From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794082714; b=2dttHicU3BWQzoFtwoMY/EIoLUemSKbFdKVrAK3IeaYg3MkR4LsVQmI2lT0NZ+fiLxsJ EQsI6rUofZfWbROiZdJ56SxuWTilH54UgrNc9klDbFOBkXPkv4b0DVKZiiqZ6n0aAdi4+ cHR/6pwmNV3B/g+rEC0++NOmKFe/AYqIenfywkIklXKnF9+zvKMRj+fnlVRbXAemfm9aq mbYTAZ0fabAPALFwRUCILwO7L+7CCYXvxrSO6Qgyp04eu2kOPEFq0zLL9eho0oWhT7NEL hdFAA53Uq79shfQwC/Q1YYaCHJkfE4mApEOcSaxraCSyP1dtPO3IyR2+ZGCO+VwQrDw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794082714; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=0QctvfANf8m71klIHep/iiL0jBDeYa3bUuHZCrSLd+U=; b=ZhTvDor3gVW4HkcWMjSLQWzFrBokT53C8SXGT4NWmCvhSxCIrqaVkx6ZERtHPte1KM6e l1tfS5kMkmFwD+TTAxrbLzRHeGvZFKlSBTZvnLFgcHLKqwcZyCKfIQ83wd7GIlxu/uYIz Cc5p79Zr0QkBSnCsPr5T4YSRifUydv3tudWWgO/CaFogJPf3kCdVxXsJR0f+KTU0cr8ON OggmmqpYSEAYfIm4XpBnOa0T+YwnSdgjcgPx44HrP3dyBXTUW4PgHneyxgSQ9Bg47noQ+ uWxIjKNhLjUsD87NYw6jVmlv1crQVw76N47+hJABI99UwP1LEQVHSX/DiffOIC5nkwQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MZTnlbIG; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 944C8606A326 for ; Sat, 7 Nov 2026 20:18:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MZTnlbIG Received: by smtp.kernel.org (Postfix) with ESMTPSA id 287EB1F0089F; Sat, 7 Nov 2026 20:18:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794082714; bh=0QctvfANf8m71klIHep/iiL0jBDeYa3bUuHZCrSLd+U=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=MZTnlbIGEU8Tx9q1gI7QEoRw7flNo9r6oLAYyy08vDomrC10Petl80l0htRdYK1ba UeA3yQ+Ux1LOtDmRaEGO2Ra42g24KnLL8Hd6Y6J4s85s92APX9M9twQXG7K5ghMGHD l1qbPgeU+qp4A/Jx/ZPoNVDk9IHn97T/vzjZk70/63U8WlBSIq1dSIcFaAnM9tO2e0 PQ/+UTN1pv2DIUT9jXWNgkRuT/Wg9ESXcj/muPVJ8TcqIo/sAGbCi1H/+dmnOIqIbk B7hstRTfxJCK5xx9rI92QMB7lOLFOPRjhjdTvGMidWnlC5XaqhTwwYc9CbBBSM485P YXTuoy9jRXj5g== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH 6.18.y 1/5] mm/damon/core: skip applying scheme if region split for quota fails Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: "Andrew Morton" , "Usama Arif" , damon@lists.linux.dev, linux-mm@kvack.org In-Reply-To: <20261107201001.206120-2-sj@kernel.org> References: <20261107201001.206120-1-sj@kernel.org> <20261107201001.206120-2-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 07 Nov 2026 20:18:33 +0000 X-Mailing-List: damon@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [Low] mm/damon: damos_apply_scheme() inflates stats on region split failure -- commit dd2b638af6fec217ed7123ab31fe119102f17f78 Author: SJ Park mm/damon/core: skip applying scheme if region split for quota fails This commit updates damon_split_region_at() to return an error code on allocation failure and skips applying the DAMOS scheme in damos_apply_scheme() when splitting a region to fit within the size quota fails. Link: https://lore.kernel.org/20260901131850.98037-1-sj@kernel.org Link: https://lore.kernel.org/20260901131850.98037-2-sj@kernel.org Link: https://lore.kernel.org/20260718171523.87547-1-sj@kernel.org [1] > diff --git a/mm/damon/core.c b/mm/damon/core.c > index 8fa788b0d709c..4c536a9b958e4 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c [ ... ] > @@ -2000,7 +2000,8 @@ static void damos_apply_scheme(struct damon_ctx *c,= struct damon_target *t, > c->min_sz_region); > if (!sz) > goto update_stat; > - damon_split_region_at(t, r, sz); > + if (damon_split_region_at(t, r, sz)) > + goto update_stat; > } > if (damos_filter_out(c, t, r, s)) > return; [Severity: Low] Does jumping to update_stat when damon_split_region_at() fails inflate s->stat.nr_tried and s->stat.sz_tried? At this point sz holds the non-zero aligned quota remainder, so damos_update_stat() increments s->stat.nr_tried and adds sz to s->stat.sz_tried even though damos_filter_out() and c->ops.apply_scheme() were skipped. Because quota->charged_sz is not updated on this failure path, subsequent oversized matching regions in the walk will repeatedly add sz to s->stat.sz_tried while allocation keeps failing. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261107201001.2061= 20-1-sj@kernel.org?part=3D1