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b=IlX87D/Lq6R17YTQTyg93CU3XzxNg0LyM3R516eJBKICYpiceSdQBusGt9JxbwAEY Oetopq4JPfNlc51yws7g3VFOllGU7RnvGvMJ/IDBbvF0s1NwRFdxsHETeTVJwcPfz4 kBf7PsyHKeql9NIFUHUuzLd1iVk/zA2+RDkeRcpVToRyKEQRgo4L+KHWhMbocTLpwP iZLmKnR0prC5s0ikktVP/0z/7YoHQquIEdNsZ53gQRgE5ooCJnRNHiJeW8QTXZzCQx jnjAhSzs4eBYFKatCXzMxLp0tr9uMUlNhdNx+YiOZx09TPEy72jGOXhM4pcmoirpqC dbtTtVxXSbeBg== From: SJ Park To: Donggeun Yoo Cc: SJ Park , akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 1/2] mm/damon/core: charge only the part of a region the filter left Date: Wed, 16 Sep 2026 18:24:19 -0700 Message-ID: <20260917012420.101087-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260917003553.2465523-2-donggeunyoo.kernel@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 24421100002 X-Stat-Signature: iy86st6ejc9nd3nfknprykdkrsfr5359 X-HE-Tag: 1789608268-215105 X-HE-Meta: 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 dLdFrOBt qkBl8+kbatIf0eZkHvYoYAJERhWQMUdER5gbrzxNpov45LSU1QWp4P+ov7VYtoKHpfx2ef0wQ+aK6yZX+3BJ5fQlnts4W/tsP5WirHFkELifCTWVejKSSLatzJ5OOooWcHOPxeO4uX+NWA7pQPbvLWbSdkWy7UpZ3tVauwbmzr0QeUuFuc2vHx3uE1eIeX4qMA2+4MkrekhWisURSnvtHQqSKz7Rwdd2iV2Y7qnErjdvn6WTL0ImP8mI5ECtulMOkrHgYDgg1628SWqcwD24csROmLwtsjkLQUfohfeY0mqIaqu8GEqJDpMPZDBDtaRqpvcW3KgFr4kvy0t4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 17 Sep 2026 09:35:52 +0900 Donggeun Yoo wrote: > An address range DAMOS filter that partially overlaps a monitoring > region splits the region at the filter boundary, so the scheme action is > applied to only one side of it. damos_apply_scheme() reads the region > size once on entry, before damos_core_filter_out() performs that split. > > The quota charge and the statistics update therefore account for the > region as it was before the trim. schemes//stats/sz_tried counts > memory the filter excluded, which Documentation/mm/damon/design.rst says > is not counted as tried, and with quotas/bytes set the excluded part is > charged against the budget, throttling the scheme to a fraction of what > was configured. The user impact is that DAMOS could work unexpectedly slow, due to over-charged quota. Also DAMOS stat could be confusing. No critical events such as crashes or leask happen. If above is not incorrect, I will add that to the commit message when I add this patch to damon/next tree. Let me know if anything is incorrect. > > Re-read the region size after the core filters have run. Thank you for finding and fixing this bug! > > Fixes: ab9bda001b68 ("mm/damon/core: introduce address range type damos filter") > Cc: # 6.6.x > Signed-off-by: Donggeun Yoo Reviewed-by: SJ Park Thanks, SJ [...]