diff --git a/paddle/memory/detail/system_allocator.h b/paddle/memory/detail/system_allocator.h
index 04efcd9709445f7787a8f2b23d70f4cfa5d3a42d..82ba322e057575c460b1d51d719c9b0fa459273e 100644
--- a/paddle/memory/detail/system_allocator.h
+++ b/paddle/memory/detail/system_allocator.h
@@ -20,13 +20,11 @@ namespace paddle {
 namespace memory {
 namespace detail {
 
-// SystemAllocator is the parent class of CPUAllocator and
-// GPUAllocator.  A BuddyAllocator object uses a SystemAllocator*
-// pointing to the underlying system allocator.  An alternative to
-// this class hierarchy is to pass a system allocator class to
-// BuddyAllocator as a template parameter.  This approach makes
-// BuddyAllocator a class template, and it's very complicated
-// algorithm would make the buddy_allocator.h messy.
+/**
+ * \brief SystemAllocator is the parent class of CPUAllocator and GPUAllocator.
+ *        A BuddyAllocator object uses a SystemAllocator* pointing to the
+ *        underlying system allocator.
+ */
 class SystemAllocator {
  public:
   virtual ~SystemAllocator() {}
diff --git a/paddle/platform/gpu_info.cc b/paddle/platform/gpu_info.cc
index 9b917f9d35f7f7179a5330e523560bc87dfcebe0..a1383d3524aedf834c329425419b989d47668bea 100644
--- a/paddle/platform/gpu_info.cc
+++ b/paddle/platform/gpu_info.cc
@@ -65,7 +65,6 @@ size_t GpuMinChunkSize() {
 }
 
 size_t GpuMaxChunkSize() {
-  // Allow to allocate the maximum chunk size is roughly 3% of CPU memory.
   size_t total = 0;
   size_t available = 0;