From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CF4EB32C92D; Wed, 3 Jun 2026 18:14:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780510495; cv=none; b=ppOa62NLkb0Am8ureoxY5cHNxMDnxEjWTsXwWdiPBRVOFB3QE4u1EJQIGFMcHG/QCLSDS+ph4VHYctCC0+1xyv9cO7emRoveHemx70XldCUGXk1YmHeYWjkjhRdted5Ubl32oaSUFp3NCAAVrm4lahRT7AharSnCrfRaz38fjJw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780510495; c=relaxed/simple; bh=Zh3bOPf3WGGGuDpapVApizEvYFMTNyzllD1587uNksE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=SslGmAuJUZIUi15KVeH9QK2rkWRAO/yjdCxOmt03UlA/VTdswZWzjAZ0ZfgjL2YzFC5aOPaq1gI+ZHdCpnmK63IbWkgazeowoubD+CmqWX8opJ14xAQEHtsEwwjEdVdVp8oa7lE7/5tlYrZ0XqdE20l74cS7+Y+mKaXWLYgidjk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EYt4jGOF; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EYt4jGOF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 922DF1F0089B; Wed, 3 Jun 2026 18:14:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780510494; bh=6WrRoXO8ws2YpgPqY1eyvviLf48IBcpkEZY8IYp2NLo=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=EYt4jGOFf5LyezMTLV9dtf2WymLahWZzOV9zIlsR/s0qVRxpHXAAirSEbS46iArUz 3jFo9xc18HpY/AIlMplWvxVe2GOAw49DmR+mT+asEMqWykbJ3kaGZxjmXlhW4c8Ors EW/vIn7AffpcwBX08cwjSweCluQTp3Sevfta9TJlQ7MM6F7ZVYwEsQy2HTUikfeGFa xQZRg7I4AP/QtUfwHSQZfCZmhKiph4Mdhz2KEt6agP6Meih8rA58vz+GsKjWNqY2AQ pEIH9ry/aBOAEjUXK0Ra/KnN1Fh7TD8mTUn2t3uUQKfwGWOkiN7vTRf9U+IHj5k+B0 fFWYzzBA9yA4Q== Date: Wed, 3 Jun 2026 11:14:52 -0700 From: Jakub Kicinski To: Pedro Falcato Cc: Andy Lutomirski , Linus Torvalds , Askar Safin , akpm@linux-foundation.org, axboe@kernel.dk, brauner@kernel.org, david@kernel.org, dhowells@redhat.com, hch@infradead.org, jack@suse.cz, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, miklos@szeredi.hu, netdev@vger.kernel.org, patches@lists.linux.dev, viro@zeniv.linux.org.uk, willy@infradead.org Subject: Re: [PATCH 0/3] vmsplice: make vmsplice a trivial wrapper for preadv2/pwritev2 Message-ID: <20260603111452.7e7bb17c@kernel.org> In-Reply-To: References: <20260602225426.122258-1-safinaskar@gmail.com> 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 Wed, 3 Jun 2026 12:43:54 +0100 Pedro Falcato wrote: > > Am I understanding correctly that this will completely break zerocopy > > sendfile? sendfile is, internally, splice-to-a-secret-per-task-pipe > > and then splice to the socket. How much to people care? These days, > > a lot of high-bandwidth network senders are sending encrypted data, > > which is not zerocopy frompagecache. But there are surely some users > > You can do zerocopy from the page cache, even with TLS on top, by having > your (fancy) NIC do TLS offloading for you. See https://people.freebsd.org/~gallatin/talks/euro2019-ktls.pdf. > Linux works similarly. Slide 26 is particularly interesting. > (No KTLS I assume is using simple sendmsg()'s from user memory, SW TLS > and NIC KTLS are both sendfile(), per the slides) FTR this datapoint should come with the caveat that kTLS _offload_ does not support TLS 1.3 today. So how much that configuration is used in practice is unclear.