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/*
* Copyright (C) 2013-2017 Canonical, Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* This code is a complete clean re-write of the stress tool by
* Colin Ian King <colin.king@canonical.com> and attempts to be
* backwardly compatible with the stress tool by Amos Waterland
* <apw@rossby.metr.ou.edu> but has more stress tests and more
* functionality.
*
*/
#include "stress-ng.h"
static size_t opt_vm_splice_bytes = DEFAULT_VM_SPLICE_BYTES;
static bool set_vm_splice_bytes = false;
void stress_set_vm_splice_bytes(const char *optarg)
{
set_vm_splice_bytes = true;
opt_vm_splice_bytes = (size_t)get_uint64_byte(optarg);
check_range("vm-splice-bytes", opt_vm_splice_bytes,
MIN_VM_SPLICE_BYTES, MAX_VM_SPLICE_BYTES);
}
#if defined(__linux__) && NEED_GLIBC(2,5,0)
/*
* stress_splice
* stress copying of /dev/zero to /dev/null
*/
int stress_vm_splice(
uint64_t *const counter,
const uint32_t instance,
const uint64_t max_ops,
const char *name)
{
int fd, fds[2];
uint8_t *buf;
const size_t page_size = stress_get_pagesize();
size_t sz;
(void)instance;
if (!set_vm_splice_bytes) {
if (opt_flags & OPT_FLAGS_MAXIMIZE)
opt_vm_splice_bytes = MAX_VM_SPLICE_BYTES;
if (opt_flags & OPT_FLAGS_MINIMIZE)
opt_vm_splice_bytes = MIN_VM_SPLICE_BYTES;
}
sz = opt_vm_splice_bytes & ~(page_size - 1);
buf = mmap(NULL, sz, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
if (buf == MAP_FAILED) {
int rc = exit_status(errno);
pr_fail_dbg(name, "mmap");
return rc;
}
if (pipe(fds) < 0) {
(void)munmap(buf, sz);
pr_fail_err(name, "pipe");
return EXIT_FAILURE;
}
if ((fd = open("/dev/null", O_WRONLY)) < 0) {
(void)munmap(buf, sz);
(void)close(fds[0]);
(void)close(fds[1]);
pr_fail_err(name, "open");
return EXIT_FAILURE;
}
do {
int ret;
ssize_t bytes;
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = sz;
bytes = vmsplice(fds[1], &iov, 1, 0);
if (bytes < 0)
break;
ret = splice(fds[0], NULL, fd, NULL,
opt_vm_splice_bytes, SPLICE_F_MOVE);
if (ret < 0)
break;
(*counter)++;
} while (opt_do_run && (!max_ops || *counter < max_ops));
(void)munmap(buf, sz);
(void)close(fd);
(void)close(fds[0]);
(void)close(fds[1]);
return EXIT_SUCCESS;
}
#else
int stress_vm_splice(
uint64_t *const counter,
const uint32_t instance,
const uint64_t max_ops,
const char *name)
{
return stress_not_implemented(counter, instance, max_ops, name);
}
#endif
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