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=1794168467; b=W7PTqBKKO5m1b946UTIzViUj6eXCaekZOP6VsSFaGcU820fZ2rPSvdkU9c7zIXBdLF3D 64PUU2/GLXcMU0hvVsOhau08uJgk8TrHLZzsof4kQPq9UnDgBTFWvAQpyooT4NbqTcaMn 72cSvr269GIkoti3H5dEuudgD2S+4A9R7G0WLq/bMlL/5nZvCqfjeLU5oXLGK17PooChe cxuA/XggMgFDF1mtNO+T1v+Nv7TguBw4IvQeexAfYEXyLiGmrJT0oJDbVoge5nZKttBeP Hd7Abya3PZp1tWFIMGMWzBgX5EoiLAtt1VX66W0n0w9jtT1vLhEu+kfO49IE+X3FFcw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794168467; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=2TO+CpsEMkIicevAnwrknqp+HSpjmNynu9r53SRPWuc=; b=q99VcVMmC4rhL1A5/VgmLSgZa3t3Xhpkwgr2lfvUHkqYwkDZZrDb42DF0fyL0cZMOTbj ib/oe9Nl4SxJxC8GdHANRX8oxiNOGAaXjJGLrtj0hOtrWJ5PqInluwCF/k4Oe/zFc1AXD VLZm8HY5q9AEZJCOqHbhZ2jYAdm//bBbhhgXta7MguwJ6CbOk7H4Gw6lg7rF8Df476pWN mI/LrPkA9+DuDqcm+obZxBZhhtxP032f2lJoLnYPQYGo7BzHMsR6+FGZ+4u65z4j1hoxU Za4zmNDu1yOe/ccfidAMp64rXCDGnM88FzbBVlkyjEAIKSQMIK7uhMqFkrXkZjxY8CQ== 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=PgRwkHww; 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 234EF606A31C for ; Sun, 8 Nov 2026 20:07:46 +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=PgRwkHww Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77A2E1F0089F; Sun, 8 Nov 2026 20:07:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794168466; bh=2TO+CpsEMkIicevAnwrknqp+HSpjmNynu9r53SRPWuc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PgRwkHwwOmAE2ueWzcsEYsrtwZZxIFcB2QYHHOQN15qQM43ZwDti1n3zhOrGbqixh sGNZoR1ISIeGqbr89cNSvODGlFtogYezoGsOmDsVjetf3yvL6zuLz3JLUeZuvg2+y7 uch30Ku/7hh5fwy9s43S5p9JbR45T908c0Ni6/IGw/nV9A6y74QvNnyae9vPMUipi0 sM2aYCx6Nh2KCZYMppTuclvoixIoRt/joRxrIbKwV7MME6QQvt6ftUfO0XMFBqwFJO fepI2Bnk/djZYaXlKHUjODQFFOq+dMtFdBd2xuskq5zrSCP/b1b3rHAWW69TWsG7Bu OG7UitbI8h0qQ== From: SJ Park To: sashiko-bot@kernel.org Cc: SJ Park , "Andrew Morton" , "Usama Arif" , damon@lists.linux.dev, linux-mm@kvack.org Subject: Re: [PATCH 6.12.y 1/5] mm/damon/core: skip applying scheme if region split for quota fails Date: Sun, 8 Nov 2026 12:07:38 -0800 Message-ID: <20261108200739.116084-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: X-Mailing-List: damon@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Sun, 08 Nov 2026 20:00:20 +0000 sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 1 potential > issue to consider: > - [Low] mm/damon/core: inaccurate tried stats on split failure in > damos_apply_scheme() > -- > > commit 2d3797cf5f053ac8bc0b4587f17ff69eb9813ce6 > 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 remaining > 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 81d44e41de210..6ef77741b783b 100644 > > --- a/mm/damon/core.c > > +++ b/mm/damon/core.c > > [ ... ] > > > @@ -1470,7 +1470,8 @@ 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; > > } > > if (damos_filter_out(c, t, r, s)) > > return; > > [Severity: Low] > Does jumping to update_stat when damon_split_region_at() fails > inaccurately inflate s->stat.nr_tried and s->stat.sz_tried? At this > point sz holds the non-zero remaining quota, so damos_update_stat() > increments s->stat.nr_tried and adds sz to s->stat.sz_tried even though > scheme application and damos_filter_out() were skipped. Because > quota->charged_sz is not updated on this failure path, any further > matching regions that also fail to split in the same walk will > repeatedly add the remaining quota to s->stat.sz_tried. Trivial user impact issue that also exists in the mainline. No blocker for this patch. > > -- > Sashiko AI review ยท https://sashiko.dev/#/patchset/20261108195145.115792-1-sj@kernel.org?part=1 > Thanks, SJ