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8215221: Serial GC misreports young GC time

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Reviewed-by: kbarrett, manc
This commit is contained in:
Aleksey Shipilev 2019-03-07 10:50:52 +01:00
parent 9b70cef920
commit ba8645f09a
2 changed files with 99 additions and 83 deletions
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178
src/hotspot/share/gc/shared/genCollectedHeap.cpp
View File

@ -557,8 +557,6 @@ void GenCollectedHeap::do_collection(bool full,
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 @@ void GenCollectedHeap::do_collection(bool full,
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 @@ void GenCollectedHeap::do_collection(bool full,
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);
}

4
src/hotspot/share/gc/shared/genCollectedHeap.hpp
View File

@ -497,6 +497,10 @@ private:
// 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