8241845: Shenandoah: align ShenandoahHeapRegions to cache lines
Reviewed-by: rkennke
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
index fd31daa..af5b2ab 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
@@ -181,6 +181,7 @@
size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
+ size_t region_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
//
// Reserve and commit memory for heap
@@ -279,6 +280,15 @@
//
// Create regions and region sets
//
+ size_t region_align = align_up(sizeof(ShenandoahHeapRegion), SHENANDOAH_CACHE_LINE_SIZE);
+ size_t region_storage_size = align_up(region_align * _num_regions, region_page_size);
+
+ ReservedSpace region_storage(region_storage_size, region_page_size);
+ MemTracker::record_virtual_memory_type(region_storage.base(), mtGC);
+ if (!region_storage.special()) {
+ os::commit_memory_or_exit(region_storage.base(), region_storage_size, region_page_size, false,
+ "Cannot commit region memory");
+ }
_regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
_free_set = new ShenandoahFreeSet(this, _num_regions);
@@ -290,7 +300,10 @@
for (size_t i = 0; i < _num_regions; i++) {
HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i;
bool is_committed = i < num_committed_regions;
- ShenandoahHeapRegion* r = new ShenandoahHeapRegion(start, i, is_committed);
+ void* loc = region_storage.base() + i * region_align;
+
+ ShenandoahHeapRegion* r = new (loc) ShenandoahHeapRegion(start, i, is_committed);
+ assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity");
_marking_context->initialize_top_at_mark_start(r);
_regions[i] = r;
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.hpp b/src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.hpp
index 56abb72..a6b394a 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.hpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.hpp
@@ -36,7 +36,7 @@
class VMStructs;
class ShenandoahHeapRegionStateConstant;
-class ShenandoahHeapRegion : public CHeapObj<mtGC> {
+class ShenandoahHeapRegion {
friend class VMStructs;
friend class ShenandoahHeapRegionStateConstant;
private:
@@ -262,9 +262,6 @@
HeapWord* _update_watermark;
- // Claim some space at the end to protect next region
- shenandoah_padding(0);
-
public:
ShenandoahHeapRegion(HeapWord* start, size_t index, bool committed);
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahPadding.hpp b/src/hotspot/share/gc/shenandoah/shenandoahPadding.hpp
index a442ad7..b6038d9 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahPadding.hpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahPadding.hpp
@@ -30,7 +30,9 @@
// versions here. Shared code provides DEFAULT_CACHE_LINE_SIZE, which is
// inconveniently large by default.
+#define SHENANDOAH_CACHE_LINE_SIZE 64
+
#define shenandoah_padding(id) \
- DEFINE_PAD_MINUS_SIZE(id, 64, 0)
+ DEFINE_PAD_MINUS_SIZE(id, SHENANDOAH_CACHE_LINE_SIZE, 0)
#endif // SHARE_GC_SHENANDOAH_SHENANDOAHPADDING_INLINE_HPP
