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b=bUFTzikzItrtUlko3n6C3LvCjx/JvnCMWkKLdlem/PpTyZE/FGS+Nq2o5AY3rDAaa NgBo0S5Ih821wBlAQ5L4oaL5YIDF1i6kg4l2I/3K1EDCatj7I95X6A/FAo2ubM3hoH CbD/zhbR7PNelKLBIPEFyzZ8Rgylqp0pK+eTMB768ZxsTNRDM9pubG2GRDg6d9juRP IhZmXgQDFj4ojcYW1b68Z7OBPjVZ5fNKM//OTGpvLcRWVkScwvFxVJ7SR/A+vqKA67 B1n8xt2jxqKbMtUYsOhRjeFjcivub1YFVotx3p8udVAqMOLeR66IuhxYW7nDYShuSu KpeJ2ZZvtoZAg== From: SeongJae Park To: Kefeng Wang Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, sunnanyong@huawei.com Subject: Re: [PATCH] mm/damon/vaddr: attempt per-vma lock during page table walk Date: Mon, 11 May 2026 18:31:15 -0700 Message-ID: <20260512013116.80435-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260511132546.1973270-1-wangkefeng.wang@huawei.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: 44z9gi1fixwashfi1584hizo3m3nw1iw X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 99CD040002 X-Rspam-User: X-HE-Tag: 1778549480-285343 X-HE-Meta: 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 qsPB4kB/ 47mpLNqM0UpYA97lMvc1czgFmw1rkRR06W9Bv0FOyZ35az4G6gXymiAQrpv/iGW5gzTqSjAJgUrce05i+uVB3H4Mk06paZ5+VEWm4jo0xySugtB5+3hZvPQ3CKRY+NHTd7FJwB22rm+XDTCNxnOOrD5448dV2YTNqsqve7ZgzqsMS3hsRGYoynh/Vfj9IjrFS859OKMiRfFgkEe+atmMmUd4jYWQS+1fbCzeu7yeMhBtKM7c= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 11 May 2026 21:25:46 +0800 Kefeng Wang 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 Looks good to me. Nonetheless, because I'm not familiar with per-vma locking, I'd like to wait for Sashiko review. Thanks, SJ [...]