[PATCH v1] mm/contpte: Optimize loop to reduce redundant operations

Xavier
2025-04-07T09:25:59Z

This commit optimizes the contpte_ptep_get function by adding early
termination logic. It checks if the dirty and young bits of orig_pte
are already set and skips redundant bit-setting operations during
the loop. This reduces unnecessary iterations and improves performance.

Signed-off-by: Xavier <xavier_qy@163.com>
---
arch/arm64/mm/contpte.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
index bcac4f55f9c1..ca15d8f52d14 100644
--- a/arch/arm64/mm/contpte.c
+++ b/arch/arm64/mm/contpte.c
@@ -163,17 +163,26 @@ pte_t contpte_ptep_get(pte_t *ptep, pte_t orig_pte)

pte_t pte;
int i;
+ bool dirty = false;
+ bool young = false;

ptep = contpte_align_down(ptep);

for (i = 0; i < CONT_PTES; i++, ptep++) {
pte = __ptep_get(ptep);

- if (pte_dirty(pte))
+ if (!dirty && pte_dirty(pte)) {
+ dirty = true;
orig_pte = pte_mkdirty(orig_pte);
+ }

- if (pte_young(pte))
+ if (!young && pte_young(pte)) {
+ young = true;
orig_pte = pte_mkyoung(orig_pte);
+ }
+
+ if (dirty && young)
+ break;
}

return orig_pte;
--
2.34.1