From: Donet Tom <donettom@linux.ibm.com>
The split_huge_page_test fails on systems with a 64KB base page size.
This is because the order of a 2MB huge page is different:
On 64KB systems, the order is 5.
On 4KB systems, it's 9.
The test currently assumes a maximum huge page order of 9, which is only
valid for 4KB base page systems. On systems with 64KB pages, attempting
to split huge pages beyond their actual order (5) causes the test to fail.
In this patch, we calculate the huge page order based on the system's base
page size. With this change, the tests now run successfully on both 64KB
and 4KB page size systems.
Fixes: fa6c02315f745 ("mm: huge_memory: a new debugfs interface for splitting THP tests")
Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
---
tools/testing/selftests/mm/cow.c | 5 -----
.../selftests/mm/split_huge_page_test.c | 22 ++++++++++++-------
tools/testing/selftests/mm/uffd-wp-mremap.c | 5 -----
tools/testing/selftests/mm/vm_util.h | 5 +++++
4 files changed, 19 insertions(+), 18 deletions(-)
diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
index 90ee5779662f..e742d9313798 100644
--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -41,11 +41,6 @@ static size_t hugetlbsizes[10];
static int gup_fd;
static bool has_huge_zeropage;
-static int sz2ord(size_t size)
-{
- return __builtin_ctzll(size / pagesize);
-}
-
static int detect_thp_sizes(size_t sizes[], int max)
{
int count = 0;
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
index eadbeb820d71..7cbeaebc9d71 100644
--- a/tools/testing/selftests/mm/split_huge_page_test.c
+++ b/tools/testing/selftests/mm/split_huge_page_test.c
@@ -523,6 +523,9 @@ int main(int argc, char **argv)
const char *fs_loc;
bool created_tmp;
int offset;
+ unsigned int max_order;
+ unsigned int nr_pages;
+ unsigned int tests;
ksft_print_header();
@@ -534,35 +537,38 @@ int main(int argc, char **argv)
if (argc > 1)
optional_xfs_path = argv[1];
- ksft_set_plan(1+8+1+9+9+8*4+2);
-
pagesize = getpagesize();
pageshift = ffs(pagesize) - 1;
pmd_pagesize = read_pmd_pagesize();
if (!pmd_pagesize)
ksft_exit_fail_msg("Reading PMD pagesize failed\n");
+ nr_pages = pmd_pagesize / pagesize;
+ max_order = sz2ord(pmd_pagesize);
+ tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
+ ksft_set_plan(tests);
+
fd_size = 2 * pmd_pagesize;
split_pmd_zero_pages();
- for (i = 0; i < 9; i++)
+ for (i = 0; i < max_order; i++)
if (i != 1)
split_pmd_thp_to_order(i);
split_pte_mapped_thp();
- for (i = 0; i < 9; i++)
+ for (i = 0; i < max_order; i++)
split_file_backed_thp(i);
created_tmp = prepare_thp_fs(optional_xfs_path, fs_loc_template,
&fs_loc);
- for (i = 8; i >= 0; i--)
+ for (i = max_order - 1; i >= 0; i--)
split_thp_in_pagecache_to_order_at(fd_size, fs_loc, i, -1);
- for (i = 0; i < 9; i++)
+ for (i = 0; i < max_order; i++)
for (offset = 0;
- offset < pmd_pagesize / pagesize;
- offset += MAX(pmd_pagesize / pagesize / 4, 1 << i))
+ offset < nr_pages;
+ offset += MAX(nr_pages / 4, 1 << i))
split_thp_in_pagecache_to_order_at(fd_size, fs_loc, i, offset);
cleanup_thp_fs(fs_loc, created_tmp);
diff --git a/tools/testing/selftests/mm/uffd-wp-mremap.c b/tools/testing/selftests/mm/uffd-wp-mremap.c
index 13ceb5628970..7140b2f9c452 100644
--- a/tools/testing/selftests/mm/uffd-wp-mremap.c
+++ b/tools/testing/selftests/mm/uffd-wp-mremap.c
@@ -19,11 +19,6 @@ static size_t thpsizes[20];
static int nr_hugetlbsizes;
static size_t hugetlbsizes[10];
-static int sz2ord(size_t size)
-{
- return __builtin_ctzll(size / pagesize);
-}
-
static int detect_thp_sizes(size_t sizes[], int max)
{
int count = 0;
diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h
index 1843ad48d32b..85f7dae9a0c1 100644
--- a/tools/testing/selftests/mm/vm_util.h
+++ b/tools/testing/selftests/mm/vm_util.h
@@ -127,6 +127,11 @@ static inline void log_test_result(int result)
ksft_test_result_report(result, "%s\n", test_name);
}
+static inline int sz2ord(size_t size)
+{
+ return __builtin_ctzll(size / getpagesize());
+}
+
void *sys_mremap(void *old_address, unsigned long old_size,
unsigned long new_size, int flags, void *new_address);
--
2.47.1On Sat, Aug 16, 2025 at 09:31:10AM +0530, Aboorva Devarajan wrote:
>From: Donet Tom <donettom@linux.ibm.com>
>
>The split_huge_page_test fails on systems with a 64KB base page size.
>This is because the order of a 2MB huge page is different:
>
>On 64KB systems, the order is 5.
>
>On 4KB systems, it's 9.
>
>The test currently assumes a maximum huge page order of 9, which is only
>valid for 4KB base page systems. On systems with 64KB pages, attempting
>to split huge pages beyond their actual order (5) causes the test to fail.
>
>In this patch, we calculate the huge page order based on the system's base
>page size. With this change, the tests now run successfully on both 64KB
>and 4KB page size systems.
>
>Fixes: fa6c02315f745 ("mm: huge_memory: a new debugfs interface for splitting THP tests")
>Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
>Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
>Reviewed-by: Dev Jain <dev.jain@arm.com>
>Reviewed-by: Zi Yan <ziy@nvidia.com>
>Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Nit below:
>---
> tools/testing/selftests/mm/cow.c | 5 -----
> .../selftests/mm/split_huge_page_test.c | 22 ++++++++++++-------
> tools/testing/selftests/mm/uffd-wp-mremap.c | 5 -----
> tools/testing/selftests/mm/vm_util.h | 5 +++++
> 4 files changed, 19 insertions(+), 18 deletions(-)
>
>diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
>index 90ee5779662f..e742d9313798 100644
>--- a/tools/testing/selftests/mm/cow.c
>+++ b/tools/testing/selftests/mm/cow.c
>@@ -41,11 +41,6 @@ static size_t hugetlbsizes[10];
> static int gup_fd;
> static bool has_huge_zeropage;
>
>-static int sz2ord(size_t size)
>-{
>- return __builtin_ctzll(size / pagesize);
>-}
>-
> static int detect_thp_sizes(size_t sizes[], int max)
> {
> int count = 0;
>diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
>index eadbeb820d71..7cbeaebc9d71 100644
>--- a/tools/testing/selftests/mm/split_huge_page_test.c
>+++ b/tools/testing/selftests/mm/split_huge_page_test.c
>@@ -523,6 +523,9 @@ int main(int argc, char **argv)
> const char *fs_loc;
> bool created_tmp;
> int offset;
>+ unsigned int max_order;
>+ unsigned int nr_pages;
>+ unsigned int tests;
>
> ksft_print_header();
>
>@@ -534,35 +537,38 @@ int main(int argc, char **argv)
> if (argc > 1)
> optional_xfs_path = argv[1];
>
>- ksft_set_plan(1+8+1+9+9+8*4+2);
>-
> pagesize = getpagesize();
> pageshift = ffs(pagesize) - 1;
> pmd_pagesize = read_pmd_pagesize();
> if (!pmd_pagesize)
> ksft_exit_fail_msg("Reading PMD pagesize failed\n");
>
>+ nr_pages = pmd_pagesize / pagesize;
>+ max_order = sz2ord(pmd_pagesize);
^
extra space here
>+ tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
>+ ksft_set_plan(tests);
>+
> fd_size = 2 * pmd_pagesize;
>
> split_pmd_zero_pages();
>
--
Wei Yang
Help you, Help me
On Sat, 2025-08-16 at 14:31 +0000, Wei Yang wrote:
> On Sat, Aug 16, 2025 at 09:31:10AM +0530, Aboorva Devarajan wrote:
> > From: Donet Tom <donettom@linux.ibm.com>
> >
> > The split_huge_page_test fails on systems with a 64KB base page
> > size.
> > This is because the order of a 2MB huge page is different:
> >
> > On 64KB systems, the order is 5.
> >
> > On 4KB systems, it's 9.
> >
> > The test currently assumes a maximum huge page order of 9, which is
> > only
> > valid for 4KB base page systems. On systems with 64KB pages,
> > attempting
> > to split huge pages beyond their actual order (5) causes the test
> > to fail.
> >
> > In this patch, we calculate the huge page order based on the
> > system's base
> > page size. With this change, the tests now run successfully on both
> > 64KB
> > and 4KB page size systems.
> >
> > Fixes: fa6c02315f745 ("mm: huge_memory: a new debugfs interface for
> > splitting THP tests")
> > Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
> > Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
> > Reviewed-by: Dev Jain <dev.jain@arm.com>
> > Reviewed-by: Zi Yan <ziy@nvidia.com>
> > Signed-off-by: Donet Tom <donettom@linux.ibm.com>
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
>
> Nit below:
>
> > ---
> > tools/testing/selftests/mm/cow.c | 5 -----
> > .../selftests/mm/split_huge_page_test.c | 22 ++++++++++++----
> > ---
> > tools/testing/selftests/mm/uffd-wp-mremap.c | 5 -----
> > tools/testing/selftests/mm/vm_util.h | 5 +++++
> > 4 files changed, 19 insertions(+), 18 deletions(-)
> >
> > diff --git a/tools/testing/selftests/mm/cow.c
> > b/tools/testing/selftests/mm/cow.c
> > index 90ee5779662f..e742d9313798 100644
> > --- a/tools/testing/selftests/mm/cow.c
> > +++ b/tools/testing/selftests/mm/cow.c
> > @@ -41,11 +41,6 @@ static size_t hugetlbsizes[10];
> > static int gup_fd;
> > static bool has_huge_zeropage;
> >
> > -static int sz2ord(size_t size)
> > -{
> > - return __builtin_ctzll(size / pagesize);
> > -}
> > -
> > static int detect_thp_sizes(size_t sizes[], int max)
> > {
> > int count = 0;
> > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c
> > b/tools/testing/selftests/mm/split_huge_page_test.c
> > index eadbeb820d71..7cbeaebc9d71 100644
> > --- a/tools/testing/selftests/mm/split_huge_page_test.c
> > +++ b/tools/testing/selftests/mm/split_huge_page_test.c
> > @@ -523,6 +523,9 @@ int main(int argc, char **argv)
> > const char *fs_loc;
> > bool created_tmp;
> > int offset;
> > + unsigned int max_order;
> > + unsigned int nr_pages;
> > + unsigned int tests;
> >
> > ksft_print_header();
> >
> > @@ -534,35 +537,38 @@ int main(int argc, char **argv)
> > if (argc > 1)
> > optional_xfs_path = argv[1];
> >
> > - ksft_set_plan(1+8+1+9+9+8*4+2);
> > -
> > pagesize = getpagesize();
> > pageshift = ffs(pagesize) - 1;
> > pmd_pagesize = read_pmd_pagesize();
> > if (!pmd_pagesize)
> > ksft_exit_fail_msg("Reading PMD pagesize
> > failed\n");
> >
> > + nr_pages = pmd_pagesize / pagesize;
> > + max_order = sz2ord(pmd_pagesize);
> ^
> extra space here
Hi Wei,
Thanks for the review. I’ve sent a fixup patch for this:
https://lore.kernel.org/all/20250819041239.167537-1-aboorvad@linux.ibm.com/
Andrew,
Could you please apply the above fixup patch?
Regards,
Aboorva
>
> > + tests = 2 + (max_order - 1) + (2 * max_order) + (max_order
> > - 1) * 4 + 2;
> > + ksft_set_plan(tests);
> > +
> > fd_size = 2 * pmd_pagesize;
> >
> > split_pmd_zero_pages();
> >
Removed an extra space in split_huge_page_test that was introduced
by commit 4b76e221794b ("mm/selftests: fix split_huge_page_test
failure on systems with 64KB page size").
Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
---
tools/testing/selftests/mm/split_huge_page_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
index 54e86f00aabc..faf7e1f88743 100644
--- a/tools/testing/selftests/mm/split_huge_page_test.c
+++ b/tools/testing/selftests/mm/split_huge_page_test.c
@@ -544,7 +544,7 @@ int main(int argc, char **argv)
ksft_exit_fail_msg("Reading PMD pagesize failed\n");
nr_pages = pmd_pagesize / pagesize;
- max_order = sz2ord(pmd_pagesize, pagesize);
+ max_order = sz2ord(pmd_pagesize, pagesize);
tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
ksft_set_plan(tests);
--
2.47.1On 19.08.25 06:12, Aboorva Devarajan wrote:
> Removed an extra space in split_huge_page_test that was introduced
> by commit 4b76e221794b ("mm/selftests: fix split_huge_page_test
> failure on systems with 64KB page size").
>
> Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
> ---
> tools/testing/selftests/mm/split_huge_page_test.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
> index 54e86f00aabc..faf7e1f88743 100644
> --- a/tools/testing/selftests/mm/split_huge_page_test.c
> +++ b/tools/testing/selftests/mm/split_huge_page_test.c
> @@ -544,7 +544,7 @@ int main(int argc, char **argv)
> ksft_exit_fail_msg("Reading PMD pagesize failed\n");
>
> nr_pages = pmd_pagesize / pagesize;
> - max_order = sz2ord(pmd_pagesize, pagesize);
> + max_order = sz2ord(pmd_pagesize, pagesize);
> tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
> ksft_set_plan(tests);
>
Please just comment next time one the respective patch as review comment.
--
Cheers
David / dhildenb
On 19.08.25 09:25, David Hildenbrand wrote:
> On 19.08.25 06:12, Aboorva Devarajan wrote:
>> Removed an extra space in split_huge_page_test that was introduced
>> by commit 4b76e221794b ("mm/selftests: fix split_huge_page_test
>> failure on systems with 64KB page size").
>>
>> Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
>> ---
>> tools/testing/selftests/mm/split_huge_page_test.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
>> index 54e86f00aabc..faf7e1f88743 100644
>> --- a/tools/testing/selftests/mm/split_huge_page_test.c
>> +++ b/tools/testing/selftests/mm/split_huge_page_test.c
>> @@ -544,7 +544,7 @@ int main(int argc, char **argv)
>> ksft_exit_fail_msg("Reading PMD pagesize failed\n");
>>
>> nr_pages = pmd_pagesize / pagesize;
>> - max_order = sz2ord(pmd_pagesize, pagesize);
>> + max_order = sz2ord(pmd_pagesize, pagesize);
>> tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
>> ksft_set_plan(tests);
>>
>
> Please just comment next time one the respective patch as review comment.
>
To clarify what I mean is something like this:
https://lkml.kernel.org/r/3dca2de4-9a6a-4efe-a86c-83f9509831fc@gmail.com
Gives more context when the subject directly highlights to which patch
you are replying.
--
Cheers
David / dhildenb
On Tue, 2025-08-19 at 09:28 +0200, David Hildenbrand wrote:
> On 19.08.25 09:25, David Hildenbrand wrote:
> > On 19.08.25 06:12, Aboorva Devarajan wrote:
> > > Removed an extra space in split_huge_page_test that was introduced
> > > by commit 4b76e221794b ("mm/selftests: fix split_huge_page_test
> > > failure on systems with 64KB page size").
> > >
> > > Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
> > > ---
> > > tools/testing/selftests/mm/split_huge_page_test.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
> > > index 54e86f00aabc..faf7e1f88743 100644
> > > --- a/tools/testing/selftests/mm/split_huge_page_test.c
> > > +++ b/tools/testing/selftests/mm/split_huge_page_test.c
> > > @@ -544,7 +544,7 @@ int main(int argc, char **argv)
> > > ksft_exit_fail_msg("Reading PMD pagesize failed\n");
> > >
> > > nr_pages = pmd_pagesize / pagesize;
> > > - max_order = sz2ord(pmd_pagesize, pagesize);
> > > + max_order = sz2ord(pmd_pagesize, pagesize);
> > > tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2;
> > > ksft_set_plan(tests);
> > >
> >
> > Please just comment next time one the respective patch as review comment.
> >
>
> To clarify what I mean is something like this:
>
> https://lkml.kernel.org/r/3dca2de4-9a6a-4efe-a86c-83f9509831fc@gmail.com
>
> Gives more context when the subject directly highlights to which patch
> you are replying.
Hi David,
Thanks for pointing this out. I’ll make sure to follow this.
Regards,
Aboorva
© 2016 - 2025 Red Hat, Inc.