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Add optional mmap(3) allocator

master
Justin R. Cutler 6 years ago
parent
commit
5b6bb204bf
  1. 22
      CMakeLists.txt
  2. 4
      config.h.in
  3. 139
      src/mmap_allocator.c
  4. 21
      test/coroutine.c
  5. 29
      threadless/mmap_allocator.h

22
CMakeLists.txt

@ -1,8 +1,20 @@
cmake_minimum_required(VERSION 3.5)
include (CheckFunctionExists)
include (CheckSymbolExists)
check_function_exists(mmap HAVE_MMAP)
if(HAVE_MMAP)
check_symbol_exists(MAP_ANONYMOUS sys/mman.h HAVE_MAP_ANONYMOUS)
if(NOT HAVE_MAP_ANONYMOUS)
check_symbol_exists(MAP_ANON sys/mman.h HAVE_MAP_ANON)
endif()
check_function_exists(mremap HAVE_MREMAP)
endif()
configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_BINARY_DIR}/config.h)
set(CMAKE_C_FLAGS "-Wall -Wextra -pedantic -Werror -std=c99")
INCLUDE_DIRECTORIES(${CMAKE_CURRENT_SOURCE_DIR})
include_directories(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
add_library (allocation src/allocation.c)
@ -10,6 +22,12 @@ add_library (coroutine src/coroutine.c)
target_link_libraries (coroutine LINK_PUBLIC allocation)
add_library (default_allocator src/default_allocator.c)
set(ALLOCATORS default_allocator)
if(HAVE_MMAP)
add_library (mmap_allocator src/mmap_allocator.c)
set(ALLOCATORS ${ALLOCATORS} mmap_allocator)
endif()
add_executable (test-coroutine test/coroutine.c)
target_link_libraries (test-coroutine LINK_PUBLIC coroutine default_allocator)
target_link_libraries (test-coroutine LINK_PUBLIC coroutine ${ALLOCATORS})

4
config.h.in

@ -0,0 +1,4 @@
#cmakedefine HAVE_MMAP
#cmakedefine HAVE_MREMAP
#cmakedefine HAVE_MAP_ANONYMOUS
#cmakedefine HAVE_MAP_ANON

139
src/mmap_allocator.c

@ -0,0 +1,139 @@
/* threadless.io
* Copyright (c) 2016 Justin R. Cutler
* Licensed under the MIT License. See LICENSE file in the project root for
* full license information.
*/
/** @file
* @c mmap(3) allocator implementation
* @author Justin R. Cutler <justin.r.cutler@gmail.com>
*/
#define _GNU_SOURCE
/* HAVE_* */
#include "config.h"
/* errno, ENOSYS */
#include <errno.h>
/* size_t, NULL */
#include <stddef.h>
#ifndef HAVE_MREMAP
/* memcpy */
# include <string.h>
#endif
/* mmap, munmap, PROT_*, MAP_*, mremap(optional), MREMAP_*(optional) */
#include <sys/mman.h>
/* sysconf, _SC_PAGESIZE */
#include <unistd.h>
/* ... */
#include <threadless/mmap_allocator.h>
#ifndef HAVE_MMAP
# error Need mmap()
#endif
#if defined(HAVE_MAP_ANONYMOUS) || defined(HAVE_MAP_ANON)
# ifndef HAVE_MAP_ANONYMOUS
# define MAP_ANONYMOUS MAP_ANON
# endif
#else
# error Need MAP_ANONYMOUS or MAP_ANON
#endif
static void *do_mmap(size_t size)
{
return mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0);
}
static void *do_mremap(void *memory, size_t old_size, size_t new_size)
{
void *new_memory;
#ifdef HAVE_MREMAP
new_memory = mremap(memory, old_size, new_size, MREMAP_MAYMOVE);
#else
/* slow remap: mmap + copy + munmap */
size_t copy_size = (new_size < old_size) ? new_size : old_size;
new_memory = do_mmap(new_size);
if (MAP_FAILED != new_memory) {
memcpy(new_memory, memory, copy_size);
(void) munmap(memory, old_size);
}
#endif
return new_memory;
}
static int mmap_allocate(allocation_t *allocation, size_t size)
{
static size_t page_size = 0;
static size_t page_mask = 0;
void *new_memory = MAP_FAILED;
if (!page_size) {
/* get page size */
long result = sysconf(_SC_PAGESIZE);
if (result > 0 && !(result & (result - 1))) {
page_size = (size_t) result;
page_mask = page_size - 1;
} else {
/* not a power of 2 */
errno = ENOSYS;
return -1;
}
}
/* round size up to multiple of page_size */
size = (size + page_size - 1) & ~page_mask;
/* no action required */
if (size == allocation->size) {
return 0;
}
if (0 == size) {
if (NULL != allocation->memory && 0 != allocation->size) {
(void)munmap(allocation->memory, allocation->size);
}
new_memory = NULL;
} else if (0 == allocation->size) {
new_memory = do_mmap(size);
} else {
new_memory = do_mremap(allocation->memory, allocation->size, size);
}
if (MAP_FAILED == new_memory) {
/* operation failed */
return -1;
}
/* update allocation */
allocation->memory = new_memory;
allocation->size = size;
return 0;
}
static void mmap_destroy(allocator_t *allocator)
{
/* ignore allocator */
(void) allocator;
}
static allocator_t mmap_allocator = {
.allocate = mmap_allocate,
.destroy = mmap_destroy,
};
allocator_t *allocator_get_mmap(void)
{
return &mmap_allocator;
}

21
test/coroutine.c

@ -8,6 +8,9 @@
* @author Justin R. Cutler <justin.r.cutler@gmail.com>
*/
/* HAVE_* */
#include "config.h"
/* printf, perror */
#include <stdio.h>
/* EXIT_SUCCESS, EXIT_FAILURE */
@ -15,6 +18,10 @@
/* allocator_t, allocator_get_default, allocator_destroy */
#include <threadless/default_allocator.h>
#ifdef HAVE_MMAP
/* allocator_get_mmap */
# include <threadless/mmap_allocator.h>
#endif
/* ... */
#include <threadless/coroutine.h>
@ -93,14 +100,24 @@ fail:
int main(int argc, char *argv[])
{
int error;
allocator_t *allocator = allocator_get_default();
allocator_t *allocator;
(void) argc;
(void) argv;
printf("default allocator:\n");
allocator = allocator_get_default();
error = run(allocator);
allocator_destroy(allocator);
#ifdef HAVE_MMAP
if (!error) {
printf("mmap allocator:\n");
allocator = allocator_get_mmap();
error = run(allocator);
allocator_destroy(allocator);
}
#endif
return !error ? EXIT_SUCCESS : EXIT_FAILURE;
}

29
threadless/mmap_allocator.h

@ -0,0 +1,29 @@
/* threadless.io
* Copyright (c) 2016 Justin R. Cutler
* Licensed under the MIT License. See LICENSE file in the project root for
* full license information.
*/
/** @file
* @c mmap(3) allocator interface definition
* @author Justin R. Cutler <justin.r.cutler@gmail.com>
*/
#ifndef THREADLESS_MMAP_ALLOCATOR_H
#define THREADLESS_MMAP_ALLOCATOR_H
/* allocator_t */
#include <threadless/allocation.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/** Get @c mmap(3) allocator instance
* @returns default allocator
*/
allocator_t *allocator_get_mmap(void);
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* THREADLESS_MMAP_ALLOCATOR_H */
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