Trim arenas for JIT
Moved arena pool into the runtime. Added arena trimming to arena
pool. When called, this madvises the used memory.
Changed the JIT compiler to trim arenas after compilation. Changed
the arena mmap name to dalvik-LinearAlloc.
Native PSS before:
80353 kB: Native
80775 kB: Native
78116 kB: Native
After:
73357 kB: Native
70181 kB: Native
70306 kB: Native
Bug: 17950037
Bug: 17643507
Bug: 19264997
Change-Id: I63e7a898fd6e909c2c677fa57b5917a7b1398930
diff --git a/runtime/base/arena_allocator.cc b/runtime/base/arena_allocator.cc
index e6380bf..70d138d 100644
--- a/runtime/base/arena_allocator.cc
+++ b/runtime/base/arena_allocator.cc
@@ -26,8 +26,9 @@
namespace art {
-// Memmap is a bit slower than malloc according to my measurements.
-static constexpr bool kUseMemMap = false;
+// Memmap is a bit slower than malloc to allocate, but this is mitigated by the arena pool which
+// only allocates few arenas and recycles them afterwards.
+static constexpr bool kUseMemMap = true;
static constexpr bool kUseMemSet = true && kUseMemMap;
static constexpr size_t kValgrindRedZoneBytes = 8;
constexpr size_t Arena::kDefaultSize;
@@ -129,8 +130,8 @@
next_(nullptr) {
if (kUseMemMap) {
std::string error_msg;
- map_ = MemMap::MapAnonymous("dalvik-arena", nullptr, size, PROT_READ | PROT_WRITE, false, false,
- &error_msg);
+ map_ = MemMap::MapAnonymous("dalvik-LinearAlloc", nullptr, size, PROT_READ | PROT_WRITE, false,
+ false, &error_msg);
CHECK(map_ != nullptr) << error_msg;
memory_ = map_->Begin();
size_ = map_->Size();
@@ -148,8 +149,15 @@
}
}
+void Arena::Release() {
+ if (kUseMemMap && bytes_allocated_ > 0) {
+ map_->MadviseDontNeedAndZero();
+ bytes_allocated_ = 0;
+ }
+}
+
void Arena::Reset() {
- if (bytes_allocated_) {
+ if (bytes_allocated_ > 0) {
if (kUseMemSet || !kUseMemMap) {
memset(Begin(), 0, bytes_allocated_);
} else {
@@ -162,6 +170,9 @@
ArenaPool::ArenaPool()
: lock_("Arena pool lock"),
free_arenas_(nullptr) {
+ if (kUseMemMap) {
+ MemMap::Init();
+ }
}
ArenaPool::~ArenaPool() {
@@ -189,6 +200,13 @@
return ret;
}
+void ArenaPool::TrimMaps() {
+ MutexLock lock(Thread::Current(), lock_);
+ for (auto* arena = free_arenas_; arena != nullptr; arena = arena->next_) {
+ arena->Release();
+ }
+}
+
size_t ArenaPool::GetBytesAllocated() const {
size_t total = 0;
MutexLock lock(Thread::Current(), lock_);