Mercurial > hg > icedtea8-forest > hotspot
changeset 10825:6d0e445c7814
8165808: Add release barriers when allocating objects with concurrent collection
Summary: Add release_set_klass, use in slow-path allocators.
Reviewed-by: jmasa, dholmes, aph
author | kbarrett |
---|---|
date | Thu, 15 Sep 2016 12:10:43 -0400 |
parents | 3e0eb70a007e |
children | e05b04137e36 |
files | src/share/vm/gc_interface/collectedHeap.hpp src/share/vm/gc_interface/collectedHeap.inline.hpp src/share/vm/oops/oop.hpp src/share/vm/oops/oop.inline.hpp |
diffstat | 4 files changed, 45 insertions(+), 34 deletions(-) [+] |
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--- a/src/share/vm/gc_interface/collectedHeap.hpp Tue Nov 26 09:27:16 2019 -0500 +++ b/src/share/vm/gc_interface/collectedHeap.hpp Thu Sep 15 12:10:43 2016 -0400 @@ -320,9 +320,6 @@ inline static oop array_allocate(KlassHandle klass, int size, int length, TRAPS); inline static oop array_allocate_nozero(KlassHandle klass, int size, int length, TRAPS); - inline static void post_allocation_install_obj_klass(KlassHandle klass, - oop obj); - // Raw memory allocation facilities // The obj and array allocate methods are covers for these methods. // mem_allocate() should never be
--- a/src/share/vm/gc_interface/collectedHeap.inline.hpp Tue Nov 26 09:27:16 2019 -0500 +++ b/src/share/vm/gc_interface/collectedHeap.inline.hpp Thu Sep 15 12:10:43 2016 -0400 @@ -39,14 +39,22 @@ // Inline allocation implementations. void CollectedHeap::post_allocation_setup_common(KlassHandle klass, - HeapWord* obj) { - post_allocation_setup_no_klass_install(klass, obj); - post_allocation_install_obj_klass(klass, oop(obj)); + HeapWord* obj_ptr) { + post_allocation_setup_no_klass_install(klass, obj_ptr); + oop obj = (oop)obj_ptr; +#if ! INCLUDE_ALL_GCS + obj->set_klass(klass()); +#else + // Need a release store to ensure array/class length, mark word, and + // object zeroing are visible before setting the klass non-NULL, for + // concurrent collectors. + obj->release_set_klass(klass()); +#endif } void CollectedHeap::post_allocation_setup_no_klass_install(KlassHandle klass, - HeapWord* objPtr) { - oop obj = (oop)objPtr; + HeapWord* obj_ptr) { + oop obj = (oop)obj_ptr; assert(obj != NULL, "NULL object pointer"); if (UseBiasedLocking && (klass() != NULL)) { @@ -57,18 +65,6 @@ } } -void CollectedHeap::post_allocation_install_obj_klass(KlassHandle klass, - oop obj) { - // These asserts are kind of complicated because of klassKlass - // and the beginning of the world. - assert(klass() != NULL || !Universe::is_fully_initialized(), "NULL klass"); - assert(klass() == NULL || klass()->is_klass(), "not a klass"); - assert(obj != NULL, "NULL object pointer"); - obj->set_klass(klass()); - assert(!Universe::is_fully_initialized() || obj->klass() != NULL, - "missing klass"); -} - // Support for jvmti and dtrace inline void post_allocation_notify(KlassHandle klass, oop obj, int size) { // support low memory notifications (no-op if not enabled) @@ -86,25 +82,26 @@ } void CollectedHeap::post_allocation_setup_obj(KlassHandle klass, - HeapWord* obj, + HeapWord* obj_ptr, int size) { - post_allocation_setup_common(klass, obj); + post_allocation_setup_common(klass, obj_ptr); + oop obj = (oop)obj_ptr; assert(Universe::is_bootstrapping() || - !((oop)obj)->is_array(), "must not be an array"); + !obj->is_array(), "must not be an array"); // notify jvmti and dtrace - post_allocation_notify(klass, (oop)obj, size); + post_allocation_notify(klass, obj, size); } void CollectedHeap::post_allocation_setup_array(KlassHandle klass, - HeapWord* obj, + HeapWord* obj_ptr, int length) { - // Set array length before setting the _klass field - // in post_allocation_setup_common() because the klass field - // indicates that the object is parsable by concurrent GC. + // Set array length before setting the _klass field because a + // non-NULL klass field indicates that the object is parsable by + // concurrent GC. assert(length >= 0, "length should be non-negative"); - ((arrayOop)obj)->set_length(length); - post_allocation_setup_common(klass, obj); - oop new_obj = (oop)obj; + ((arrayOop)obj_ptr)->set_length(length); + post_allocation_setup_common(klass, obj_ptr); + oop new_obj = (oop)obj_ptr; assert(new_obj->is_array(), "must be an array"); // notify jvmti and dtrace (must be after length is set for dtrace) post_allocation_notify(klass, new_obj, new_obj->size());
--- a/src/share/vm/oops/oop.hpp Tue Nov 26 09:27:16 2019 -0500 +++ b/src/share/vm/oops/oop.hpp Thu Sep 15 12:10:43 2016 -0400 @@ -87,6 +87,7 @@ narrowKlass* compressed_klass_addr(); void set_klass(Klass* k); + void release_set_klass(Klass* k); // For klass field compression int klass_gap() const;
--- a/src/share/vm/oops/oop.inline.hpp Tue Nov 26 09:27:16 2019 -0500 +++ b/src/share/vm/oops/oop.inline.hpp Thu Sep 15 12:10:43 2016 -0400 @@ -103,10 +103,14 @@ return &_metadata._compressed_klass; } +#define CHECK_SET_KLASS(k) \ + do { \ + assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \ + assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \ + } while (0) + inline void oopDesc::set_klass(Klass* k) { - // since klasses are promoted no store check is needed - assert(Universe::is_bootstrapping() || k != NULL, "must be a real Klass*"); - assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass*"); + CHECK_SET_KLASS(k); if (UseCompressedClassPointers) { *compressed_klass_addr() = Klass::encode_klass_not_null(k); } else { @@ -114,6 +118,18 @@ } } +inline void oopDesc::release_set_klass(Klass* k) { + CHECK_SET_KLASS(k); + if (UseCompressedClassPointers) { + OrderAccess::release_store(compressed_klass_addr(), + Klass::encode_klass_not_null(k)); + } else { + OrderAccess::release_store_ptr(klass_addr(), k); + } +} + +#undef CHECK_SET_KLASS + inline int oopDesc::klass_gap() const { return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()); }