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=1794092215; b=VHPNmPyZnRTB+sBbKqlbJd//0dSDoNVacW8zzPAAo+MShcShniheE0HqzL1EyczF8NYB 5BzZtLO0O5Xpe4dIwruqm9HKuvqv6l7ucO2oNgQEXyOKgXIFQWlRy37eKKPoMo0ruy+d/ N8maBINQ5dpqZ7IXeiCkvQZHTONuZnJKJ89s893I4uCocTmeqt5hJ2ciz3Os/3Q3buVsB t1hq3a8mfHkob6P1SB8oKMvHA5+lms3n3LcmBuA/5NHpNwxpo8TTyPUZO72OlR5PZzedA 4YWMtRk9StocZCgKQPRXOSbc8+WsZNHNRvuixA1gZrMYGMDWYQmqEl5L4gizzQE6znw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794092215; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=8wUwXJNx8JD7Fl9dgQdIfo0QjeGVmxmT1LPcE0XUKqw=; b=WjTEE/a1Rq+/0YNIL1llhpoH82+9GAE1cuuTp58cp8wNRh8xBUqCKIUIpWqRPckXa3rU bg4kIOaFsIy07vpwwWBmADQkc+ZVmVH2LQkrDmx97SdWTx/9URrCydBLoo12gbd/kPU6S OybMpKoYQ1FLto+sr86fBl+LfIWBu4mnioBwWtJ6ETYr3J1ZMhaRkBPyOZc09hQyx5g/g uekCKPXoVOZS9jiDqRPfFvnamyb/2hoSww9h6DY2vE6TEZMYL/iUDCxRDfGxHlNrtjj8O Ahbp22qI4EluLdlCj5imYgyz48Z7Q/f2b9jbLe7ChUcXcCHkiqJX1TV63H0H0hoMz7A== 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=DLchhquA; 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 E636A606A326 for ; Sat, 7 Nov 2026 22:56:54 +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=DLchhquA Received: by smtp.kernel.org (Postfix) with ESMTPSA id 345101F0089F; Sat, 7 Nov 2026 22:56:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794092214; bh=8wUwXJNx8JD7Fl9dgQdIfo0QjeGVmxmT1LPcE0XUKqw=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=DLchhquAjxZ4d+JYytrasILc/gJMBTIr4SAHeTcBr6036pTK4jVv0PePY54yGNLWd 1Bdzm6yxhulvRkXT+gvnNFsNVRIvr9u9g/Df8pR0CWlzj4o4aoWrCA6DS+jybjuIEf O4h7WB1YW02o4Y3AzzHqKxW5afsZrJIfyVN7zpBllKgSVbziqn0Sth185PcBx1+dgj 2psPju/Om+1RcnzCadXIFmXSPjieZrAFPsj7ARJb72ku/8V1mvHlAGrVOymyBlCJ5H i/tN//2+7oBX/ex30ytKRj+o8fsT59k20qiT3QVQyMhf51WYf3l+FMCa4f4tlyozA7 iWD8B+Cjz22hA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH 6.1.y 1/2] 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: <20261107224800.340250-2-sj@kernel.org> References: <20261107224800.340250-1-sj@kernel.org> <20261107224800.340250-2-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 07 Nov 2026 22:56:53 +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: inflated tried stats in damon_do_apply_schemes() on split failure -- commit 2d405ecddea503227b3b4138fe63cbeb95dc50b9 Author: SJ Park mm/damon/core: skip applying scheme if region split for quota fails This commit changes damon_split_region_at() to return an error on memory allocation failure and skips applying the DAMOS scheme in damon_do_apply_schemes() 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 f0da5cb2b88a0..9206737d05ae7 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c [ ... ] > @@ -810,7 +810,8 @@ static void damon_do_apply_schemes(struct damon_ctx *= c, > 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: Low] Does jumping to update_stat here inflate s->stat.nr_tried and s->stat.sz_tried when damon_split_region_at() fails? Unlike the !sz path right above, sz holds the non-zero remaining quota when damon_split_region_at() is called, and update_stat unconditionally accounts it: mm/damon/core.c:damon_do_apply_schemes() { ... update_stat: s->stat.nr_tried++; s->stat.sz_tried +=3D sz; ... } Because c->ops.apply_scheme() is skipped and quota->charged_sz is not advanced, any subsequent matching regions in the same pass that also fail to split will repeatedly add sz to s->stat.sz_tried. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261107224800.3402= 50-1-sj@kernel.org?part=3D1