src/node_buffer.h

@@ -68,8 +68,13 @@ class NODE_EXTERN Buffer: public ObjectWrap {
   // mirrors deps/v8/src/objects.h
   static const unsigned int kMaxLength = 0x3fffffff;
 
-  // exported in lib/buffer.js as Buffer.poolSize
-  static const unsigned int kPoolSize = 32768;
+  // Exported in lib/buffer.js as Buffer.poolSize. It's this big for two
+  // reasons:
+  //
+  // 1) It reduces the number of mmap() syscalls we have to make.
+  // 2) It gives the kernel a fighting chance to map it as two huge pages
+  //    instead of myriads of 4 kB pages.
+  static const unsigned int kPoolSize = 8 * 1024 * 1024;
 
   static v8::Persistent<v8::FunctionTemplate> constructor_template;
 

src/slab_allocator.h

@@ -19,13 +19,14 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+#include "node_buffer.h"  // Buffer::kPoolSize
 #include "v8.h"
 
 namespace node {
 
 class SlabAllocator {
 public:
-  SlabAllocator(unsigned int size = 10485760); // default to 10M
+  SlabAllocator(unsigned int size = Buffer::kPoolSize);
   ~SlabAllocator();
 
   // allocate memory from slab, attaches the slice to `obj`

src/stream_wrap.cc

@@ -32,8 +32,6 @@
 #include <stdlib.h> // abort()
 #include <limits.h> // INT_MAX
 
-#define SLAB_SIZE (1024 * 1024)
-
 
 namespace node {
 
@@ -91,7 +89,7 @@ void StreamWrap::Initialize(Handle<Object> target) {
   if (initialized) return;
   initialized = true;
 
-  slab_allocator = new SlabAllocator(SLAB_SIZE);
+  slab_allocator = new SlabAllocator;
   AtExit(DeleteSlabAllocator, NULL);
 
   HandleScope scope;

src/udp_wrap.cc

@@ -28,8 +28,6 @@
 
 #include <stdlib.h>
 
-#define SLAB_SIZE (1024 * 1024)
-
 
 using namespace v8;
 
@@ -67,7 +65,7 @@ UDPWrap::~UDPWrap() {
 void UDPWrap::Initialize(Handle<Object> target) {
   HandleWrap::Initialize(target);
 
-  slab_allocator = new SlabAllocator(SLAB_SIZE);
+  slab_allocator = new SlabAllocator;
   AtExit(DeleteSlabAllocator, NULL);
 
   HandleScope scope;