changeset 53275:08041b0d7c08

6490394: G1: Allow heap shrinking / memory unmapping after reclaiming regions during Remark Reviewed-by: sjohanss, sangheki
author tschatzl
date Wed, 31 Oct 2018 13:43:57 +0100
parents 418fb8bb5151
children 14ef0f74667b
files src/hotspot/share/gc/g1/g1CollectedHeap.cpp src/hotspot/share/gc/g1/g1CollectedHeap.hpp src/hotspot/share/gc/g1/g1ConcurrentMark.cpp test/hotspot/jtreg/gc/g1/humongousObjects/objectGraphTest/TestObjectGraphAfterGC.java
diffstat 4 files changed, 22 insertions(+), 22 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Wed Oct 31 13:43:57 2018 +0100
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Wed Oct 31 13:43:57 2018 +0100
@@ -1043,7 +1043,7 @@
   assert(num_free_regions() == 0, "we should not have added any free regions");
   rebuild_region_sets(false /* free_list_only */);
   abort_refinement();
-  resize_if_necessary_after_full_collection();
+  resize_heap_if_necessary();
 
   // Rebuild the strong code root lists for each region
   rebuild_strong_code_roots();
@@ -1149,7 +1149,7 @@
                                   clear_all_soft_refs);
 }
 
-void G1CollectedHeap::resize_if_necessary_after_full_collection() {
+void G1CollectedHeap::resize_heap_if_necessary() {
   // Capacity, free and used after the GC counted as full regions to
   // include the waste in the following calculations.
   const size_t capacity_after_gc = capacity();
@@ -1206,7 +1206,7 @@
     // Don't expand unless it's significant
     size_t expand_bytes = minimum_desired_capacity - capacity_after_gc;
 
-    log_debug(gc, ergo, heap)("Attempt heap expansion (capacity lower than min desired capacity after Full GC). "
+    log_debug(gc, ergo, heap)("Attempt heap expansion (capacity lower than min desired capacity). "
                               "Capacity: " SIZE_FORMAT "B occupancy: " SIZE_FORMAT "B live: " SIZE_FORMAT "B "
                               "min_desired_capacity: " SIZE_FORMAT "B (" UINTX_FORMAT " %%)",
                               capacity_after_gc, used_after_gc, used(), minimum_desired_capacity, MinHeapFreeRatio);
@@ -1218,7 +1218,7 @@
     // Capacity too large, compute shrinking size
     size_t shrink_bytes = capacity_after_gc - maximum_desired_capacity;
 
-    log_debug(gc, ergo, heap)("Attempt heap shrinking (capacity higher than max desired capacity after Full GC). "
+    log_debug(gc, ergo, heap)("Attempt heap shrinking (capacity higher than max desired capacity). "
                               "Capacity: " SIZE_FORMAT "B occupancy: " SIZE_FORMAT "B live: " SIZE_FORMAT "B "
                               "maximum_desired_capacity: " SIZE_FORMAT "B (" UINTX_FORMAT " %%)",
                               capacity_after_gc, used_after_gc, used(), maximum_desired_capacity, MaxHeapFreeRatio);
@@ -1394,8 +1394,8 @@
 void G1CollectedHeap::shrink(size_t shrink_bytes) {
   _verifier->verify_region_sets_optional();
 
-  // We should only reach here at the end of a Full GC which means we
-  // should not not be holding to any GC alloc regions. The method
+  // We should only reach here at the end of a Full GC or during Remark which
+  // means we should not not be holding to any GC alloc regions. The method
   // below will make sure of that and do any remaining clean up.
   _allocator->abandon_gc_alloc_regions();
 
@@ -4399,13 +4399,13 @@
   }
 
   bool do_heap_region(HeapRegion* r) {
-    // After full GC, no region should have a remembered set.
-    r->rem_set()->clear(true);
     if (r->is_empty()) {
+      assert(r->rem_set()->is_empty(), "Empty regions should have empty remembered sets.");
       // Add free regions to the free list
       r->set_free();
       _hrm->insert_into_free_list(r);
     } else if (!_free_list_only) {
+      assert(r->rem_set()->is_empty(), "At this point remembered sets must have been cleared.");
 
       if (r->is_archive() || r->is_humongous()) {
         // We ignore archive and humongous regions. We left these sets unchanged.
@@ -4443,10 +4443,9 @@
       _archive_allocator->clear_used();
     }
   }
-  assert(used_unlocked() == recalculate_used(),
-         "inconsistent used_unlocked(), "
-         "value: " SIZE_FORMAT " recalculated: " SIZE_FORMAT,
-         used_unlocked(), recalculate_used());
+  assert(used() == recalculate_used(),
+         "inconsistent used(), value: " SIZE_FORMAT " recalculated: " SIZE_FORMAT,
+         used(), recalculate_used());
 }
 
 bool G1CollectedHeap::is_in_closed_subset(const void* p) const {
--- a/src/hotspot/share/gc/g1/g1CollectedHeap.hpp	Wed Oct 31 13:43:57 2018 +0100
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.hpp	Wed Oct 31 13:43:57 2018 +0100
@@ -468,9 +468,6 @@
   // Callback from VM_G1CollectFull operation, or collect_as_vm_thread.
   virtual void do_full_collection(bool clear_all_soft_refs);
 
-  // Resize the heap if necessary after a full collection.
-  void resize_if_necessary_after_full_collection();
-
   // Callback from VM_G1CollectForAllocation operation.
   // This function does everything necessary/possible to satisfy a
   // failed allocation request (including collection, expansion, etc.)
@@ -528,6 +525,8 @@
     return _g1mm;
   }
 
+  void resize_heap_if_necessary();
+
   // Expand the garbage-first heap by at least the given size (in bytes!).
   // Returns true if the heap was expanded by the requested amount;
   // false otherwise.
--- a/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp	Wed Oct 31 13:43:57 2018 +0100
+++ b/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp	Wed Oct 31 13:43:57 2018 +0100
@@ -1178,6 +1178,8 @@
       ClassLoaderDataGraph::purge();
     }
 
+    _g1h->resize_heap_if_necessary();
+
     compute_new_sizes();
 
     verify_during_pause(G1HeapVerifier::G1VerifyRemark, VerifyOption_G1UsePrevMarking, "Remark after");
--- a/test/hotspot/jtreg/gc/g1/humongousObjects/objectGraphTest/TestObjectGraphAfterGC.java	Wed Oct 31 13:43:57 2018 +0100
+++ b/test/hotspot/jtreg/gc/g1/humongousObjects/objectGraphTest/TestObjectGraphAfterGC.java	Wed Oct 31 13:43:57 2018 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -56,29 +56,29 @@
  * @run driver ClassFileInstaller sun.hotspot.WhiteBox
  *                                sun.hotspot.WhiteBox$WhiteBoxPermission
  *
- * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * @run main/othervm -Xms200M -Xmx200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:+UnlockExperimentalVMOptions -XX:MaxGCPauseMillis=30000 -XX:G1MixedGCLiveThresholdPercent=100 -XX:G1HeapWastePercent=0
  * -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectGraphAfterGC_MIXED_GC.gc.log -XX:MaxTenuringThreshold=1
  * -XX:G1MixedGCCountTarget=1  -XX:G1OldCSetRegionThresholdPercent=100 -XX:SurvivorRatio=1 -XX:InitiatingHeapOccupancyPercent=0
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC MIXED_GC
  *
- * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * @run main/othervm -Xms200M -Xmx200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:G1HeapRegionSize=1M -Xlog:gc*=debug:file=TestObjectGraphAfterGC_YOUNG_GC.gc.log
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC YOUNG_GC
  *
- * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * @run main/othervm -Xms200M -Xmx200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectGraphAfterGC_FULL_GC.gc.log
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC FULL_GC
  *
- * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * @run main/othervm -Xms200M -Xmx200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectGraphAfterGC_FULL_GC_MEMORY_PRESSURE.gc.log
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC FULL_GC_MEMORY_PRESSURE
  *
- * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * @run main/othervm -Xms200M -Xmx200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectGraphAfterGC_CMC.gc.log -XX:MaxTenuringThreshold=16
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC CMC
  *
- * @run main/othervm -Xms200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
+ * @run main/othervm -Xms200M -Xmx200M -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
  * -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectGraphAfterGC_CMC_NO_SURV_ROOTS.gc.log -XX:MaxTenuringThreshold=1
  * gc.g1.humongousObjects.objectGraphTest.TestObjectGraphAfterGC CMC_NO_SURV_ROOTS
  *