From deca030d34f5ca7f1e60d7a572f0a17066111a1f Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sun, 21 Jul 2019 14:31:39 -0600
Subject: [PATCH] fix finalization pessimization

Recurring during finalization marking could potentially delay
finalization that should happen in the same collection.
---
 racket/src/racket/gc2/newgc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/racket/src/racket/gc2/newgc.c b/racket/src/racket/gc2/newgc.c
index dd1b36c631..3f71e46af9 100644
--- a/racket/src/racket/gc2/newgc.c
+++ b/racket/src/racket/gc2/newgc.c
@@ -2672,10 +2672,13 @@ inline static int check_finalizers(NewGC *gc, int level, int old_gen, int fuel)
 
   if (!fuel) return 0;
 
+  GC_mark_no_recur(gc, 0);
+
   GCDEBUG((DEBUGOUTF, "CFNL: Checking level %i finalizers\n", level));
   while(work) {
     if (!fuel) {
       GC_ASSERT(old_gen);
+      GC_mark_no_recur(gc, 1);
       return 0;
     }
     if (fuel > 0) {
@@ -2742,6 +2745,8 @@ inline static int check_finalizers(NewGC *gc, int level, int old_gen, int fuel)
     }
   }
 
+  GC_mark_no_recur(gc, 1);
+
   return fuel;
 }