8215221: Serial GC misreports young GC time
Reviewed-by: kbarrett, manc
diff --git a/src/hotspot/share/gc/shared/genCollectedHeap.cpp b/src/hotspot/share/gc/shared/genCollectedHeap.cpp
index 283c4e2..048ffca 100644
--- a/src/hotspot/share/gc/shared/genCollectedHeap.cpp
+++ b/src/hotspot/share/gc/shared/genCollectedHeap.cpp
@@ -557,8 +557,6 @@
return; // GC is disabled (e.g. JNI GetXXXCritical operation)
}
- GCIdMark gc_id_mark;
-
const bool do_clear_all_soft_refs = clear_all_soft_refs ||
soft_ref_policy()->should_clear_all_soft_refs();
@@ -566,103 +564,114 @@
const size_t metadata_prev_used = MetaspaceUtils::used_bytes();
- print_heap_before_gc();
- {
- FlagSetting fl(_is_gc_active, true);
+ FlagSetting fl(_is_gc_active, true);
- bool complete = full && (max_generation == OldGen);
- bool old_collects_young = complete && !ScavengeBeforeFullGC;
- bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
+ bool complete = full && (max_generation == OldGen);
+ bool old_collects_young = complete && !ScavengeBeforeFullGC;
+ bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab);
- FormatBuffer<> gc_string("%s", "Pause ");
- if (do_young_collection) {
- gc_string.append("Young");
- } else {
- gc_string.append("Full");
- }
+ size_t young_prev_used = _young_gen->used();
+ size_t old_prev_used = _old_gen->used();
+ bool run_verification = total_collections() >= VerifyGCStartAt;
+ bool prepared_for_verification = false;
+ bool do_full_collection = false;
+
+ if (do_young_collection) {
+ GCIdMark gc_id_mark;
GCTraceCPUTime tcpu;
- GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true);
+ GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true);
+
+ print_heap_before_gc();
+
+ if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
+ prepare_for_verify();
+ prepared_for_verification = true;
+ }
gc_prologue(complete);
increment_total_collections(complete);
- size_t young_prev_used = _young_gen->used();
- size_t old_prev_used = _old_gen->used();
+ collect_generation(_young_gen,
+ full,
+ size,
+ is_tlab,
+ run_verification && VerifyGCLevel <= 0,
+ do_clear_all_soft_refs,
+ false);
- bool run_verification = total_collections() >= VerifyGCStartAt;
-
- bool prepared_for_verification = false;
- bool collected_old = false;
-
- if (do_young_collection) {
- if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) {
- prepare_for_verify();
- prepared_for_verification = true;
- }
-
- collect_generation(_young_gen,
- full,
- size,
- is_tlab,
- run_verification && VerifyGCLevel <= 0,
- do_clear_all_soft_refs,
- false);
-
- if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
- size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
- // Allocation request was met by young GC.
- size = 0;
- }
+ if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) &&
+ size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) {
+ // Allocation request was met by young GC.
+ size = 0;
}
- bool must_restore_marks_for_biased_locking = false;
+ // Ask if young collection is enough. If so, do the final steps for young collection,
+ // and fallthrough to the end.
+ do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
+ if (!do_full_collection) {
+ // Adjust generation sizes.
+ _young_gen->compute_new_size();
- if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) {
- if (!complete) {
- // The full_collections increment was missed above.
- increment_total_full_collections();
- }
+ print_heap_change(young_prev_used, old_prev_used);
+ MetaspaceUtils::print_metaspace_change(metadata_prev_used);
- if (!prepared_for_verification && run_verification &&
- VerifyGCLevel <= 1 && VerifyBeforeGC) {
- prepare_for_verify();
- }
+ // Track memory usage and detect low memory after GC finishes
+ MemoryService::track_memory_usage();
- if (do_young_collection) {
- // We did a young GC. Need a new GC id for the old GC.
- GCIdMark gc_id_mark;
- GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
- collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
- } else {
- // No young GC done. Use the same GC id as was set up earlier in this method.
- collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true);
- }
-
- must_restore_marks_for_biased_locking = true;
- collected_old = true;
+ gc_epilogue(complete);
}
- // Update "complete" boolean wrt what actually transpired --
- // for instance, a promotion failure could have led to
- // a whole heap collection.
- complete = complete || collected_old;
+ print_heap_after_gc();
+
+ } else {
+ // No young collection, ask if we need to perform Full collection.
+ do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation);
+ }
+
+ if (do_full_collection) {
+ GCIdMark gc_id_mark;
+ GCTraceCPUTime tcpu;
+ GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true);
+
+ print_heap_before_gc();
+
+ if (!prepared_for_verification && run_verification &&
+ VerifyGCLevel <= 1 && VerifyBeforeGC) {
+ prepare_for_verify();
+ }
+
+ if (!do_young_collection) {
+ gc_prologue(complete);
+ increment_total_collections(complete);
+ }
+
+ // Accounting quirk: total full collections would be incremented when "complete"
+ // is set, by calling increment_total_collections above. However, we also need to
+ // account Full collections that had "complete" unset.
+ if (!complete) {
+ increment_total_full_collections();
+ }
+
+ collect_generation(_old_gen,
+ full,
+ size,
+ is_tlab,
+ run_verification && VerifyGCLevel <= 1,
+ do_clear_all_soft_refs,
+ true);
// Adjust generation sizes.
- if (collected_old) {
- _old_gen->compute_new_size();
- }
+ _old_gen->compute_new_size();
_young_gen->compute_new_size();
- if (complete) {
- // Delete metaspaces for unloaded class loaders and clean up loader_data graph
- ClassLoaderDataGraph::purge();
- MetaspaceUtils::verify_metrics();
- // Resize the metaspace capacity after full collections
- MetaspaceGC::compute_new_size();
- update_full_collections_completed();
- }
+ // Delete metaspaces for unloaded class loaders and clean up loader_data graph
+ ClassLoaderDataGraph::purge();
+ MetaspaceUtils::verify_metrics();
+ // Resize the metaspace capacity after full collections
+ MetaspaceGC::compute_new_size();
+ update_full_collections_completed();
print_heap_change(young_prev_used, old_prev_used);
MetaspaceUtils::print_metaspace_change(metadata_prev_used);
@@ -672,18 +681,21 @@
gc_epilogue(complete);
- if (must_restore_marks_for_biased_locking) {
- BiasedLocking::restore_marks();
- }
- }
+ BiasedLocking::restore_marks();
- print_heap_after_gc();
+ print_heap_after_gc();
+ }
#ifdef TRACESPINNING
ParallelTaskTerminator::print_termination_counts();
#endif
}
+bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab,
+ GenCollectedHeap::GenerationType max_gen) const {
+ return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab);
+}
+
void GenCollectedHeap::register_nmethod(nmethod* nm) {
CodeCache::register_scavenge_root_nmethod(nm);
}
diff --git a/src/hotspot/share/gc/shared/genCollectedHeap.hpp b/src/hotspot/share/gc/shared/genCollectedHeap.hpp
index a49626d..2ce5f74 100644
--- a/src/hotspot/share/gc/shared/genCollectedHeap.hpp
+++ b/src/hotspot/share/gc/shared/genCollectedHeap.hpp
@@ -497,6 +497,10 @@
// Save the tops of the spaces in all generations
void record_gen_tops_before_GC() PRODUCT_RETURN;
+
+ // Return true if we need to perform full collection.
+ bool should_do_full_collection(size_t size, bool full,
+ bool is_tlab, GenerationType max_gen) const;
};
#endif // SHARE_GC_SHARED_GENCOLLECTEDHEAP_HPP
