != &base->t_base);
+ BUG_ON(tmp->base != base);
curr = curr->next;
internal_add_timer(base, tmp);
}
@@ -432,7 +418,7 @@ static inline void __run_timers(tvec_bas
{
struct timer_list *timer;

- spin_lock_irq(&base->t_base.lock);
+ spin_lock_irq(&base->lock);
while (time_after_eq(jiffies, base->timer_jiffies)) {
struct list_head work_list = LIST_HEAD_INIT(work_list);
struct list_head *head = &work_list;
@@ -458,7 +444,7 @@ static inline void __run_timers(tvec_bas

set_running_timer(base, timer);
detach_timer(timer, 1);
- spin_unlock_irq(&base->t_base.lock);
+ spin_unlock_irq(&base->lock);
{
int preempt_count = preempt_count();
fn(data);
@@ -471,11 +457,11 @@ static inline void __run_timers(tvec_bas
BUG();
}
}
- spin_lock_irq(&base->t_base.lock);
+ spin_lock_irq(&base->lock);
}
}
set_running_timer(base, NULL);
- spin_unlock_irq(&base->t_base.lock);
+ spin_unlock_irq(&base->lock);
}

#ifdef CONFIG_NO_IDLE_HZ
@@ -506,7 +492,7 @@ unsigned long next_timer_interrupt(void)
hr_expires += jiffies;

base = __get_cpu_var(tvec_bases);
- spin_lock(&base->t_base.lock);
+ spin_lock(&base->lock);
expires = base->timer_jiffies + (LONG_MAX >> 1);
list = NULL;

@@ -554,7 +540,7 @@ found:
expires = nte->expires;
}
}
- spin_unlock(&base->t_base.lock);
+ spin_unlock(&base->lock);

if (time_before(hr_expires, expires))
return hr_expires;
@@ -1530,7 +1516,7 @@ static int __devinit init_timers_cpu(int
}
per_cpu(tvec_bases, cpu) = base;
}
- spin_lock_init(&base->t_base.lock);
+ spin_lock_init(&base->lock);
for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j);
INIT_LIST_HEAD(base->tv4.vec + j);
@@ -1552,7 +1538,7 @@ static void migrate_timer_list(tvec_base
while (!list_empty(head)) {
timer = list_entry(head->next, struct timer_list, entry);
detach_timer(timer, 0);
- timer->base = &new_base->t_base;
+ timer->base = new_base;
internal_add_timer(new_base, timer);
}
}
@@ -1568,11 +1554,11 @@ static void __devinit migrate_timers(int
new_base = get_cpu_var(tvec_bases);

local_irq_disable();
- spin_lock(&new_base->t_base.lock);
- spin_lock(&old_base->t_base.lock);
+ spin_lock(&new_base->lock);
+ spin_lock(&old_base->lock);
+
+ BUG_ON(old_base->running_timer);

- if (old_base->t_base.running_timer)
- BUG();
for (i = 0; i < TVR_SIZE; i++)
migrate_timer_list(new_base, old_base->tv1.vec + i);
for (i = 0; i < TVN_SIZE; i++) {
@@ -1582,8 +1568,8 @@ static void __devinit migrate_timers(int
migrate_timer_list(new_base, old_base->tv5.vec + i);
}

- spin_unlock(&old_base->t_base.lock);
- spin_unlock(&new_base->t_base.lock);
+ spin_unlock(&old_base->lock);
+ spin_unlock(&new_base->lock);
local_irq_enable();
put_cpu_var(tvec_bases);
}
-
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Next message: James Morris: "Re: [RFC][PATCH 1/2] Virtualization of UTS"
Previous message: mchehab: "[PATCH 00/29] V4L/DVB updates"
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