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 288E32D7398 for ; Tue, 1 Sep 2026 13:32:38 +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=1788269560; cv=none; b=o5yI0jEjUuK2fEZy9GoxHx0J7yH1O3KLXDJh1SKHhz8iveXOdTLLh+aGDtySd+KuyCAfZw/teVJ5DBpMcxaUnbq0p/leR4Je05qlhrSebldres3NwNbN1YXQIkL12iAlMHwxifgMQVbdHwPBALUJRRIcK1FgJuQJAgw1MpTiDiM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788269560; c=relaxed/simple; bh=yEh/5sEQrm61sJGCl2JE+v4RNVZxmVQVgxyFy7+91+Q=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=OYcki6Cg8fjs3qHQhERAEEipHR4RP7x2Zl65pxOcIh0l3Se3p/zu3uy8HuaboD+mvneBLjL1B9dlzYenlyNADMAHM4glZoADqsgnACca2Fxx7k09xBSHvGPBh59qFsUcdGz+NXuJPGc6cD25OxuNvJRWuz7evXNX1Y3IfoF0cN4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hYadJe0j; 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="hYadJe0j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6A1B1F000E9; Tue, 1 Sep 2026 13:32:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788269558; bh=fwlZrZ/D24jHPFKrwXxH8DnKdz2KyrCYaGMY85Ubaqw=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=hYadJe0j7btZ0DPNdBYz5Q1+AAOw2UJlZKa2Utk2v++Tw7Jub5s4w2arfkZTUumpn X8/K85aac2lLOhksw82yp+Y8AB5f2WxN5136sofXf7RXRSYVnmVrFz8tTT9Irn0A2o KOkXGI9wBoH12w3tloyVLoVmoAQ/scKqIkZix9aBoIjlAhDsWvK0/9gubUZTFAiwxy JGYhPzKf30CDZArGMkbzIyUGhjF8DfNU2F7ZhNGwfRcY1fc//3AuZqHEzkXSWxGpRe XeQznlhLT+4Ri4dGZ2kPE0sjGDENhir75ubzm6Ffey3FhIKrq7V3OolukfgSnbINdK JPR5lIQXZ51jA== From: sashiko-bot@kernel.org Subject: Re: [PATCH 4/7] mm/damon/vaddr: respect folio end for DAMOS_MIGRATE_{HOT,COLD} Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20260901131326.97615-5-sj@kernel.org> References: <20260901131326.97615-1-sj@kernel.org> <20260901131326.97615-5-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 01 Sep 2026 13:32:38 +0000 Message-Id: <20260901133238.A6A1B1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: > For applying DAMOS_MIGRATE_{HOT,COLD} actions to a region, DAMON virtual > address space operation set (vaddr) calls walk_page_range[_vma]() for > the region. The pmd walk entry function, namely > damon_va_migrate_pmd_entry(), collects folios of addresses of the region > in the pmd. It starts from the walking address and advances the address > by the size of the folio of the address until it goes out of the pmd or > the region. >=20 > Let's suppose it is for the first pmd of the region, and the region > start address is in the middle of a large folio. Also, the next folios > are small. Then, some of the next folios could be skipped. Fix the > issue by advancing the address to exactly the start address of the next > folio. >=20 > The user impact is that DAMOS action is applied to less than expected > amount of memory. Given the best effort nature of DAMON, it is no big > problem, but it is clearly a bug that is better to be fixed. >=20 > The issue was discovered [1] by Sashiko. >=20 > [1] https://lore.kernel.org/20260514015053.149396-1-sj@kernel.org >=20 > Fixes: 09efc56a3b1c ("mm/damon/vaddr: consistently use only pmd_entry for= damos_migrate") > Cc: # 6.19.x > Signed-off-by: SJ Park Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260901131326.9761= 5-1-sj@kernel.org?part=3D4