From 2ed7582e679830b263e510820721c9178de44958 Mon Sep 17 00:00:00 2001
From: Kristian Larsson <kristian@spritelink.net>
Date: Fri, 5 Apr 2024 09:22:45 +0200
Subject: [PATCH] Place jump0 in wctx

We just want to initialize jump0 once per worker thread which we now
achieve by placing jump0 in our worker context wctx. Previous to this,
we would rerun the $PUSH every time we entered wt_work_cb, and thus
actually push a new exception jump point to the stack - effectively a
memory "leak" with run-away memory consumption as a consequence.
---
 base/rts/rts.c | 14 +++++++-------
 base/rts/rts.h |  1 +
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/base/rts/rts.c b/base/rts/rts.c
index e4160549..7824c8d0 100644
--- a/base/rts/rts.c
+++ b/base/rts/rts.c
@@ -1500,7 +1500,6 @@ void wt_wake_cb(uv_async_t *ev) {
 void wt_work_cb(uv_check_t *ev) {
     WorkerCtx wctx = (WorkerCtx)pthread_getspecific(pkey_wctx);
     assert(wctx->id >= 0 && wctx->id < 256);
-    volatile JumpBuf jump0 = NULL;
 
     struct timespec ts_start, ts1, ts2, ts3;
     long long int runtime = 0;
@@ -1525,9 +1524,9 @@ void wt_work_cb(uv_check_t *ev) {
         wt_stats[wctx->id].state = WT_Working;
 
         $R r;
-        if (jump0 || $PUSH()) {                         // Normal path
-            if (!jump0) {
-                jump0 = wctx->jump_top;
+        if (wctx->jump0 || $PUSH()) {                         // Normal path
+            if (!wctx->jump0) {
+                wctx->jump0 = wctx->jump_top;
             }
             rtsd_printf("## Running actor %ld : %s", current->$globkey, current->$class->$GCINFO);
             r = cont->$class->__call__(cont, val);
@@ -1550,9 +1549,9 @@ void wt_work_cb(uv_check_t *ev) {
             else if (diff < (long long int)100 * 1000000000) { wt_stats[wctx->id].conts_100s++; }
             else                              { wt_stats[wctx->id].conts_inf++; }
         } else {                                        // Exceptional path
-            assert(jump0 != NULL);
-            assert(jump0->xval != NULL);
-            B_BaseException ex = jump0->xval;
+            assert(wctx->jump0 != NULL);
+            assert(wctx->jump0->xval != NULL);
+            B_BaseException ex = wctx->jump0->xval;
             rtsd_printf("## (%d) Actor %ld : %s longjmp exception: %s", wctx->id, current->$globkey, current->$class->$GCINFO, ex->$class->$GCINFO);
             r = $R_FAIL(ex);
         }
@@ -1704,6 +1703,7 @@ void *main_loop(void *idx) {
     wctx->id = (long)idx;
     wctx->uv_loop = uv_loops[wctx->id];
     wctx->jump_top = NULL;
+    wctx->jump0 = NULL;
     pthread_setspecific(pkey_wctx, (void *)wctx);
 
     char tname[11]; // Enough for "Worker XXX\0"
diff --git a/base/rts/rts.h b/base/rts/rts.h
index 5fc2e42c..fe26c288 100644
--- a/base/rts/rts.h
+++ b/base/rts/rts.h
@@ -231,6 +231,7 @@ struct WorkerCtx {
     long id;
     uv_loop_t *uv_loop;
     volatile JumpBuf jump_top;
+    volatile JumpBuf jump0;
 };
 
 JumpBuf $PUSH_BUF();