From b0ca2963595a04a7bde0d9f3db461675d672d8f8 Mon Sep 17 00:00:00 2001
From: Steven Schveighoffer <schveiguy@gmail.com>
Date: Mon, 23 Dec 2024 11:28:51 -0500
Subject: [PATCH] [GC] Make sure we don't take a GC lock for grow/shrink calls
 without entering a busy state. (#414)

---
 sdlib/d/gc/tcache.d | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/sdlib/d/gc/tcache.d b/sdlib/d/gc/tcache.d
index 716dc2270..afcaf0071 100644
--- a/sdlib/d/gc/tcache.d
+++ b/sdlib/d/gc/tcache.d
@@ -303,13 +303,13 @@ public:
 				auto npages = getPageCount(size);
 
 				if (epages < npages) {
-					if (!pd.arena.growLarge(emap, e, npages)) {
+					if (!growLarge(pd, npages)) {
 						goto LargeResizeFailed;
 					}
 
 					triggerAllocationEvent((npages - epages) * PageSize);
 				} else if (epages > npages) {
-					if (!pd.arena.shrinkLarge(emap, e, npages)) {
+					if (!shrinkLarge(pd, npages)) {
 						goto LargeResizeFailed;
 					}
 
@@ -708,7 +708,7 @@ private:
 
 		auto npages = getPageCount(newCapacity);
 		if (epages < npages) {
-			if (!pd.arena.growLarge(emap, e, npages)) {
+			if (!growLarge(pd, npages)) {
 				return false;
 			}
 
@@ -722,6 +722,20 @@ private:
 		return true;
 	}
 
+	bool growLarge(PageDescriptor pd, uint npages) {
+		state.enterBusyState();
+		scope(exit) state.exitBusyState();
+
+		return pd.arena.growLarge(emap, pd.extent, npages);
+	}
+
+	bool shrinkLarge(PageDescriptor pd, uint npages) {
+		state.enterBusyState();
+		scope(exit) state.exitBusyState();
+
+		return pd.arena.shrinkLarge(emap, pd.extent, npages);
+	}
+
 	auto getPageDescriptor(void* ptr) {
 		auto pd = maybeGetPageDescriptor(ptr);
 		assert(pd.extent !is null);