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hv: timer: make the timer list be ordered

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make the timer list be ordered to speed up expried timer
process and next timer event finding.

Add timer would not schedule timer unless it's the next
timer event.

Signed-off-by: Li, Fei1 <fei1.li@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
This commit is contained in:
Li, Fei1 2018-04-25 16:47:12 +08:00 committed by Jack Ren
parent 6fc5116776
commit 5df2efad4a
2 changed files with 65 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

114
hypervisor/arch/x86/timer.c
View File

@ -48,41 +48,6 @@ struct per_cpu_timers {
static DEFINE_CPU_DATA(struct per_cpu_timers, cpu_timers);
static DEFINE_CPU_DATA(struct dev_handler_node *, timer_node);
static struct timer *find_expired_timer(
struct per_cpu_timers *cpu_timer,
uint64_t tsc_now)
{
struct timer *timer = NULL, *tmp;
struct list_head *pos;
list_for_each(pos, &cpu_timer->timer_list) {
tmp = list_entry(pos, struct timer, node);
if (tmp->fire_tsc <= tsc_now) {
timer = tmp;
break;
}
}
return timer;
}
static struct timer *_search_nearest_timer(
struct per_cpu_timers *cpu_timer)
{
struct timer *timer;
struct timer *target = NULL;
struct list_head *pos;
list_for_each(pos, &cpu_timer->timer_list) {
timer = list_entry(pos, struct timer, node);
if (target == NULL)
target = timer;
else if (timer->fire_tsc < target->fire_tsc)
target = timer;
}
return target;
}
static void run_timer(struct timer *timer)
{
@ -100,30 +65,64 @@ static int tsc_deadline_handler(__unused int irq, __unused void *data)
return 0;
}
static inline void schedule_next_timer(struct per_cpu_timers *cpu_timer)
static inline void update_physical_timer(struct per_cpu_timers *cpu_timer)
{
struct timer *timer;
struct timer *timer = NULL;
/* find the next event timer */
if (!list_empty(&cpu_timer->timer_list)) {
timer = list_entry((&cpu_timer->timer_list)->next,
struct timer, node);
timer = _search_nearest_timer(cpu_timer);
if (timer) {
/* it is okay to program a expired time */
msr_write(MSR_IA32_TSC_DEADLINE, timer->fire_tsc);
}
}
static void __add_timer(struct per_cpu_timers *cpu_timer,
struct timer *timer,
bool *need_update)
{
struct list_head *pos, *prev;
struct timer *tmp;
uint64_t tsc = timer->fire_tsc;
prev = &cpu_timer->timer_list;
list_for_each(pos, &cpu_timer->timer_list) {
tmp = list_entry(pos, struct timer, node);
if (tmp->fire_tsc < tsc)
prev = &tmp->node;
else
break;
}
list_add(&timer->node, prev);
if (need_update)
/* update the physical timer if we're on the timer_list head */
*need_update = (prev == &cpu_timer->timer_list);
}
int add_timer(struct timer *timer)
{
struct per_cpu_timers *cpu_timer;
int pcpu_id;
bool need_update;
if (timer == NULL || timer->func == NULL || timer->fire_tsc == 0)
return -EINVAL;
/* limit minimal periodic timer cycle period */
if (timer->mode == TICK_MODE_PERIODIC)
timer->period_in_cycle = max(timer->period_in_cycle,
US_TO_TICKS(MIN_TIMER_PERIOD_US));
pcpu_id = get_cpu_id();
cpu_timer = &per_cpu(cpu_timers, pcpu_id);
list_add_tail(&timer->node, &cpu_timer->timer_list);
__add_timer(cpu_timer, timer, &need_update);
schedule_next_timer(cpu_timer);
if (need_update)
update_physical_timer(cpu_timer);
TRACE_2L(TRACE_TIMER_ACTION_ADDED, timer->fire_tsc, 0);
return 0;
@ -212,35 +211,38 @@ int timer_softirq(int pcpu_id)
{
struct per_cpu_timers *cpu_timer;
struct timer *timer;
int max = MAX_TIMER_ACTIONS;
struct list_head *pos, *n;
int tries = MAX_TIMER_ACTIONS;
uint64_t current_tsc = rdtsc();
/* handle passed timer */
cpu_timer = &per_cpu(cpu_timers, pcpu_id);
/* This is to make sure we are not blocked due to delay inside func()
* force to exit irq handler after we serviced >31 timers
* caller used to add_timer() in timer->func(), if there is a delay
* caller used to __add_timer() for periodic timer, if there is a delay
* inside func(), it will infinitely loop here, because new added timer
* already passed due to previously func()'s delay.
*/
timer = find_expired_timer(cpu_timer, rdtsc());
while (timer && --max > 0) {
del_timer(timer);
list_for_each_safe(pos, n, &cpu_timer->timer_list) {
timer = list_entry(pos, struct timer, node);
/* timer expried */
if (timer->fire_tsc <= current_tsc && --tries > 0) {
del_timer(timer);
run_timer(timer);
run_timer(timer);
if (timer->mode == TICK_MODE_PERIODIC) {
timer->fire_tsc += max(timer->period_in_cycle,
US_TO_TICKS(MIN_TIMER_PERIOD_US));
add_timer(timer);
}
/* search next one */
timer = find_expired_timer(cpu_timer, rdtsc());
if (timer->mode == TICK_MODE_PERIODIC) {
/* update periodic timer fire tsc */
timer->fire_tsc += timer->period_in_cycle;
__add_timer(cpu_timer, timer, NULL);
}
} else
break;
}
/* update nearest timer */
schedule_next_timer(cpu_timer);
update_physical_timer(cpu_timer);
return 0;
}

7
hypervisor/include/arch/x86/timer.h
View File

@ -48,6 +48,10 @@ struct timer {
void *priv_data; /* func private data */
};
/*
* Don't initialize a timer twice if it has been add to the timer list
* after call add_timer. If u want, delete the timer from the list first.
*/
static inline void initialize_timer(struct timer *timer,
timer_handle_t func,
void *priv_data,
@ -65,6 +69,9 @@ static inline void initialize_timer(struct timer *timer,
}
}
/*
* Don't call add_timer/del_timer in the timer callback function.
*/
int add_timer(struct timer *timer);
void del_timer(struct timer *timer);