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=1794169418; b=RsQE5x9dZbKEIxMTonmY+jG04oBXJFB3otoPS4dNnm3XpKmylwSEwMe73XrVJLwRODD5 nJthI2k10S1XvAodu0BhObUsAkC/CynIFfXxEpVJNBAQJJLs45m5Kz+mnbdPT/dG5SRlI KdXCe76mRdUeCkP19pl5PNxDwJzNsX/O2Y6vjvlo0mVXfIbxKW0X6GLg3tx/hMzEIhNtU dlzF+sT73X8lxRWNhFTc1YjLJcBgklzYJbFmmj/+kFmJ4alyqfRozLmOGCOT60klLKTW1 D7wqisM3iCIQr3mllDfrchQcNPZAlabLJTzRSa+FbrLqyHJyUl0phUUM+QHcrXj5eMA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794169418; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=RLSNq312cKLDEo3U4exWhRNTp6plA4woo3CVLNEmLks=; b=r7u8xzC877o7zJzj1f3r8YK35KOdc6/0LzbZGHSmeG+sD+SVWbxNI4pyoZAE2yHMO2RT hh81qFiFS4HXsNzKigWxn292gd5VZNneU3XgmeY0iyMrRlj2UuZWIfiSpYywyry1s35s6 D7+k+ZdtkLjC6vHO+S8a20jFQGxL5QdA/Hb98UrDvYlWIIGXgqs+S+UcoKT+vhS631PeE PsG2X6mhPLiRpNoNRs8uomJtJpRigOGaLVI+AaYbsXkCoz3GFktOUwl/7lZ43bQRFNTJI PTUF0SCHiE5pzXTNhV8quWKXvbsCyzx4+buNinx18ZIENN8uGlMY7ThV3UAQnRdcBdg== 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=evCJOY+g; 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 0724F60729A8 for ; Sun, 8 Nov 2026 20:23:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=evCJOY+g Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F2DC1F008A5; Sun, 8 Nov 2026 20:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794169417; bh=RLSNq312cKLDEo3U4exWhRNTp6plA4woo3CVLNEmLks=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=evCJOY+gVUzp1DzjbiFmkH/UuXhVATwMh845mwI4vVAh+Aa/q0GFq0cVn8tFnIO9A 5TCvjXUI75bQz0elpEuxKCFYvuScWi2cHh6OeupP6bAtMpQiik+Hp+f+K3Z6PgSdBZ YjNFeyiiuUJLlGAgQgp9aEXbdrv3E5Bd0KYIUuMIjJw2V5AWmDjw8fqRqIBtymfj/D N3fr0iIppXQ5GKTAJTZ6An87iDVqgbhPyvHPRbosKi13NgqPe7ued6w3ES30fbwyPt xIOjqFJfoio2T6CBZgpsb/oLNKUncrosAxykc7yQTqxEvLIyuEo64V9R63sIcv7MGE fkPCTTYMs6Cig== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 6.6.y 1/3] 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: <20261108201456.116824-2-sj@kernel.org> References: <20261108201456.116824-1-sj@kernel.org> <20261108201456.116824-2-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 08 Nov 2026 20:23:37 +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: - [Medium] mm/damon: false tried stats on split failure in damos_apply_scheme() -- commit 17459070b1916b2d77f607f0fb7f0f9158e6224f 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() if 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 b5b6d00d7a3b5..9d4a78deaa06a 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c [ ... ] > @@ -1004,7 +1004,8 @@ static void damos_apply_scheme(struct damon_ctx *c,= struct damon_target *t, > DAMON_MIN_REGION); > if (!sz) > goto update_stat; > - damon_split_region_at(t, r, sz); > + if (damon_split_region_at(t, r, sz)) > + goto update_stat; [Severity: Medium] Does jumping to update_stat here falsely inflate s->stat.nr_tried and s->stat.sz_tried when damon_split_region_at() fails? At this point sz is the non-zero remaining quota size, and damos_update_stat(s, sz, sz_applied) unconditionally 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 split failure, every subsequent matching region in the walk that exceeds the remaining quota and fails to split will also add sz to s->stat.sz_tried again. Returning early here, as damos_filter_out() does just below, would avoid counting skipped regions as tried. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261108201456.1168= 24-1-sj@kernel.org?part=3D1