From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 040DD3A7F47; Wed, 8 Jul 2026 13:54:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783518861; cv=none; b=RAid1W7/P45lacPqb+7tbvdxH0uR2x1bGf2D0DyMV6oO+Zve5gzhftSm2kvQ1OJANDmx3oOAnJrB0p0SDe4l5DkDD3rJywps7kKh/3xWwVBlaor3vbuc3aGlZ0Bk+UXfmQUqE255OAHyr0QSagItfYEjk+/lFP/Nr0//60YC1Vw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783518861; c=relaxed/simple; bh=AZMJUdVmjm3VM/8AMZAZNtwCMKErBw44WDwuaV8n29Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lOp9SCxbEoZ+CbA8dpGlKFQglmhgqEH0359EI5wyQ0cs6sMA+JXVWv4LERoJ+saftmZKIAZJorZ3579UPRLVcvEqZl63nPCKfEwwLvCxw5SVkCRXrawzQwsc1BUyMvylOhFQf1MHfSgiY0GK99wDo6xa4Lqb3z4xf6bxZaD2OxI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S/nLD9o/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S/nLD9o/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DDD91F00ADB; Wed, 8 Jul 2026 13:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783518847; bh=FjsCU14SCNwzNXGXZ9ta5DksRZeNC0xj5z1tjd9bQ8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=S/nLD9o/Qjh5tLPHZqt1VNLZ0pYci7WKgWei0fOiiIL7v1uDHsi+1JOGmXBNrP8yb Qor5+oDR4q2k7eAAeiKqlYmxFX/4KaYFrj3khAxKzgyMXpGgjxZ4oXkYd9xJ11f7NU pbON4T27mUBQPijrP08XfiB3jzxwCUOejAyzlTgeOB2Avlq7BAyjHDOpmXETx1reCb Ihj58yCh7axxdgD/EsifvO694uENNrVq4k4zNTLOFgJyKDiHKFmMQE8duZNSHk3B8K gcD5fkpWvgwD/64QMNhyE6rp90INaypFchsMXJlWgP1omWbfeWjhXZ1hYUK5FHx3Jr V2k1nP6Z0/W6Q== From: SJ Park To: Andrew Morton Cc: SJ Park , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 7/7] mm/damon/core: handle unreset probe_hits in probe_hits_mvsum() Date: Wed, 8 Jul 2026 06:53:57 -0700 Message-ID: <20260708135359.122587-8-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260708135359.122587-1-sj@kernel.org> References: <20260708135359.122587-1-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 If damon_update_monitoring_result() is called at the end of the aggregation interval, probe_hits is not reset. That's because the value will be exposed to the user via damon_region_aggregated trace event. Meanwhile, damon_probe_hits_mvsum() can be called in this state. Due to its logic, it will return a value that is incorrectly high. This could happen if the user requested DAMOS schemes applied regions sysfs files update exactly in the time sequence. The impact is minor, but better to avoid. Check the timing and simply return the fully aggregated last_probe_hits, like damon_nr_accesses_mvsum() also does. It is not 100% accurate since it is the last interval's aggregation. But better than the value that is completely reset. Signed-off-by: SJ Park --- mm/damon/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index 15d31285515d6..11473aa1f70f4 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -290,6 +290,9 @@ unsigned char damon_probe_hits_mvsum(int probe_idx, struct damon_region *r, ctx->passed_sample_intervals; left_window_bp = mult_frac(left_window, 10000, window_len); + if (left_window_bp == 10000) + return r->last_probe_hits[probe_idx]; + return damon_mvsum(r->probe_hits[probe_idx], r->last_probe_hits[probe_idx], left_window_bp); } -- 2.47.3