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8061205: MetadataOnStackMark only needs to walk code cache during class redefinition

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Only do full metadata walk during class redefinition and only walk handles during class unloading.

Reviewed-by: sspitsyn, stefank
This commit is contained in:
Coleen Phillimore 2015-03-13 12:40:39 -04:00
parent 984cf4c9b5
commit 7b384c6958
19 changed files with 147 additions and 248 deletions
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61
hotspot/src/share/vm/code/nmethod.cpp
View file

@ -1572,17 +1572,12 @@ void nmethod::post_compiled_method_unload() {
set_unload_reported();
}
void static clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_alive, bool mark_on_stack) {
void static clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_alive) {
if (ic->is_icholder_call()) {
// The only exception is compiledICHolder oops which may
// yet be marked below. (We check this further below).
CompiledICHolder* cichk_oop = ic->cached_icholder();
if (mark_on_stack) {
Metadata::mark_on_stack(cichk_oop->holder_method());
Metadata::mark_on_stack(cichk_oop->holder_klass());
}
if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&
cichk_oop->holder_klass()->is_loader_alive(is_alive)) {
return;
@ -1590,10 +1585,6 @@ void static clean_ic_if_metadata_is_dead(CompiledIC *ic, BoolObjectClosure *is_a
} else {
Metadata* ic_oop = ic->cached_metadata();
if (ic_oop != NULL) {
if (mark_on_stack) {
Metadata::mark_on_stack(ic_oop);
}
if (ic_oop->is_klass()) {
if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {
return;
@ -1634,8 +1625,7 @@ void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred)
// The RedefineClasses() API can cause the class unloading invariant
// to no longer be true. See jvmtiExport.hpp for details.
// Also, leave a debugging breadcrumb in local flag.
bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
if (a_class_was_redefined) {
if (JvmtiExport::has_redefined_a_class()) {
// This set of the unloading_occurred flag is done before the
// call to post_compiled_method_unload() so that the unloading
// of this nmethod is reported.
@ -1654,7 +1644,7 @@ void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred)
while(iter.next()) {
if (iter.type() == relocInfo::virtual_call_type) {
CompiledIC *ic = CompiledIC_at(&iter);
clean_ic_if_metadata_is_dead(ic, is_alive, false);
clean_ic_if_metadata_is_dead(ic, is_alive);
}
}
}
@ -1741,33 +1731,6 @@ bool nmethod::unload_if_dead_at(RelocIterator* iter_at_oop, BoolObjectClosure *i
return false;
}
void nmethod::mark_metadata_on_stack_at(RelocIterator* iter_at_metadata) {
assert(iter_at_metadata->type() == relocInfo::metadata_type, "Wrong relocation type");
metadata_Relocation* r = iter_at_metadata->metadata_reloc();
// In this metadata, we must only follow those metadatas directly embedded in
// the code. Other metadatas (oop_index>0) are seen as part of
// the metadata section below.
assert(1 == (r->metadata_is_immediate()) +
(r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),
"metadata must be found in exactly one place");
if (r->metadata_is_immediate() && r->metadata_value() != NULL) {
Metadata* md = r->metadata_value();
if (md != _method) Metadata::mark_on_stack(md);
}
}
void nmethod::mark_metadata_on_stack_non_relocs() {
// Visit the metadata section
for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {
if (*p == Universe::non_oop_word() || *p == NULL) continue; // skip non-oops
Metadata* md = *p;
Metadata::mark_on_stack(md);
}
// Visit metadata not embedded in the other places.
if (_method != NULL) Metadata::mark_on_stack(_method);
}
bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_occurred) {
ResourceMark rm;
@ -1790,19 +1753,13 @@ bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_
// The RedefineClasses() API can cause the class unloading invariant
// to no longer be true. See jvmtiExport.hpp for details.
// Also, leave a debugging breadcrumb in local flag.
bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();
if (a_class_was_redefined) {
if (JvmtiExport::has_redefined_a_class()) {
// This set of the unloading_occurred flag is done before the
// call to post_compiled_method_unload() so that the unloading
// of this nmethod is reported.
unloading_occurred = true;
}
// When class redefinition is used all metadata in the CodeCache has to be recorded,
// so that unused "previous versions" can be purged. Since walking the CodeCache can
// be expensive, the "mark on stack" is piggy-backed on this parallel unloading code.
bool mark_metadata_on_stack = a_class_was_redefined;
// Exception cache
clean_exception_cache(is_alive);
@ -1818,7 +1775,7 @@ bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_
if (unloading_occurred) {
// If class unloading occurred we first iterate over all inline caches and
// clear ICs where the cached oop is referring to an unloaded klass or method.
clean_ic_if_metadata_is_dead(CompiledIC_at(&iter), is_alive, mark_metadata_on_stack);
clean_ic_if_metadata_is_dead(CompiledIC_at(&iter), is_alive);
}
postponed |= clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), is_alive, this);
@ -1839,16 +1796,10 @@ bool nmethod::do_unloading_parallel(BoolObjectClosure* is_alive, bool unloading_
break;
case relocInfo::metadata_type:
if (mark_metadata_on_stack) {
mark_metadata_on_stack_at(&iter);
}
break; // nothing to do.
}
}
if (mark_metadata_on_stack) {
mark_metadata_on_stack_non_relocs();
}
if (is_unloaded) {
return postponed;
}