[RFC PATCH 2/3] mm/mincore: Use can_pte_batch_count() in mincore_pte_range() for pte batch mincore_pte_range()
From: Zhang Qilong
Date: Mon Oct 27 2025 - 10:04:20 EST
In current mincore_pte_range(), if pte_batch_hint() return one
pte, it's not efficient, just call new added can_pte_batch_count().
In ARM64 qemu, with 8 CPUs, 32G memory, a simple test demo like:
1. mmap 1G anon memory
2. write 1G data by 4k step
3. mincore the mmaped 1G memory
4. get the time consumed by mincore
Tested the following cases:
- 4k, disabled all hugepage setting.
- 64k mTHP, only enable 64k hugepage setting.
Before
Case status | Consumed time (us) |
----------------------------------|
4k | 7356 |
64k mTHP | 3670 |
Pathed:
Case status | Consumed time (us) |
----------------------------------|
4k | 4419 |
64k mTHP | 3061 |
The result is evident and demonstrate a significant improvement in
the pte batch. While verification within a single environment may
have inherent randomness. there is a high probability of achieving
positive effects.
Signed-off-by: Zhang Qilong <zhangqilong3@xxxxxxxxxx>
---
mm/mincore.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/mm/mincore.c b/mm/mincore.c
index 8ec4719370e1..2cc5d276d1cd 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -178,18 +178,14 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
/* We need to do cache lookup too for pte markers */
if (pte_none_mostly(pte))
__mincore_unmapped_range(addr, addr + PAGE_SIZE,
vma, vec);
else if (pte_present(pte)) {
- unsigned int batch = pte_batch_hint(ptep, pte);
-
- if (batch > 1) {
- unsigned int max_nr = (end - addr) >> PAGE_SHIFT;
-
- step = min_t(unsigned int, batch, max_nr);
- }
+ unsigned int max_nr = (end - addr) >> PAGE_SHIFT;
+ step = can_pte_batch_count(vma, ptep, &pte,
+ max_nr, 0);
for (i = 0; i < step; i++)
vec[i] = 1;
} else { /* pte is a swap entry */
*vec = mincore_swap(pte_to_swp_entry(pte), false);
}
--
2.43.0