I never had much luck running mm selftests so I spent a couple of hours digging into why.
Looks like most of the reason is missing SKIP checks, so this series is just adding a bunch of those that I found. I did not do anything like all of them, just the ones I spotted in gup_test, mmap, userfaultfd and memfd_secret.
Signed-off-by: Brendan Jackman jackmanb@google.com --- Brendan Jackman (6): selftests/mm: Report errno when things fail selftests/mm: Fix assumption that sudo is present selftests/mm: Skip uffd-stress if userfaultfd not available selftests/mm: Skip uffd-wp-mremap if userfaultfd not available selftests/mm: Print some details when uffd-stress gets bad params selftests/mm: Don't fail uffd-stress if too many CPUs
tools/testing/selftests/mm/gup_longterm.c | 32 ++++++++++++++--------------- tools/testing/selftests/mm/run_vmtests.sh | 22 ++++++++++++++++---- tools/testing/selftests/mm/uffd-stress.c | 11 +++++++--- tools/testing/selftests/mm/uffd-wp-mremap.c | 5 ++++- 4 files changed, 46 insertions(+), 24 deletions(-) --- base-commit: 87a132e73910e8689902aed7f2fc229d6908383b change-id: 20250220-mm-selftests-2d7d0542face
Best regards,
Just reporting failure doesn't tell you what went wrong. This can fail in different ways so report errno to help the reader get started debugging.
Signed-off-by: Brendan Jackman jackmanb@google.com --- tools/testing/selftests/mm/gup_longterm.c | 32 +++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-)
diff --git a/tools/testing/selftests/mm/gup_longterm.c b/tools/testing/selftests/mm/gup_longterm.c index 9423ad439a6140163bdef2974615bb86406a8c14..46a2139b3a646f6c050eb031a770f615be76c433 100644 --- a/tools/testing/selftests/mm/gup_longterm.c +++ b/tools/testing/selftests/mm/gup_longterm.c @@ -96,13 +96,13 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) int ret;
if (ftruncate(fd, size)) { - ksft_test_result_fail("ftruncate() failed\n"); + ksft_test_result_fail("ftruncate() failed (%d)\n", errno); return; }
if (fallocate(fd, 0, 0, size)) { if (size == pagesize) - ksft_test_result_fail("fallocate() failed\n"); + ksft_test_result_fail("fallocate() failed (%d)\n", errno); else ksft_test_result_skip("need more free huge pages\n"); return; @@ -112,7 +112,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) shared ? MAP_SHARED : MAP_PRIVATE, fd, 0); if (mem == MAP_FAILED) { if (size == pagesize || shared) - ksft_test_result_fail("mmap() failed\n"); + ksft_test_result_fail("mmap() failed (%d)\n", errno); else ksft_test_result_skip("need more free huge pages\n"); return; @@ -130,7 +130,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) */ ret = mprotect(mem, size, PROT_READ); if (ret) { - ksft_test_result_fail("mprotect() failed\n"); + ksft_test_result_fail("mprotect() failed (%d)\n", errno); goto munmap; } /* FALLTHROUGH */ @@ -165,18 +165,18 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) args.flags |= rw ? PIN_LONGTERM_TEST_FLAG_USE_WRITE : 0; ret = ioctl(gup_fd, PIN_LONGTERM_TEST_START, &args); if (ret && errno == EINVAL) { - ksft_test_result_skip("PIN_LONGTERM_TEST_START failed\n"); + ksft_test_result_skip("PIN_LONGTERM_TEST_START failed (EINVAL)n"); break; } else if (ret && errno == EFAULT) { ksft_test_result(!should_work, "Should have failed\n"); break; } else if (ret) { - ksft_test_result_fail("PIN_LONGTERM_TEST_START failed\n"); + ksft_test_result_fail("PIN_LONGTERM_TEST_START failed (%d)\n", errno); break; }
if (ioctl(gup_fd, PIN_LONGTERM_TEST_STOP)) - ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed\n"); + ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed (%d)\n", errno);
/* * TODO: if the kernel ever supports long-term R/W pinning on @@ -202,7 +202,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) /* Skip on errors, as we might just lack kernel support. */ ret = io_uring_queue_init(1, &ring, 0); if (ret < 0) { - ksft_test_result_skip("io_uring_queue_init() failed\n"); + ksft_test_result_skip("io_uring_queue_init() failed (%d)\n", errno); break; } /* @@ -215,13 +215,13 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) /* Only new kernels return EFAULT. */ if (ret && (errno == ENOSPC || errno == EOPNOTSUPP || errno == EFAULT)) { - ksft_test_result(!should_work, "Should have failed\n"); + ksft_test_result(!should_work, "Should have failed (%d)\n", errno); } else if (ret) { /* * We might just lack support or have insufficient * MEMLOCK limits. */ - ksft_test_result_skip("io_uring_register_buffers() failed\n"); + ksft_test_result_skip("io_uring_register_buffers() failed (%d)\n", errno); } else { ksft_test_result(should_work, "Should have worked\n"); io_uring_unregister_buffers(&ring); @@ -249,7 +249,7 @@ static void run_with_memfd(test_fn fn, const char *desc)
fd = memfd_create("test", 0); if (fd < 0) { - ksft_test_result_fail("memfd_create() failed\n"); + ksft_test_result_fail("memfd_create() failed (%d)\n", errno); return; }
@@ -266,13 +266,13 @@ static void run_with_tmpfile(test_fn fn, const char *desc)
file = tmpfile(); if (!file) { - ksft_test_result_fail("tmpfile() failed\n"); + ksft_test_result_fail("tmpfile() failed (%d)\n", errno); return; }
fd = fileno(file); if (fd < 0) { - ksft_test_result_fail("fileno() failed\n"); + ksft_test_result_fail("fileno() failed (%d)\n", errno); goto close; }
@@ -290,12 +290,12 @@ static void run_with_local_tmpfile(test_fn fn, const char *desc)
fd = mkstemp(filename); if (fd < 0) { - ksft_test_result_fail("mkstemp() failed\n"); + ksft_test_result_fail("mkstemp() failed (%d)\n", errno); return; }
if (unlink(filename)) { - ksft_test_result_fail("unlink() failed\n"); + ksft_test_result_fail("unlink() failed (%d)\n", errno); goto close; }
@@ -317,7 +317,7 @@ static void run_with_memfd_hugetlb(test_fn fn, const char *desc,
fd = memfd_create("test", flags); if (fd < 0) { - ksft_test_result_skip("memfd_create() failed\n"); + ksft_test_result_skip("memfd_create() failed (%d)\n", errno); return; }
On 20/02/25 8:33 pm, Brendan Jackman wrote:
Just reporting failure doesn't tell you what went wrong. This can fail in different ways so report errno to help the reader get started debugging.
IMHO it would be even better if we reported strerror(errno).
Signed-off-by: Brendan Jackman jackmanb@google.com
tools/testing/selftests/mm/gup_longterm.c | 32 +++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-)
diff --git a/tools/testing/selftests/mm/gup_longterm.c b/tools/testing/selftests/mm/gup_longterm.c index 9423ad439a6140163bdef2974615bb86406a8c14..46a2139b3a646f6c050eb031a770f615be76c433 100644 --- a/tools/testing/selftests/mm/gup_longterm.c +++ b/tools/testing/selftests/mm/gup_longterm.c @@ -96,13 +96,13 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) int ret; if (ftruncate(fd, size)) {
ksft_test_result_fail("ftruncate() failed\n");
ksft_test_result_fail("ftruncate() failed (%d)\n", errno);if (fallocate(fd, 0, 0, size)) { if (size == pagesize)
ksft_test_result_fail("fallocate() failed\n");
ksft_test_result_fail("fallocate() failed (%d)\n", errno);@@ -112,7 +112,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) shared ? MAP_SHARED : MAP_PRIVATE, fd, 0); if (mem == MAP_FAILED) { if (size == pagesize || shared)
ksft_test_result_fail("mmap() failed\n");
ksft_test_result_fail("mmap() failed (%d)\n", errno);@@ -130,7 +130,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) */ ret = mprotect(mem, size, PROT_READ); if (ret) {
ksft_test_result_fail("mprotect() failed\n");
ksft_test_result_fail("mprotect() failed (%d)\n", errno); goto munmap;@@ -165,18 +165,18 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) args.flags |= rw ? PIN_LONGTERM_TEST_FLAG_USE_WRITE : 0; ret = ioctl(gup_fd, PIN_LONGTERM_TEST_START, &args); if (ret && errno == EINVAL) {
ksft_test_result_skip("PIN_LONGTERM_TEST_START failed\n");
ksft_test_result_skip("PIN_LONGTERM_TEST_START failed (EINVAL)n"); break;
ksft_test_result_fail("PIN_LONGTERM_TEST_START failed\n");
ksft_test_result_fail("PIN_LONGTERM_TEST_START failed (%d)\n", errno); break;if (ioctl(gup_fd, PIN_LONGTERM_TEST_STOP))
ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed\n");
ksft_print_msg("[INFO] PIN_LONGTERM_TEST_STOP failed (%d)\n", errno);/* * TODO: if the kernel ever supports long-term R/W pinning on @@ -202,7 +202,7 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) /* Skip on errors, as we might just lack kernel support. */ ret = io_uring_queue_init(1, &ring, 0); if (ret < 0) {
ksft_test_result_skip("io_uring_queue_init() failed\n");
ksft_test_result_skip("io_uring_queue_init() failed (%d)\n", errno); break;@@ -215,13 +215,13 @@ static void do_test(int fd, size_t size, enum test_type type, bool shared) /* Only new kernels return EFAULT. */ if (ret && (errno == ENOSPC || errno == EOPNOTSUPP || errno == EFAULT)) {
ksft_test_result(!should_work, "Should have failed\n");
ksft_test_result(!should_work, "Should have failed (%d)\n", errno);
ksft_test_result_skip("io_uring_register_buffers() failed\n");
ksft_test_result_skip("io_uring_register_buffers() failed (%d)\n", errno);@@ -249,7 +249,7 @@ static void run_with_memfd(test_fn fn, const char *desc) fd = memfd_create("test", 0); if (fd < 0) {
ksft_test_result_fail("memfd_create() failed\n");
ksft_test_result_fail("memfd_create() failed (%d)\n", errno);@@ -266,13 +266,13 @@ static void run_with_tmpfile(test_fn fn, const char *desc) file = tmpfile(); if (!file) {
ksft_test_result_fail("tmpfile() failed\n");
ksft_test_result_fail("tmpfile() failed (%d)\n", errno);fd = fileno(file); if (fd < 0) {
ksft_test_result_fail("fileno() failed\n");
ksft_test_result_fail("fileno() failed (%d)\n", errno);@@ -290,12 +290,12 @@ static void run_with_local_tmpfile(test_fn fn, const char *desc) fd = mkstemp(filename); if (fd < 0) {
ksft_test_result_fail("mkstemp() failed\n");
ksft_test_result_fail("mkstemp() failed (%d)\n", errno);if (unlink(filename)) {
ksft_test_result_fail("unlink() failed\n");
ksft_test_result_fail("unlink() failed (%d)\n", errno);@@ -317,7 +317,7 @@ static void run_with_memfd_hugetlb(test_fn fn, const char *desc, fd = memfd_create("test", flags); if (fd < 0) {
ksft_test_result_skip("memfd_create() failed\n");
ksft_test_result_skip("memfd_create() failed (%d)\n", errno);
If we are root, sudo isn't needed. If we are not root, we need sudo, so skip the test if it isn't present.
We already do this for on-fault-limit, but this uses separate infrastructure since that is specifically for sudo-ing to the nobody user.
Note this ptrace_skip configuration still fails if that file doesn't exist, but in that case the test is still fine, so this just prints an error but doesn't break anything. I suspect that's probably deliberate.
Signed-off-by: Brendan Jackman jackmanb@google.com --- tools/testing/selftests/mm/run_vmtests.sh | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index da7e266681031d2772fb0c4139648904a18e0bf9..9c963f50927ab2b10c3f942cedd087087d4d0def 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -89,6 +89,17 @@ RUN_ALL=false RUN_DESTRUCTIVE=false TAP_PREFIX="# "
+# We can do stuff as root either if we are already root, or if sudo exists. +if [ "$(id -u)" == 0 ]; then + HAVE_SUDO_ROOT=true + SUDO_ROOT= +elif command -v sudo >/dev/null 2>&1; then + HAVE_SUDO_ROOT=true + SUDO_ROOT=sudo +else + HAVE_SUDO_ROOT=false +fi + while getopts "aht:n" OPT; do case ${OPT} in "a") RUN_ALL=true ;; @@ -384,10 +395,13 @@ CATEGORY="madv_guard" run_test ./guard-pages # MADV_POPULATE_READ and MADV_POPULATE_WRITE tests CATEGORY="madv_populate" run_test ./madv_populate
-if [ -x ./memfd_secret ] -then -(echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope 2>&1) | tap_prefix -CATEGORY="memfd_secret" run_test ./memfd_secret +if [ -x ./memfd_secret ]; then + if $HAVE_SUDO_ROOT; then + (echo 0 | $SUDO_ROOT tee /proc/sys/kernel/yama/ptrace_scope 2>&1) | tap_prefix + CATEGORY="memfd_secret" run_test ./memfd_secret + else + echo "# SKIP ./memfd_secret" + fi fi
# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100
It's pretty obvious that the test wouldn't work if you don't have the feature enabled. But, it's still useful to SKIP instead of failing so the reader can immediately tell that this is the reason why.
Signed-off-by: Brendan Jackman jackmanb@google.com --- tools/testing/selftests/mm/uffd-stress.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index a4b83280998ab7ce8d31e91d8f9fbb47ef11d742..db5366b4766e5bfa2d1150d2f3c2d32469a6e28b 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -411,8 +411,8 @@ static void parse_test_type_arg(const char *raw_type) * feature. */
- if (uffd_get_features(&features)) - err("failed to get available features"); + if (uffd_get_features(&features) && errno == ENOENT) + ksft_exit_skip("failed to get avialable features (%d)\n", errno);
test_uffdio_wp = test_uffdio_wp && (features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
On 20/02/25 8:33 pm, Brendan Jackman wrote:
It's pretty obvious that the test wouldn't work if you don't have the feature enabled. But, it's still useful to SKIP instead of failing so the reader can immediately tell that this is the reason why.
Signed-off-by: Brendan Jackman jackmanb@google.com
tools/testing/selftests/mm/uffd-stress.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index a4b83280998ab7ce8d31e91d8f9fbb47ef11d742..db5366b4766e5bfa2d1150d2f3c2d32469a6e28b 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -411,8 +411,8 @@ static void parse_test_type_arg(const char *raw_type) * feature. */
- if (uffd_get_features(&features))
err("failed to get available features");
- if (uffd_get_features(&features) && errno == ENOENT)
ksft_exit_skip("failed to get avialable features (%d)\n", errno);
s/avialable/available
test_uffdio_wp = test_uffdio_wp && (features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
On Thu, 20 Feb 2025 at 19:06, Dev Jain dev.jain@arm.com wrote:
if (uffd_get_features(&features))err("failed to get available features");
if (uffd_get_features(&features) && errno == ENOENT)ksft_exit_skip("failed to get avialable features (%d)\n", errno);s/avialable/available
Oh thanks. I thought I had codespell running automatically on my diffs, I'll have to look at why that wasn't caught.
It's obvious that this should fail in that case, but still, save the reader the effort of figuring out that they've run into this by just SKIPping
Signed-off-by: Brendan Jackman jackmanb@google.com --- tools/testing/selftests/mm/uffd-wp-mremap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/uffd-wp-mremap.c b/tools/testing/selftests/mm/uffd-wp-mremap.c index 2c4f984bd73caa17e12b9f4a5bb71e7fdf5d8554..c2ba7d46c7b4581a3c32a6b6acd148e3e89c2172 100644 --- a/tools/testing/selftests/mm/uffd-wp-mremap.c +++ b/tools/testing/selftests/mm/uffd-wp-mremap.c @@ -182,7 +182,10 @@ static void test_one_folio(size_t size, bool private, bool swapout, bool hugetlb
/* Register range for uffd-wp. */ if (userfaultfd_open(&features)) { - ksft_test_result_fail("userfaultfd_open() failed\n"); + if (errno == ENOENT) + ksft_test_result_skip("userfaultfd not available\n"); + else + ksft_test_result_fail("userfaultfd_open() failed\n"); goto out; } if (uffd_register(uffd, mem, size, false, true, false)) {
So this can be debugged more easily.
Signed-off-by: Brendan Jackman jackmanb@google.com --- tools/testing/selftests/mm/uffd-stress.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index db5366b4766e5bfa2d1150d2f3c2d32469a6e28b..1facfb79e09aa4113e344d7d90dec06a37264058 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -456,7 +456,8 @@ int main(int argc, char **argv)
nr_pages_per_cpu = bytes / page_size / nr_cpus; if (!nr_pages_per_cpu) { - _err("invalid MiB"); + _err("invalid MiB %lu (%lu / %lu / %lu)", + nr_pages_per_cpu, bytes, page_size, nr_cpus); usage(); }
On Thu, 20 Feb 2025 at 16:03, Brendan Jackman jackmanb@google.com wrote:
nr_pages_per_cpu = bytes / page_size / nr_cpus; if (!nr_pages_per_cpu) {
_err("invalid MiB");
_err("invalid MiB %lu (%lu / %lu / %lu)",nr_pages_per_cpu, bytes, page_size, nr_cpus);
Oh this is actually wrong - the number it's printing isn't MiB.
Assuming there's a v2 I'll fix that up. Otherwise honestly this patch could just be dropped, it's not important.
This calculation divides a fixed parameter by an environment-dependent parameter i.e. the number of CPUs.
The simple way to avoid machine-specific failures here is to just put a cap on the max value of the latter.
Suggested-by: Mateusz Guzik mjguzik@gmail.com Signed-off-by: Brendan Jackman jackmanb@google.com --- tools/testing/selftests/mm/uffd-stress.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index 1facfb79e09aa4113e344d7d90dec06a37264058..f306accbef255c79bc3eeba8b9e42161a88fc10e 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -453,6 +453,10 @@ int main(int argc, char **argv) }
nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); + if (nr_cpus > 32) { + /* Don't let calculation below go to zero. */ + nr_cpus = 32; + }
nr_pages_per_cpu = bytes / page_size / nr_cpus; if (!nr_pages_per_cpu) {
On 20/02/25 8:33 pm, Brendan Jackman wrote:
This calculation divides a fixed parameter by an environment-dependent parameter i.e. the number of CPUs.
The simple way to avoid machine-specific failures here is to just put a cap on the max value of the latter.
I haven't read the test, but if nr_cpus is being computed, then this value must be important to the test somehow? Would it potentially be wrong to let the test run for nr_cpus != actual number of cpus?
Also, if the patch is correct then will it be better to also print a diagnostic telling the user that the number of cpus is going to be capped for the test to run?
Suggested-by: Mateusz Guzik mjguzik@gmail.com Signed-off-by: Brendan Jackman jackmanb@google.com
tools/testing/selftests/mm/uffd-stress.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index 1facfb79e09aa4113e344d7d90dec06a37264058..f306accbef255c79bc3eeba8b9e42161a88fc10e 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -453,6 +453,10 @@ int main(int argc, char **argv) } nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
- if (nr_cpus > 32) {
/* Don't let calculation below go to zero. */nr_cpus = 32;- }
nr_pages_per_cpu = bytes / page_size / nr_cpus; if (!nr_pages_per_cpu) {
On Thu, 20 Feb 2025 at 16:48, Dev Jain dev.jain@arm.com wrote:
On 20/02/25 8:33 pm, Brendan Jackman wrote:
This calculation divides a fixed parameter by an environment-dependent parameter i.e. the number of CPUs.
The simple way to avoid machine-specific failures here is to just put a cap on the max value of the latter.
I haven't read the test, but if nr_cpus is being computed, then this value must be important to the test somehow? Would it potentially be wrong to let the test run for nr_cpus != actual number of cpus?
Based on my _extremely hasty_ reading, the variable is misnamed and it's actually a thread count not a CPU count. I can double check that's the case and rename it.
Also, if the patch is correct then will it be better to also print a diagnostic telling the user that the number of cpus is going to be capped for the test to run?
Sure. The level of detail in the logging and error messages is extremely low here so I didn't feel like being too anomalous, but why not.
On Thu, 20 Feb 2025 at 16:55, Brendan Jackman jackmanb@google.com wrote:
On Thu, 20 Feb 2025 at 16:48, Dev Jain dev.jain@arm.com wrote:
On 20/02/25 8:33 pm, Brendan Jackman wrote:
This calculation divides a fixed parameter by an environment-dependent parameter i.e. the number of CPUs.
The simple way to avoid machine-specific failures here is to just put a cap on the max value of the latter.
I haven't read the test, but if nr_cpus is being computed, then this value must be important to the test somehow? Would it potentially be wrong to let the test run for nr_cpus != actual number of cpus?
Based on my _extremely hasty_ reading, the variable is misnamed and it's actually a thread count not a CPU count. I can double check that's the case and rename it.
Oh yeah actually, it's only misnamed because I made it misnamed. So this patch needs to rename it for sure, thanks for pointing it out.
(But yeah I upgraded my extremely hasty reading to an only hasty reading and I still don't think this test cares about the actual CPU topology).
linux-kselftest-mirror@lists.linaro.org
-
Brendan Jackman -
Dev Jain