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[PATCH] tvec_bases too large for per-cpu data

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With internal Xen-enabled kernels we see the kernel's static per-cpu data
area exceed the limit of 32k on x86-64, and even native x86-64 kernels get
fairly close to that limit.  I generally question whether it is reasonable
to have data structures several kb in size allocated as per-cpu data when
the space there is rather limited.

The biggest arch-independent consumer is tvec_bases (over 4k on 32-bit
archs, over 8k on 64-bit ones), which now gets converted to use dynamically
allocated memory instead.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jan Beulich 2006-03-24 03:15:54 -08:00 committed by Linus Torvalds
parent c98d8cfbc6
commit a4a6198b80
1 changed files with 34 additions and 11 deletions
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45
kernel/timer.c
View file

@ -86,7 +86,8 @@ struct tvec_t_base_s {
} ____cacheline_aligned_in_smp; } ____cacheline_aligned_in_smp;
typedef struct tvec_t_base_s tvec_base_t; typedef struct tvec_t_base_s tvec_base_t;
static DEFINE_PER_CPU(tvec_base_t, tvec_bases); static DEFINE_PER_CPU(tvec_base_t *, tvec_bases);
static tvec_base_t boot_tvec_bases;
static inline void set_running_timer(tvec_base_t *base, static inline void set_running_timer(tvec_base_t *base,
struct timer_list *timer) struct timer_list *timer)
@ -157,7 +158,7 @@ EXPORT_SYMBOL(__init_timer_base);
void fastcall init_timer(struct timer_list *timer) void fastcall init_timer(struct timer_list *timer)
{ {
timer->entry.next = NULL; 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())->t_base;
} }
EXPORT_SYMBOL(init_timer); EXPORT_SYMBOL(init_timer);
@ -218,7 +219,7 @@ int __mod_timer(struct timer_list *timer, unsigned long expires)
ret = 1; ret = 1;
} }
new_base = &__get_cpu_var(tvec_bases); new_base = __get_cpu_var(tvec_bases);
if (base != &new_base->t_base) { if (base != &new_base->t_base) {
/* /*
@ -258,7 +259,7 @@ EXPORT_SYMBOL(__mod_timer);
*/ */
void add_timer_on(struct timer_list *timer, int cpu) void add_timer_on(struct timer_list *timer, int cpu)
{ {
tvec_base_t *base = &per_cpu(tvec_bases, cpu); tvec_base_t *base = per_cpu(tvec_bases, cpu);
unsigned long flags; unsigned long flags;
BUG_ON(timer_pending(timer) || !timer->function); BUG_ON(timer_pending(timer) || !timer->function);
@ -504,7 +505,7 @@ unsigned long next_timer_interrupt(void)
} }
hr_expires += jiffies; hr_expires += jiffies;
base = &__get_cpu_var(tvec_bases); base = __get_cpu_var(tvec_bases);
spin_lock(&base->t_base.lock); spin_lock(&base->t_base.lock);
expires = base->timer_jiffies + (LONG_MAX >> 1); expires = base->timer_jiffies + (LONG_MAX >> 1);
list = NULL; list = NULL;
@ -901,7 +902,7 @@ EXPORT_SYMBOL(xtime_lock);
*/ */
static void run_timer_softirq(struct softirq_action *h) static void run_timer_softirq(struct softirq_action *h)
{ {
tvec_base_t *base = &__get_cpu_var(tvec_bases); tvec_base_t *base = __get_cpu_var(tvec_bases);
hrtimer_run_queues(); hrtimer_run_queues();
if (time_after_eq(jiffies, base->timer_jiffies)) if (time_after_eq(jiffies, base->timer_jiffies))
@ -1256,12 +1257,32 @@ asmlinkage long sys_sysinfo(struct sysinfo __user *info)
return 0; return 0;
} }
static void __devinit init_timers_cpu(int cpu) static int __devinit init_timers_cpu(int cpu)
{ {
int j; int j;
tvec_base_t *base; tvec_base_t *base;
base = &per_cpu(tvec_bases, cpu); base = per_cpu(tvec_bases, cpu);
if (!base) {
static char boot_done;
/*
* Cannot do allocation in init_timers as that runs before the
* allocator initializes (and would waste memory if there are
* more possible CPUs than will ever be installed/brought up).
*/
if (boot_done) {
base = kmalloc_node(sizeof(*base), GFP_KERNEL,
cpu_to_node(cpu));
if (!base)
return -ENOMEM;
memset(base, 0, sizeof(*base));
} else {
base = &boot_tvec_bases;
boot_done = 1;
}
per_cpu(tvec_bases, cpu) = base;
}
spin_lock_init(&base->t_base.lock); spin_lock_init(&base->t_base.lock);
for (j = 0; j < TVN_SIZE; j++) { for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j); INIT_LIST_HEAD(base->tv5.vec + j);
@ -1273,6 +1294,7 @@ static void __devinit init_timers_cpu(int cpu)
INIT_LIST_HEAD(base->tv1.vec + j); INIT_LIST_HEAD(base->tv1.vec + j);
base->timer_jiffies = jiffies; base->timer_jiffies = jiffies;
return 0;
} }
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
@ -1295,8 +1317,8 @@ static void __devinit migrate_timers(int cpu)
int i; int i;
BUG_ON(cpu_online(cpu)); BUG_ON(cpu_online(cpu));
old_base = &per_cpu(tvec_bases, cpu); old_base = per_cpu(tvec_bases, cpu);
new_base = &get_cpu_var(tvec_bases); new_base = get_cpu_var(tvec_bases);
local_irq_disable(); local_irq_disable();
spin_lock(&new_base->t_base.lock); spin_lock(&new_base->t_base.lock);
@ -1326,7 +1348,8 @@ static int __devinit timer_cpu_notify(struct notifier_block *self,
long cpu = (long)hcpu; long cpu = (long)hcpu;
switch(action) { switch(action) {
case CPU_UP_PREPARE: case CPU_UP_PREPARE:
init_timers_cpu(cpu); if (init_timers_cpu(cpu) < 0)
return NOTIFY_BAD;
break; break;
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD: case CPU_DEAD: