`struct rb_thread_sched_waiting`

Introduce `struct rb_thread_sched_waiting` and `timer_th.waiting`
can contain other than `rb_thread_t`.

thread_pthread.c

@@ -2873,6 +2873,17 @@ static void timer_thread_wakeup_thread(rb_thread_t *th);
 
 #include "thread_pthread_mn.c"
 
+static rb_thread_t *
+thread_sched_waiting_thread(struct rb_thread_sched_waiting *w)
+{
+    if (w) {
+        return (rb_thread_t *)((size_t)w - offsetof(rb_thread_t, sched.waiting_reason));
+    }
+    else {
+        return NULL;
+    }
+}
+
 static int
 timer_thread_set_timeout(rb_vm_t *vm)
 {
@@ -2905,7 +2916,9 @@ timer_thread_set_timeout(rb_vm_t *vm)
     if (vm->ractor.sched.timeslice_wait_inf) {
         rb_native_mutex_lock(&timer_th.waiting_lock);
         {
-            rb_thread_t *th = ccan_list_top(&timer_th.waiting, rb_thread_t, sched.waiting_reason.node);
+            struct rb_thread_sched_waiting *w = ccan_list_top(&timer_th.waiting, struct rb_thread_sched_waiting, node);
+            rb_thread_t *th = thread_sched_waiting_thread(w);
+
             if (th && (th->sched.waiting_reason.flags & thread_sched_waiting_timeout)) {
                 rb_hrtime_t now = rb_hrtime_now();
                 rb_hrtime_t hrrel = rb_hrtime_sub(th->sched.waiting_reason.data.timeout, now);
@@ -2955,22 +2968,22 @@ timer_thread_check_exceed(rb_hrtime_t abs, rb_hrtime_t now)
 static rb_thread_t *
 timer_thread_deq_wakeup(rb_vm_t *vm, rb_hrtime_t now)
 {
-    rb_thread_t *th = ccan_list_top(&timer_th.waiting, rb_thread_t, sched.waiting_reason.node);
+    struct rb_thread_sched_waiting *w = ccan_list_top(&timer_th.waiting, struct rb_thread_sched_waiting, node);
 
-    if (th != NULL &&
-        (th->sched.waiting_reason.flags & thread_sched_waiting_timeout) &&
-        timer_thread_check_exceed(th->sched.waiting_reason.data.timeout, now)) {
+    if (w != NULL &&
+        (w->flags & thread_sched_waiting_timeout) &&
+        timer_thread_check_exceed(w->data.timeout, now)) {
 
         RUBY_DEBUG_LOG("wakeup th:%u", rb_th_serial(th));
 
         // delete from waiting list
-        ccan_list_del_init(&th->sched.waiting_reason.node);
+        ccan_list_del_init(&w->node);
 
         // setup result
-        th->sched.waiting_reason.flags = thread_sched_waiting_none;
-        th->sched.waiting_reason.data.result = 0;
+        w->flags = thread_sched_waiting_none;
+        w->data.result = 0;
 
-        return th;
+        return thread_sched_waiting_thread(w);
     }
 
     return NULL;

thread_pthread.h

@@ -17,6 +17,31 @@
 #define RB_NATIVETHREAD_LOCK_INIT PTHREAD_MUTEX_INITIALIZER
 #define RB_NATIVETHREAD_COND_INIT PTHREAD_COND_INITIALIZER
 
+// this data should be protected by timer_th.waiting_lock
+struct rb_thread_sched_waiting {
+    enum thread_sched_waiting_flag {
+        thread_sched_waiting_none     = 0x00,
+        thread_sched_waiting_timeout  = 0x01,
+        thread_sched_waiting_io_read  = 0x02,
+        thread_sched_waiting_io_write = 0x08,
+        thread_sched_waiting_io_force = 0x40, // ignore readable
+    } flags;
+
+    struct {
+        // should be compat with hrtime.h
+#ifdef MY_RUBY_BUILD_MAY_TIME_TRAVEL
+        int128_t timeout;
+#else
+        uint64_t timeout;
+#endif
+        int fd; // -1 for timeout only
+        int result;
+    } data;
+
+    // connected to timer_th.waiting
+    struct ccan_list_node node;
+};
+
 // per-Thead scheduler helper data
 struct rb_thread_sched_item {
     struct {
@@ -38,30 +63,7 @@ struct rb_thread_sched_item {
         struct ccan_list_node zombie_threads;
     } node;
 
-    // this data should be protected by timer_th.waiting_lock
-    struct {
-        enum thread_sched_waiting_flag {
-            thread_sched_waiting_none     = 0x00,
-            thread_sched_waiting_timeout  = 0x01,
-            thread_sched_waiting_io_read  = 0x02,
-            thread_sched_waiting_io_write = 0x08,
-            thread_sched_waiting_io_force = 0x40, // ignore readable
-        } flags;
-
-        struct {
-            // should be compat with hrtime.h
-#ifdef MY_RUBY_BUILD_MAY_TIME_TRAVEL
-            int128_t timeout;
-#else
-            uint64_t timeout;
-#endif
-            int fd; // -1 for timeout only
-            int result;
-        } data;
-
-        // connected to timer_th.waiting
-        struct ccan_list_node node;
-    } waiting_reason;
+    struct rb_thread_sched_waiting waiting_reason;
 
     bool finished;
     bool malloc_stack;

thread_pthread_mn.c

@@ -546,15 +546,18 @@ static void
 verify_waiting_list(void)
 {
 #if VM_CHECK_MODE > 0
-    rb_thread_t *wth, *prev_wth = NULL;
-    ccan_list_for_each(&timer_th.waiting, wth, sched.waiting_reason.node) {
+    struct rb_thread_sched_waiting *w, *prev_w = NULL;
+
+    // waiting list's timeout order should be [1, 2, 3, ..., 0, 0, 0]
+
+    ccan_list_for_each(&timer_th.waiting, w, node) {
         // fprintf(stderr, "verify_waiting_list th:%u abs:%lu\n", rb_th_serial(wth), (unsigned long)wth->sched.waiting_reason.data.timeout);
-        if (prev_wth) {
-            rb_hrtime_t timeout = wth->sched.waiting_reason.data.timeout;
-            rb_hrtime_t prev_timeout = prev_wth->sched.waiting_reason.data.timeout;
+        if (prev_w) {
+            rb_hrtime_t timeout = w->data.timeout;
+            rb_hrtime_t prev_timeout = w->data.timeout;
             VM_ASSERT(timeout == 0 || prev_timeout <= timeout);
         }
-        prev_wth = wth;
+        prev_w = w;
     }
 #endif
 }
@@ -632,16 +635,17 @@ kqueue_unregister_waiting(int fd, enum thread_sched_waiting_flag flags)
 static bool
 kqueue_already_registered(int fd)
 {
-    rb_thread_t *wth, *found_wth = NULL;
-    ccan_list_for_each(&timer_th.waiting, wth, sched.waiting_reason.node) {
+    struct rb_thread_sched_waiting *w, *found_w = NULL;
+
+    ccan_list_for_each(&timer_th.waiting, w, node) {
         // Similar to EEXIST in epoll_ctl, but more strict because it checks fd rather than flags
         //   for simplicity
-        if (wth->sched.waiting_reason.flags && wth->sched.waiting_reason.data.fd == fd) {
-            found_wth = wth;
+        if (w->flags && w->data.fd == fd) {
+            found_w = w;
             break;
         }
     }
-    return found_wth != NULL;
+    return found_w != NULL;
 }
 
 #endif // HAVE_SYS_EVENT_H
@@ -786,20 +790,20 @@ timer_thread_register_waiting(rb_thread_t *th, int fd, enum thread_sched_waiting
                 VM_ASSERT(flags & thread_sched_waiting_timeout);
 
                 // insert th to sorted list (TODO: O(n))
-                rb_thread_t *wth, *prev_wth = NULL;
+                struct rb_thread_sched_waiting *w, *prev_w = NULL;
 
-                ccan_list_for_each(&timer_th.waiting, wth, sched.waiting_reason.node) {
-                    if ((wth->sched.waiting_reason.flags & thread_sched_waiting_timeout) &&
-                        wth->sched.waiting_reason.data.timeout < abs) {
-                        prev_wth = wth;
+                ccan_list_for_each(&timer_th.waiting, w, node) {
+                    if ((w->flags & thread_sched_waiting_timeout) &&
+                        w->data.timeout < abs) {
+                        prev_w = w;
                     }
                     else {
                         break;
                     }
                 }
 
-                if (prev_wth) {
-                    ccan_list_add_after(&timer_th.waiting, &prev_wth->sched.waiting_reason.node, &th->sched.waiting_reason.node);
+                if (prev_w) {
+                    ccan_list_add_after(&timer_th.waiting, &prev_w->node, &th->sched.waiting_reason.node);
                 }
                 else {
                     ccan_list_add(&timer_th.waiting, &th->sched.waiting_reason.node);