[glib] gio: Bump copy buffer size to 256k by default

[Bastien Nocera <hadess src gnome org>]

commit 3b5b5696ed121ef6ff48fd076fccf95053db33a7
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Nov 2 11:58:14 2016 +0100

    gio: Bump copy buffer size to 256k by default
    
    This is small enough that it shouldn't cause problems on most machines
    we support, but big enough to increase throughput on a lot of devices
    and network protocols.
    
    Note that the actual value is 256k minus malloc overhead, so that it
    fits nicely in a 256k block (as suggested by Alexander Larsson).
    
    See https://bugzilla.gnome.org/show_bug.cgi?id=773632
    
    https://bugzilla.gnome.org/show_bug.cgi?id=773823

 gio/gfile.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gio/gfile.c b/gio/gfile.c
index 218d9af..af0587b 100644
--- a/gio/gfile.c
+++ b/gio/gfile.c
@@ -2765,7 +2765,8 @@ g_file_copy_attributes (GFile           *source,
   return res;
 }
 
-#define STREAM_BUFFER_SIZE (1024*64)
+/* 256k minus malloc overhead */
+#define STREAM_BUFFER_SIZE (1024*256 - 2 *sizeof(gpointer))
 
 static gboolean
 copy_stream_with_progress (GInputStream           *in,