Commit ff83c66e authored by Alex Bligh's avatar Alex Bligh Committed by Stefan Hajnoczi

aio / timers: Split QEMUClock into QEMUClock and QEMUTimerList

Split QEMUClock into QEMUClock and QEMUTimerList so that we can
have more than one QEMUTimerList associated with the same clock.

Introduce a main_loop_timerlist concept and make existing
qemu_clock_* calls that actually should operate on a QEMUTimerList
call the relevant QEMUTimerList implementations, using the clock's
default timerlist. This vastly reduces the invasiveness of this
change and means the API stays constant for existing users.

Introduce a list of QEMUTimerLists associated with each clock
so that reenabling the clock can cause all the notifiers
to be called. Note the code to do the notifications is added
in a later patch.

Switch QEMUClockType to an enum. Remove global variables vm_clock,
host_clock and rt_clock and add compatibility defines. Do not
fix qemu_next_alarm_deadline as it's going to be deleted.

Add qemu_clock_use_for_deadline to indicate whether a particular
clock should be used for deadline calculations. When use_icount
is true, vm_clock should not be used for deadline calculations
as it does not contain a nanosecond count. Instead, icount
timeouts come from the execution thread doing aio_notify or
qemu_notify as appropriate. This function is used in the next
patch.
Signed-off-by: default avatarAlex Bligh <alex@alex.org.uk>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent f9a976b7
#ifndef QEMU_TIMER_H
#define QEMU_TIMER_H
#include "qemu/typedefs.h"
#include "qemu-common.h"
#include "qemu/main-loop.h"
#include "qemu/notify.h"
......@@ -11,34 +12,84 @@
#define SCALE_US 1000
#define SCALE_NS 1
#define QEMU_CLOCK_REALTIME 0
#define QEMU_CLOCK_VIRTUAL 1
#define QEMU_CLOCK_HOST 2
/**
* QEMUClockType:
*
* The following clock types are available:
*
* @QEMU_CLOCK_REALTIME: Real time clock
*
* The real time clock should be used only for stuff which does not
* change the virtual machine state, as it is run even if the virtual
* machine is stopped. The real time clock has a frequency of 1000
* Hz.
*
* Formerly rt_clock
*
* @QEMU_CLOCK_VIRTUAL: virtual clock
*
* The virtual clock is only run during the emulation. It is stopped
* when the virtual machine is stopped. Virtual timers use a high
* precision clock, usually cpu cycles (use ticks_per_sec).
*
* Formerly vm_clock
*
* @QEMU_CLOCK_HOST: host clock
*
* The host clock should be use for device models that emulate accurate
* real time sources. It will continue to run when the virtual machine
* is suspended, and it will reflect system time changes the host may
* undergo (e.g. due to NTP). The host clock has the same precision as
* the virtual clock.
*
* Formerly host_clock
*/
typedef enum {
QEMU_CLOCK_REALTIME = 0,
QEMU_CLOCK_VIRTUAL = 1,
QEMU_CLOCK_HOST = 2,
QEMU_CLOCK_MAX
} QEMUClockType;
typedef struct QEMUClock QEMUClock;
typedef struct QEMUTimerList QEMUTimerList;
typedef void QEMUTimerCB(void *opaque);
/* The real time clock should be used only for stuff which does not
change the virtual machine state, as it is run even if the virtual
machine is stopped. The real time clock has a frequency of 1000
Hz. */
extern QEMUClock *rt_clock;
struct QEMUTimer {
int64_t expire_time; /* in nanoseconds */
QEMUTimerList *timer_list;
QEMUTimerCB *cb;
void *opaque;
QEMUTimer *next;
int scale;
};
extern QEMUClock *qemu_clocks[QEMU_CLOCK_MAX];
/* The virtual clock is only run during the emulation. It is stopped
when the virtual machine is stopped. Virtual timers use a high
precision clock, usually cpu cycles (use ticks_per_sec). */
extern QEMUClock *vm_clock;
/**
* qemu_clock_ptr:
* @type: type of clock
*
* Translate a clock type into a pointer to QEMUClock object.
*
* Returns: a pointer to the QEMUClock object
*/
static inline QEMUClock *qemu_clock_ptr(QEMUClockType type)
{
return qemu_clocks[type];
}
/* The host clock should be use for device models that emulate accurate
real time sources. It will continue to run when the virtual machine
is suspended, and it will reflect system time changes the host may
undergo (e.g. due to NTP). The host clock has the same precision as
the virtual clock. */
extern QEMUClock *host_clock;
/* These three clocks are maintained here with separate variable
* names for compatibility only.
*/
#define rt_clock (qemu_clock_ptr(QEMU_CLOCK_REALTIME))
#define vm_clock (qemu_clock_ptr(QEMU_CLOCK_VIRTUAL))
#define host_clock (qemu_clock_ptr(QEMU_CLOCK_HOST))
int64_t qemu_get_clock_ns(QEMUClock *clock);
int64_t qemu_clock_has_timers(QEMUClock *clock);
int64_t qemu_clock_expired(QEMUClock *clock);
bool qemu_clock_has_timers(QEMUClock *clock);
bool qemu_clock_expired(QEMUClock *clock);
int64_t qemu_clock_deadline(QEMUClock *clock);
/**
......@@ -52,6 +103,121 @@ int64_t qemu_clock_deadline(QEMUClock *clock);
*/
int64_t qemu_clock_deadline_ns(QEMUClock *clock);
/**
* qemu_clock_use_for_deadline:
* @clock: the clock to operate on
*
* Determine whether a clock should be used for deadline
* calculations. Some clocks, for instance vm_clock with
* use_icount set, do not count in nanoseconds. Such clocks
* are not used for deadline calculations, and are presumed
* to interrupt any poll using qemu_notify/aio_notify
* etc.
*
* Returns: true if the clock runs in nanoseconds and
* should be used for a deadline.
*/
bool qemu_clock_use_for_deadline(QEMUClock *clock);
/**
* qemu_clock_get_main_loop_timerlist:
* @clock: the clock to operate on
*
* Return the default timer list assocatiated with a clock.
*
* Returns: the default timer list
*/
QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock);
/**
* timerlist_new:
* @type: the clock type to associate with the timerlist
*
* Create a new timerlist associated with the clock of
* type @type.
*
* Returns: a pointer to the QEMUTimerList created
*/
QEMUTimerList *timerlist_new(QEMUClockType type);
/**
* timerlist_free:
* @timer_list: the timer list to free
*
* Frees a timer_list. It must have no active timers.
*/
void timerlist_free(QEMUTimerList *timer_list);
/**
* timerlist_has_timers:
* @timer_list: the timer list to operate on
*
* Determine whether a timer list has active timers
*
* Returns: true if the timer list has timers.
*/
bool timerlist_has_timers(QEMUTimerList *timer_list);
/**
* timerlist_expired:
* @timer_list: the timer list to operate on
*
* Determine whether a timer list has any timers which
* are expired.
*
* Returns: true if the timer list has timers which
* have expired.
*/
bool timerlist_expired(QEMUTimerList *timer_list);
/**
* timerlist_deadline:
* @timer_list: the timer list to operate on
*
* Determine the deadline for a timer_list. This is
* a legacy function which returns INT32_MAX if the
* timer list has no timers or if the earliest timer
* expires later than INT32_MAX nanoseconds away.
*
* Returns: the number of nanoseconds until the earliest
* timer expires or INT32_MAX in the situations listed
* above
*/
int64_t timerlist_deadline(QEMUTimerList *timer_list);
/**
* timerlist_deadline_ns:
* @timer_list: the timer list to operate on
*
* Determine the deadline for a timer_list, i.e.
* the number of nanoseconds until the first timer
* expires. Return -1 if there are no timers.
*
* Returns: the number of nanoseconds until the earliest
* timer expires -1 if none
*/
int64_t timerlist_deadline_ns(QEMUTimerList *timer_list);
/**
* timerlist_getclock:
* @timer_list: the timer list to operate on
*
* Determine the clock associated with a timer list.
*
* Returns: the clock associated with the timer list.
*/
QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list);
/**
* timerlist_run_timers:
* @timer_list: the timer list to use
*
* Call all expired timers associated with the timer list.
*
* Returns: true if any timer expired
*/
bool timerlist_run_timers(QEMUTimerList *timer_list);
/**
* qemu_timeout_ns_to_ms:
* @ns: nanosecond timeout value
......@@ -84,6 +250,50 @@ void qemu_unregister_clock_reset_notifier(QEMUClock *clock,
QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
QEMUTimerCB *cb, void *opaque);
/**
* timer_init:
* @ts: the timer to be initialised
* @timer_list: the timer list to attach the timer to
* @scale: the scale value for the tiemr
* @cb: the callback to be called when the timer expires
* @opaque: the opaque pointer to be passed to the callback
*
* Initialise a new timer and associate it with @timer_list.
* The caller is responsible for allocating the memory.
*
* You need not call an explicit deinit call. Simply make
* sure it is not on a list with timer_del.
*/
void timer_init(QEMUTimer *ts,
QEMUTimerList *timer_list, int scale,
QEMUTimerCB *cb, void *opaque);
/**
* timer_new_tl:
* @timer_list: the timer list to attach the timer to
* @scale: the scale value for the tiemr
* @cb: the callback to be called when the timer expires
* @opaque: the opaque pointer to be passed to the callback
*
* Creeate a new timer and associate it with @timer_list.
* The memory is allocated by the function.
*
* This is not the preferred interface unless you know you
* are going to call timer_free. Use timer_init instead.
*
* Returns: a pointer to the timer
*/
static inline QEMUTimer *timer_new_tl(QEMUTimerList *timer_list,
int scale,
QEMUTimerCB *cb,
void *opaque)
{
QEMUTimer *ts = g_malloc0(sizeof(QEMUTimer));
timer_init(ts, timer_list, scale, cb, opaque);
return ts;
}
void qemu_free_timer(QEMUTimer *ts);
void qemu_del_timer(QEMUTimer *ts);
void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time);
......@@ -92,11 +302,61 @@ bool timer_pending(QEMUTimer *ts);
bool timer_expired(QEMUTimer *timer_head, int64_t current_time);
uint64_t timer_expire_time_ns(QEMUTimer *ts);
/* New format calling conventions for timers */
/**
* timer_free:
* @ts: the timer
*
* Free a timer (it must not be on the active list)
*/
static inline void timer_free(QEMUTimer *ts)
{
qemu_free_timer(ts);
}
/**
* timer_del:
* @ts: the timer
*
* Delete a timer from the active list.
*/
static inline void timer_del(QEMUTimer *ts)
{
qemu_del_timer(ts);
}
/**
* timer_mod_ns:
* @ts: the timer
* @expire_time: the expiry time in nanoseconds
*
* Modify a timer to expire at @expire_time
*/
static inline void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
{
qemu_mod_timer_ns(ts, expire_time);
}
/**
* timer_mod:
* @ts: the timer
* @expire_time: the expire time in the units associated with the timer
*
* Modify a timer to expiry at @expire_time, taking into
* account the scale associated with the timer.
*/
static inline void timer_mod(QEMUTimer *ts, int64_t expire_timer)
{
qemu_mod_timer(ts, expire_timer);
}
/**
* qemu_run_timers:
* @clock: clock on which to operate
*
* Run all the timers associated with a clock.
* Run all the timers associated with the default timer list
* of a clock.
*
* Returns: true if any timer ran.
*/
......@@ -105,7 +365,8 @@ bool qemu_run_timers(QEMUClock *clock);
/**
* qemu_run_all_timers:
*
* Run all the timers associated with every clock.
* Run all the timers associated with the default timer list
* of every clock.
*
* Returns: true if any timer ran.
*/
......@@ -138,13 +399,54 @@ static inline int64_t qemu_soonest_timeout(int64_t timeout1, int64_t timeout2)
return ((uint64_t) timeout1 < (uint64_t) timeout2) ? timeout1 : timeout2;
}
/**
* qemu_new_timer_ns:
* @clock: the clock to associate with the timer
* @callback: the callback to call when the timer expires
* @opaque: the opaque pointer to pass to the callback
*
* Create a new timer with nanosecond scale on the default timer list
* associated with the clock.
*
* Returns: a pointer to the newly created timer
*/
static inline QEMUTimer *qemu_new_timer_ns(QEMUClock *clock, QEMUTimerCB *cb,
void *opaque)
{
return qemu_new_timer(clock, SCALE_NS, cb, opaque);
}
static inline QEMUTimer *qemu_new_timer_ms(QEMUClock *clock, QEMUTimerCB *cb,
/**
* qemu_new_timer_us:
* @clock: the clock to associate with the timer
* @callback: the callback to call when the timer expires
* @opaque: the opaque pointer to pass to the callback
*
* Create a new timer with microsecond scale on the default timer list
* associated with the clock.
*
* Returns: a pointer to the newly created timer
*/
static inline QEMUTimer *qemu_new_timer_us(QEMUClock *clock,
QEMUTimerCB *cb,
void *opaque)
{
return qemu_new_timer(clock, SCALE_US, cb, opaque);
}
/**
* qemu_new_timer_ms:
* @clock: the clock to associate with the timer
* @callback: the callback to call when the timer expires
* @opaque: the opaque pointer to pass to the callback
*
* Create a new timer with millisecond scale on the default timer list
* associated with the clock.
*
* Returns: a pointer to the newly created timer
*/
static inline QEMUTimer *qemu_new_timer_ms(QEMUClock *clock,
QEMUTimerCB *cb,
void *opaque)
{
return qemu_new_timer(clock, SCALE_MS, cb, opaque);
......
......@@ -49,22 +49,29 @@
/* timers */
struct QEMUClock {
QEMUTimer *active_timers;
QEMUTimerList *main_loop_timerlist;
QLIST_HEAD(, QEMUTimerList) timerlists;
NotifierList reset_notifiers;
int64_t last;
int type;
QEMUClockType type;
bool enabled;
};
struct QEMUTimer {
int64_t expire_time; /* in nanoseconds */
QEMUClock *qemu_clocks[QEMU_CLOCK_MAX];
/* A QEMUTimerList is a list of timers attached to a clock. More
* than one QEMUTimerList can be attached to each clock, for instance
* used by different AioContexts / threads. Each clock also has
* a list of the QEMUTimerLists associated with it, in order that
* reenabling the clock can call all the notifiers.
*/
struct QEMUTimerList {
QEMUClock *clock;
QEMUTimerCB *cb;
void *opaque;
QEMUTimer *next;
int scale;
QEMUTimer *active_timers;
QLIST_ENTRY(QEMUTimerList) list;
};
struct qemu_alarm_timer {
......@@ -93,21 +100,25 @@ static int64_t qemu_next_alarm_deadline(void)
{
int64_t delta = INT64_MAX;
int64_t rtdelta;
int64_t hdelta;
if (!use_icount && vm_clock->enabled && vm_clock->active_timers) {
delta = vm_clock->active_timers->expire_time -
qemu_get_clock_ns(vm_clock);
if (!use_icount && vm_clock->enabled &&
vm_clock->main_loop_timerlist->active_timers) {
delta = vm_clock->main_loop_timerlist->active_timers->expire_time -
qemu_get_clock_ns(vm_clock);
}
if (host_clock->enabled && host_clock->active_timers) {
int64_t hdelta = host_clock->active_timers->expire_time -
qemu_get_clock_ns(host_clock);
if (host_clock->enabled &&
host_clock->main_loop_timerlist->active_timers) {
hdelta = host_clock->main_loop_timerlist->active_timers->expire_time -
qemu_get_clock_ns(host_clock);
if (hdelta < delta) {
delta = hdelta;
}
}
if (rt_clock->enabled && rt_clock->active_timers) {
rtdelta = (rt_clock->active_timers->expire_time -
qemu_get_clock_ns(rt_clock));
if (rt_clock->enabled &&
rt_clock->main_loop_timerlist->active_timers) {
rtdelta = (rt_clock->main_loop_timerlist->active_timers->expire_time -
qemu_get_clock_ns(rt_clock));
if (rtdelta < delta) {
delta = rtdelta;
}
......@@ -231,11 +242,42 @@ next:
}
}
QEMUClock *rt_clock;
QEMUClock *vm_clock;
QEMUClock *host_clock;
static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock)
{
QEMUTimerList *timer_list;
/* Assert if we do not have a clock. If you see this
* assertion in means that the clocks have not been
* initialised before a timerlist is needed. This
* normally happens if an AioContext is used before
* init_clocks() is called within main().
*/
assert(clock);
timer_list = g_malloc0(sizeof(QEMUTimerList));
timer_list->clock = clock;
QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
return timer_list;
}
QEMUTimerList *timerlist_new(QEMUClockType type)
{
return timerlist_new_from_clock(qemu_clock_ptr(type));
}
static QEMUClock *qemu_clock_new(int type)
void timerlist_free(QEMUTimerList *timer_list)
{
assert(!timerlist_has_timers(timer_list));
if (timer_list->clock) {
QLIST_REMOVE(timer_list, list);
if (timer_list->clock->main_loop_timerlist == timer_list) {
timer_list->clock->main_loop_timerlist = NULL;
}
}
g_free(timer_list);
}
static QEMUClock *qemu_clock_new(QEMUClockType type)
{
QEMUClock *clock;
......@@ -243,10 +285,17 @@ static QEMUClock *qemu_clock_new(int type)
clock->type = type;
clock->enabled = true;
clock->last = INT64_MIN;
QLIST_INIT(&clock->timerlists);
notifier_list_init(&clock->reset_notifiers);
clock->main_loop_timerlist = timerlist_new_from_clock(clock);
return clock;
}
bool qemu_clock_use_for_deadline(QEMUClock *clock)
{
return !(use_icount && (clock->type == QEMU_CLOCK_VIRTUAL));
}
void qemu_clock_enable(QEMUClock *clock, bool enabled)
{
bool old = clock->enabled;
......@@ -256,24 +305,36 @@ void qemu_clock_enable(QEMUClock *clock, bool enabled)
}
}
int64_t qemu_clock_has_timers(QEMUClock *clock)
bool timerlist_has_timers(QEMUTimerList *timer_list)
{
return !!clock->active_timers;
return !!timer_list->active_timers;
}
int64_t qemu_clock_expired(QEMUClock *clock)
bool qemu_clock_has_timers(QEMUClock *clock)
{
return (clock->active_timers &&
clock->active_timers->expire_time < qemu_get_clock_ns(clock));
return timerlist_has_timers(clock->main_loop_timerlist);
}
int64_t qemu_clock_deadline(QEMUClock *clock)
bool timerlist_expired(QEMUTimerList *timer_list)
{
return (timer_list->active_timers &&
timer_list->active_timers->expire_time <
qemu_get_clock_ns(timer_list->clock));
}
bool qemu_clock_expired(QEMUClock *clock)
{
return timerlist_expired(clock->main_loop_timerlist);
}
int64_t timerlist_deadline(QEMUTimerList *timer_list)
{
/* To avoid problems with overflow limit this to 2^32. */
int64_t delta = INT32_MAX;
if (clock->enabled && clock->active_timers) {
delta = clock->active_timers->expire_time - qemu_get_clock_ns(clock);
if (timer_list->clock->enabled && timer_list->active_timers) {
delta = timer_list->active_timers->expire_time -
qemu_get_clock_ns(timer_list->clock);
}
if (delta < 0) {
delta = 0;
......@@ -281,20 +342,26 @@ int64_t qemu_clock_deadline(QEMUClock *clock)
return delta;
}
int64_t qemu_clock_deadline(QEMUClock *clock)
{
return timerlist_deadline(clock->main_loop_timerlist);
}
/*
* As above, but return -1 for no deadline, and do not cap to 2^32
* as we know the result is always positive.
*/
int64_t qemu_clock_deadline_ns(QEMUClock *clock)
int64_t timerlist_deadline_ns(QEMUTimerList *timer_list)
{
int64_t delta;
if (!clock->enabled || !clock->active_timers) {
if (!timer_list->clock->enabled || !timer_list->active_timers) {
return -1;
}
delta = clock->active_timers->expire_time - qemu_get_clock_ns(clock);
delta = timer_list->active_timers->expire_time -
qemu_get_clock_ns(timer_list->clock);
if (delta <= 0) {
return 0;
......@@ -303,6 +370,21 @@ int64_t qemu_clock_deadline_ns(QEMUClock *clock)
return delta;
}
int64_t qemu_clock_deadline_ns(QEMUClock *clock)
{
return timerlist_deadline_ns(clock->main_loop_timerlist);
}
QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list)
{
return timer_list->clock;
}
QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock)
{
return clock->main_loop_timerlist;
}
/* Transition function to convert a nanosecond timeout to ms
* This is used where a system does not support ppoll
*/
......@@ -351,17 +433,21 @@ int qemu_poll_ns(GPollFD *fds, guint nfds, int64_t timeout)
}
QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
QEMUTimerCB *cb, void *opaque)
void timer_init(QEMUTimer *ts,
QEMUTimerList *timer_list, int scale,
QEMUTimerCB *cb, void *opaque)
{
QEMUTimer *ts;
ts = g_malloc0(sizeof(QEMUTimer));
ts->clock = clock;
ts->timer_list = timer_list;
ts->cb = cb;
ts->opaque = opaque;
ts->scale = scale;
return ts;
}
QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
QEMUTimerCB *cb, void *opaque)
{