[LTP] [PATCH v3] mmapstress06: Convert to new API
Wei Gao
wegao@suse.com
Sat Jun 6 12:08:05 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 compatible with both cgroups v1 and v2.
- Dirties all pages of a 256MB shared anonymous mapping inside the
child cgroup, forcing the kernel to swap out memory when hitting the
128MB limit.
- Disables Transparent Huge Pages (THP) on the mapping using
madvise(..., MADV_NOHUGEPAGE) to avoid triggering cgroup OOM-kills.
- Added CONFIG_SWAP=y and CONFIG_MEMCG=y kernel configuration checks.
- Utilized declarative .min_mem_avail and .min_swap_avail for framework-level
resource validation.
Signed-off-by: Wei Gao <wegao@suse.com>
---
v2->v3:
- Reduced map_size from 1000MB to 256MB, and mem_limit from 500MB to 128MB.
- Enabled compatibility with both Cgroups v1 and v2:
- Replaced the manual sysinfo-based swap space check in setup() with declarative .min_mem_avail and .min_swap_avail structure members.
- Added madvise(..., MADV_NOHUGEPAGE) to disable Transparent Huge Pages (THP) on the mapped region to avoid premature MemCG OOM-kills under tight cgroup limits.
- Included <sys/wait.h> header for WIFEXITED/WEXITSTATUS and cleaned up unused headers (<sys/sysinfo.h> and tst_safe_macros.h).
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..ca2e856d8 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/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
+#include <stdlib.h>
+#include "tst_test.h"
+
+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;
-/***** LTP Port *****/
-#include "test.h"
-#define FAILED 0
-#define PASSED 1
+static void run_test(void)
+{
+ int status;
-int local_flag = PASSED;
-char *TCID = "mmapstress06"; //mfile_swap
-FILE *temp;
-int TST_TOTAL = 1;
+ cg_child = tst_cg_group_mk(tst_cg, "child");
-int anyfail();
-void ok_exit();
-/***** ** ** *****/
+ /* Set memory limit to force swapping of the mapping */
+ SAFE_CG_PRINTF(cg_child, "memory.max", "%lu", (unsigned long)mem_limit);
-#define ANON_GRAN_PAGES_MAX (32U)
+ if (TST_CG_VER_IS_V1(cg_child, "memory"))
+ SAFE_CG_PRINT(cg_child, "memory.swap.max", "-1");
+ else
+ 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);
+
+ /*
+ * Disable Transparent Huge Pages (THP) for this mapping.
+ * Under tight cgroup memory limits (128 MB), allocating huge
+ * pages can easily trigger MemCG OOM-kills. Disabling THP forces
+ * standard 4 KB pages, ensuring stable swapping and avoiding
+ * premature OOM.
+ */
+ if (madvise(mmapaddr, map_size, MADV_NOHUGEPAGE) < 0)
+ tst_res(TWARN | TERRNO, "madvise(MADV_NOHUGEPAGE) failed");
+
+ 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);
+
+ 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();
+ if (!SAFE_CG_HAS(tst_cg, "memory.swap.max"))
+ tst_brk(TCONF, "Cgroup swap controller is not enabled/supported");
+
+ page_size = getpagesize();
+
+ mem_limit = 128 * TST_MB;
+ map_size = 256 * 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 },
+ .min_mem_avail = 256,
+ .min_swap_avail = 128,
+ .needs_kconfigs = (const char *[]) {
+ "CONFIG_SWAP=y",
+ "CONFIG_MEMCG=y",
+ NULL
+ },
+};
--
2.54.0
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