8372747: G1: Conservative heap alignment does not account for card table constraint

jsikstro · jsikstro · commit f0bc43599df3 · 2025-12-01T09:15:42.000Z
diff --git a/src/hotspot/share/gc/g1/g1Arguments.cpp b/src/hotspot/share/gc/g1/g1Arguments.cpp
@@ -77,10 +77,11 @@ void G1Arguments::initialize_alignments() {
 }
 
 size_t G1Arguments::conservative_max_heap_alignment() {
-  if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
-    return G1HeapRegion::max_ergonomics_size();
-  }
-  return G1HeapRegion::max_region_size();
+  const size_t region_size = FLAG_IS_DEFAULT(G1HeapRegionSize)
+                           ? G1HeapRegion::max_ergonomics_size()
+                           : G1HeapRegion::max_region_size();
+
+  return MAX2(region_size, calculate_heap_alignment(SpaceAlignment));
 }
 
 void G1Arguments::initialize_verification_types() {

Original file line number	Diff line number	Diff line change
`@@ -77,10 +77,11 @@ void G1Arguments::initialize_alignments() {`
`77`	`77`	`}`
`78`	`78`
`79`	`79`	`size_t G1Arguments::conservative_max_heap_alignment() {`
`80`		`- if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {`
`81`		`- return G1HeapRegion::max_ergonomics_size();`
`82`		`- }`
`83`		`- return G1HeapRegion::max_region_size();`
	`80`	`+ const size_t region_size = FLAG_IS_DEFAULT(G1HeapRegionSize)`
	`81`	`+ ? G1HeapRegion::max_ergonomics_size()`
	`82`	`+ : G1HeapRegion::max_region_size();`
	`83`	`+`
	`84`	`+ return MAX2(region_size, calculate_heap_alignment(SpaceAlignment));`
`84`	`85`	`}`
`85`	`86`
`86`	`87`	`void G1Arguments::initialize_verification_types() {`