Add hash set
More memory efficient than libcxx since we do not box the values.
Change intern table to use new hash set. Clean up intern table by
removing const casts and deleting unnecessary code.
Changed the class linker to use a hash set, also added a pre-zygote
class table.
5 samples of:
adb shell stop && adb shell start && sleep 60 && adb shell dumpsys meminfo
Before:
165929 kB: Native
175859 kB: Native
168434 kB: Native
166559 kB: Native
169958 kB: Native
After:
160972 kB: Native
159439 kB: Native
157204 kB: Native
165093 kB: Native
163039 kB: Native
TODO: Add HashTable which is implemented by using a HashSet.
TODO: Use for DexFile::find_class_def_misses_.
TODO: Investigate using mem maps instead of native heap.
Bug: 17808975
Change-Id: I93e376cf6eb9628cf52f4aefdadb6157acfb799a
(cherry picked from commit e05d1d5fd86867afc7513b1c546375dba11eee50)
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index a1cae4d..7b2ba43 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -23,6 +23,7 @@
#include <vector>
#include "base/allocator.h"
+#include "base/hash_set.h"
#include "base/macros.h"
#include "base/mutex.h"
#include "dex_file.h"
@@ -145,7 +146,7 @@
// Finds a class by its descriptor, returning NULL if it isn't wasn't loaded
// by the given 'class_loader'.
mirror::Class* LookupClass(Thread* self, const char* descriptor,
- const mirror::ClassLoader* class_loader)
+ mirror::ClassLoader* class_loader)
LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -158,7 +159,7 @@
// General class unloading is not supported, this is used to prune
// unwanted classes during image writing.
- bool RemoveClass(const char* descriptor, const mirror::ClassLoader* class_loader)
+ bool RemoveClass(const char* descriptor, mirror::ClassLoader* class_loader)
LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -458,6 +459,17 @@
return class_roots;
}
+ // Move all of the image classes into the class table for faster lookups.
+ void MoveImageClassesToClassTable()
+ LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+ // Move the class table to the pre-zygote table to reduce memory usage. This works by ensuring
+ // that no more classes are ever added to the pre zygote table which makes it that the pages
+ // always remain shared dirty instead of private dirty.
+ void MoveClassTableToPreZygote()
+ LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
private:
const OatFile::OatMethod FindOatMethodFor(mirror::ArtMethod* method, bool* found)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -685,7 +697,7 @@
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::Class* LookupClassFromTableLocked(const char* descriptor,
- const mirror::ClassLoader* class_loader,
+ mirror::ClassLoader* class_loader,
size_t hash)
SHARED_LOCKS_REQUIRED(Locks::classlinker_classes_lock_, Locks::mutator_lock_);
@@ -693,9 +705,6 @@
LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
- void MoveImageClassesToClassTable() LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
- LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
- SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::Class* LookupClassFromImage(const char* descriptor)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -724,15 +733,43 @@
std::vector<GcRoot<mirror::DexCache>> dex_caches_ GUARDED_BY(dex_lock_);
std::vector<const OatFile*> oat_files_ GUARDED_BY(dex_lock_);
+ class ClassDescriptorHashEquals {
+ public:
+ // Same class loader and descriptor.
+ std::size_t operator()(const GcRoot<mirror::Class>& root) const NO_THREAD_SAFETY_ANALYSIS;
+ bool operator()(const GcRoot<mirror::Class>& a, const GcRoot<mirror::Class>& b)
+ NO_THREAD_SAFETY_ANALYSIS;
+ // Same class loader and descriptor.
+ std::size_t operator()(const std::pair<const char*, mirror::ClassLoader*>& element) const
+ NO_THREAD_SAFETY_ANALYSIS;
+ bool operator()(const GcRoot<mirror::Class>& a,
+ const std::pair<const char*, mirror::ClassLoader*>& b)
+ NO_THREAD_SAFETY_ANALYSIS;
+ // Same descriptor.
+ bool operator()(const GcRoot<mirror::Class>& a, const char* descriptor)
+ NO_THREAD_SAFETY_ANALYSIS;
+ std::size_t operator()(const char* descriptor) const NO_THREAD_SAFETY_ANALYSIS;
+ };
+ class GcRootEmptyFn {
+ public:
+ void MakeEmpty(GcRoot<mirror::Class>& item) const {
+ item = GcRoot<mirror::Class>();
+ }
+ bool IsEmpty(const GcRoot<mirror::Class>& item) const {
+ return item.IsNull();
+ }
+ };
- // multimap from a string hash code of a class descriptor to
- // mirror::Class* instances. Results should be compared for a matching
- // Class::descriptor_ and Class::class_loader_.
- typedef AllocationTrackingMultiMap<size_t, GcRoot<mirror::Class>, kAllocatorTagClassTable> Table;
+ // hash set which hashes class descriptor, and compares descriptors nad class loaders. Results
+ // should be compared for a matching Class descriptor and class loader.
+ typedef HashSet<GcRoot<mirror::Class>, GcRootEmptyFn, ClassDescriptorHashEquals,
+ ClassDescriptorHashEquals, TrackingAllocator<GcRoot<mirror::Class>, kAllocatorTagClassTable>>
+ Table;
// This contains strong roots. To enable concurrent root scanning of
// the class table, be careful to use a read barrier when accessing this.
Table class_table_ GUARDED_BY(Locks::classlinker_classes_lock_);
- std::vector<std::pair<size_t, GcRoot<mirror::Class>>> new_class_roots_;
+ Table pre_zygote_class_table_ GUARDED_BY(Locks::classlinker_classes_lock_);
+ std::vector<GcRoot<mirror::Class>> new_class_roots_;
// Do we need to search dex caches to find image classes?
bool dex_cache_image_class_lookup_required_;