A task in the kernel (task_mm_cid_work) runs somewhat periodically to
compact the mm_cid for each process. Add a test to validate that it runs
correctly and timely.
The test spawns 1 thread pinned to each CPU, then each thread, including
the main one, runs in short bursts for some time. During this period, the
mm_cids should be spanning all numbers between 0 and nproc.
At the end of this phase, a thread with high enough mm_cid (>= nproc/2)
is selected to be the new leader, all other threads terminate.
After some time, the only running thread should see 0 as mm_cid, if that
doesn't happen, the compaction mechanism didn't work and the test fails.
The test never fails if only 1 core is available, in which case, we
cannot test anything as the only available mm_cid is 0.
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
Signed-off-by: Gabriele Monaco <gmonaco(a)redhat.com>
---
tools/testing/selftests/rseq/.gitignore | 1 +
tools/testing/selftests/rseq/Makefile | 2 +-
.../selftests/rseq/mm_cid_compaction_test.c | 200 ++++++++++++++++++
3 files changed, 202 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/rseq/mm_cid_compaction_test.c
diff --git a/tools/testing/selftests/rseq/.gitignore b/tools/testing/selftests/rseq/.gitignore
index 0fda241fa62b0..b3920c59bf401 100644
--- a/tools/testing/selftests/rseq/.gitignore
+++ b/tools/testing/selftests/rseq/.gitignore
@@ -3,6 +3,7 @@ basic_percpu_ops_test
basic_percpu_ops_mm_cid_test
basic_test
basic_rseq_op_test
+mm_cid_compaction_test
param_test
param_test_benchmark
param_test_compare_twice
diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile
index 0d0a5fae59547..bc4d940f66d40 100644
--- a/tools/testing/selftests/rseq/Makefile
+++ b/tools/testing/selftests/rseq/Makefile
@@ -17,7 +17,7 @@ OVERRIDE_TARGETS = 1
TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \
param_test_benchmark param_test_compare_twice param_test_mm_cid \
param_test_mm_cid_benchmark param_test_mm_cid_compare_twice \
- syscall_errors_test
+ syscall_errors_test mm_cid_compaction_test
TEST_GEN_PROGS_EXTENDED = librseq.so
diff --git a/tools/testing/selftests/rseq/mm_cid_compaction_test.c b/tools/testing/selftests/rseq/mm_cid_compaction_test.c
new file mode 100644
index 0000000000000..7ddde3b657dd6
--- /dev/null
+++ b/tools/testing/selftests/rseq/mm_cid_compaction_test.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: LGPL-2.1
+#define _GNU_SOURCE
+#include <assert.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stddef.h>
+
+#include "../kselftest.h"
+#include "rseq.h"
+
+#define VERBOSE 0
+#define printf_verbose(fmt, ...) \
+ do { \
+ if (VERBOSE) \
+ printf(fmt, ##__VA_ARGS__); \
+ } while (0)
+
+/* 0.5 s */
+#define RUNNER_PERIOD 500000
+/* Number of runs before we terminate or get the token */
+#define THREAD_RUNS 5
+
+/*
+ * Number of times we check that the mm_cid were compacted.
+ * Checks are repeated every RUNNER_PERIOD.
+ */
+#define MM_CID_COMPACT_TIMEOUT 10
+
+struct thread_args {
+ int cpu;
+ int num_cpus;
+ pthread_mutex_t *token;
+ pthread_barrier_t *barrier;
+ pthread_t *tinfo;
+ struct thread_args *args_head;
+};
+
+static void __noreturn *thread_runner(void *arg)
+{
+ struct thread_args *args = arg;
+ int i, ret, curr_mm_cid;
+ cpu_set_t cpumask;
+
+ CPU_ZERO(&cpumask);
+ CPU_SET(args->cpu, &cpumask);
+ ret = pthread_setaffinity_np(pthread_self(), sizeof(cpumask), &cpumask);
+ if (ret) {
+ errno = ret;
+ perror("Error: failed to set affinity");
+ abort();
+ }
+ pthread_barrier_wait(args->barrier);
+
+ for (i = 0; i < THREAD_RUNS; i++)
+ usleep(RUNNER_PERIOD);
+ curr_mm_cid = rseq_current_mm_cid();
+ /*
+ * We select one thread with high enough mm_cid to be the new leader.
+ * All other threads (including the main thread) will terminate.
+ * After some time, the mm_cid of the only remaining thread should
+ * converge to 0, if not, the test fails.
+ */
+ if (curr_mm_cid >= args->num_cpus / 2 &&
+ !pthread_mutex_trylock(args->token)) {
+ printf_verbose(
+ "cpu%d has mm_cid=%d and will be the new leader.\n",
+ sched_getcpu(), curr_mm_cid);
+ for (i = 0; i < args->num_cpus; i++) {
+ if (args->tinfo[i] == pthread_self())
+ continue;
+ ret = pthread_join(args->tinfo[i], NULL);
+ if (ret) {
+ errno = ret;
+ perror("Error: failed to join thread");
+ abort();
+ }
+ }
+ pthread_barrier_destroy(args->barrier);
+ free(args->tinfo);
+ free(args->token);
+ free(args->barrier);
+ free(args->args_head);
+
+ for (i = 0; i < MM_CID_COMPACT_TIMEOUT; i++) {
+ curr_mm_cid = rseq_current_mm_cid();
+ printf_verbose("run %d: mm_cid=%d on cpu%d.\n", i,
+ curr_mm_cid, sched_getcpu());
+ if (curr_mm_cid == 0)
+ exit(EXIT_SUCCESS);
+ usleep(RUNNER_PERIOD);
+ }
+ exit(EXIT_FAILURE);
+ }
+ printf_verbose("cpu%d has mm_cid=%d and is going to terminate.\n",
+ sched_getcpu(), curr_mm_cid);
+ pthread_exit(NULL);
+}
+
+int test_mm_cid_compaction(void)
+{
+ cpu_set_t affinity;
+ int i, j, ret = 0, num_threads;
+ pthread_t *tinfo;
+ pthread_mutex_t *token;
+ pthread_barrier_t *barrier;
+ struct thread_args *args;
+
+ sched_getaffinity(0, sizeof(affinity), &affinity);
+ num_threads = CPU_COUNT(&affinity);
+ tinfo = calloc(num_threads, sizeof(*tinfo));
+ if (!tinfo) {
+ perror("Error: failed to allocate tinfo");
+ return -1;
+ }
+ args = calloc(num_threads, sizeof(*args));
+ if (!args) {
+ perror("Error: failed to allocate args");
+ ret = -1;
+ goto out_free_tinfo;
+ }
+ token = malloc(sizeof(*token));
+ if (!token) {
+ perror("Error: failed to allocate token");
+ ret = -1;
+ goto out_free_args;
+ }
+ barrier = malloc(sizeof(*barrier));
+ if (!barrier) {
+ perror("Error: failed to allocate barrier");
+ ret = -1;
+ goto out_free_token;
+ }
+ if (num_threads == 1) {
+ fprintf(stderr, "Cannot test on a single cpu. "
+ "Skipping mm_cid_compaction test.\n");
+ /* only skipping the test, this is not a failure */
+ goto out_free_barrier;
+ }
+ pthread_mutex_init(token, NULL);
+ ret = pthread_barrier_init(barrier, NULL, num_threads);
+ if (ret) {
+ errno = ret;
+ perror("Error: failed to initialise barrier");
+ goto out_free_barrier;
+ }
+ for (i = 0, j = 0; i < CPU_SETSIZE && j < num_threads; i++) {
+ if (!CPU_ISSET(i, &affinity))
+ continue;
+ args[j].num_cpus = num_threads;
+ args[j].tinfo = tinfo;
+ args[j].token = token;
+ args[j].barrier = barrier;
+ args[j].cpu = i;
+ args[j].args_head = args;
+ if (!j) {
+ /* The first thread is the main one */
+ tinfo[0] = pthread_self();
+ ++j;
+ continue;
+ }
+ ret = pthread_create(&tinfo[j], NULL, thread_runner, &args[j]);
+ if (ret) {
+ errno = ret;
+ perror("Error: failed to create thread");
+ abort();
+ }
+ ++j;
+ }
+ printf_verbose("Started %d threads.\n", num_threads);
+
+ /* Also main thread will terminate if it is not selected as leader */
+ thread_runner(&args[0]);
+
+ /* only reached in case of errors */
+out_free_barrier:
+ free(barrier);
+out_free_token:
+ free(token);
+out_free_args:
+ free(args);
+out_free_tinfo:
+ free(tinfo);
+
+ return ret;
+}
+
+int main(int argc, char **argv)
+{
+ if (!rseq_mm_cid_available()) {
+ fprintf(stderr, "Error: rseq_mm_cid unavailable\n");
+ return -1;
+ }
+ if (test_mm_cid_compaction())
+ return -1;
+ return 0;
+}
--
2.49.0
This series is built on top of the Fuad's v7 "mapping guest_memfd backed
memory at the host" [1].
With James's KVM userfault [2], it is possible to handle stage-2 faults
in guest_memfd in userspace. However, KVM itself also triggers faults
in guest_memfd in some cases, for example: PV interfaces like kvmclock,
PV EOI and page table walking code when fetching the MMIO instruction on
x86. It was agreed in the guest_memfd upstream call on 23 Jan 2025 [3]
that KVM would be accessing those pages via userspace page tables. In
order for such faults to be handled in userspace, guest_memfd needs to
support userfaultfd.
Changes since v2 [4]:
- James: Fix sgp type when calling shmem_get_folio_gfp
- James: Improved vm_ops->fault() error handling
- James: Add and make use of the can_userfault() VMA operation
- James: Add UFFD_FEATURE_MINOR_GUEST_MEMFD feature flag
- James: Fix typos and add more checks in the test
Nikita
[1] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/
[2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com/…
[3] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo…
[4] https://lore.kernel.org/kvm/20250402160721.97596-1-kalyazin@amazon.com/T/
Nikita Kalyazin (6):
mm: userfaultfd: generic continue for non hugetlbfs
mm: provide can_userfault vma operation
mm: userfaultfd: use can_userfault vma operation
KVM: guest_memfd: add support for userfaultfd minor
mm: userfaultfd: add UFFD_FEATURE_MINOR_GUEST_MEMFD
KVM: selftests: test userfaultfd minor for guest_memfd
fs/userfaultfd.c | 3 +-
include/linux/mm.h | 5 +
include/linux/mm_types.h | 4 +
include/linux/userfaultfd_k.h | 10 +-
include/uapi/linux/userfaultfd.h | 8 +-
mm/hugetlb.c | 9 +-
mm/shmem.c | 17 +++-
mm/userfaultfd.c | 47 ++++++---
.../testing/selftests/kvm/guest_memfd_test.c | 99 +++++++++++++++++++
virt/kvm/guest_memfd.c | 10 ++
10 files changed, 188 insertions(+), 24 deletions(-)
base-commit: 3cc51efc17a2c41a480eed36b31c1773936717e0
--
2.47.1
Currently testing of userspace and in-kernel API use two different
frameworks. kselftests for the userspace ones and Kunit for the
in-kernel ones. Besides their different scopes, both have different
strengths and limitations:
Kunit:
* Tests are normal kernel code.
* They use the regular kernel toolchain.
* They can be packaged and distributed as modules conveniently.
Kselftests:
* Tests are normal userspace code
* They need a userspace toolchain.
A kernel cross toolchain is likely not enough.
* A fair amout of userland is required to run the tests,
which means a full distro or handcrafted rootfs.
* There is no way to conveniently package and run kselftests with a
given kernel image.
* The kselftests makefiles are not as powerful as regular kbuild.
For example they are missing proper header dependency tracking or more
complex compiler option modifications.
Therefore kunit is much easier to run against different kernel
configurations and architectures.
This series aims to combine kselftests and kunit, avoiding both their
limitations. It works by compiling the userspace kselftests as part of
the regular kernel build, embedding them into the kunit kernel or module
and executing them from there. If the kernel toolchain is not fit to
produce userspace because of a missing libc, the kernel's own nolibc can
be used instead.
The structured TAP output from the kselftest is integrated into the
kunit KTAP output transparently, the kunit parser can parse the combined
logs together.
Further room for improvements:
* Call each test in its completely dedicated namespace
* Handle additional test files besides the test executable through
archives. CPIO, cramfs, etc.
* Compatibility with kselftest_harness.h (in progress)
* Expose the blobs in debugfs
* Provide some convience wrappers around compat userprogs
* Figure out a migration path/coexistence solution for
kunit UAPI and tools/testing/selftests/
Output from the kunit example testcase, note the output of
"example_uapi_tests".
$ ./tools/testing/kunit/kunit.py run --kunitconfig lib/kunit example
...
Running tests with:
$ .kunit/linux kunit.filter_glob=example kunit.enable=1 mem=1G console=tty kunit_shutdown=halt
[11:53:53] ================== example (10 subtests) ===================
[11:53:53] [PASSED] example_simple_test
[11:53:53] [SKIPPED] example_skip_test
[11:53:53] [SKIPPED] example_mark_skipped_test
[11:53:53] [PASSED] example_all_expect_macros_test
[11:53:53] [PASSED] example_static_stub_test
[11:53:53] [PASSED] example_static_stub_using_fn_ptr_test
[11:53:53] [PASSED] example_priv_test
[11:53:53] =================== example_params_test ===================
[11:53:53] [SKIPPED] example value 3
[11:53:53] [PASSED] example value 2
[11:53:53] [PASSED] example value 1
[11:53:53] [SKIPPED] example value 0
[11:53:53] =============== [PASSED] example_params_test ===============
[11:53:53] [PASSED] example_slow_test
[11:53:53] ======================= (4 subtests) =======================
[11:53:53] [PASSED] procfs
[11:53:53] [PASSED] userspace test 2
[11:53:53] [SKIPPED] userspace test 3: some reason
[11:53:53] [PASSED] userspace test 4
[11:53:53] ================ [PASSED] example_uapi_test ================
[11:53:53] ===================== [PASSED] example =====================
[11:53:53] ============================================================
[11:53:53] Testing complete. Ran 16 tests: passed: 11, skipped: 5
[11:53:53] Elapsed time: 67.543s total, 1.823s configuring, 65.655s building, 0.058s running
Based on v6.15-rc1.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
---
Changes in v3:
- Reintroduce CONFIG_CC_CAN_LINK_STATIC
- Enable CONFIG_ARCH_HAS_NOLIBC for m68k and SPARC
- Properly handle 'clean' target for userprogs
- Use ramfs over tmpfs to reduce dependencies
- Inherit userprogs byte order and ABI from kernel
- Drop now unnecessary "#ifndef NOLIBC"
- Pick up review tags
- Drop usage of __private in blob.h,
sparse complains and it is not really necessary
- Fix execution on loongarch when using clang
- Drop userprogs libgcc handling, it was ugly and is not yet necessary
- Link to v2: https://lore.kernel.org/r/20250407-kunit-kselftests-v2-0-454114e287fd@linut…
Changes in v2:
- Rebase onto v6.15-rc1
- Add documentation and kernel docs
- Resolve invalid kconfig breakages
- Drop already applied patch "kbuild: implement CONFIG_HEADERS_INSTALL for Usermode Linux"
- Drop userprogs CONFIG_WERROR integration, it doesn't need to be part of this series
- Replace patch prefix "kconfig" with "kbuild"
- Rename kunit_uapi_run_executable() to kunit_uapi_run_kselftest()
- Generate private, conflict-free symbols in the blob framework
- Handle kselftest exit codes
- Handle SIGABRT
- Forward output also to kunit debugfs log
- Install a fd=0 stdin filedescriptor
- Link to v1: https://lore.kernel.org/r/20250217-kunit-kselftests-v1-0-42b4524c3b0a@linut…
---
Thomas Weißschuh (16):
kbuild: userprogs: avoid duplicating of flags inherited from kernel
kbuild: userprogs: also inherit byte order and ABI from kernel
init: re-add CONFIG_CC_CAN_LINK_STATIC
kbuild: userprogs: add nolibc support
kbuild: introduce CONFIG_ARCH_HAS_NOLIBC
kbuild: doc: add label for userprogs section
kbuild: introduce blob framework
kunit: tool: Add test for nested test result reporting
kunit: tool: Don't overwrite test status based on subtest counts
kunit: tool: Parse skipped tests from kselftest.h
kunit: Always descend into kunit directory during build
kunit: qemu_configs: loongarch: Enable LSX/LSAX
kunit: Introduce UAPI testing framework
kunit: uapi: Add example for UAPI tests
kunit: uapi: Introduce preinit executable
kunit: uapi: Validate usability of /proc
Documentation/dev-tools/kunit/api/index.rst | 5 +
Documentation/dev-tools/kunit/api/uapi.rst | 12 +
Documentation/kbuild/makefiles.rst | 38 ++-
MAINTAINERS | 2 +
Makefile | 7 +-
include/kunit/uapi.h | 24 ++
include/linux/blob.h | 31 +++
init/Kconfig | 7 +
lib/Makefile | 4 -
lib/kunit/Kconfig | 10 +
lib/kunit/Makefile | 20 +-
lib/kunit/kunit-example-test.c | 15 ++
lib/kunit/kunit-example-uapi.c | 54 ++++
lib/kunit/uapi-preinit.c | 63 +++++
lib/kunit/uapi.c | 294 +++++++++++++++++++++
scripts/Makefile.blobs | 19 ++
scripts/Makefile.build | 6 +
scripts/Makefile.clean | 2 +-
scripts/Makefile.userprogs | 13 +-
scripts/blob-wrap.c | 27 ++
tools/include/nolibc/Kconfig.nolibc | 15 ++
tools/testing/kunit/kunit_parser.py | 13 +-
tools/testing/kunit/kunit_tool_test.py | 9 +
tools/testing/kunit/qemu_configs/loongarch.py | 2 +
.../test_is_test_passed-failure-nested.log | 10 +
.../test_data/test_is_test_passed-kselftest.log | 3 +-
26 files changed, 686 insertions(+), 19 deletions(-)
---
base-commit: f07a3558c4a5d76f3fea004075e5151c4516d055
change-id: 20241015-kunit-kselftests-56273bc40442
Best regards,
--
Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
Code using IS_ENABLED(CONFIG_MODULES) as a C expression may need access
to the module structure definitions to compile.
Make sure these structure definitions are always visible.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
---
Thomas Weißschuh (3):
module: move 'struct module_use' to internal.h
module: make structure definitions always visible
kunit: test: Drop CONFIG_MODULE ifdeffery
include/linux/module.h | 30 ++++++++++++------------------
kernel/module/internal.h | 7 +++++++
lib/kunit/test.c | 8 --------
3 files changed, 19 insertions(+), 26 deletions(-)
---
base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
change-id: 20250611-kunit-ifdef-modules-0fefd13ae153
Best regards,
--
Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
We already have a selftest for harness, while there is not usage
of FIXTURE_VARIANT.
Patch 2 add FIXTURE_VARIANT usage in the selftest.
Patch 1 is a typo fix.
v2:
* drop patch 2 in v1
* adjust patch 2 based on Thomas comment
Wei Yang (2):
selftests: harness: correct typo of __constructor_order_forward in
comment
selftests: harness: Add kselftest harness selftest with variant
tools/testing/selftests/kselftest_harness.h | 2 +-
.../kselftest_harness/harness-selftest.c | 30 +++++++++++++++++++
.../harness-selftest.expected | 20 ++++++++++---
3 files changed, 47 insertions(+), 5 deletions(-)
--
2.34.1
nolibc only supports symbol-based stackprotectors, based on the global
variable __stack_chk_guard. Support for this differs between
architectures and toolchains. Some use the symbol mode by default, some
require a flag to enable it and some don't support it at all.
Before the nolibc test Makefile required the availability of
"-mstack-protector-guard=global" to enable stackprotectors.
While this flag makes sure that the correct mode is available it doesn't
work where the correct mode is the only supported one and therefore the
flag is not implemented.
Switch to a more dynamic probing mechanism.
This correctly enables stack protectors for mips, loongarch and m68k.
Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net>
---
tools/testing/selftests/nolibc/Makefile | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 94176ffe46463548cc9bc787933b6cefa83d6502..853f3a846d4c0fb187922d3063ec3d1a9a30ae46 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -195,7 +195,10 @@ CFLAGS_sparc32 = $(call cc-option,-m32)
ifeq ($(origin XARCH),command line)
CFLAGS_XARCH = $(CFLAGS_$(XARCH))
endif
-CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
+_CFLAGS_STACKPROTECTOR = $(call cc-option,-fstack-protector-all) $(call cc-option,-mstack-protector-guard=global)
+CFLAGS_STACKPROTECTOR ?= $(call try-run, \
+ echo 'void foo(void) {}' | $(CC) -x c - -o - -S $(_CFLAGS_STACKPROTECTOR) | grep -q __stack_chk_guard, \
+ $(_CFLAGS_STACKPROTECTOR))
CFLAGS_SANITIZER ?= $(call cc-option,-fsanitize=undefined -fsanitize-trap=all)
CFLAGS ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -W -Wall -Wextra \
$(call cc-option,-fno-stack-protector) $(call cc-option,-Wmissing-prototypes) \
---
base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
change-id: 20250530-nolibc-stackprotector-robust-77c9f55a3921
Best regards,
--
Thomas Weißschuh <linux(a)weissschuh.net>
When running the khugepaged selftest for shmem (./khugepaged all:shmem),
I encountered the following test failures:
"
Run test: collapse_full (khugepaged:shmem)
Collapse multiple fully populated PTE table.... Fail
...
Run test: collapse_single_pte_entry (khugepaged:shmem)
Collapse PTE table with single PTE entry present.... Fail
...
Run test: collapse_full_of_compound (khugepaged:shmem)
Allocate huge page... OK
Split huge page leaving single PTE page table full of compound pages... OK
Collapse PTE table full of compound pages.... Fail
"
The reason for the failure is that, it will set MADV_NOHUGEPAGE to prevent
khugepaged from continuing to scan shmem VMA after khugepaged finishes
scanning in the wait_for_scan() function. Moreover, shmem requires a refault
to establish PMD mappings.
However, after commit 2b0f922323cc, PMD mappings are prevented if the VMA is
set with MADV_NOHUGEPAGE flag, so shmem cannot establish PMD mappings during
refault.
To fix this issue, we can set the MADV_NOHUGEPAGE flag after the shmem refault.
With this fix, the shmem test case passes.
Fixes: 2b0f922323cc ("mm: don't install PMD mappings when THPs are disabled by the hw/process/vma")
Signed-off-by: Baolin Wang <baolin.wang(a)linux.alibaba.com>
---
tools/testing/selftests/mm/khugepaged.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c
index 8a4d34cce36b..d462f62d8116 100644
--- a/tools/testing/selftests/mm/khugepaged.c
+++ b/tools/testing/selftests/mm/khugepaged.c
@@ -561,8 +561,6 @@ static bool wait_for_scan(const char *msg, char *p, int nr_hpages,
usleep(TICK);
}
- madvise(p, nr_hpages * hpage_pmd_size, MADV_NOHUGEPAGE);
-
return timeout == -1;
}
@@ -585,6 +583,7 @@ static void khugepaged_collapse(const char *msg, char *p, int nr_hpages,
if (ops != &__anon_ops)
ops->fault(p, 0, nr_hpages * hpage_pmd_size);
+ madvise(p, nr_hpages * hpage_pmd_size, MADV_NOHUGEPAGE);
if (ops->check_huge(p, expect ? nr_hpages : 0))
success("OK");
else
--
2.43.5