Re: [PATCH RFC] mm: madvise: use walk_page_range_vma() for madvise_free_single_vma()

From: Dev Jain
Date: Tue Jun 03 2025 - 02:12:18 EST



On 03/06/25 7:01 am, Barry Song wrote:
From: Barry Song <v-songbaohua@xxxxxxxx>

We've already found the VMA before calling madvise_free_single_vma(),
so calling walk_page_range() and doing find_vma() again seems
unnecessary. It also prevents potential optimizations for MADV_FREE
to use a per-VMA lock.

Cc: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Lokesh Gidra <lokeshgidra@xxxxxxxxxx>
Cc: Tangquan Zheng <zhengtangquan@xxxxxxxx>
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
---
mm/madvise.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index d408ffa404b3..c6a28a2d3ff8 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -826,7 +826,7 @@ static int madvise_free_single_vma(struct madvise_behavior *madv_behavior,
mmu_notifier_invalidate_range_start(&range);
tlb_start_vma(tlb, vma);
- walk_page_range(vma->vm_mm, range.start, range.end,
+ walk_page_range_vma(vma, range.start, range.end,
&madvise_free_walk_ops, tlb);
tlb_end_vma(tlb, vma);
mmu_notifier_invalidate_range_end(&range);

Can similar optimizations be made in madvise_willneed(), madvise_cold_page_range(), etc?