From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-16.mta1.migadu.com [95.215.58.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 85692242D62 for ; Mon, 24 Aug 2026 01:34:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787535263; cv=none; b=vB4EfJ7ILCk3pTh9ln0WGBQJ/VLccnH7kCFpCKJYhuHkkKiuquCO+Xzl06ch2yj75NW/GFIf836K2N1EHgiLazMnb7UDnZ9c7BIxHY4XhhlIISeTzcPK5X5qezr9Z14DBEgUiS9jQiNeWVRvcwIWgAEy2DX4wMpu1daEvfuj1zc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787535263; c=relaxed/simple; bh=+No1hTfbrcIhWY5jWR+1vFIfuDqvsIjriS5i2p59EfE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kKudNkDityTgT97N3YpbZT1HmFyUbxrZDjTb0usQvR8r6QUqwMBEmNfUh3/Jf5SZRG2nBWoYThouEa5S8sk4LT/lnrovL+XVCvzd7he+Dk2Dyup9uIeoO6PjZjIG+gXxVFNj2UwHs/SapRKGAJeCjonuYAg49YXB0yho+BO40tc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=B1IXXeLh; arc=none smtp.client-ip=95.215.58.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="B1IXXeLh" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=+No1hTfbrcIhWY5jWR+1vFIfuDqvsIjriS5i2p59EfE=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787535259; v=1; x=1788140059; b=B1IXXeLhJ43pGGsUqZ+VHNFFTNsQ+JpYgMyr1LDqoajP5aM6c4fCcME/6EVeg064Lq1LYMmx WGTl3aY8pDcorEoAvKKpnJ1e6l2d5zTwt+RELp3a6qFLosN+XceNzfu8tfVBxjfd/9pg60fnVAu 5TQdheVdy/h+DhKnHSIBr30E= X-Envelope-To: linux-kernel@vger.kernel.org Received: from fedora (203.175.12.242) by smtp.migadu.com with ESMTPS id 0ab54891e4b8e38a; Mon, 24 Aug 2026 01:34:09 +0000 X-Mizu-Trace-ID: 0ab54891e4b8e38a X-Migadu-Flow: FLOW_OUT Date: Mon, 24 Aug 2026 09:33:50 +0800 From: Hangbin Liu To: Nikolay Aleksandrov Cc: Jay Vosburgh , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Hangbin Liu Subject: Re: [PATCH net v4 2/2] bonding: fix u32 overflow in compute_gap() Message-ID: References: <20260820-bond_overflow-v4-0-805ba0d3efb6@kylinos.cn> <20260820-bond_overflow-v4-2-805ba0d3efb6@kylinos.cn> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hi Nikolay, On Fri, Aug 21, 2026 at 04:12:31PM +0300, Nikolay Aleksandrov wrote: > Completely untested, but something like: > > -static u64 compute_gap(struct slave *slave) > +static s64 compute_gap(struct slave *slave) > { > u64 slave_load = SLAVE_TLB_INFO(slave).load << 3; > u32 raw_speed = READ_ONCE(slave->speed); > u64 speed = (u64)raw_speed << 20; > > if (raw_speed == (u32)SPEED_UNKNOWN) > - return 0; > - > - if (speed <= slave_load) > - return 0; > + return S64_MIN; > > - return speed - slave_load; > + return (s64)speed - (s64)slave_load; > } I get what you mean now. I think this is a boundary‑choice problem. I reject all unknown‑speed and overloaded NICs, while you believe we should keep overloaded NICs. What if someone argues we ought to retain unknown‑speed but non‑overloaded NICs (though I do not see how we could compute that)? In any case, I am fine with your design. If there are no other objections, I will resend the patch following your plan. Thanks Hangbin > > Then change the selection variables and comparison: > > - u64 max_gap = 0; > + s64 max_gap = S64_MIN; > > ... > > - u64 gap = compute_gap(slave); > + s64 gap = compute_gap(slave); > > - if (max_gap <= gap) { > + if (!least_loaded || max_gap < gap) { > > This should choose the slave with smallest gap and put the unknown speed behind all > slaves with known speeds.