Re: [PATCH] mm/damon/vaddr: attempt per-vma lock during page table walk

[SeongJae Park <sj@kernel.org>]

On Mon, 11 May 2026 21:25:46 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote:

> Currently, DAMON virtual address operations use mmap_read_lock
> during page table walks, which can cause unnecessary contention
> under high concurrency.
> 
> Introduce damon_va_walk_page_range() to first attempt acquiring a
> per-vma lock. If the VMA is found and the range is fully contained
> within it, the page table walk proceeds with the per-vma lock
> instead of mmap_read_lock.
> 
> This optimization is particularly effective for damon_va_young()
> and damon_va_mkold(), which are frequently called and typically
> operate within a single VMA.

Makes sense.  Do you have some measurements?

> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>

Looks good to me.  Nonetheless, because I'm not familiar with per-vma locking,
I'd like to wait for Sashiko review.


Thanks,
SJ

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