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 833CD26A1CF; Tue, 27 Jan 2026 01:31:26 +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=1769477486; cv=none; b=jl8WChLo1QV7Ca9r+qWSOZLpFOS65FAHkOS0p/eHydFaxngDQBuDRQ22b1vzcyw1lGfR/ORgfkk2scHMGrnzmGKsAlig/T+kWi+R31hNgsqtJVmUkpobfwIGegji+Mh/IMQXqmu1ZIEeyKU5wXb9cgWpLv68AYgX0SGmYvkayRE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769477486; c=relaxed/simple; bh=6CGGydCka0qS3s2jXLp1lv9LhM9hYNyCJigg9Eh53z0=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kENzdlvSnQbK/lrtxPf018i/Y3bbBQtZJKth65IbqFY6A4Ha/PTOuJupX4QgTbP4wD6YWARtSVLFu45D+balXz4Rak0WSxA+72UQi/B9y3DhhXGf8omlATz3ac6Q/ZIXMCpEmfQlXXU1OJ8JTmS0R1YyqYci8X0rPTke5y+bPn0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bKNR1oFu; 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="bKNR1oFu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDCEBC116C6; Tue, 27 Jan 2026 01:31:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769477486; bh=6CGGydCka0qS3s2jXLp1lv9LhM9hYNyCJigg9Eh53z0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bKNR1oFuFrwyurIijVwm3sk6j9TTAkmtj1kBXhGdgVNZkFa5byO66dCNrrm5ahU8f I/eTNZdyGbS/L903Bava2+sxi7k5o7bsWt2695T2opSqORtjdUz4PMfyowmWhLBZhW zdg17SCGg+eWuCokEmKo5p0QZ0YRxu+l73kZHbiuQhVE4Jvvny3Ca2gXjApK59Lb0C 5jEPOWcwnc/vTrDnAgCeRAkJ8JRJHqAgY7vsjBMXfmm/mxs2utoJ96H9jNrxyOWLtl Roz0C5YvfJHH2FvmIvIxKQVy6kP/5m9dueWqQ4IMevNfHjICU4zFrwHtJCgpdGb4RA ML4Xm9CIabH8Q== Date: Mon, 26 Jan 2026 17:31:24 -0800 From: Jakub Kicinski To: Bobby Eshleman Cc: Mina Almasry , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , Neal Cardwell , David Ahern , Arnd Bergmann , Jonathan Corbet , Andrew Lunn , Shuah Khan , Donald Hunter , Stanislav Fomichev , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, asml.silence@gmail.com, matttbe@kernel.org, skhawaja@google.com, Bobby Eshleman Subject: Re: [PATCH net-next v10 0/5] net: devmem: improve cpu cost of RX token management Message-ID: <20260126173124.1f0bb98e@kernel.org> In-Reply-To: References: <20260115-scratch-bobbyeshleman-devmem-tcp-token-upstream-v10-0-686d0af71978@meta.com> <20260120170749.101e8bcc@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 26 Jan 2026 10:45:22 -0800 Bobby Eshleman wrote: > I'm onboard with improving what we have since it helps all of us > currently using this API, though I'm not opposed to discussing a > redesign in another thread/RFC. I do see the attraction to locating the > core logic in one place and possibly reducing some complexity around > socket/binding relationships. > > FWIW regarding nl, I do see it supports rtnl lock-free operations via > '62256f98f244 rtnetlink: add RTNL_FLAG_DOIT_UNLOCKED' and routing was > recently made lockless with that. I don't see / know of any fast path > precedent. I'm aware there are some things I'm not sure about being > relevant performance-wise, like hitting skb alloc an additional time > every release batch. I'd want to do some minimal latency comparisons > between that path and sockopt before diving head-first. FTR I'm not really pushing Netlink specifically, it may work it may not. Perhaps some other ioctl-y thing exists. Just in general setsockopt() on a specific socket feels increasingly awkward for buffer flow. Maybe y'all disagree. I thought I'd clarify since I may be seen as "Mr Netlink Everywhere" :)