From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9C5253B3C01 for ; Thu, 26 Mar 2026 07:51:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774511506; cv=none; b=Hh8Ikyyay/o+AgZ4/47GsMJPm0473Bt6hY+PW1tuT1C+MbIfrNxYmJI4IXtWEIVh2rhDc/EXyHc6OQtCJ0aIsGaoB3prg/GUB0zMAIqmN43pIKWpmHOan+iVuXoAgB8sR6oxYsX/HLA/XoBWdt6BEFdZXmDWNuO++/GMnoVsxKc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774511506; c=relaxed/simple; bh=oq3tl6l65dbdiBDBB/a3W2orhb+HovVIBT226iNNBu8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CJfxzTNdL1uXlIrcdluvYGnpbWVxNwtayfHTrECRcBbk+lJL5ftOeFCN68gt+/aTGJHHSXzDypZ7TqqKL2hmoiaQzexqZPfJZl9u7x5th/pYwYB+LkDW5BrYmaZMZxgw/0vjgPbahFAEjqBcP9FIp5J86LxyPMjPyQLgfPvGdGc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Uo442Gsc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Uo442Gsc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1377C2BCB6; Thu, 26 Mar 2026 07:51:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774511506; bh=oq3tl6l65dbdiBDBB/a3W2orhb+HovVIBT226iNNBu8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Uo442GsciOK6onkG1AEsLvJdq82PjiY/TBiBo++AW/LvKuUBvogNKTQIAkLXRTJEp /uh310z1gCJDOwPp4LEuI/kBJbsEe1xBWfLWRy8MWvQJcswA1W8g20B8iAcB99NpB5 MjVcUluBaJR+DtHDC1+f2goXJCvmu/qm8Ah6ZfsbIUQ8fS7S/j0I2SPbRpzZ7icrMD 1cs6lighWRCPLvN9QXZ0tT1g7+M1x9LmXHM/BSbpyMj+bt0wAfI3ORJE2mWu9+9l3V DnqsxRmWDy5ArNPDyCZmU5OE7A1PIAdqnTVzM3kJWTxPhsaVULXxyEGRGAAi8RMkpE U2UFx57k5KbXA== Date: Thu, 26 Mar 2026 16:51:44 +0900 From: "Harry Yoo (Oracle)" To: Michal Hocko Cc: Qi Zheng , hannes@cmpxchg.org, hughd@google.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@kernel.org, ljs@kernel.org, ziy@nvidia.com, yosry.ahmed@linux.dev, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, bhe@redhat.com, usamaarif642@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: Re: [PATCH v2 0/4] fix unexpected type conversions and potential overflows Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Mar 26, 2026 at 08:14:36AM +0100, Michal Hocko wrote: > On Wed 25-03-26 22:13:21, Qi Zheng wrote: > > From: Qi Zheng > > > > Hi all, > > > > As Harry Yoo pointed out [1], in scenarios where massive state updates occur > > (e.g., during the reparenting of LRU folios), the values passed to memcg stat > > update functions can accumulate and exceed the upper limit of a 32-bit integer. > > Is this a real problem without reparenting? In other words is this a > follow up for that work or something that we need on its own? This is not a problem (as discussed in [1]) without reparenting. [1] https://lore.kernel.org/linux-mm/138d9363-ab0c-4f5c-bedc-b326f5aaee91@linux.dev -- Cheers, Harry / Hyeonggon