commit dd162fb5990cedf80a5093ecc0e77df82af5f754
author Mathieu Chartier <mathieuc@google.com> Wed Aug 06 17:06:33 2014 -0700
committer Mathieu Chartier <mathieuc@google.com> Mon Aug 11 18:47:53 2014 -0700
tree d438b60c6ea77636b77c0f7edae96711cb8278a3
parent 6814d7b68ee13ec1a13ace669b025aa080d8b53e

Change FreeMemory and TotalMemory behavior.

TotalMemory is now equal to the footprint limit (around when the
next GC will occur).
FreeMemory is now equal to TotalMemory() - bytes_allocated_.
Also added more memory dumping info to DumpGcPerformanceInfo.

Bug: 16520008
Bug: 15819878

Change-Id: Ifa59a2f2136dd0704097411ee183925e6c387fae

runtime/gc/heap.h

diff --git a/runtime/gc/heap.h b/runtime/gc/heap.h
index 1851662..d5b49d8 100644
--- a/runtime/gc/heap.h
+++ b/runtime/gc/heap.h
@@ -401,18 +401,18 @@
   size_t GetObjectsAllocated() const LOCKS_EXCLUDED(Locks::heap_bitmap_lock_);
 
   // Returns the total number of objects allocated since the heap was created.
-  size_t GetObjectsAllocatedEver() const;
+  uint64_t GetObjectsAllocatedEver() const;
 
   // Returns the total number of bytes allocated since the heap was created.
-  size_t GetBytesAllocatedEver() const;
+  uint64_t GetBytesAllocatedEver() const;
 
   // Returns the total number of objects freed since the heap was created.
-  size_t GetObjectsFreedEver() const {
+  uint64_t GetObjectsFreedEver() const {
     return total_objects_freed_ever_;
   }
 
   // Returns the total number of bytes freed since the heap was created.
-  size_t GetBytesFreedEver() const {
+  uint64_t GetBytesFreedEver() const {
     return total_bytes_freed_ever_;
   }
 
@@ -421,19 +421,32 @@
   // were specified. Android apps start with a growth limit (small heap size) which is
   // cleared/extended for large apps.
   size_t GetMaxMemory() const {
-    return growth_limit_;
+    // There is some race conditions in the allocation code that can cause bytes allocated to
+    // become larger than growth_limit_ in rare cases.
+    return std::max(GetBytesAllocated(), growth_limit_);
   }
 
-  // Implements java.lang.Runtime.totalMemory, returning the amount of memory consumed by an
-  // application.
+  // Implements java.lang.Runtime.totalMemory, returning approximate amount of memory currently
+  // consumed by an application.
   size_t GetTotalMemory() const;
 
-  // Implements java.lang.Runtime.freeMemory.
+  // Returns approximately how much free memory we have until the next GC happens.
+  size_t GetFreeMemoryUntilGC() const {
+    return max_allowed_footprint_ - GetBytesAllocated();
+  }
+
+  // Returns approximately how much free memory we have until the next OOME happens.
+  size_t GetFreeMemoryUntilOOME() const {
+    return growth_limit_ - GetBytesAllocated();
+  }
+
+  // Returns how much free memory we have until we need to grow the heap to perform an allocation.
+  // Similar to GetFreeMemoryUntilGC. Implements java.lang.Runtime.freeMemory.
   size_t GetFreeMemory() const {
     size_t byte_allocated = num_bytes_allocated_.LoadSequentiallyConsistent();
-    // Make sure we don't get a negative number since the max allowed footprint is only updated
-    // after the GC. But we can still allocate even if bytes_allocated > max_allowed_footprint_.
-    return std::max(max_allowed_footprint_, byte_allocated) - byte_allocated;
+    size_t total_memory = GetTotalMemory();
+    // Make sure we don't get a negative number.
+    return total_memory - std::min(total_memory, byte_allocated);
   }
 
   // get the space that corresponds to an object's address. Current implementation searches all
@@ -885,10 +898,10 @@
   size_t concurrent_start_bytes_;
 
   // Since the heap was created, how many bytes have been freed.
-  size_t total_bytes_freed_ever_;
+  uint64_t total_bytes_freed_ever_;
 
   // Since the heap was created, how many objects have been freed.
-  size_t total_objects_freed_ever_;
+  uint64_t total_objects_freed_ever_;
 
   // Number of bytes allocated.  Adjusted after each allocation and free.
   Atomic<size_t> num_bytes_allocated_;