* [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
@ 2026-09-02 17:56 Yeoreum Yun
2026-09-02 19:29 ` Andrew Morton
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-09-02 17:56 UTC (permalink / raw)
To: linux-mm, linux-kselftest
Cc: akpm, david, ljs, liam, vbabka, rppt, surenb, mhocko, shuah, ziy,
baolin.wang, nico.pache, ryan.roberts, dev.jain, baohua,
lance.yang, usama.arif, kas, Yeoreum Yun
HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
When this macro is used in some test, test result would be strange in
the system where PAGE_SIZE is more than 4KB.
Here is example with transhuge-stress test with 16KB PAGE_SIZE:
transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
...
ok 1 Completed
Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
helper, read_pmd_pagesize().
Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
After this patch, output of transhuge-stress:
transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram
2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages
2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages
2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages
2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages
2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages
2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages
2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages
2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages
...
ok 1 Completed
Suggested-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
tools/testing/selftests/mm/guard-regions.c | 12 +++++--
tools/testing/selftests/mm/ksm_tests.c | 17 ++++++----
tools/testing/selftests/mm/run_vmtests.sh | 4 +--
tools/testing/selftests/mm/transhuge-stress.c | 22 +++++++------
tools/testing/selftests/mm/vm_util.c | 32 ++++++++++++++++---
tools/testing/selftests/mm/vm_util.h | 9 ++----
6 files changed, 66 insertions(+), 30 deletions(-)
diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c
index 5c8ec3ca75d7..d370592b291f 100644
--- a/tools/testing/selftests/mm/guard-regions.c
+++ b/tools/testing/selftests/mm/guard-regions.c
@@ -2195,14 +2195,22 @@ TEST_F(guard_regions, pagemap_scan)
TEST_F(guard_regions, collapse)
{
const unsigned long page_size = self->page_size;
- const unsigned long size = 2 * HPAGE_SIZE;
- const unsigned long num_pages = size / page_size;
+ uint64_t hpage_size;
+ unsigned long size;
+ unsigned long num_pages;
char *ptr;
int i;
if (!thp_available())
SKIP(return, "Transparent Hugepages not available\n");
+ hpage_size = read_pmd_pagesize();
+ if (!hpage_size)
+ ksft_exit_fail_msg("reading hpage_size failed\n");
+
+ size = 2 * hpage_size;
+ num_pages = size / page_size;
+
/* Need file to be correct size for tests for non-anon. */
if (variant->backing != ANON_BACKED)
ASSERT_EQ(ftruncate(self->fd, size), 0);
diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c
index 5fd7792a0d47..278e77055007 100644
--- a/tools/testing/selftests/mm/ksm_tests.c
+++ b/tools/testing/selftests/mm/ksm_tests.c
@@ -521,6 +521,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
struct timespec start_time, end_time;
unsigned long scan_time_ns;
int pagemap_fd, n_normal_pages, n_huge_pages;
+ uint64_t hpage_size = read_pmd_pagesize();
+
+ if (!hpage_size) {
+ ksft_exit_fail_msg("reading hpage_size failed\n");
+ }
if (!thp_is_enabled()) {
ksft_print_msg("Transparent Hugepages not available\n");
@@ -530,10 +535,10 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
map_size *= MB;
size_t len = map_size;
- len -= len % HPAGE_SIZE;
- map_ptr_orig = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
+ len -= len % hpage_size;
+ map_ptr_orig = mmap(NULL, len + hpage_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
- map_ptr = map_ptr_orig + HPAGE_SIZE - (uintptr_t)map_ptr_orig % HPAGE_SIZE;
+ map_ptr = map_ptr_orig + hpage_size - (uintptr_t)map_ptr_orig % hpage_size;
if (map_ptr_orig == MAP_FAILED)
err(2, "initial mmap");
@@ -547,7 +552,7 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
n_normal_pages = 0;
n_huge_pages = 0;
- for (void *p = map_ptr; p < map_ptr + len; p += HPAGE_SIZE) {
+ for (void *p = map_ptr; p < map_ptr + len; p += hpage_size) {
if (allocate_transhuge(p, pagemap_fd) < 0)
n_normal_pages++;
else
@@ -578,11 +583,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
ksft_print_msg("Average speed: %.3f MiB/s\n", (map_size / MB) /
((double)scan_time_ns / NSEC_PER_SEC));
- munmap(map_ptr_orig, len + HPAGE_SIZE);
+ munmap(map_ptr_orig, len + hpage_size);
return KSFT_PASS;
err_out:
- munmap(map_ptr_orig, len + HPAGE_SIZE);
+ munmap(map_ptr_orig, len + hpage_size);
return KSFT_FAIL;
}
diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index d09f9f6a384e..24aa1de27c25 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -360,8 +360,8 @@ fi
CATEGORY="memfd_secret" run_test ./memfd_secret
fi
-# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100
-CATEGORY="ksm" run_test ./ksm_tests -H -s 100
+# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 512
+CATEGORY="ksm" run_test ./ksm_tests -H -s 512
# KSM KSM_MERGE_TIME test with size of 100
CATEGORY="ksm" run_test ./ksm_tests -P -s 100
# KSM MADV_MERGEABLE test with 10 identical pages
diff --git a/tools/testing/selftests/mm/transhuge-stress.c b/tools/testing/selftests/mm/transhuge-stress.c
index 8eb0c5630e7e..66ae94afaf8d 100644
--- a/tools/testing/selftests/mm/transhuge-stress.c
+++ b/tools/testing/selftests/mm/transhuge-stress.c
@@ -35,6 +35,8 @@ int main(int argc, char **argv)
size_t map_len;
int pagemap_fd;
int duration = 0;
+ uint64_t hpage_size = read_pmd_pagesize();
+ uint64_t hpage_shift = hpshift();
ksft_print_header();
@@ -70,23 +72,23 @@ int main(int argc, char **argv)
}
warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
- " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
- ram >> (20 + HPAGE_SHIFT - pshift() - 1));
+ " and %zd MiB of ram", len >> hpage_shift, len >> 20,
+ ram >> (20 + hpage_shift - pshift() - 1));
pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
if (pagemap_fd < 0)
ksft_exit_fail_msg("open pagemap\n");
- len -= len % HPAGE_SIZE;
- ptr = mmap(NULL, len + HPAGE_SIZE, PROT_RW, mmap_flags, backing_fd, 0);
+ len -= len % hpage_size;
+ ptr = mmap(NULL, len + hpage_size, PROT_RW, mmap_flags, backing_fd, 0);
if (ptr == MAP_FAILED)
ksft_exit_fail_msg("initial mmap");
- ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;
+ ptr += hpage_size - (uintptr_t)ptr % hpage_size;
if (madvise(ptr, len, MADV_HUGEPAGE))
ksft_exit_fail_msg("MADV_HUGEPAGE");
- map_len = ram >> (HPAGE_SHIFT - 1);
+ map_len = ram >> (hpage_shift - 1);
map = malloc(map_len);
if (!map)
ksft_exit_fail_msg("map malloc\n");
@@ -99,7 +101,7 @@ int main(int argc, char **argv)
memset(map, 0, map_len);
clock_gettime(CLOCK_MONOTONIC, &a);
- for (p = ptr; p < ptr + len; p += HPAGE_SIZE) {
+ for (p = ptr; p < ptr + len; p += hpage_size) {
int64_t pfn;
pfn = allocate_transhuge(p, pagemap_fd);
@@ -107,7 +109,7 @@ int main(int argc, char **argv)
if (pfn < 0) {
nr_failed++;
} else {
- size_t idx = pfn >> (HPAGE_SHIFT - pshift());
+ size_t idx = pfn >> (hpage_shift - pshift());
nr_succeed++;
if (idx >= map_len) {
@@ -123,7 +125,7 @@ int main(int argc, char **argv)
}
/* split transhuge page, keep last page */
- if (madvise(p, HPAGE_SIZE - psize(), MADV_DONTNEED))
+ if (madvise(p, hpage_size - psize(), MADV_DONTNEED))
ksft_exit_fail_msg("MADV_DONTNEED");
}
clock_gettime(CLOCK_MONOTONIC, &b);
@@ -131,7 +133,7 @@ int main(int argc, char **argv)
ksft_print_msg("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t"
"%4d succeed, %4d failed, %4d different pages\n",
- s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20),
+ s, s * 1000 / (len >> hpage_shift), len / s / (1 << 20),
nr_succeed, nr_failed, nr_pages);
if (duration > 0 && b.tv_sec - start.tv_sec >= duration) {
diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
index 4821a3563036..4332f8fb2104 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -21,6 +21,8 @@
unsigned int __page_size;
unsigned int __page_shift;
+uint64_t __hpage_size;
+uint64_t __hpage_shift;
uint64_t pagemap_get_entry(int fd, char *start)
{
@@ -161,6 +163,9 @@ uint64_t read_pmd_pagesize(void)
char buf[20];
ssize_t num_read;
+ if (__hpage_size)
+ return __hpage_size;
+
fd = open(PMD_SIZE_FILE_PATH, O_RDONLY);
if (fd == -1)
return 0;
@@ -173,7 +178,24 @@ uint64_t read_pmd_pagesize(void)
buf[num_read] = '\0';
close(fd);
- return strtoul(buf, NULL, 10);
+ __hpage_size = strtoul(buf, NULL, 10);
+
+ return __hpage_size;
+}
+
+uint64_t hpshift(void)
+{
+ if (!__hpage_shift) {
+ if (!__hpage_size) {
+ __hpage_size = read_pmd_pagesize();
+ if (!__hpage_size)
+ ksft_exit_fail_msg("reading __hpage_size failed\n");
+ }
+
+ __hpage_shift = (ffsl(__hpage_size) - 1);
+ }
+
+ return __hpage_shift;
}
unsigned long rss_anon(void)
@@ -452,14 +474,16 @@ bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size
int64_t allocate_transhuge(void *ptr, int pagemap_fd)
{
uint64_t ent[2];
+ uint64_t hpage_size = read_pmd_pagesize();
+ uint64_t hpage_shift = hpshift();
/* drop pmd */
- if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
+ if (mmap(ptr, hpage_size, PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_ANONYMOUS |
MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
ksft_exit_fail_msg("mmap transhuge\n");
- if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
+ if (madvise(ptr, hpage_size, MADV_HUGEPAGE))
ksft_exit_fail_msg("MADV_HUGEPAGE\n");
/* allocate transparent huge page */
@@ -471,7 +495,7 @@ int64_t allocate_transhuge(void *ptr, int pagemap_fd)
if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) &&
PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) &&
- !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - pshift())) - 1)))
+ !(PAGEMAP_PFN(ent[0]) & ((1 << (hpage_shift - pshift())) - 1)))
return PAGEMAP_PFN(ent[0]);
return -1;
diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
index 9a49af88702e..20a6334605c7 100644
--- a/tools/testing/selftests/mm/vm_util.h
+++ b/tools/testing/selftests/mm/vm_util.h
@@ -31,6 +31,8 @@
extern unsigned int __page_size;
extern unsigned int __page_shift;
+extern uint64_t __hpage_size;
+extern uint64_t __hpage_shift;
/*
* Represents an open fd and PROCMAP_QUERY state for binary (via ioctl)
@@ -89,6 +91,7 @@ unsigned long pagemap_get_pfn(int fd, char *start);
void clear_softdirty(void);
bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len);
uint64_t read_pmd_pagesize(void);
+uint64_t hpshift(void);
unsigned long rss_anon(void);
bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
@@ -157,12 +160,6 @@ int ksm_stop(void);
int get_hardware_corrupted_size(unsigned long *val);
int unpoison_memory(unsigned long pfn);
-/*
- * On ppc64 this will only work with radix 2M hugepage size
- */
-#define HPAGE_SHIFT 21
-#define HPAGE_SIZE (1 << HPAGE_SHIFT)
-
#define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0)
#define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1))
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-02 17:56 [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Yeoreum Yun
@ 2026-09-02 19:29 ` Andrew Morton
2026-09-03 8:51 ` Yeoreum Yun
2026-09-03 8:56 ` Lorenzo Stoakes (ARM)
2026-09-03 11:12 ` Sarthak Sharma
2 siblings, 1 reply; 9+ messages in thread
From: Andrew Morton @ 2026-09-02 19:29 UTC (permalink / raw)
To: Yeoreum Yun
Cc: linux-mm, linux-kselftest, david, ljs, liam, vbabka, rppt, surenb,
mhocko, shuah, ziy, baolin.wang, nico.pache, ryan.roberts,
dev.jain, baohua, lance.yang, usama.arif, kas
On Wed, 2 Sep 2026 18:56:11 +0100 Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> When this macro is used in some test, test result would be strange in
> the system where PAGE_SIZE is more than 4KB.
>
> Here is example with transhuge-stress test with 16KB PAGE_SIZE:
>
> ...
>
> ok 1 Completed
>
> Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
> helper, read_pmd_pagesize().
>
> Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
>
> After this patch, output of transhuge-stress:
>
> ...
>
> ok 1 Completed
Thanks. Sashiko made claims. The first looks legit, although minor:
https://sashiko.dev/#/patchset/20260902175611.1241118-1-yeoreum.yun@arm.com
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-02 19:29 ` Andrew Morton
@ 2026-09-03 8:51 ` Yeoreum Yun
0 siblings, 0 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-09-03 8:51 UTC (permalink / raw)
To: Andrew Morton
Cc: Yeoreum Yun, linux-mm, linux-kselftest, david, ljs, liam, vbabka,
rppt, surenb, mhocko, shuah, ziy, baolin.wang, nico.pache,
ryan.roberts, dev.jain, baohua, lance.yang, usama.arif, kas
On Wed, Sep 02, 2026 at 12:29:32PM -0700, Andrew Morton wrote:
> On Wed, 2 Sep 2026 18:56:11 +0100 Yeoreum Yun <yeoreum.yun@arm.com> wrote:
>
> > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> > When this macro is used in some test, test result would be strange in
> > the system where PAGE_SIZE is more than 4KB.
> >
> > Here is example with transhuge-stress test with 16KB PAGE_SIZE:
> >
> > ...
> >
> > ok 1 Completed
> >
> > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
> > helper, read_pmd_pagesize().
> >
> > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> > is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
> >
> > After this patch, output of transhuge-stress:
> >
> > ...
> >
> > ok 1 Completed
>
> Thanks. Sashiko made claims. The first looks legit, although minor:
> https://sashiko.dev/#/patchset/20260902175611.1241118-1-yeoreum.yun@arm.com
Thanks! I'll fix!
--
Sincerely,
Yeoreum Yun
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-02 17:56 [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Yeoreum Yun
2026-09-02 19:29 ` Andrew Morton
@ 2026-09-03 8:56 ` Lorenzo Stoakes (ARM)
2026-09-03 11:39 ` Yeoreum Yun
2026-09-03 11:12 ` Sarthak Sharma
2 siblings, 1 reply; 9+ messages in thread
From: Lorenzo Stoakes (ARM) @ 2026-09-03 8:56 UTC (permalink / raw)
To: Yeoreum Yun
Cc: linux-mm, linux-kselftest, akpm, david, liam, vbabka, rppt,
surenb, mhocko, shuah, ziy, baolin.wang, nico.pache, ryan.roberts,
dev.jain, baohua, lance.yang, usama.arif, kas
On Wed, Sep 02, 2026 at 06:56:11PM +0100, Yeoreum Yun wrote:
> HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> When this macro is used in some test, test result would be strange in
> the system where PAGE_SIZE is more than 4KB.
>
> Here is example with transhuge-stress test with 16KB PAGE_SIZE:
>
> transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
> 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
> 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
> ...
> ok 1 Completed
>
> Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
> helper, read_pmd_pagesize().
>
> Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
Probably worth spelling out Least Common Denominator for those who might
mistaken this for a kind of display panel :P
I also wonder if it's worth pulling that out as a separate patch in a series for
better bisectability?
>
> After this patch, output of transhuge-stress:
>
> transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram
> 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages
> 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages
> 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages
> 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages
> 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages
> ...
> ok 1 Completed
>
> Suggested-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Firstly THANK YOU for doing this :) hugely appreciated.
Also thank you again for the birthday cakes ;)
And apologies for the nitpicks :P
> ---
> tools/testing/selftests/mm/guard-regions.c | 12 +++++--
> tools/testing/selftests/mm/ksm_tests.c | 17 ++++++----
> tools/testing/selftests/mm/run_vmtests.sh | 4 +--
> tools/testing/selftests/mm/transhuge-stress.c | 22 +++++++------
> tools/testing/selftests/mm/vm_util.c | 32 ++++++++++++++++---
> tools/testing/selftests/mm/vm_util.h | 9 ++----
> 6 files changed, 66 insertions(+), 30 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c
> index 5c8ec3ca75d7..d370592b291f 100644
> --- a/tools/testing/selftests/mm/guard-regions.c
> +++ b/tools/testing/selftests/mm/guard-regions.c
> @@ -2195,14 +2195,22 @@ TEST_F(guard_regions, pagemap_scan)
> TEST_F(guard_regions, collapse)
> {
> const unsigned long page_size = self->page_size;
> - const unsigned long size = 2 * HPAGE_SIZE;
> - const unsigned long num_pages = size / page_size;
> + uint64_t hpage_size;
> + unsigned long size;
> + unsigned long num_pages;
> char *ptr;
> int i;
>
> if (!thp_available())
> SKIP(return, "Transparent Hugepages not available\n");
>
> + hpage_size = read_pmd_pagesize();
> + if (!hpage_size)
> + ksft_exit_fail_msg("reading hpage_size failed\n");
> +
> + size = 2 * hpage_size;
> + num_pages = size / page_size;
> +
> /* Need file to be correct size for tests for non-anon. */
> if (variant->backing != ANON_BACKED)
> ASSERT_EQ(ftruncate(self->fd, size), 0);
> diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c
> index 5fd7792a0d47..278e77055007 100644
> --- a/tools/testing/selftests/mm/ksm_tests.c
> +++ b/tools/testing/selftests/mm/ksm_tests.c
> @@ -521,6 +521,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> struct timespec start_time, end_time;
> unsigned long scan_time_ns;
> int pagemap_fd, n_normal_pages, n_huge_pages;
> + uint64_t hpage_size = read_pmd_pagesize();
NIT: can this be const?
> +
> + if (!hpage_size) {
> + ksft_exit_fail_msg("reading hpage_size failed\n");
> + }
NIT: can drop the {}
>
> if (!thp_is_enabled()) {
> ksft_print_msg("Transparent Hugepages not available\n");
> @@ -530,10 +535,10 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> map_size *= MB;
> size_t len = map_size;
>
> - len -= len % HPAGE_SIZE;
> - map_ptr_orig = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
> + len -= len % hpage_size;
> + map_ptr_orig = mmap(NULL, len + hpage_size, PROT_READ | PROT_WRITE,
> MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
> - map_ptr = map_ptr_orig + HPAGE_SIZE - (uintptr_t)map_ptr_orig % HPAGE_SIZE;
> + map_ptr = map_ptr_orig + hpage_size - (uintptr_t)map_ptr_orig % hpage_size;
>
> if (map_ptr_orig == MAP_FAILED)
> err(2, "initial mmap");
> @@ -547,7 +552,7 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
>
> n_normal_pages = 0;
> n_huge_pages = 0;
> - for (void *p = map_ptr; p < map_ptr + len; p += HPAGE_SIZE) {
> + for (void *p = map_ptr; p < map_ptr + len; p += hpage_size) {
> if (allocate_transhuge(p, pagemap_fd) < 0)
> n_normal_pages++;
> else
> @@ -578,11 +583,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> ksft_print_msg("Average speed: %.3f MiB/s\n", (map_size / MB) /
> ((double)scan_time_ns / NSEC_PER_SEC));
>
> - munmap(map_ptr_orig, len + HPAGE_SIZE);
> + munmap(map_ptr_orig, len + hpage_size);
> return KSFT_PASS;
>
> err_out:
> - munmap(map_ptr_orig, len + HPAGE_SIZE);
> + munmap(map_ptr_orig, len + hpage_size);
> return KSFT_FAIL;
> }
>
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index d09f9f6a384e..24aa1de27c25 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -360,8 +360,8 @@ fi
> CATEGORY="memfd_secret" run_test ./memfd_secret
> fi
>
> -# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100
> -CATEGORY="ksm" run_test ./ksm_tests -H -s 100
> +# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 512
> +CATEGORY="ksm" run_test ./ksm_tests -H -s 512
See above re: splitting out.
> # KSM KSM_MERGE_TIME test with size of 100
> CATEGORY="ksm" run_test ./ksm_tests -P -s 100
> # KSM MADV_MERGEABLE test with 10 identical pages
> diff --git a/tools/testing/selftests/mm/transhuge-stress.c b/tools/testing/selftests/mm/transhuge-stress.c
> index 8eb0c5630e7e..66ae94afaf8d 100644
> --- a/tools/testing/selftests/mm/transhuge-stress.c
> +++ b/tools/testing/selftests/mm/transhuge-stress.c
> @@ -35,6 +35,8 @@ int main(int argc, char **argv)
> size_t map_len;
> int pagemap_fd;
> int duration = 0;
> + uint64_t hpage_size = read_pmd_pagesize();
> + uint64_t hpage_shift = hpshift();
NIT: could be consts?
>
> ksft_print_header();
>
> @@ -70,23 +72,23 @@ int main(int argc, char **argv)
> }
>
> warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
> - " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
> - ram >> (20 + HPAGE_SHIFT - pshift() - 1));
> + " and %zd MiB of ram", len >> hpage_shift, len >> 20,
> + ram >> (20 + hpage_shift - pshift() - 1));
>
> pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
> if (pagemap_fd < 0)
> ksft_exit_fail_msg("open pagemap\n");
>
> - len -= len % HPAGE_SIZE;
> - ptr = mmap(NULL, len + HPAGE_SIZE, PROT_RW, mmap_flags, backing_fd, 0);
> + len -= len % hpage_size;
> + ptr = mmap(NULL, len + hpage_size, PROT_RW, mmap_flags, backing_fd, 0);
> if (ptr == MAP_FAILED)
> ksft_exit_fail_msg("initial mmap");
> - ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;
> + ptr += hpage_size - (uintptr_t)ptr % hpage_size;
>
> if (madvise(ptr, len, MADV_HUGEPAGE))
> ksft_exit_fail_msg("MADV_HUGEPAGE");
>
> - map_len = ram >> (HPAGE_SHIFT - 1);
> + map_len = ram >> (hpage_shift - 1);
> map = malloc(map_len);
> if (!map)
> ksft_exit_fail_msg("map malloc\n");
> @@ -99,7 +101,7 @@ int main(int argc, char **argv)
> memset(map, 0, map_len);
>
> clock_gettime(CLOCK_MONOTONIC, &a);
> - for (p = ptr; p < ptr + len; p += HPAGE_SIZE) {
> + for (p = ptr; p < ptr + len; p += hpage_size) {
> int64_t pfn;
>
> pfn = allocate_transhuge(p, pagemap_fd);
> @@ -107,7 +109,7 @@ int main(int argc, char **argv)
> if (pfn < 0) {
> nr_failed++;
> } else {
> - size_t idx = pfn >> (HPAGE_SHIFT - pshift());
> + size_t idx = pfn >> (hpage_shift - pshift());
>
> nr_succeed++;
> if (idx >= map_len) {
> @@ -123,7 +125,7 @@ int main(int argc, char **argv)
> }
>
> /* split transhuge page, keep last page */
> - if (madvise(p, HPAGE_SIZE - psize(), MADV_DONTNEED))
> + if (madvise(p, hpage_size - psize(), MADV_DONTNEED))
> ksft_exit_fail_msg("MADV_DONTNEED");
> }
> clock_gettime(CLOCK_MONOTONIC, &b);
> @@ -131,7 +133,7 @@ int main(int argc, char **argv)
>
> ksft_print_msg("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t"
> "%4d succeed, %4d failed, %4d different pages\n",
> - s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20),
> + s, s * 1000 / (len >> hpage_shift), len / s / (1 << 20),
> nr_succeed, nr_failed, nr_pages);
>
> if (duration > 0 && b.tv_sec - start.tv_sec >= duration) {
> diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
> index 4821a3563036..4332f8fb2104 100644
> --- a/tools/testing/selftests/mm/vm_util.c
> +++ b/tools/testing/selftests/mm/vm_util.c
> @@ -21,6 +21,8 @@
>
> unsigned int __page_size;
> unsigned int __page_shift;
> +uint64_t __hpage_size;
> +uint64_t __hpage_shift;
>
> uint64_t pagemap_get_entry(int fd, char *start)
> {
> @@ -161,6 +163,9 @@ uint64_t read_pmd_pagesize(void)
> char buf[20];
> ssize_t num_read;
>
> + if (__hpage_size)
> + return __hpage_size;
> +
> fd = open(PMD_SIZE_FILE_PATH, O_RDONLY);
> if (fd == -1)
> return 0;
> @@ -173,7 +178,24 @@ uint64_t read_pmd_pagesize(void)
> buf[num_read] = '\0';
> close(fd);
>
> - return strtoul(buf, NULL, 10);
> + __hpage_size = strtoul(buf, NULL, 10);
> +
> + return __hpage_size;
> +}
> +
> +uint64_t hpshift(void)
> +{
> + if (!__hpage_shift) {
> + if (!__hpage_size) {
> + __hpage_size = read_pmd_pagesize();
> + if (!__hpage_size)
> + ksft_exit_fail_msg("reading __hpage_size failed\n");
> + }
This nesting is a bit horrifying :P
Maybe:
if (__hpage_shift && __hpage_size)
return;
if (!__hpage_size) {
...
}
if (!__hpage_shift) {
...
}
?
> +
> + __hpage_shift = (ffsl(__hpage_size) - 1);
> + }
> +
> + return __hpage_shift;
> }
>
> unsigned long rss_anon(void)
> @@ -452,14 +474,16 @@ bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size
> int64_t allocate_transhuge(void *ptr, int pagemap_fd)
> {
> uint64_t ent[2];
> + uint64_t hpage_size = read_pmd_pagesize();
> + uint64_t hpage_shift = hpshift();
NIT: could be const?
>
> /* drop pmd */
> - if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
> + if (mmap(ptr, hpage_size, PROT_READ | PROT_WRITE,
> MAP_FIXED | MAP_ANONYMOUS |
> MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
> ksft_exit_fail_msg("mmap transhuge\n");
>
> - if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
> + if (madvise(ptr, hpage_size, MADV_HUGEPAGE))
> ksft_exit_fail_msg("MADV_HUGEPAGE\n");
>
> /* allocate transparent huge page */
> @@ -471,7 +495,7 @@ int64_t allocate_transhuge(void *ptr, int pagemap_fd)
>
> if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) &&
> PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) &&
> - !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - pshift())) - 1)))
> + !(PAGEMAP_PFN(ent[0]) & ((1 << (hpage_shift - pshift())) - 1)))
> return PAGEMAP_PFN(ent[0]);
>
> return -1;
> diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
> index 9a49af88702e..20a6334605c7 100644
> --- a/tools/testing/selftests/mm/vm_util.h
> +++ b/tools/testing/selftests/mm/vm_util.h
> @@ -31,6 +31,8 @@
>
> extern unsigned int __page_size;
> extern unsigned int __page_shift;
> +extern uint64_t __hpage_size;
> +extern uint64_t __hpage_shift;
>
> /*
> * Represents an open fd and PROCMAP_QUERY state for binary (via ioctl)
> @@ -89,6 +91,7 @@ unsigned long pagemap_get_pfn(int fd, char *start);
> void clear_softdirty(void);
> bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len);
> uint64_t read_pmd_pagesize(void);
> +uint64_t hpshift(void);
> unsigned long rss_anon(void);
> bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
> bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
> @@ -157,12 +160,6 @@ int ksm_stop(void);
> int get_hardware_corrupted_size(unsigned long *val);
> int unpoison_memory(unsigned long pfn);
>
> -/*
> - * On ppc64 this will only work with radix 2M hugepage size
> - */
> -#define HPAGE_SHIFT 21
> -#define HPAGE_SIZE (1 << HPAGE_SHIFT)
> -
Worth calling this change out in commit msg also?
> #define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0)
> #define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1))
>
> --
> LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
>
--
Cheers, Lorenzo
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-03 8:56 ` Lorenzo Stoakes (ARM)
@ 2026-09-03 11:39 ` Yeoreum Yun
2026-09-03 14:46 ` Yeoreum Yun
0 siblings, 1 reply; 9+ messages in thread
From: Yeoreum Yun @ 2026-09-03 11:39 UTC (permalink / raw)
To: Lorenzo Stoakes (ARM)
Cc: Yeoreum Yun, linux-mm, linux-kselftest, akpm, david, liam, vbabka,
rppt, surenb, mhocko, shuah, ziy, baolin.wang, nico.pache,
ryan.roberts, dev.jain, baohua, lance.yang, usama.arif, kas
> On Wed, Sep 02, 2026 at 06:56:11PM +0100, Yeoreum Yun wrote:
> > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> > When this macro is used in some test, test result would be strange in
> > the system where PAGE_SIZE is more than 4KB.
> >
> > Here is example with transhuge-stress test with 16KB PAGE_SIZE:
> >
> > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
> > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
> > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
> > ...
> > ok 1 Completed
> >
> > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
> > helper, read_pmd_pagesize().
> >
> > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> > is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
>
> Probably worth spelling out Least Common Denominator for those who might
> mistaken this for a kind of display panel :P
Bad typo :( LCM (least common multiple) :(
>
> I also wonder if it's worth pulling that out as a separate patch in a series for
> better bisectability?
Okay. I'll separate it.
>
> >
> > After this patch, output of transhuge-stress:
> >
> > transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram
> > 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> > 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> > 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> > 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages
> > 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages
> > 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages
> > 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages
> > 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages
> > ...
> > ok 1 Completed
> >
> > Suggested-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
>
> Firstly THANK YOU for doing this :) hugely appreciated.
>
> Also thank you again for the birthday cakes ;)
>
> And apologies for the nitpicks :P
No worries! Thanks for your comment ;)
>
> > ---
> > tools/testing/selftests/mm/guard-regions.c | 12 +++++--
> > tools/testing/selftests/mm/ksm_tests.c | 17 ++++++----
> > tools/testing/selftests/mm/run_vmtests.sh | 4 +--
> > tools/testing/selftests/mm/transhuge-stress.c | 22 +++++++------
> > tools/testing/selftests/mm/vm_util.c | 32 ++++++++++++++++---
> > tools/testing/selftests/mm/vm_util.h | 9 ++----
> > 6 files changed, 66 insertions(+), 30 deletions(-)
> >
> > diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c
> > index 5c8ec3ca75d7..d370592b291f 100644
> > --- a/tools/testing/selftests/mm/guard-regions.c
> > +++ b/tools/testing/selftests/mm/guard-regions.c
> > @@ -2195,14 +2195,22 @@ TEST_F(guard_regions, pagemap_scan)
> > TEST_F(guard_regions, collapse)
> > {
> > const unsigned long page_size = self->page_size;
> > - const unsigned long size = 2 * HPAGE_SIZE;
> > - const unsigned long num_pages = size / page_size;
> > + uint64_t hpage_size;
> > + unsigned long size;
> > + unsigned long num_pages;
> > char *ptr;
> > int i;
> >
> > if (!thp_available())
> > SKIP(return, "Transparent Hugepages not available\n");
> >
> > + hpage_size = read_pmd_pagesize();
> > + if (!hpage_size)
> > + ksft_exit_fail_msg("reading hpage_size failed\n");
> > +
> > + size = 2 * hpage_size;
> > + num_pages = size / page_size;
> > +
> > /* Need file to be correct size for tests for non-anon. */
> > if (variant->backing != ANON_BACKED)
> > ASSERT_EQ(ftruncate(self->fd, size), 0);
> > diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c
> > index 5fd7792a0d47..278e77055007 100644
> > --- a/tools/testing/selftests/mm/ksm_tests.c
> > +++ b/tools/testing/selftests/mm/ksm_tests.c
> > @@ -521,6 +521,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> > struct timespec start_time, end_time;
> > unsigned long scan_time_ns;
> > int pagemap_fd, n_normal_pages, n_huge_pages;
> > + uint64_t hpage_size = read_pmd_pagesize();
>
> NIT: can this be const?
Acked.
>
> > +
> > + if (!hpage_size) {
> > + ksft_exit_fail_msg("reading hpage_size failed\n");
> > + }
>
> NIT: can drop the {}
Acked.
>
> >
> > if (!thp_is_enabled()) {
> > ksft_print_msg("Transparent Hugepages not available\n");
> > @@ -530,10 +535,10 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> > map_size *= MB;
> > size_t len = map_size;
> >
> > - len -= len % HPAGE_SIZE;
> > - map_ptr_orig = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
> > + len -= len % hpage_size;
> > + map_ptr_orig = mmap(NULL, len + hpage_size, PROT_READ | PROT_WRITE,
> > MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
> > - map_ptr = map_ptr_orig + HPAGE_SIZE - (uintptr_t)map_ptr_orig % HPAGE_SIZE;
> > + map_ptr = map_ptr_orig + hpage_size - (uintptr_t)map_ptr_orig % hpage_size;
> >
> > if (map_ptr_orig == MAP_FAILED)
> > err(2, "initial mmap");
> > @@ -547,7 +552,7 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> >
> > n_normal_pages = 0;
> > n_huge_pages = 0;
> > - for (void *p = map_ptr; p < map_ptr + len; p += HPAGE_SIZE) {
> > + for (void *p = map_ptr; p < map_ptr + len; p += hpage_size) {
> > if (allocate_transhuge(p, pagemap_fd) < 0)
> > n_normal_pages++;
> > else
> > @@ -578,11 +583,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot,
> > ksft_print_msg("Average speed: %.3f MiB/s\n", (map_size / MB) /
> > ((double)scan_time_ns / NSEC_PER_SEC));
> >
> > - munmap(map_ptr_orig, len + HPAGE_SIZE);
> > + munmap(map_ptr_orig, len + hpage_size);
> > return KSFT_PASS;
> >
> > err_out:
> > - munmap(map_ptr_orig, len + HPAGE_SIZE);
> > + munmap(map_ptr_orig, len + hpage_size);
> > return KSFT_FAIL;
> > }
> >
> > diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> > index d09f9f6a384e..24aa1de27c25 100755
> > --- a/tools/testing/selftests/mm/run_vmtests.sh
> > +++ b/tools/testing/selftests/mm/run_vmtests.sh
> > @@ -360,8 +360,8 @@ fi
> > CATEGORY="memfd_secret" run_test ./memfd_secret
> > fi
> >
> > -# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100
> > -CATEGORY="ksm" run_test ./ksm_tests -H -s 100
> > +# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 512
> > +CATEGORY="ksm" run_test ./ksm_tests -H -s 512
>
> See above re: splitting out.
Okay. I'll split!
>
> > # KSM KSM_MERGE_TIME test with size of 100
> > CATEGORY="ksm" run_test ./ksm_tests -P -s 100
> > # KSM MADV_MERGEABLE test with 10 identical pages
> > diff --git a/tools/testing/selftests/mm/transhuge-stress.c b/tools/testing/selftests/mm/transhuge-stress.c
> > index 8eb0c5630e7e..66ae94afaf8d 100644
> > --- a/tools/testing/selftests/mm/transhuge-stress.c
> > +++ b/tools/testing/selftests/mm/transhuge-stress.c
> > @@ -35,6 +35,8 @@ int main(int argc, char **argv)
> > size_t map_len;
> > int pagemap_fd;
> > int duration = 0;
> > + uint64_t hpage_size = read_pmd_pagesize();
> > + uint64_t hpage_shift = hpshift();
>
> NIT: could be consts?
Okay.
>
> >
> > ksft_print_header();
> >
> > @@ -70,23 +72,23 @@ int main(int argc, char **argv)
> > }
> >
> > warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
> > - " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
> > - ram >> (20 + HPAGE_SHIFT - pshift() - 1));
> > + " and %zd MiB of ram", len >> hpage_shift, len >> 20,
> > + ram >> (20 + hpage_shift - pshift() - 1));
> >
> > pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
> > if (pagemap_fd < 0)
> > ksft_exit_fail_msg("open pagemap\n");
> >
> > - len -= len % HPAGE_SIZE;
> > - ptr = mmap(NULL, len + HPAGE_SIZE, PROT_RW, mmap_flags, backing_fd, 0);
> > + len -= len % hpage_size;
> > + ptr = mmap(NULL, len + hpage_size, PROT_RW, mmap_flags, backing_fd, 0);
> > if (ptr == MAP_FAILED)
> > ksft_exit_fail_msg("initial mmap");
> > - ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;
> > + ptr += hpage_size - (uintptr_t)ptr % hpage_size;
> >
> > if (madvise(ptr, len, MADV_HUGEPAGE))
> > ksft_exit_fail_msg("MADV_HUGEPAGE");
> >
> > - map_len = ram >> (HPAGE_SHIFT - 1);
> > + map_len = ram >> (hpage_shift - 1);
> > map = malloc(map_len);
> > if (!map)
> > ksft_exit_fail_msg("map malloc\n");
> > @@ -99,7 +101,7 @@ int main(int argc, char **argv)
> > memset(map, 0, map_len);
> >
> > clock_gettime(CLOCK_MONOTONIC, &a);
> > - for (p = ptr; p < ptr + len; p += HPAGE_SIZE) {
> > + for (p = ptr; p < ptr + len; p += hpage_size) {
> > int64_t pfn;
> >
> > pfn = allocate_transhuge(p, pagemap_fd);
> > @@ -107,7 +109,7 @@ int main(int argc, char **argv)
> > if (pfn < 0) {
> > nr_failed++;
> > } else {
> > - size_t idx = pfn >> (HPAGE_SHIFT - pshift());
> > + size_t idx = pfn >> (hpage_shift - pshift());
> >
> > nr_succeed++;
> > if (idx >= map_len) {
> > @@ -123,7 +125,7 @@ int main(int argc, char **argv)
> > }
> >
> > /* split transhuge page, keep last page */
> > - if (madvise(p, HPAGE_SIZE - psize(), MADV_DONTNEED))
> > + if (madvise(p, hpage_size - psize(), MADV_DONTNEED))
> > ksft_exit_fail_msg("MADV_DONTNEED");
> > }
> > clock_gettime(CLOCK_MONOTONIC, &b);
> > @@ -131,7 +133,7 @@ int main(int argc, char **argv)
> >
> > ksft_print_msg("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t"
> > "%4d succeed, %4d failed, %4d different pages\n",
> > - s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20),
> > + s, s * 1000 / (len >> hpage_shift), len / s / (1 << 20),
> > nr_succeed, nr_failed, nr_pages);
> >
> > if (duration > 0 && b.tv_sec - start.tv_sec >= duration) {
> > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
> > index 4821a3563036..4332f8fb2104 100644
> > --- a/tools/testing/selftests/mm/vm_util.c
> > +++ b/tools/testing/selftests/mm/vm_util.c
> > @@ -21,6 +21,8 @@
> >
> > unsigned int __page_size;
> > unsigned int __page_shift;
> > +uint64_t __hpage_size;
> > +uint64_t __hpage_shift;
> >
> > uint64_t pagemap_get_entry(int fd, char *start)
> > {
> > @@ -161,6 +163,9 @@ uint64_t read_pmd_pagesize(void)
> > char buf[20];
> > ssize_t num_read;
> >
> > + if (__hpage_size)
> > + return __hpage_size;
> > +
> > fd = open(PMD_SIZE_FILE_PATH, O_RDONLY);
> > if (fd == -1)
> > return 0;
> > @@ -173,7 +178,24 @@ uint64_t read_pmd_pagesize(void)
> > buf[num_read] = '\0';
> > close(fd);
> >
> > - return strtoul(buf, NULL, 10);
> > + __hpage_size = strtoul(buf, NULL, 10);
> > +
> > + return __hpage_size;
> > +}
> > +
> > +uint64_t hpshift(void)
> > +{
> > + if (!__hpage_shift) {
> > + if (!__hpage_size) {
> > + __hpage_size = read_pmd_pagesize();
> > + if (!__hpage_size)
> > + ksft_exit_fail_msg("reading __hpage_size failed\n");
> > + }
>
> This nesting is a bit horrifying :P
>
> Maybe:
>
> if (__hpage_shift && __hpage_size)
> return;
>
> if (!__hpage_size) {
> ...
> }
>
> if (!__hpage_shift) {
> ...
> }
>
> ?
I see. I'll untie the nesting.
>
> > +
> > + __hpage_shift = (ffsl(__hpage_size) - 1);
> > + }
> > +
> > + return __hpage_shift;
> > }
> >
> > unsigned long rss_anon(void)
> > @@ -452,14 +474,16 @@ bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size
> > int64_t allocate_transhuge(void *ptr, int pagemap_fd)
> > {
> > uint64_t ent[2];
> > + uint64_t hpage_size = read_pmd_pagesize();
> > + uint64_t hpage_shift = hpshift();
>
> NIT: could be const?
Okay ;)
>
> >
> > /* drop pmd */
> > - if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
> > + if (mmap(ptr, hpage_size, PROT_READ | PROT_WRITE,
> > MAP_FIXED | MAP_ANONYMOUS |
> > MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
> > ksft_exit_fail_msg("mmap transhuge\n");
> >
> > - if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
> > + if (madvise(ptr, hpage_size, MADV_HUGEPAGE))
> > ksft_exit_fail_msg("MADV_HUGEPAGE\n");
> >
> > /* allocate transparent huge page */
> > @@ -471,7 +495,7 @@ int64_t allocate_transhuge(void *ptr, int pagemap_fd)
> >
> > if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) &&
> > PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) &&
> > - !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - pshift())) - 1)))
> > + !(PAGEMAP_PFN(ent[0]) & ((1 << (hpage_shift - pshift())) - 1)))
> > return PAGEMAP_PFN(ent[0]);
> >
> > return -1;
> > diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
> > index 9a49af88702e..20a6334605c7 100644
> > --- a/tools/testing/selftests/mm/vm_util.h
> > +++ b/tools/testing/selftests/mm/vm_util.h
> > @@ -31,6 +31,8 @@
> >
> > extern unsigned int __page_size;
> > extern unsigned int __page_shift;
> > +extern uint64_t __hpage_size;
> > +extern uint64_t __hpage_shift;
> >
> > /*
> > * Represents an open fd and PROCMAP_QUERY state for binary (via ioctl)
> > @@ -89,6 +91,7 @@ unsigned long pagemap_get_pfn(int fd, char *start);
> > void clear_softdirty(void);
> > bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len);
> > uint64_t read_pmd_pagesize(void);
> > +uint64_t hpshift(void);
> > unsigned long rss_anon(void);
> > bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
> > bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size);
> > @@ -157,12 +160,6 @@ int ksm_stop(void);
> > int get_hardware_corrupted_size(unsigned long *val);
> > int unpoison_memory(unsigned long pfn);
> >
> > -/*
> > - * On ppc64 this will only work with radix 2M hugepage size
> > - */
> > -#define HPAGE_SHIFT 21
> > -#define HPAGE_SIZE (1 << HPAGE_SHIFT)
> > -
>
> Worth calling this change out in commit msg also?
It was spelled out as They're removed ;).
>
> > #define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0)
> > #define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1))
> >
> > --
> > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
> >
>
> --
Thanks!
--
Sincerely,
Yeoreum Yun
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-03 11:39 ` Yeoreum Yun
@ 2026-09-03 14:46 ` Yeoreum Yun
2026-09-03 14:47 ` Lorenzo Stoakes (ARM)
0 siblings, 1 reply; 9+ messages in thread
From: Yeoreum Yun @ 2026-09-03 14:46 UTC (permalink / raw)
To: Lorenzo Stoakes (ARM)
Cc: Yeoreum Yun, linux-mm, linux-kselftest, akpm, david, liam, vbabka,
rppt, surenb, mhocko, shuah, ziy, baolin.wang, nico.pache,
ryan.roberts, dev.jain, baohua, lance.yang, usama.arif, kas
> > On Wed, Sep 02, 2026 at 06:56:11PM +0100, Yeoreum Yun wrote:
> > > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> > > When this macro is used in some test, test result would be strange in
> > > the system where PAGE_SIZE is more than 4KB.
> > >
> > > Here is example with transhuge-stress test with 16KB PAGE_SIZE:
> > >
> > > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
> > > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
> > > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > ...
> > > ok 1 Completed
> > >
> > > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> > > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
> > > helper, read_pmd_pagesize().
> > >
> > > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> > > is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
> >
> > Probably worth spelling out Least Common Denominator for those who might
> > mistaken this for a kind of display panel :P
>
> Bad typo :( LCM (least common multiple) :(
>
> >
> > I also wonder if it's worth pulling that out as a separate patch in a series for
> > better bisectability?
>
> Okay. I'll separate it.
Hmm, I think it would be better to keep the change as is, including the
updated ksm_tests parameter. Although allocate_transhuge() correctly
allocates mappings aligned to the PMD page size, `ksm_tests -H -s 100`
would otherwise fail because 100 MiB is not a multiple of the PMD page
size.
[...]
--
Sincerely,
Yeoreum Yun
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-03 14:46 ` Yeoreum Yun
@ 2026-09-03 14:47 ` Lorenzo Stoakes (ARM)
0 siblings, 0 replies; 9+ messages in thread
From: Lorenzo Stoakes (ARM) @ 2026-09-03 14:47 UTC (permalink / raw)
To: Yeoreum Yun
Cc: linux-mm, linux-kselftest, akpm, david, liam, vbabka, rppt,
surenb, mhocko, shuah, ziy, baolin.wang, nico.pache, ryan.roberts,
dev.jain, baohua, lance.yang, usama.arif, kas
On Thu, Sep 03, 2026 at 03:46:20PM +0100, Yeoreum Yun wrote:
> > > On Wed, Sep 02, 2026 at 06:56:11PM +0100, Yeoreum Yun wrote:
> > > > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> > > > When this macro is used in some test, test result would be strange in
> > > > the system where PAGE_SIZE is more than 4KB.
> > > >
> > > > Here is example with transhuge-stress test with 16KB PAGE_SIZE:
> > > >
> > > > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
> > > > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
> > > > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
> > > > ...
> > > > ok 1 Completed
> > > >
> > > > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> > > > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
> > > > helper, read_pmd_pagesize().
> > > >
> > > > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> > > > is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
> > >
> > > Probably worth spelling out Least Common Denominator for those who might
> > > mistaken this for a kind of display panel :P
> >
> > Bad typo :( LCM (least common multiple) :(
> >
> > >
> > > I also wonder if it's worth pulling that out as a separate patch in a series for
> > > better bisectability?
> >
> > Okay. I'll separate it.
>
> Hmm, I think it would be better to keep the change as is, including the
> updated ksm_tests parameter. Although allocate_transhuge() correctly
> allocates mappings aligned to the PMD page size, `ksm_tests -H -s 100`
> would otherwise fail because 100 MiB is not a multiple of the PMD page
> size.
OK, just add a note about it in the commit msg :)
>
> [...]
>
> --
> Sincerely,
> Yeoreum Yun
--
Cheers, Lorenzo
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-02 17:56 [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Yeoreum Yun
2026-09-02 19:29 ` Andrew Morton
2026-09-03 8:56 ` Lorenzo Stoakes (ARM)
@ 2026-09-03 11:12 ` Sarthak Sharma
2026-09-03 11:40 ` Yeoreum Yun
2 siblings, 1 reply; 9+ messages in thread
From: Sarthak Sharma @ 2026-09-03 11:12 UTC (permalink / raw)
To: Yeoreum Yun, linux-mm, linux-kselftest
Cc: akpm, david, ljs, liam, vbabka, rppt, surenb, mhocko, shuah, ziy,
baolin.wang, nico.pache, ryan.roberts, dev.jain, baohua,
lance.yang, usama.arif, kas
Hi Yeoreum!
On 9/2/26 11:26 PM, Yeoreum Yun wrote:
> HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> When this macro is used in some test, test result would be strange in
> the system where PAGE_SIZE is more than 4KB.
>
> Here is example with transhuge-stress test with 16KB PAGE_SIZE:
>
> transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
> 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
> 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
> 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
> ...
> ok 1 Completed
>
> Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
Nit : pre-existing
> helper, read_pmd_pagesize().
> > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
>
> After this patch, output of transhuge-stress:
>
> transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram
> 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages
> 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages
> 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages
> 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages
> 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages
> ...
> ok 1 Completed
>
> Suggested-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
[...]
> diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
> index 4821a3563036..4332f8fb2104 100644
> --- a/tools/testing/selftests/mm/vm_util.c
> +++ b/tools/testing/selftests/mm/vm_util.c
> @@ -21,6 +21,8 @@
>
> unsigned int __page_size;
> unsigned int __page_shift;
> +uint64_t __hpage_size;
> +uint64_t __hpage_shift;
I was wondering, would it make more sense to call these __pmd_pagesize
and __pmd_shift instead?
hpage_size is used at places for mTHPs of arbitrary sizes and these
values come from read_pmd_pagesize(). So calling __hpage_size as the PMD
size seems a bit weird. Also, there is already a pmd_pagesize variable
in vm_util.c, so I feel the PMD specific names would be more consistent.
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro
2026-09-03 11:12 ` Sarthak Sharma
@ 2026-09-03 11:40 ` Yeoreum Yun
0 siblings, 0 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-09-03 11:40 UTC (permalink / raw)
To: Sarthak Sharma
Cc: Yeoreum Yun, linux-mm, linux-kselftest, akpm, david, ljs, liam,
vbabka, rppt, surenb, mhocko, shuah, ziy, baolin.wang, nico.pache,
ryan.roberts, dev.jain, baohua, lance.yang, usama.arif, kas
Hi Sarthak,
> Hi Yeoreum!
>
> On 9/2/26 11:26 PM, Yeoreum Yun wrote:
> > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE.
> > When this macro is used in some test, test result would be strange in
> > the system where PAGE_SIZE is more than 4KB.
> >
> > Here is example with transhuge-stress test with 16KB PAGE_SIZE:
> >
> > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram
> > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages
> > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages
> > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages
> > ...
> > ok 1 Completed
> >
> > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift()
> > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist
>
> Nit : pre-existing
Sorry for typo ;)
>
> > helper, read_pmd_pagesize().
> > > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which
> > is the LCD pmd_size among 4KB, 16KB and 64KB page_size.
> >
> > After this patch, output of transhuge-stress:
> >
> > transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram
> > 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> > 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> > 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages
> > 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages
> > 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages
> > 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages
> > 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages
> > 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages
> > ...
> > ok 1 Completed
> >
> > Suggested-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> > ---
>
> [...]
>
> > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
> > index 4821a3563036..4332f8fb2104 100644
> > --- a/tools/testing/selftests/mm/vm_util.c
> > +++ b/tools/testing/selftests/mm/vm_util.c
> > @@ -21,6 +21,8 @@
> >
> > unsigned int __page_size;
> > unsigned int __page_shift;
> > +uint64_t __hpage_size;
> > +uint64_t __hpage_shift;
>
> I was wondering, would it make more sense to call these __pmd_pagesize
> and __pmd_shift instead?
>
> hpage_size is used at places for mTHPs of arbitrary sizes and these
> values come from read_pmd_pagesize(). So calling __hpage_size as the PMD
> size seems a bit weird. Also, there is already a pmd_pagesize variable
> in vm_util.c, so I feel the PMD specific names would be more consistent.
That seems better. Thanks!
--
Sincerely,
Yeoreum Yun
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2026-09-03 14:48 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-09-02 17:56 [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Yeoreum Yun
2026-09-02 19:29 ` Andrew Morton
2026-09-03 8:51 ` Yeoreum Yun
2026-09-03 8:56 ` Lorenzo Stoakes (ARM)
2026-09-03 11:39 ` Yeoreum Yun
2026-09-03 14:46 ` Yeoreum Yun
2026-09-03 14:47 ` Lorenzo Stoakes (ARM)
2026-09-03 11:12 ` Sarthak Sharma
2026-09-03 11:40 ` Yeoreum Yun
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