From c7f5cb3aea92165d20c4a89ffbee18e3ab03b9a2 Mon Sep 17 00:00:00 2001
From: Luke Gruber <luke.gruber@shopify.com>
Date: Thu, 11 Dec 2025 10:43:41 -0500
Subject: [PATCH] move th->event_serial to rb_thread_sched_item

---
 thread_pthread.c    | 2 +-
 thread_pthread.h    | 3 ++-
 thread_pthread_mn.c | 6 +++---
 vm_core.h           | 1 -
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/thread_pthread.c b/thread_pthread.c
index 66323598607398..a2e42da13e70b1 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -2988,7 +2988,7 @@ timer_thread_deq_wakeup(rb_vm_t *vm, rb_hrtime_t now, uint32_t *event_serial)
 static void
 timer_thread_wakeup_thread_locked(struct rb_thread_sched *sched, rb_thread_t *th, uint32_t event_serial)
 {
-    if (sched->running != th && th->event_serial == event_serial) {
+    if (sched->running != th && th->sched.event_serial == event_serial) {
         thread_sched_to_ready_common(sched, th, true, false);
     }
 }
diff --git a/thread_pthread.h b/thread_pthread.h
index f579e53781a74c..992e9fb0803d67 100644
--- a/thread_pthread.h
+++ b/thread_pthread.h
@@ -48,7 +48,7 @@ struct rb_thread_sched_waiting {
     struct ccan_list_node node;
 };
 
-// per-Thead scheduler helper data
+// per-Thread scheduler helper data
 struct rb_thread_sched_item {
     struct {
         struct ccan_list_node ubf;
@@ -70,6 +70,7 @@ struct rb_thread_sched_item {
     } node;
 
     struct rb_thread_sched_waiting waiting_reason;
+    uint32_t event_serial;
 
     bool finished;
     bool malloc_stack;
diff --git a/thread_pthread_mn.c b/thread_pthread_mn.c
index ad4d0915e790b2..5c21f212e4ab37 100644
--- a/thread_pthread_mn.c
+++ b/thread_pthread_mn.c
@@ -65,7 +65,7 @@ thread_sched_wait_events(struct rb_thread_sched *sched, rb_thread_t *th, int fd,
 
     volatile bool timedout = false, need_cancel = false;
 
-    uint32_t event_serial = ++th->event_serial; // overflow is okay
+    uint32_t event_serial = ++th->sched.event_serial; // overflow is okay
 
     if (ubf_set(th, ubf_event_waiting, (void *)th)) {
         return false;
@@ -81,11 +81,11 @@ thread_sched_wait_events(struct rb_thread_sched *sched, rb_thread_t *th, int fd,
             RB_INTERNAL_THREAD_HOOK(RUBY_INTERNAL_THREAD_EVENT_SUSPENDED, th);
 
             if (th->sched.waiting_reason.flags == thread_sched_waiting_none) {
-                th->event_serial++;
+                th->sched.event_serial++;
                 // timer thread has dequeued us already, but it won't try to wake us because we bumped our serial
             }
             else if (RUBY_VM_INTERRUPTED(th->ec)) {
-                th->event_serial++; // make sure timer thread doesn't try to wake us
+                th->sched.event_serial++; // make sure timer thread doesn't try to wake us
                 need_cancel = true;
             }
             else {
diff --git a/vm_core.h b/vm_core.h
index 4195ea5e59c9a4..d391c4258a4337 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -1130,7 +1130,6 @@ typedef struct rb_thread_struct {
     struct rb_thread_sched_item sched;
     bool mn_schedulable;
     rb_atomic_t serial; // only for RUBY_DEBUG_LOG()
-    uint32_t event_serial;
 
     VALUE last_status; /* $? */