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b=UXXpJ6ScDKGWLDx/HgUzJ5sqtbpEXFA2Ctwbjq6K2MtMcDWYaEX94Gk0asH/tH/kA iQfsHpW/G5+QPyWYgHQZ+raxxja9UDbc5KaMY8qqcx5ypmJbgKxucYJQz7ACutyeC+ hXENuFNiGhVTw4JzOBuubKINL8mI5jUDxDXctc9B3c0YOhH8OCYi8NOK8bcZ0amjtQ FoVq4/zPENKLAwqqXzyjFl4Xzc3DMIw7QoLRGt+hPIfl7nLtbnkvvzEeUYznXte1W1 /NuGYU8As7v2GwZj24s0uelAhG9/j9W/z3vQuKMfFMgElgdclAyuQMjdkU0Ftp8dFa WfGIV4wkZQ10A== From: SJ Park To: Igor Putko Cc: SJ Park , akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/damon/vaddr: remove redundant RCU lock Date: Tue, 30 Jun 2026 07:03:36 -0700 Message-ID: <20260630140337.91100-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260630130253.3843-1-igorpetindev@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: zeg9fqchwy3xy3jzi13waueianzcr6gh X-Rspam-User: X-Rspamd-Queue-Id: 78BAD18000F X-Rspamd-Server: rspam02 X-HE-Tag: 1782828232-40944 X-HE-Meta: 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 iffoRl+P U8vLZ1T63V8UwZzUctmbjRn5/kwcGTYewRGQye52+L20KWS/YVaNFKZc6k8AOAYu/LiYxZk50NwCVHNdk6g8Pomz4Yq3kHD+ejyxG6HkAungrWge3qhBCRRXmqkZJwcvFIs4zz2pggkNaZpveOwCqVWGrAtx2wGfgkM9IJfmYv2DW2rHIoyenDqRUgVLFw/hxum0cNbahMiPGfRABhb1FcJdCRdvY6t8uI6SMVSUa5M3hXJOUwRUzDhemwqakxGSY0DY46PO0sgl75+xPqLd3TtD8oncXIQUH/ndFVPaYwmL8wUxw954+aPPuNcLu3zaAjBAWii2xUcediYpyVQ7dbn7Sig== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello Igor, Thank you for this patch. >From next time, please give enough time for others to comment before posting a new revision of the patch. Also, please post a new revision as a new thread with a changelog [1] including links to previous revisions, rather than a reply to the previous revision. On Tue, 30 Jun 2026 16:02:53 +0300 Igor Putko wrote: > __damon_va_three_regions() is called only by damon_va_three_regions(), > which already holds mmap_read_lock(). Since mmap_read_lock() is held, > the maple tree and VMA list are protected from concurrent changes. > Remove the unnecessary rcu_read_lock() and rcu_read_unlock() calls. This is not explaining the test part change. Could you please update for that? Also, have you had a chance to theoretically or experiemently confirm the problem [2] that motivated to add the rcu_read_lock() at that place is not reintroduced by this change? If so, could you please add that to the commit log, too? Thanks, SJ [1] https://docs.kernel.org/process/submitting-patches.html#commentary [2] https://lore.kernel.org/b83651a0-5b24-4206-b860-cb54ffdf209b@roeck-us.net [...]