genode/repos/os/include/ram_fs/param.h
2019-03-18 15:57:00 +01:00

43 lines
1.0 KiB
C++

/*
* \brief Dimensioning of the hierarchic 'Chunk' structure for the RAM fs
* \author Norman Feske
* \date 2019-03-17
*/
/*
* Copyright (C) 2019 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__RAM_FS__PARAM_H_
#define _INCLUDE__RAM_FS__PARAM_H_
/* Genode includes */
#include <base/stdint.h>
namespace Ram_fs
{
using Genode::size_t;
/*
* Let number of level-0 and level-1 entries depend on the machine-word
* size to allow the use of more than 2 GiB on 64-bit machines.
*
* 32 bit: 64*64*128*4096 = 2 GiB
* 64 bit: 128*128*128*4096 = 8 GiB
*/
static constexpr size_t num_level_0_entries()
{
return sizeof(size_t) == 8 ? 128 : 64;
}
static constexpr size_t num_level_1_entries() { return num_level_0_entries(); }
static constexpr size_t num_level_2_entries() { return 128; }
static constexpr size_t num_level_3_entries() { return 4096; }
}
#endif /* _INCLUDE__RAM_FS__PARAM_H_ */