dalvik/vm: Dalvik startup with a low memory footprint

Initialize concurrentStartBytes and createMspace using HEAP_MIN_FREE.
This helps save Android framework memory after boot.

This is for low memory targets only(<=512MB RAM & hdpi resolution)
Also, set TARGET_ARCH_LOWMEM in the BoardConfig.mk file of a device
for this patch to take effect.

Change-Id: Ia1dec6e89ef8285f1e12644bcdc6ca17a15e37a2

2 files changed, 49 insertions, 17 deletions

diff --git a/vm/Android.mk b/vm/Android.mk
index 8cca3f39b..bdd164eca 100644
--- a/vm/Android.mk
+++ b/vm/Android.mk
@@ -56,6 +56,9 @@ include $(LOCAL_PATH)/ReconfigureDvm.mk
 # Overwrite default settings
 LOCAL_MODULE := libdvm
 LOCAL_CFLAGS += $(target_smp_flag)
+ifeq ($(TARGET_ARCH_LOWMEM),true)
+  LOCAL_CFLAGS += -DDALVIK_LOWMEM
+endif
 
 # Define WITH_ADDRESS_SANITIZER to build an ASan-instrumented version of the
 # library in /system/lib/asan/libdvm.so.
@@ -150,6 +153,9 @@ ifeq ($(WITH_HOST_DALVIK),true)
     LOCAL_CFLAGS += $(host_inline_arg5_flag)
     # TODO: split out the asflags.
     LOCAL_ASFLAGS := $(LOCAL_CFLAGS)
+    ifeq ($(TARGET_ARCH_LOWMEM),true)
+      LOCAL_CFLAGS += -DDALVIK_LOWMEM
+    endif
     LOCAL_MODULE_TAGS := optional
     LOCAL_MODULE := libdvm
 
diff --git a/vm/alloc/HeapSource.cpp b/vm/alloc/HeapSource.cpp
index 8f1c4cbe2..caf30af02 100644
--- a/vm/alloc/HeapSource.cpp
+++ b/vm/alloc/HeapSource.cpp
@@ -35,7 +35,17 @@ static void setIdealFootprint(size_t max);
 static size_t getMaximumSize(const HeapSource *hs);
 static void trimHeaps();
 
+#ifdef DALVIK_LOWMEM
+static const bool lowmem = true;
+#else
+static const bool lowmem = false;
+#endif
+
 #define HEAP_UTILIZATION_MAX        1024
+#define DEFAULT_HEAP_UTILIZATION    512     // Range 1..HEAP_UTILIZATION_MAX
+#define HEAP_IDEAL_FREE_DEFAULT     (2 * 1024 * 1024)
+static unsigned int heapIdeaFree = HEAP_IDEAL_FREE_DEFAULT;
+#define HEAP_MIN_FREE               ((heapIdeaFree) / 4)
 
 /* How long to wait after a GC before performing a heap trim
  * operation to reclaim unused pages.
@@ -450,16 +460,30 @@ static bool addNewHeap(HeapSource *hs)
                   overhead, hs->maximumSize);
         return false;
     }
-    size_t morecoreStart = MAX(SYSTEM_PAGE_SIZE, gDvm.heapStartingSize);
-    heap.maximumSize = hs->growthLimit - overhead;
-    heap.concurrentStartBytes = hs->minFree - concurrentStart;
-    heap.base = base;
-    heap.limit = heap.base + heap.maximumSize;
-    heap.brk = heap.base + morecoreStart;
-    if (!remapNewHeap(hs, &heap)) {
-      return false;
+
+    if(lowmem) {
+        heap.maximumSize = hs->growthLimit - overhead;
+        heap.concurrentStartBytes = HEAP_MIN_FREE - concurrentStart;
+        heap.base = base;
+        heap.limit = heap.base + heap.maximumSize;
+        heap.brk = heap.base + HEAP_MIN_FREE;
+        if (!remapNewHeap(hs, &heap)) {
+          return false;
+        }
+        heap.msp = createMspace(base, HEAP_MIN_FREE, hs->maximumSize - overhead);
+    }
+    else {
+        size_t morecoreStart = MAX(SYSTEM_PAGE_SIZE, gDvm.heapStartingSize);
+        heap.maximumSize = hs->growthLimit - overhead;
+        heap.concurrentStartBytes = hs->minFree - concurrentStart;
+        heap.base = base;
+        heap.limit = heap.base + heap.maximumSize;
+        heap.brk = heap.base + morecoreStart;
+        if (!remapNewHeap(hs, &heap)) {
+          return false;
+        }
+        heap.msp = createMspace(base, morecoreStart, hs->minFree);
     }
-    heap.msp = createMspace(base, morecoreStart, hs->minFree);
     if (heap.msp == NULL) {
         return false;
     }
@@ -698,14 +722,16 @@ fail:
 
 bool dvmHeapSourceStartupAfterZygote()
 {
-    //For each new application forked, we need to reset softLimit and
-    //concurrentStartBytes to be the correct expected value, not the one
-    //inherit from Zygote
-    HeapSource* hs   = gHs;
-
-    hs->softLimit=SIZE_MAX;
-    hs->heaps[0].concurrentStartBytes = mspace_footprint(hs->heaps[0].msp) - concurrentStart;
-    return gDvm.concurrentMarkSweep ? gcDaemonStartup() : true;
+    if(lowmem) {
+        return gDvm.concurrentMarkSweep ? gcDaemonStartup() : true;
+    }
+    else {
+        HeapSource* hs    = gHs;
+
+        hs->softLimit=SIZE_MAX;
+        hs->heaps[0].concurrentStartBytes = mspace_footprint(hs->heaps[0].msp) - concurrentStart;
+        return gDvm.concurrentMarkSweep ? gcDaemonStartup() : true;
+    }
 }
 
 /*