* [PATCH] tools/mm/thp_swap_allocator_test: Fix small folio alignment
@ 2025-12-09 3:17 Kaushlendra Kumar
2025-12-16 3:31 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Kaushlendra Kumar @ 2025-12-09 3:17 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, Kaushlendra Kumar
Use ALIGNMENT_SMALLFOLIO instead of ALIGNMENT_MTHP when allocating
small folios to ensure correct memory alignment for the test case.
Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
---
tools/mm/thp_swap_allocator_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/mm/thp_swap_allocator_test.c b/tools/mm/thp_swap_allocator_test.c
index 83afc52275a5..d4434df3dcff 100644
--- a/tools/mm/thp_swap_allocator_test.c
+++ b/tools/mm/thp_swap_allocator_test.c
@@ -142,7 +142,7 @@ int main(int argc, char *argv[])
}
if (use_small_folio) {
- mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_MTHP);
+ mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_SMALLFOLIO);
if (mem2 == NULL) {
fprintf(stderr, "Failed to allocate small folios memory\n");
free(mem1);
--
2.34.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] tools/mm/thp_swap_allocator_test: Fix small folio alignment
2025-12-09 3:17 [PATCH] tools/mm/thp_swap_allocator_test: Fix small folio alignment Kaushlendra Kumar
@ 2025-12-16 3:31 ` Andrew Morton
2025-12-18 3:04 ` Kumar, Kaushlendra
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2025-12-16 3:31 UTC (permalink / raw)
To: Kaushlendra Kumar; +Cc: linux-mm
On Tue, 9 Dec 2025 08:47:45 +0530 Kaushlendra Kumar <kaushlendra.kumar@intel.com> wrote:
> Use ALIGNMENT_SMALLFOLIO instead of ALIGNMENT_MTHP when allocating
> small folios to ensure correct memory alignment for the test case.
>
> ...
>
> --- a/tools/mm/thp_swap_allocator_test.c
> +++ b/tools/mm/thp_swap_allocator_test.c
> @@ -142,7 +142,7 @@ int main(int argc, char *argv[])
> }
>
> if (use_small_folio) {
> - mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_MTHP);
> + mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_SMALLFOLIO);
> if (mem2 == NULL) {
> fprintf(stderr, "Failed to allocate small folios memory\n");
> free(mem1);
What are the worst-case userspace visible runtime effects of this change?
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread* RE: [PATCH] tools/mm/thp_swap_allocator_test: Fix small folio alignment
2025-12-16 3:31 ` Andrew Morton
@ 2025-12-18 3:04 ` Kumar, Kaushlendra
0 siblings, 0 replies; 3+ messages in thread
From: Kumar, Kaushlendra @ 2025-12-18 3:04 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-mm
On Tue, 9 Dec 2025, Andrew Morton wrote:
> On Tue, 9 Dec 2025 08:47:45 +0530 Kaushlendra Kumar wrote:
>> Use ALIGNMENT_SMALLFOLIO instead of ALIGNMENT_MTHP when allocating
>> small folios to ensure correct memory alignment for the test case.
>>
>> ...
>>
>> --- a/tools/mm/thp_swap_allocator_test.c
>> +++ b/tools/mm/thp_swap_allocator_test.c
>> @@ -142,7 +142,7 @@ int main(int argc, char *argv[])
>> }
>>
>> if (use_small_folio) {
>> - mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_MTHP);
>> + mem2 = aligned_alloc_mem(MEMSIZE_SMALLFOLIO, ALIGNMENT_SMALLFOLIO);
>> if (mem2 == NULL) {
>> fprintf(stderr, "Failed to allocate small folios memory\n");
>> free(mem1);
>
> What are the worst-case userspace visible runtime effects of this change?
Before: test allocates small folios with 64KB alignment (ALIGNMENT_MTHP) when
only 4KB alignment (ALIGNMENT_SMALLFOLIO) is needed. This wastes address space
and may cause allocation failures on systems with fragmented memory.
Worst-case impact: this only affects thp_swap_allocator_test tool behavior.
-Kaushlendra
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-12-09 3:17 [PATCH] tools/mm/thp_swap_allocator_test: Fix small folio alignment Kaushlendra Kumar
2025-12-16 3:31 ` Andrew Morton
2025-12-18 3:04 ` Kumar, Kaushlendra
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