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 B66E834CDD for ; Tue, 30 Jun 2026 04:23:37 +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=1782793418; cv=none; b=TWk8DLld+558+xSRNXkIcZFN1pt3St1TnpfCQ9uiHE6KEEfeKvzZgL+OuxReoHluQYwpYMx6jC3biS03BfMbdkimoWTKo+5zgjuq0Pl+mtfCHgLbCTi1ChpeXyHFAFaRnvWO12iF93z2l/HkSQFYnlQcFPbRfwI/bEbmNpOAm4c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782793418; c=relaxed/simple; bh=cYfGsMyrq8j7BXKqFBCoG0KSxynxNDLaN5UTT6bMjKI=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=RVWDwlL4osA7HBjLu8sB4L21Ca/x4uGsIhM51bvUx8UtI/+pCd9jffr/V05nh449NE8O3QzTt4w0OAIH73LVa0tNTWAjdwllDYP1TFTDIWNaW9mbf+5fu//zI4tuaLAMrPK2XFKB3bbLbs4T8QqNyl6Nc23tba1nvaaRPeD9dg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IdU9W4TD; 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="IdU9W4TD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F8CE1F000E9; Tue, 30 Jun 2026 04:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782793417; bh=gMyz+5j6Ajm68sXFnLUQO7pKClrJ5EENZtjPBrD9Xr4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=IdU9W4TDtH3ZgIbxNfxBt5YurYbzLSOv4HujuQ1bg3yB/EFEekLGI4ZIqP98Lilu8 8DbDVTdPz3aorMIQoGCKutP1r9KBabnQ5W23TyiSs6vhQF1lX6gZkskIBWGKPQ6bBJ BPZkzS4VVBls4KPX7cBhttxEOqvG1kyTtdi2qtX/DtmqP7gGsYKm+5cYIwefO1Fax+ 8skRrFkUcbPr/whFQZyt61piDq7VnpAkse3SKJqKhQeOuJAkqNUd9A2is6gsIKL+E8 ddzcbNUvDeSRr5VAHIzvvhI+z+t9zmhIo7q36sZ7GW5c+MYww47eAfUiw5OGb4tmYe T3E4grBJVI75g== From: sashiko-bot@kernel.org Subject: Re: [PATCH 04/18] mm/damon/core: handle unreset nr_accesses in damon_nr_accesses_mvsum() Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20260630040812.149729-5-sj@kernel.org> References: <20260630040812.149729-1-sj@kernel.org> <20260630040812.149729-5-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 30 Jun 2026 04:23:36 +0000 Message-Id: <20260630042337.2F8CE1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] damon_nr_accesses_mvsum() incorrectly returns stale data (r->las= t_nr_accesses) when damon_set_attrs() is called exactly at the end of an ag= gregation window. -- commit ebe6cc65ba2de465cab83d7ffe913bb9f8304f66 Author: SJ Park mm/damon/core: handle unreset nr_accesses in damon_nr_accesses_mvsum() This commit adds logic to damon_nr_accesses_mvsum() to return last_nr_accesses when the remaining window is full. It aims to avoid unnecessarily counting unreset nr_accesses when damon_set_attrs() is called at the end of an aggregation window. > diff --git a/mm/damon/core.c b/mm/damon/core.c > index 94dd425ee4353..df79f4d10bdc3 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c > @@ -266,6 +266,9 @@ unsigned int damon_nr_accesses_mvsum(struct damon_reg= ion *r, > ctx->passed_sample_intervals; > left_window_bp =3D mult_frac(left_window, 10000, window_len); > =20 > + if (left_window_bp =3D=3D 10000) > + return r->last_nr_accesses; > + [Severity: Medium] Will this early return cause the function to return stale data from the=20 previous window instead of freshly accumulated data? If damon_set_attrs() is called at the end of an aggregation window, damon_update_monitoring_result() processes this with aggregating =3D false.= =20 This intentionally preserves the fully accumulated r->nr_accesses for the newly completed window.=20 After damon_set_attrs() pushes ctx->next_aggregation_sis forward, a subsequent call to damon_nr_accesses_mvsum() will calculate left_window_bp as 10000.=20 Because of this early return, won't it discard the freshly accumulated=20 r->nr_accesses and incorrectly return the older r->last_nr_accesses instead? > return damon_mvsum(r->nr_accesses, r->last_nr_accesses, > left_window_bp); > } --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260630040812.1497= 29-1-sj@kernel.org?part=3D4