--- a/include/libtorrent/aux_/buffer.hpp
+++ b/include/libtorrent/aux_/buffer.hpp
@@ -87,17 +87,7 @@ public:
 		m_begin = static_cast<char*>(std::malloc(static_cast<std::size_t>(size)));
 		if (m_begin == nullptr) aux::throw_ex<std::bad_alloc>();
 
-		// the actual allocation may be larger than we requested. If so, let the
-		// user take advantage of every single byte
-#if (defined __GLIBC__ && !defined __UCLIBC__) || defined __FreeBSD__
-		m_size = static_cast<difference_type>(::malloc_usable_size(m_begin));
-#elif defined _MSC_VER
-		m_size = static_cast<difference_type>(::_msize(m_begin));
-#elif defined __APPLE__
-		m_size = static_cast<difference_type>(::malloc_size(m_begin));
-#else
 		m_size = size;
-#endif
 	}
 
 	// allocate an uninitialized buffer of the specified size