mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-26 05:20:53 +07:00
e8ced39d5e
Delayed allocation need to check free blocks at every write time. percpu_counter_read_positive() is not quit accurate. delayed allocation need a more accurate accounting, but using percpu_counter_sum_positive() is frequently is quite expensive. This patch added a new function to update center counter when sum per-cpu counter, to increase the accurate rate for next percpu_counter_read() and require less calling expensive percpu_counter_sum(). Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
152 lines
3.2 KiB
C
152 lines
3.2 KiB
C
/*
|
|
* Fast batching percpu counters.
|
|
*/
|
|
|
|
#include <linux/percpu_counter.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/init.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/module.h>
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static LIST_HEAD(percpu_counters);
|
|
static DEFINE_MUTEX(percpu_counters_lock);
|
|
#endif
|
|
|
|
void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
|
|
{
|
|
int cpu;
|
|
|
|
spin_lock(&fbc->lock);
|
|
for_each_possible_cpu(cpu) {
|
|
s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
|
|
*pcount = 0;
|
|
}
|
|
fbc->count = amount;
|
|
spin_unlock(&fbc->lock);
|
|
}
|
|
EXPORT_SYMBOL(percpu_counter_set);
|
|
|
|
void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
|
|
{
|
|
s64 count;
|
|
s32 *pcount;
|
|
int cpu = get_cpu();
|
|
|
|
pcount = per_cpu_ptr(fbc->counters, cpu);
|
|
count = *pcount + amount;
|
|
if (count >= batch || count <= -batch) {
|
|
spin_lock(&fbc->lock);
|
|
fbc->count += count;
|
|
*pcount = 0;
|
|
spin_unlock(&fbc->lock);
|
|
} else {
|
|
*pcount = count;
|
|
}
|
|
put_cpu();
|
|
}
|
|
EXPORT_SYMBOL(__percpu_counter_add);
|
|
|
|
/*
|
|
* Add up all the per-cpu counts, return the result. This is a more accurate
|
|
* but much slower version of percpu_counter_read_positive()
|
|
*/
|
|
s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
|
|
{
|
|
s64 ret;
|
|
int cpu;
|
|
|
|
spin_lock(&fbc->lock);
|
|
ret = fbc->count;
|
|
for_each_online_cpu(cpu) {
|
|
s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
|
|
ret += *pcount;
|
|
if (set)
|
|
*pcount = 0;
|
|
}
|
|
if (set)
|
|
fbc->count = ret;
|
|
|
|
spin_unlock(&fbc->lock);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(__percpu_counter_sum);
|
|
|
|
static struct lock_class_key percpu_counter_irqsafe;
|
|
|
|
int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
|
|
{
|
|
spin_lock_init(&fbc->lock);
|
|
fbc->count = amount;
|
|
fbc->counters = alloc_percpu(s32);
|
|
if (!fbc->counters)
|
|
return -ENOMEM;
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
mutex_lock(&percpu_counters_lock);
|
|
list_add(&fbc->list, &percpu_counters);
|
|
mutex_unlock(&percpu_counters_lock);
|
|
#endif
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(percpu_counter_init);
|
|
|
|
int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount)
|
|
{
|
|
int err;
|
|
|
|
err = percpu_counter_init(fbc, amount);
|
|
if (!err)
|
|
lockdep_set_class(&fbc->lock, &percpu_counter_irqsafe);
|
|
return err;
|
|
}
|
|
|
|
void percpu_counter_destroy(struct percpu_counter *fbc)
|
|
{
|
|
if (!fbc->counters)
|
|
return;
|
|
|
|
free_percpu(fbc->counters);
|
|
fbc->counters = NULL;
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
mutex_lock(&percpu_counters_lock);
|
|
list_del(&fbc->list);
|
|
mutex_unlock(&percpu_counters_lock);
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL(percpu_counter_destroy);
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
unsigned int cpu;
|
|
struct percpu_counter *fbc;
|
|
|
|
if (action != CPU_DEAD)
|
|
return NOTIFY_OK;
|
|
|
|
cpu = (unsigned long)hcpu;
|
|
mutex_lock(&percpu_counters_lock);
|
|
list_for_each_entry(fbc, &percpu_counters, list) {
|
|
s32 *pcount;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&fbc->lock, flags);
|
|
pcount = per_cpu_ptr(fbc->counters, cpu);
|
|
fbc->count += *pcount;
|
|
*pcount = 0;
|
|
spin_unlock_irqrestore(&fbc->lock, flags);
|
|
}
|
|
mutex_unlock(&percpu_counters_lock);
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static int __init percpu_counter_startup(void)
|
|
{
|
|
hotcpu_notifier(percpu_counter_hotcpu_callback, 0);
|
|
return 0;
|
|
}
|
|
module_init(percpu_counter_startup);
|
|
#endif
|