diff mbox series

[RESEND,v7,10/10] selftests/mm/cow: Add tests for anonymous small-sized THP

Message ID 20231122162950.3854897-11-ryan.roberts@arm.com (mailing list archive)
State New
Headers show
Series Small-sized THP for anonymous memory | expand

Commit Message

Ryan Roberts Nov. 22, 2023, 4:29 p.m. UTC 
Add tests similar to the existing PMD-sized THP tests, but which operate
on memory backed by (PTE-mapped) small-sized THP. This reuses all the
existing infrastructure. If the test suite detects that small-sized THP
is not supported by the kernel, the new tests are skipped.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 tools/testing/selftests/mm/cow.c | 71 +++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

--
2.25.1

Comments

Ryan Roberts Nov. 27, 2023, 2:02 p.m. UTC | #1 
On 22/11/2023 16:29, Ryan Roberts wrote:
> Add tests similar to the existing PMD-sized THP tests, but which operate
> on memory backed by (PTE-mapped) small-sized THP. This reuses all the
> existing infrastructure. If the test suite detects that small-sized THP
> is not supported by the kernel, the new tests are skipped.
> 
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
> ---
>  tools/testing/selftests/mm/cow.c | 71 +++++++++++++++++++++++++++++++-
>  1 file changed, 70 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
> index d03c453cfd5c..3efc395c7077 100644
> --- a/tools/testing/selftests/mm/cow.c
> +++ b/tools/testing/selftests/mm/cow.c
> @@ -29,15 +29,49 @@
>  #include "../../../../mm/gup_test.h"
>  #include "../kselftest.h"
>  #include "vm_util.h"
> +#include "thp_settings.h"
> 
>  static size_t pagesize;
>  static int pagemap_fd;
>  static size_t pmdsize;
> +static int nr_thpsmallsizes;
> +static size_t thpsmallsizes[20];

Off the back of some comments David made againt the previous patch [1], I'm
proposing to rework this a bit so that ALL thp sizes are stored in this array,
not just the non-PMD-sized sizes. This makes the changes overall a bit smaller
and easier to understand, I think...

>  static int nr_hugetlbsizes;
>  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_smallthp_sizes(size_t sizes[], int max)

This changes to detect_thp_sizes() and deposits all sizes in sizes[]

> +{
> +	int count = 0;
> +	unsigned long orders;
> +	size_t kb;
> +	int i;
> +
> +	/* thp not supported at all. */
> +	if (!pmdsize)
> +		return 0;
> +
> +	orders = thp_supported_orders();
> +
> +	/* Only interested in small-sized THP (less than PMD-size). */
> +	for (i = 0; i < sz2ord(pmdsize); i++) {
> +		if (!(orders & (1UL << i)))
> +			continue;
> +		kb = (pagesize >> 10) << i;
> +		sizes[count++] = kb * 1024;
> +		ksft_print_msg("[INFO] detected small-sized THP size: %zu KiB\n",
> +			       kb);

This just prints "[INFO] detected THP size: %zu KiB"

> +	}
> +
> +	return count;
> +}
> +
>  static void detect_huge_zeropage(void)
>  {
>  	int fd = open("/sys/kernel/mm/transparent_hugepage/use_zero_page",
> @@ -1113,6 +1147,23 @@ static void run_anon_test_case(struct test_case const *test_case)
>  		run_with_partial_mremap_thp(test_case->fn, test_case->desc, pmdsize);
>  		run_with_partial_shared_thp(test_case->fn, test_case->desc, pmdsize);
>  	}
> +	for (i = 0; i < nr_thpsmallsizes; i++) {
> +		size_t size = thpsmallsizes[i];
> +		struct thp_settings settings = *thp_current_settings();
> +
> +		settings.hugepages[sz2ord(pmdsize)].enabled = THP_NEVER;
> +		settings.hugepages[sz2ord(size)].enabled = THP_ALWAYS;
> +		thp_push_settings(&settings);
> +
> +		run_with_pte_mapped_thp(test_case->fn, test_case->desc, size);
> +		run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc, size);
> +		run_with_single_pte_of_thp(test_case->fn, test_case->desc, size);
> +		run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc, size);
> +		run_with_partial_mremap_thp(test_case->fn, test_case->desc, size);
> +		run_with_partial_shared_thp(test_case->fn, test_case->desc, size);
> +
> +		thp_pop_settings();
> +	}

This same loop covers the pmdsize tests too, and I've just added a conditional
that runs the 2 extra tests that are pmdsize only.

>  	for (i = 0; i < nr_hugetlbsizes; i++)
>  		run_with_hugetlb(test_case->fn, test_case->desc,
>  				 hugetlbsizes[i]);
> @@ -1134,6 +1185,7 @@ static int tests_per_anon_test_case(void)
> 
>  	if (pmdsize)
>  		tests += 8;
> +	tests += 6 * nr_thpsmallsizes;
>  	return tests;
>  }
> 
> @@ -1691,12 +1743,24 @@ static int tests_per_non_anon_test_case(void)
>  int main(int argc, char **argv)
>  {
>  	int err;
> +	struct thp_settings default_settings;
> 
>  	pagesize = getpagesize();
>  	pmdsize = read_pmd_pagesize();
> -	if (pmdsize)
> +	if (pmdsize) {
> +		/* Only if THP is supported. */
> +		thp_read_settings(&default_settings);
> +		default_settings.hugepages[sz2ord(pmdsize)].enabled = THP_GLOBAL;
> +		thp_save_settings();
> +		thp_push_settings(&default_settings);
> +
>  		ksft_print_msg("[INFO] detected PMD-mapped THP size: %zu KiB\n",
>  			       pmdsize / 1024);
> +
> +		nr_thpsmallsizes = detect_smallthp_sizes(thpsmallsizes,
> +						    ARRAY_SIZE(thpsmallsizes));
> +	}
> +
>  	nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
>  						    ARRAY_SIZE(hugetlbsizes));
>  	detect_huge_zeropage();
> @@ -1715,6 +1779,11 @@ int main(int argc, char **argv)
>  	run_anon_thp_test_cases();
>  	run_non_anon_test_cases();
> 
> +	if (pmdsize) {
> +		/* Only if THP is supported. */
> +		thp_restore_settings();
> +	}
> +
>  	err = ksft_get_fail_cnt();
>  	if (err)
>  		ksft_exit_fail_msg("%d out of %d tests failed\n",
> --
> 2.25.1
>
David Hildenbrand Nov. 27, 2023, 2:50 p.m. UTC | #2 
On 27.11.23 15:02, Ryan Roberts wrote:
> On 22/11/2023 16:29, Ryan Roberts wrote:
>> Add tests similar to the existing PMD-sized THP tests, but which operate
>> on memory backed by (PTE-mapped) small-sized THP. This reuses all the
>> existing infrastructure. If the test suite detects that small-sized THP
>> is not supported by the kernel, the new tests are skipped.
>>
>> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
>> ---
>>   tools/testing/selftests/mm/cow.c | 71 +++++++++++++++++++++++++++++++-
>>   1 file changed, 70 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
>> index d03c453cfd5c..3efc395c7077 100644
>> --- a/tools/testing/selftests/mm/cow.c
>> +++ b/tools/testing/selftests/mm/cow.c
>> @@ -29,15 +29,49 @@
>>   #include "../../../../mm/gup_test.h"
>>   #include "../kselftest.h"
>>   #include "vm_util.h"
>> +#include "thp_settings.h"
>>
>>   static size_t pagesize;
>>   static int pagemap_fd;
>>   static size_t pmdsize;
>> +static int nr_thpsmallsizes;
>> +static size_t thpsmallsizes[20];
> 
> Off the back of some comments David made againt the previous patch [1], I'm
> proposing to rework this a bit so that ALL thp sizes are stored in this array,
> not just the non-PMD-sized sizes. This makes the changes overall a bit smaller
> and easier to understand, I think...
> 
>>   static int nr_hugetlbsizes;
>>   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_smallthp_sizes(size_t sizes[], int max)
> 
> This changes to detect_thp_sizes() and deposits all sizes in sizes[]

Just what I wanted to propose :) Makes it simpler by removing the 
"small" terminology and just detecting thp sizes.
Ryan Roberts Nov. 27, 2023, 2:54 p.m. UTC | #3 
On 27/11/2023 14:50, David Hildenbrand wrote:
> On 27.11.23 15:02, Ryan Roberts wrote:
>> On 22/11/2023 16:29, Ryan Roberts wrote:
>>> Add tests similar to the existing PMD-sized THP tests, but which operate
>>> on memory backed by (PTE-mapped) small-sized THP. This reuses all the
>>> existing infrastructure. If the test suite detects that small-sized THP
>>> is not supported by the kernel, the new tests are skipped.
>>>
>>> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
>>> ---
>>>   tools/testing/selftests/mm/cow.c | 71 +++++++++++++++++++++++++++++++-
>>>   1 file changed, 70 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
>>> index d03c453cfd5c..3efc395c7077 100644
>>> --- a/tools/testing/selftests/mm/cow.c
>>> +++ b/tools/testing/selftests/mm/cow.c
>>> @@ -29,15 +29,49 @@
>>>   #include "../../../../mm/gup_test.h"
>>>   #include "../kselftest.h"
>>>   #include "vm_util.h"
>>> +#include "thp_settings.h"
>>>
>>>   static size_t pagesize;
>>>   static int pagemap_fd;
>>>   static size_t pmdsize;
>>> +static int nr_thpsmallsizes;
>>> +static size_t thpsmallsizes[20];
>>
>> Off the back of some comments David made againt the previous patch [1], I'm
>> proposing to rework this a bit so that ALL thp sizes are stored in this array,
>> not just the non-PMD-sized sizes. This makes the changes overall a bit smaller
>> and easier to understand, I think...
>>
>>>   static int nr_hugetlbsizes;
>>>   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_smallthp_sizes(size_t sizes[], int max)
>>
>> This changes to detect_thp_sizes() and deposits all sizes in sizes[]
> 
> Just what I wanted to propose :) Makes it simpler by removing the "small"
> terminology and just detecting thp sizes.

Great! All done and queued up for the next version. Just waiting for some
feedback on the 2 crucial patches in this series (3 & 4) :)
diff mbox series

Patch

diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
index d03c453cfd5c..3efc395c7077 100644
--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -29,15 +29,49 @@ 
 #include "../../../../mm/gup_test.h"
 #include "../kselftest.h"
 #include "vm_util.h"
+#include "thp_settings.h"

 static size_t pagesize;
 static int pagemap_fd;
 static size_t pmdsize;
+static int nr_thpsmallsizes;
+static size_t thpsmallsizes[20];
 static int nr_hugetlbsizes;
 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_smallthp_sizes(size_t sizes[], int max)
+{
+	int count = 0;
+	unsigned long orders;
+	size_t kb;
+	int i;
+
+	/* thp not supported at all. */
+	if (!pmdsize)
+		return 0;
+
+	orders = thp_supported_orders();
+
+	/* Only interested in small-sized THP (less than PMD-size). */
+	for (i = 0; i < sz2ord(pmdsize); i++) {
+		if (!(orders & (1UL << i)))
+			continue;
+		kb = (pagesize >> 10) << i;
+		sizes[count++] = kb * 1024;
+		ksft_print_msg("[INFO] detected small-sized THP size: %zu KiB\n",
+			       kb);
+	}
+
+	return count;
+}
+
 static void detect_huge_zeropage(void)
 {
 	int fd = open("/sys/kernel/mm/transparent_hugepage/use_zero_page",
@@ -1113,6 +1147,23 @@  static void run_anon_test_case(struct test_case const *test_case)
 		run_with_partial_mremap_thp(test_case->fn, test_case->desc, pmdsize);
 		run_with_partial_shared_thp(test_case->fn, test_case->desc, pmdsize);
 	}
+	for (i = 0; i < nr_thpsmallsizes; i++) {
+		size_t size = thpsmallsizes[i];
+		struct thp_settings settings = *thp_current_settings();
+
+		settings.hugepages[sz2ord(pmdsize)].enabled = THP_NEVER;
+		settings.hugepages[sz2ord(size)].enabled = THP_ALWAYS;
+		thp_push_settings(&settings);
+
+		run_with_pte_mapped_thp(test_case->fn, test_case->desc, size);
+		run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc, size);
+		run_with_single_pte_of_thp(test_case->fn, test_case->desc, size);
+		run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc, size);
+		run_with_partial_mremap_thp(test_case->fn, test_case->desc, size);
+		run_with_partial_shared_thp(test_case->fn, test_case->desc, size);
+
+		thp_pop_settings();
+	}
 	for (i = 0; i < nr_hugetlbsizes; i++)
 		run_with_hugetlb(test_case->fn, test_case->desc,
 				 hugetlbsizes[i]);
@@ -1134,6 +1185,7 @@  static int tests_per_anon_test_case(void)

 	if (pmdsize)
 		tests += 8;
+	tests += 6 * nr_thpsmallsizes;
 	return tests;
 }

@@ -1691,12 +1743,24 @@  static int tests_per_non_anon_test_case(void)
 int main(int argc, char **argv)
 {
 	int err;
+	struct thp_settings default_settings;

 	pagesize = getpagesize();
 	pmdsize = read_pmd_pagesize();
-	if (pmdsize)
+	if (pmdsize) {
+		/* Only if THP is supported. */
+		thp_read_settings(&default_settings);
+		default_settings.hugepages[sz2ord(pmdsize)].enabled = THP_GLOBAL;
+		thp_save_settings();
+		thp_push_settings(&default_settings);
+
 		ksft_print_msg("[INFO] detected PMD-mapped THP size: %zu KiB\n",
 			       pmdsize / 1024);
+
+		nr_thpsmallsizes = detect_smallthp_sizes(thpsmallsizes,
+						    ARRAY_SIZE(thpsmallsizes));
+	}
+
 	nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
 						    ARRAY_SIZE(hugetlbsizes));
 	detect_huge_zeropage();
@@ -1715,6 +1779,11 @@  int main(int argc, char **argv)
 	run_anon_thp_test_cases();
 	run_non_anon_test_cases();

+	if (pmdsize) {
+		/* Only if THP is supported. */
+		thp_restore_settings();
+	}
+
 	err = ksft_get_fail_cnt();
 	if (err)
 		ksft_exit_fail_msg("%d out of %d tests failed\n",