[LTP] [PATCH v2] mmapstress06: Convert to new API
Wei Gao
wegao@suse.com
Fri Jun 5 06:29:27 CEST 2026
Convert the mmapstress06 test case from the legacy LTP API to the new
tst_test API.
Refactor and redesign the test to be active instead of passive:
- Replaced the passive sleep-based synchronization with an active cgroup
constrained memory stress test under cgroup v2.
- Dirties all pages of the 1GB shared anonymous mapping inside the
child cgroup, forcing the kernel to swap out exactly 500MB of memory.
This large page pool avoids premature cgroup OOM-kills on systems
with larger page sizes (like 64KB on ppc64le), while keeping the total
swap usage lightweight and safe.
- Added CONFIG_SWAP=y and CONFIG_MEMCG=y kernel configuration checks.
Signed-off-by: Wei Gao <wegao@suse.com>
---
runtest/mm | 2 +-
.../kernel/mem/mmapstress/mmapstress06.c | 200 ++++++++++--------
2 files changed, 111 insertions(+), 91 deletions(-)
diff --git a/runtest/mm b/runtest/mm
index 41d624ad8..7d75b65c8 100644
--- a/runtest/mm
+++ b/runtest/mm
@@ -41,7 +41,7 @@ mmapstress02 mmapstress02
mmapstress03 mmapstress03
mmapstress04 mmapstress04
mmapstress05 mmapstress05
-mmapstress06 mmapstress06 20
+mmapstress06 mmapstress06
mmapstress07 TMPFILE=`mktemp $TMPDIR/example.XXXXXXXXXXXX`; mmapstress07 $TMPFILE
mmapstress08 mmapstress08
mmapstress09 mmapstress09 -p 20 -t 0.2
diff --git a/testcases/kernel/mem/mmapstress/mmapstress06.c b/testcases/kernel/mem/mmapstress/mmapstress06.c
index 37b7edc84..f1500eb6c 100644
--- a/testcases/kernel/mem/mmapstress/mmapstress06.c
+++ b/testcases/kernel/mem/mmapstress/mmapstress06.c
@@ -1,116 +1,136 @@
-/* IBM Corporation */
-/* 01/02/2003 Port to LTP avenkat@us.ibm.com */
-/* 06/30/2001 Port to Linux nsharoff@us.ibm.com */
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
- * Copyright (c) International Business Machines Corp., 2003
- *
- *
- * 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.
+ * Copyright (c) International Business Machines Corp., 2003
+ * Copyright (c) 2026 Linux Test Project
+ */
+
+/*\
+ * Test ``:manpage:`mmap(2)``` with swap behavior.
*
- * 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.
+ * Mmap a large anonymous shared region and force it to be swapped out
+ * by setting memory limits using Cgroups and dirtying all pages.
*
- * 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 test requires root privileges because configuring cgroup memory
+ * limits requires administrative access.
*/
-/*
- * mfile_swap:
- * Mmap a large (> ANON_GRAN_PAGES_MAX) shared, anonymous region before
- * swapping to use the second half of the kernel primitive mfile_swap.
- * However, this test does _NOT_ cause swapping to occur. Instead it should be
- * run with waves or at the same time as a test which does cause swapping (i.e.
- * vsswapin or vfork_swap)
- */
-#define _KMEMUSER
+#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/mman.h>
+#include <sys/sysinfo.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_macros.h"
-/***** LTP Port *****/
-#include "test.h"
-#define FAILED 0
-#define PASSED 1
+static struct tst_cg_group *cg_child;
+static int page_size;
+static size_t map_size;
+static size_t mem_limit;
+static pid_t child_pid = -1;
-int local_flag = PASSED;
-char *TCID = "mmapstress06"; //mfile_swap
-FILE *temp;
-int TST_TOTAL = 1;
+static void run_test(void)
+{
+ int status;
-int anyfail();
-void ok_exit();
-/***** ** ** *****/
+ cg_child = tst_cg_group_mk(tst_cg, "child");
-#define ANON_GRAN_PAGES_MAX (32U)
+ /* Set memory limit to force swapping of the mapping */
+ SAFE_CG_PRINTF(cg_child, "memory.max", "%lu", (unsigned long)mem_limit);
+ SAFE_CG_PRINT(cg_child, "memory.swap.max", "max");
-extern time_t time(time_t *);
-extern char *ctime(const time_t *);
-extern int atoi(const char *);
+ child_pid = SAFE_FORK();
+ if (!child_pid) {
+ char *mmapaddr;
+ unsigned long cg_swap_before = 0, cg_swap_after = 0;
-#define NMFPTEPG (1024)
-#define ERROR(M) (void)fprintf(stderr, "%s: errno = %d; " M "\n", \
- argv[0], errno);
+ /* Move child to the constrained cgroup */
+ SAFE_CG_PRINTF(cg_child, "cgroup.procs", "%d", getpid());
-int main(int argc, char *argv[])
-{
- caddr_t mmapaddr;
- size_t pagesize = sysconf(_SC_PAGE_SIZE);
- time_t t;
- int sleep_time = 0;
-
- if (!argc) {
- (void)fprintf(stderr, "argc == 0\n");
- anyfail();
- }
- if (argc != 2 || !(sleep_time = atoi(argv[1]))) {
- (void)fprintf(stderr, "usage: %s sleep_time\n", argv[0]);
- anyfail();
- }
- (void)time(&t);
-// (void)printf("%s: Started %s", argv[0], ctime(&t)); LTP Port
- if (sbrk(pagesize - ((ulong) sbrk(0) & (pagesize - 1))) == (char *)-1) {
- ERROR("couldn't round up brk");
- anyfail();
- }
- if ((mmapaddr = sbrk(0)) == (char *)-1) {
- ERROR("couldn't find top of brk");
- anyfail();
- }
- /* mmapaddr is now on a page boundary after the brk segment */
- if (mmap
- (mmapaddr, (ANON_GRAN_PAGES_MAX * NMFPTEPG + 1) * pagesize,
- PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, 0,
- 0) == (caddr_t) - 1) {
- ERROR("large mmap failed");
- printf("for this test to run, it needs a mmap space of\n");
- printf("%d pages\n", (ANON_GRAN_PAGES_MAX * NMFPTEPG + 1));
- return 1;
+ SAFE_CG_SCANF(cg_child, "memory.swap.current", "%lu", &cg_swap_before);
+
+ mmapaddr = SAFE_MMAP(NULL, map_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+
+ tst_res(TINFO, "Dirtying %zu bytes in child", map_size);
+
+ for (size_t i = 0; i < map_size; i += page_size)
+ mmapaddr[i] = 'a';
+
+ SAFE_CG_SCANF(cg_child, "memory.swap.current", "%lu", &cg_swap_after);
+
+ tst_res(TINFO, "Cgroup swap: %lu MB -> %lu MB",
+ cg_swap_before / TST_MB, cg_swap_after / TST_MB);
+
+ if (cg_swap_after > cg_swap_before) {
+ tst_res(TPASS, "Cgroup swap usage increased from %lu MB to %lu MB",
+ cg_swap_before / TST_MB, cg_swap_after / TST_MB);
+ } else {
+ tst_res(TFAIL, "Cgroup swap usage did not increase (before: %lu B, after: %lu B)",
+ cg_swap_before, cg_swap_after);
+ }
+
+ SAFE_MUNMAP(mmapaddr, map_size);
+ exit(0);
}
- (void)sleep(sleep_time);
- (void)time(&t);
-// (void)printf("%s: Finished %s", argv[0], ctime(&t)); LTP Port
- ok_exit();
- tst_exit();
+
+ SAFE_WAITPID(child_pid, &status, 0);
+ child_pid = -1;
+
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+ tst_res(TFAIL, "Child process failed (status: %d)", status);
+
+ cg_child = tst_cg_group_rm(cg_child);
}
-/***** LTP Port *****/
-void ok_exit(void)
+static void setup(void)
{
- tst_resm(TPASS, "Test passed");
- tst_exit();
+ struct sysinfo s;
+ unsigned long long total_swap;
+
+ if (!SAFE_CG_HAS(tst_cg, "memory.swap.max"))
+ tst_brk(TCONF, "Cgroup swap controller is not enabled/supported");
+
+ page_size = getpagesize();
+
+ mem_limit = 500 * TST_MB;
+ map_size = 1000 * TST_MB;
+
+ sysinfo(&s);
+ total_swap = (unsigned long long)s.totalswap * s.mem_unit;
+
+ if (total_swap < map_size) {
+ tst_brk(TCONF, "System swap size (%llu MB) is too small, need %llu MB",
+ total_swap / TST_MB, (unsigned long long)map_size / TST_MB);
+ }
}
-int anyfail(void)
+static void cleanup(void)
{
- tst_brkm(TFAIL, NULL, "Test failed");
+ if (child_pid > 0) {
+ SAFE_KILL(child_pid, SIGKILL);
+ SAFE_WAITPID(child_pid, NULL, 0);
+ }
+
+ if (cg_child) {
+ SAFE_CG_PRINTF(tst_cg_drain, "cgroup.procs", "%d", getpid());
+ cg_child = tst_cg_group_rm(cg_child);
+ }
}
-/***** ** ** *****/
+static struct tst_test test = {
+ .setup = setup,
+ .cleanup = cleanup,
+ .test_all = run_test,
+ .forks_child = 1,
+ .needs_root = 1,
+ .needs_cgroup_ctrls = (const char *const []){ "memory", NULL },
+ .needs_cgroup_ver = TST_CG_V2,
+ .needs_kconfigs = (const char *[]) {
+ "CONFIG_SWAP=y",
+ "CONFIG_MEMCG=y",
+ NULL
+ },
+};
--
2.54.0
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