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 2EE8B43B3C6 for ; Tue, 1 Sep 2026 13:26:55 +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=1788269217; cv=none; b=GKwwd289ROHPV2qrj0/cuuipNRFVNcczyuDzzV42ECpBr8HOkTbeDAgiiSu25RXXf9xrcIOHtL2zoMMuIyPB0RDg8y9WuH6QmwWt/zLyeXn+VuFw12eJ7B9XDFqC03ZwNw9pCV621V8yTXkuKrfjaBNmbaSADHuDs1GQ+78sD9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788269217; c=relaxed/simple; bh=TWZ7a3aBdLuGRv9RR6vQQHcs/Zv31eXabyieJqtDLUQ=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=OI0FdYH95P71d4KKYgMvD4Ds24FdvF+pfV6gp7+cte45j+hExDj6iHaybUT3GS9ihlJP0aa9wroWj4d/4RkRdVsRy8S74hCZKZ8haiQThY8AWyreJ/c0y6zqjIfEwvd4sCUrCvWU9JWux69UYkNg/GSftNgT0eb88LMIzLgLsPg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=liZV63NH; 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="liZV63NH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A544B1F000E9; Tue, 1 Sep 2026 13:26:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788269215; bh=oUtq5HxYBp86YbWTRog5lkXKhCLvUZz46rNdoJtdkr8=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=liZV63NHcTfIFcybWmE0LZ8W3LxglkrU6B+JJvBS+zfi5QbWM/pOGzCYFZFOQJwc7 0+R744cB/TPlcMfJQ0c4XrXKRBquwukHI91JnQU7yFNdz9I2r2l0HVmhrQJznYIxU/ 2hwWI5S41UwghCf+3DLvbIaK/thfJep50DqSFZJEWltsHHht3z16X6tIv2Lsw4fgq8 MnueuDMwa19rfnSPYPdjVsfTXFdDuBT4O3+cigrLW92TnD3WJmEY3VP3jP8FiE4/hr 1X4POrek4dVr6zVk8wLYNGjXGOSxu5ES3MiVx5RyoW/Bcq6GNYND5c15Sr6fXyWm58 b4PM6Z44WBi+A== From: sashiko-bot@kernel.org Subject: Re: [PATCH 5/8] 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: <20260901131850.98037-6-sj@kernel.org> References: <20260901131850.98037-1-sj@kernel.org> <20260901131850.98037-6-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 01 Sep 2026 13:26:55 +0000 Message-Id: <20260901132655.A544B1F000E9@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/20260901131850.9803= 7-1-sj@kernel.org?part=3D5