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Fri, 07 Aug 2026 09:18:32 -0700 (PDT) From: Liew Rui Yan To: sj@kernel.org Cc: aethernet65535@gmail.com, damon@lists.linux.dev, linux-mm@kvack.org Subject: Re: [PATCH 2/2] mm/damon: skip deactivated schemes in watermark checks and add fallback sleep Date: Sat, 8 Aug 2026 00:18:40 +0800 Message-ID: <20260807161840.56993-1-aethernet65535@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807140739.91238-1-sj@kernel.org> References: <20260807140739.91238-1-sj@kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi SJ, On Fri, 7 Aug 2026 07:07:39 -0700 SJ Park wrote: > This is an intended implementation. > > When all schemes are deactivated by watermarks, DAMON stops monitoring. It was > implemented in the way because we didn't want DAMON consumes system resource in > the case. But, later it turned out DAMON's resource consumption is really > negligible. Rather, it is turned out that it makes DAMON runs with stale > history when it is activated again. Particularly, regions have 'age' and their > start/end addresses that was emerged before the deactivation. Those are > meaningless and could even cause wrong DAMOS decisions. > > We don't want that anymore. For a case the user really want DAMON completely > stops, we introduced 'pause'. For max_nr_snapshot-based deactivation, we don't > intend to completely stop DAMON. > > Maybe the documentation can be updated to further clarify this. Thank you for your detailed explanation! I also glad to hear that DAMON's monitoring's resource consumption is negligible, since I plan to add a contexts//always_monitoring parameter later on, allowing users to decide for themselves whether to keep monitoring even all schemes is deactivated by watermarks. Best regards, Rui Yan