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/*
* Copyright (C) 2013-2021 Canonical, Ltd.
* Copyright (C) 2022-2025 Colin Ian King.
*
* 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.
*
*/
#include "stress-ng.h"
#include "core-mincore.h"
/*
* stress_mincore_touch_pages_slow()
* touch pages, even when they are resident
*/
static void stress_mincore_touch_pages_slow(
void *buf,
const size_t n_pages,
const size_t page_size,
const bool interruptible)
{
size_t i;
volatile char *buffer;
if (interruptible) {
for (buffer = buf, i = 0;
LIKELY(stress_continue_flag() && (i < n_pages));
i++, buffer += page_size) {
(*buffer)++;
}
for (buffer = buf, i = 0;
LIKELY(stress_continue_flag() && (i < n_pages));
i++, buffer += page_size) {
(*buffer)--;
}
} else {
for (buffer = buf, i = 0; i < n_pages; i++, buffer += page_size) {
(*buffer)++;
}
for (buffer = buf, i = 0; i < n_pages; i++, buffer += page_size) {
(*buffer)--;
}
}
}
/*
* stress_mincore_touch_pages_generic()
* touch a range of pages, ensure they are all in memory,
* can be interrupted if interruptible is true
*/
static int stress_mincore_touch_pages_generic(
void *buf,
const size_t buf_len,
const bool interruptible)
{
const size_t page_size = stress_get_page_size();
const size_t n_pages = buf_len / page_size;
#if !defined(HAVE_MINCORE)
if (!(g_opt_flags & OPT_FLAGS_MMAP_MINCORE))
return 0;
/* systems that don't have mincore */
stress_mincore_touch_pages_slow(buf, n_pages, page_size, interruptible);
return 0;
#else
/* systems that support mincore */
unsigned char *vec;
volatile char *buffer;
size_t i;
const uintptr_t uintptr = (uintptr_t)buf & (page_size - 1);
if (!(g_opt_flags & OPT_FLAGS_MMAP_MINCORE))
return 0;
if (n_pages < 1)
return -1;
vec = (unsigned char *)calloc(n_pages, 1);
if (!vec) {
stress_mincore_touch_pages_slow(buf, n_pages, page_size, interruptible);
return 0;
}
/*
* Find range of pages that are not in memory
*/
if (shim_mincore((void *)uintptr, buf_len, vec) < 0) {
free(vec);
stress_mincore_touch_pages_slow(buf, n_pages, page_size, interruptible);
return 0;
}
if (interruptible) {
/* If page is not resident in memory, touch it */
for (buffer = buf, i = 0;
LIKELY(stress_continue_flag() && (i < n_pages));
i++, buffer += page_size) {
if (!(vec[i] & 1))
(*buffer)++;
}
/* And restore contents */
for (buffer = buf, i = 0;
LIKELY(stress_continue_flag() && (i < n_pages));
i++, buffer += page_size) {
if (!(vec[i] & 1))
(*buffer)--;
}
} else {
/* If page is not resident in memory, touch it */
for (buffer = buf, i = 0; i < n_pages; i++, buffer += page_size) {
if (!(vec[i] & 1))
(*buffer)++;
}
/* And restore contents */
for (buffer = buf, i = 0; i < n_pages; i++, buffer += page_size) {
if (!(vec[i] & 1))
(*buffer)--;
}
}
free(vec);
return 0;
#endif
}
/*
* stress_mincore_touch_pages()
* touch a range of pages, ensure they are all in memory, non-interruptible
*/
int stress_mincore_touch_pages(void *buf, const size_t buf_len)
{
#if defined(MADV_POPULATE_READ) && \
defined(MADV_POPULATE_WRITE) && \
defined(HAVE_MADVISE)
int ret;
if (!(g_opt_flags & OPT_FLAGS_MMAP_MINCORE))
return 0;
ret = madvise(buf, buf_len, MADV_POPULATE_READ | MADV_POPULATE_WRITE);
if (ret == 0)
return 0;
#endif
return stress_mincore_touch_pages_generic(buf, buf_len, false);
}
/*
* stress_mincore_touch_pages()
* touch a range of pages, ensure they are all in memory, interruptible
*/
int stress_mincore_touch_pages_interruptible(void *buf, const size_t buf_len)
{
return stress_mincore_touch_pages_generic(buf, buf_len, true);
}
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