From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 0D27DB665; Thu, 20 Mar 2025 05:50:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742449821; cv=none; b=ntYNnv96JRFTfRrO703N3O8XFcQsMybRhq2M+AE5z/nm+XnIPK+LLzEOrVNBo5o0eSdShQM0vjFCy1FrtCbuMdiWNcE47g/ExyiOj8+QnmutgfPAnyQZWzddmkfB7TruiWMmmJTvgi+iDMzjlfRaXvXnLy7kydkDRLO1o9YtAK4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742449821; c=relaxed/simple; bh=BXGKzOHEz1ClBhXem+aJPa6nOMKZChuKMiZ/tPuzmAQ=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Q9qmvzmjkLNf0s0P8hcmI1dZdz43MRNMzDDSxRh+5arYlEhFGMh+ZoG8eCedCip39IYINjJO5DH3H348bmlPzXm2x11B/nEaAKjOFHYgdVUDDnfZa0TPItVBpeunxN5HOQCshFbjoYGPEw2BfXpm5Enod3VdK9wdIX0Y2mqxU8Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=B33mFDNa; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="B33mFDNa" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:To:From:Date:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description; bh=lhWq7dIR/TOnTpgqOBSfHCVpFoLt91BH+g7yyBM4SfI=; b=B33mFDNaZ+CkZcj4my3QZjC0Uh 3PRZIy0Yp3Xsv4r3l5a2rvaDyvYCESYOlvCENoyiZcxNLLYDgYZKe9dZbLUFYAkPf53tM63I65PkK 37RuqVbZKmSEDdqG4er4ZN6zEQDeMHNT6czXW25Cjc4XjidwEfa0mDtu4uM+qWuFvO5SVkpcnvDYW yjkENQtqmhR8xbECSergg7Ug3jQzrVEclDWbQb8kpVYfzTA0mY108r75769gwjlvJYFI3zMjcMB9j 554LtXg6GRfgwtNcxC8m5D7rAczXTJEMLkY+lYdPzd/lFb4qvHS0tpwZ1jPmDUIrgGAYfePkg9FYa ZuAMnwFw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tv8nK-0000000BFYh-3rAt; Thu, 20 Mar 2025 05:50:18 +0000 Date: Wed, 19 Mar 2025 22:50:18 -0700 From: Christoph Hellwig To: Joe Damato , Christoph Hellwig , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, asml.silence@gmail.com, linux-fsdevel@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, kuba@kernel.org, shuah@kernel.org, sdf@fomichev.me, mingo@redhat.com, arnd@arndb.de, brauner@kernel.org, akpm@linux-foundation.org, tglx@linutronix.de, jolsa@kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [RFC -next 00/10] Add ZC notifications to splice and sendfile Message-ID: References: <20250319001521.53249-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-fsdevel@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Mar 19, 2025 at 08:32:19AM -0700, Joe Damato wrote: > See the docs on MSG_ZEROCOPY [1], but in short when a user app calls > sendmsg and passes MSG_ZEROCOPY a completion notification is added > to the error queue. The user app can poll for these to find out when > the TX has completed and the buffer it passed to the kernel can be > overwritten. Yikes. That's not just an ugly interface, but something entirely specific to sockets and incompatible with all other asynchronous I/O interfaces. > > and why aren't you simply plugging this into io_uring and generate > > a CQE so that it works like all other asynchronous operations? > > I linked to the iouring work that Pavel did in the cover letter. > Please take a look. Please write down what matters in the cover letter, including all the important tradeoffs.