/*
* libhugetlbfs - Easy use of Linux hugepages
* Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/shm.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <hugetlbfs.h>
#include "hugetests.h"
extern int errno;
#define P "mmap-cow"
#define DESC \
"* Tests copy-on-write semantics of large pages where a number *\n"\
"* of threads map the same file with the MAP_PRIVATE flag. The *\n"\
"* threads then write into their copy of the mapping and recheck *\n"\
"* the contents to ensure they were not corrupted by the other *\n"\
"* threads. *"\
#define HTLB_FILE "mmap-cow"
#define BUF_SZ 256
#define CHILD_FAIL(thread, fmt, ...) \
do { \
verbose_printf("Thread %d (pid=%d) FAIL: " fmt, \
thread, getpid(), __VA_ARGS__); \
exit(1); \
} while (0)
/* Setup Configuration */
static int nr_hugepages; /* Number of huge pages to allocate */
static unsigned int threads; /* Number of threads to run */
static int mmap_file(int fd, char **addr, size_t size, int type)
{
int flags = 0;
*addr = mmap(NULL, size, PROT_READ|PROT_WRITE, flags | type, fd, 0);
if (*addr == MAP_FAILED)
return -1;
return 0;
}
static void do_work(int thread, size_t size, int fd)
{
char *addr;
size_t i;
char pattern = thread+65;
if (mmap_file(fd, &addr, size, MAP_PRIVATE))
CHILD_FAIL(thread, "mmap() failed: %s", strerror(errno));
verbose_printf("Thread %d (pid=%d): Mapped at address %p\n",
thread, getpid(), addr);
/* Write to the mapping with a distinct pattern */
verbose_printf("Thread %d (pid=%d): Writing %c to the mapping\n",
thread, getpid(), pattern);
for (i = 0; i < size; i++)
memcpy((char *)addr+i, &pattern, 1);
if (msync(addr, size, MS_SYNC))
CHILD_FAIL(thread, "msync() failed: %s", strerror(errno));
/* Verify the pattern */
for (i = 0; i < size; i++)
if (addr[i] != pattern)
CHILD_FAIL(thread, "Corruption at %p; "
"Got %c, Expected %c",
&addr[i], addr[i], pattern);
verbose_printf("Thread %d (pid=%d): Pattern verified\n",
thread, getpid());
/* Munmap the area */
munmap(addr, size);
close(fd);
exit(0);
}
int main(int argc, char ** argv)
{
char *addr;
long hpage_size;
size_t size;
int i, pid, status, fd, ret;
pid_t *wait_list;
test_init(argc, argv);
if (argc < 3)
CONFIG("Usage: mmap-cow <# threads> <# pages>\n");
nr_hugepages = atoi(argv[2]);
threads = atoi(argv[1]);
if ((threads+1) > nr_hugepages)
CONFIG("Need more hugepages than threads\n");
wait_list = malloc(threads * sizeof(pid_t));
if (wait_list == NULL)
CONFIG("Couldn't allocate memory for wait_list\n");
hpage_size = check_hugepagesize();
/* Have to have enough available hugepages for each thread to
* get its own copy, plus one for the parent/page-cache */
size = (nr_hugepages / (threads+1)) * hpage_size;
verbose_printf("hpage_size is %lx, Size is %zu, threads: %u\n",
hpage_size, size, threads);
/* First, open the file */
fd = hugetlbfs_unlinked_fd();
if (fd < 0)
CONFIG("hugetlbfs_unlinked_fd() failed: %s\n",
strerror(errno));
/* First, mmap the file with MAP_SHARED and fill with data
* If this is not done, then the fault handler will not be
* called in the kernel since private mappings will be
* created for the children at prefault time.
*/
if (mmap_file(fd, &addr, size, MAP_SHARED))
FAIL("Failed to create shared mapping: %s", strerror(errno));
for (i = 0; i < size; i += 8) {
memcpy(addr+i, "deadbeef", 8);
}
for (i=0; i<threads; i++) {
if ((pid = fork()) < 0)
FAIL("fork: %s", strerror(errno));
if (pid == 0)
do_work(i, size, fd);
wait_list[i] = pid;
}
for (i=0; i<threads; i++) {
ret = waitpid(wait_list[i], &status, 0);
if (ret < 0)
FAIL("waitpid(): %s", strerror(errno));
if (WEXITSTATUS(status) != 0)
FAIL("Thread %d (pid=%d) failed", i, wait_list[i]);
if (WIFSIGNALED(status))
FAIL("Thread %d (pid=%d) received unhandled signal", i,
wait_list[i]);
}
munmap(addr, size);
close(fd);
free(wait_list);
PASS();
}