--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp Wed Sep 02 00:04:29 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp Thu Jul 30 16:22:58 2009 -0400
@@ -25,6 +25,12 @@
#include "incls/_precompiled.incl"
#include "incls/_heapRegion.cpp.incl"
+int HeapRegion::LogOfHRGrainBytes = 0;
+int HeapRegion::LogOfHRGrainWords = 0;
+int HeapRegion::GrainBytes = 0;
+int HeapRegion::GrainWords = 0;
+int HeapRegion::CardsPerRegion = 0;
+
HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
HeapRegion* hr, OopClosure* cl,
CardTableModRefBS::PrecisionStyle precision,
@@ -231,6 +237,73 @@
}
}
+// Minimum region size; we won't go lower than that.
+// We might want to decrease this in the future, to deal with small
+// heaps a bit more efficiently.
+#define MIN_REGION_SIZE ( 1024 * 1024 )
+
+// Maximum region size; we don't go higher than that. There's a good
+// reason for having an upper bound. We don't want regions to get too
+// large, otherwise cleanup's effectiveness would decrease as there
+// will be fewer opportunities to find totally empty regions after
+// marking.
+#define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
+
+// The automatic region size calculation will try to have around this
+// many regions in the heap (based on the min heap size).
+#define TARGET_REGION_NUMBER 2048
+
+void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
+ // region_size in bytes
+ uintx region_size = G1HeapRegionSize;
+ if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
+ // We base the automatic calculation on the min heap size. This
+ // can be problematic if the spread between min and max is quite
+ // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
+ // the max size, the region size might be way too large for the
+ // min size. Either way, some users might have to set the region
+ // size manually for some -Xms / -Xmx combos.
+
+ region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
+ (uintx) MIN_REGION_SIZE);
+ }
+
+ int region_size_log = log2_long((jlong) region_size);
+ // Recalculate the region size to make sure it's a power of
+ // 2. This means that region_size is the largest power of 2 that's
+ // <= what we've calculated so far.
+ region_size = 1 << region_size_log;
+
+ // Now make sure that we don't go over or under our limits.
+ if (region_size < MIN_REGION_SIZE) {
+ region_size = MIN_REGION_SIZE;
+ } else if (region_size > MAX_REGION_SIZE) {
+ region_size = MAX_REGION_SIZE;
+ }
+
+ // And recalculate the log.
+ region_size_log = log2_long((jlong) region_size);
+
+ // Now, set up the globals.
+ guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
+ LogOfHRGrainBytes = region_size_log;
+
+ guarantee(LogOfHRGrainWords == 0, "we should only set it once");
+ LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
+
+ guarantee(GrainBytes == 0, "we should only set it once");
+ // The cast to int is safe, given that we've bounded region_size by
+ // MIN_REGION_SIZE and MAX_REGION_SIZE.
+ GrainBytes = (int) region_size;
+
+ guarantee(GrainWords == 0, "we should only set it once");
+ GrainWords = GrainBytes >> LogHeapWordSize;
+ guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity");
+
+ guarantee(CardsPerRegion == 0, "we should only set it once");
+ CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
+}
+
void HeapRegion::reset_after_compaction() {
G1OffsetTableContigSpace::reset_after_compaction();
// After a compaction the mark bitmap is invalid, so we must