[Qemu-devel] [RFC 2/8] timer: pick out timer list info from QemuClock

[Liu Ping Fan <qemulist@gmail.com>]

To allow timer to run on the different backend threads,
we will arm the thread's AioContext with its own timer list.
So separate these kind of info from QemuClock.

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 qemu-timer.c | 106 ++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 68 insertions(+), 38 deletions(-)

diff --git a/qemu-timer.c b/qemu-timer.c
index 32c70ed..0ee68dc 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -30,6 +30,7 @@
 
 #include "qemu/timer.h"
 #include "qemu/thread.h"
+#include "qemu/tls.h"
 #ifdef CONFIG_POSIX
 #include <pthread.h>
 #endif
@@ -44,11 +45,16 @@
 #define QEMU_CLOCK_REALTIME 0
 #define QEMU_CLOCK_VIRTUAL  1
 #define QEMU_CLOCK_HOST     2
+#define QEMU_CLOCK_MAXCNT 3
 
-struct QEMUClock {
+typedef struct TimerList {
     QEMUTimer *active_timers;
     QemuMutex active_timers_lock;
+} TimerList;
+
+static TimerList timer_list[QEMU_CLOCK_MAXCNT];
 
+struct QEMUClock {
     NotifierList reset_notifiers;
     int64_t last;
 
@@ -58,7 +64,7 @@ struct QEMUClock {
 
 struct QEMUTimer {
     int64_t expire_time;	/* in nanoseconds */
-    QEMUClock *clock;
+    TimerList *list;
     QEMUTimerCB *cb;
     void *opaque;
     QEMUTimer *next;
@@ -122,6 +128,13 @@ void alarm_timer_destroy(struct qemu_alarm_timer *t)
     g_free(t);
 }
 
+static TimerList *clock_to_timerlist(QEMUClock *clock)
+{
+    int type = clock->type;
+
+    return  &timer_list[type];
+}
+
 static bool qemu_timer_expired_ns(QEMUTimer *timer_head, int64_t current_time)
 {
     return timer_head && (timer_head->expire_time <= current_time);
@@ -131,17 +144,19 @@ static int64_t qemu_next_clock_deadline(QEMUClock *clock, int64_t delta)
 {
     int64_t expire_time, next;
     bool has_timer = false;
+    TimerList *tlist;
 
     if (!clock->enabled) {
         return delta;
     }
 
-    qemu_mutex_lock(&clock->active_timers_lock);
-    if (clock->active_timers) {
+    tlist = clock_to_timerlist(clock);
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    if (tlist->active_timers) {
         has_timer = true;
-        expire_time = clock->active_timers->expire_time;
+        expire_time = tlist->active_timers->expire_time;
     }
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_unlock(&tlist->active_timers_lock);
     if (!has_timer) {
         return delta;
     }
@@ -294,16 +309,25 @@ QEMUClock *rt_clock;
 QEMUClock *vm_clock;
 QEMUClock *host_clock;
 
+static void timer_list_init(TimerList *tlist)
+{
+    qemu_mutex_init(&tlist->active_timers_lock);
+    tlist->active_timers = NULL;
+}
+
 static QEMUClock *qemu_new_clock(int type)
 {
     QEMUClock *clock;
+    TimerList *tlist;
 
     clock = g_malloc0(sizeof(QEMUClock));
     clock->type = type;
     clock->enabled = true;
     clock->last = INT64_MIN;
     notifier_list_init(&clock->reset_notifiers);
-    qemu_mutex_init(&clock->active_timers_lock);
+    tlist = clock_to_timerlist(clock);
+    timer_list_init(tlist);
+
     return clock;
 }
 
@@ -319,10 +343,11 @@ void qemu_clock_enable(QEMUClock *clock, bool enabled)
 int64_t qemu_clock_has_timers(QEMUClock *clock)
 {
     bool has_timers;
+    TimerList *tlist = clock_to_timerlist(clock);
 
-    qemu_mutex_lock(&clock->active_timers_lock);
-    has_timers = !!clock->active_timers;
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    has_timers = !!tlist->active_timers;
+    qemu_mutex_unlock(&tlist->active_timers_lock);
     return has_timers;
 }
 
@@ -330,11 +355,12 @@ int64_t qemu_clock_expired(QEMUClock *clock)
 {
     bool has_timers;
     int64_t expire_time;
+    TimerList *tlist = clock_to_timerlist(clock);
 
-    qemu_mutex_lock(&clock->active_timers_lock);
-    has_timers = clock->active_timers;
-    expire_time = clock->active_timers->expire_time;
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    has_timers = tlist->active_timers;
+    expire_time = tlist->active_timers->expire_time;
+    qemu_mutex_unlock(&tlist->active_timers_lock);
 
     return has_timers && expire_time < qemu_get_clock_ns(clock);
 }
@@ -345,11 +371,12 @@ int64_t qemu_clock_deadline(QEMUClock *clock)
     int64_t delta = INT32_MAX;
     bool has_timers;
     int64_t expire_time;
+    TimerList *tlist = clock_to_timerlist(clock);
 
-    qemu_mutex_lock(&clock->active_timers_lock);
-    has_timers = clock->active_timers;
-    expire_time = clock->active_timers->expire_time;
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    has_timers = tlist->active_timers;
+    expire_time = tlist->active_timers->expire_time;
+    qemu_mutex_unlock(&tlist->active_timers_lock);
 
     if (has_timers) {
         delta = expire_time - qemu_get_clock_ns(clock);
@@ -366,7 +393,7 @@ QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
     QEMUTimer *ts;
 
     ts = g_malloc0(sizeof(QEMUTimer));
-    ts->clock = clock;
+    ts->list = clock_to_timerlist(clock);
     ts->cb = cb;
     ts->opaque = opaque;
     ts->scale = scale;
@@ -381,11 +408,11 @@ void qemu_free_timer(QEMUTimer *ts)
 /* stop a timer, but do not dealloc it */
 void qemu_del_timer(QEMUTimer *ts)
 {
-    QEMUClock *clock = ts->clock;
+    TimerList *tlist = ts->list;
     QEMUTimer **pt, *t;
 
-    qemu_mutex_lock(&clock->active_timers_lock);
-    pt = &ts->clock->active_timers;
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    pt = &tlist->active_timers;
     for(;;) {
         t = *pt;
         if (!t)
@@ -396,14 +423,14 @@ void qemu_del_timer(QEMUTimer *ts)
         }
         pt = &t->next;
     }
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_unlock(&tlist->active_timers_lock);
 }
 
 /* modify the current timer so that it will be fired when current_time
    >= expire_time. The corresponding callback will be called. */
 void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
 {
-    QEMUClock *clock = ts->clock;
+    TimerList *tlist = ts->list;
     QEMUTimer **pt, *t;
     AioContext *ctx = *tls_get_thread_aio_context();
     struct qemu_alarm_timer *alarm_timer = ctx->alarm_timer;
@@ -411,8 +438,8 @@ void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
     qemu_del_timer(ts);
 
     /* add the timer in the sorted list */
-    qemu_mutex_lock(&clock->active_timers_lock);
-    pt = &clock->active_timers;
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    pt = &tlist->active_timers;
     for(;;) {
         t = *pt;
         if (!qemu_timer_expired_ns(t, expire_time)) {
@@ -423,10 +450,10 @@ void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
     ts->expire_time = expire_time;
     ts->next = *pt;
     *pt = ts;
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_unlock(&tlist->active_timers_lock);
 
     /* Rearm if necessary  */
-    if (pt == &ts->clock->active_timers) {
+    if (pt == &tlist->active_timers) {
         qemu_mutex_lock(&alarm_timer->timer_modified_lock);
         alarm_timer->timer_modified = true;
         qemu_mutex_unlock(&alarm_timer->timer_modified_lock);
@@ -442,15 +469,15 @@ void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
 bool qemu_timer_pending(QEMUTimer *ts)
 {
     QEMUTimer *t;
-    QEMUClock *clock = ts->clock;
+    TimerList *tlist = ts->list;
 
-    qemu_mutex_lock(&clock->active_timers_lock);
-    for (t = ts->clock->active_timers; t != NULL; t = t->next) {
+    qemu_mutex_lock(&tlist->active_timers_lock);
+    for (t = tlist->active_timers; t != NULL; t = t->next) {
         if (t == ts) {
             break;
         }
     }
-    qemu_mutex_unlock(&clock->active_timers_lock);
+    qemu_mutex_unlock(&tlist->active_timers_lock);
     return t;
 }
 
@@ -463,22 +490,25 @@ void qemu_run_timers(QEMUClock *clock)
 {
     QEMUTimer *ts;
     int64_t current_time;
-   
+    TimerList *tlist;
+
     if (!clock->enabled)
         return;
 
     current_time = qemu_get_clock_ns(clock);
+    tlist = clock_to_timerlist(clock);
+
     for(;;) {
-        qemu_mutex_lock(&clock->active_timers_lock);
-        ts = clock->active_timers;
+        qemu_mutex_lock(&tlist->active_timers_lock);
+        ts = tlist->active_timers;
         if (!qemu_timer_expired_ns(ts, current_time)) {
-            qemu_mutex_unlock(&clock->active_timers_lock);
+            qemu_mutex_unlock(&tlist->active_timers_lock);
             break;
         }
         /* remove timer from the list before calling the callback */
-        clock->active_timers = ts->next;
+        tlist->active_timers = ts->next;
         ts->next = NULL;
-        qemu_mutex_unlock(&clock->active_timers_lock);
+        qemu_mutex_unlock(&tlist->active_timers_lock);
 
         /* run the callback (the timer list can be modified) */
         ts->cb(ts->opaque);
-- 
1.8.1.4