From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from hr2.samba.org (hr2.samba.org [144.76.82.148]) (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 7D392202C2B; Thu, 7 Aug 2025 05:23:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=144.76.82.148 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754544187; cv=none; b=T3/eRWBF1o5c9YNKdvnpYVHQ5VUi6KiFzAqu1EGeEBLA8spcEZr88hIJUNcSxR2qo6TCYFRsphxHnW3vv/2QtQBjU9WiJngzSfFxsu+a5nsLRqtvE+A0m+KQ6zu97wdaTobrJMKb8DaMQnclZtjo3WLs+ms1CTiPt4iHnTQg03E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754544187; c=relaxed/simple; bh=YUwPmVrn6K2WFWpNlidZfL01eDYcnmOzCwGou+i6x2c=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tmXgVbw5yykOS78TdDWRTH/+duxL5Mb6nIyoKpibmoDmu8HxbC889MlBMXFYTtzJ9II9MWJ0cNA+5OqF+a5Lh5/Mz85rSBFwIrXDybCsPapfZ8ocIaFqY9Qds7DhsImeTvuJtA0s8jd7YdIUOxEAqQH8NSeOk+G2asjdw5nTPhs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=samba.org; spf=pass smtp.mailfrom=samba.org; dkim=pass (3072-bit key) header.d=samba.org header.i=@samba.org header.b=Vq5WqrP5; arc=none smtp.client-ip=144.76.82.148 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=samba.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samba.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (3072-bit key) header.d=samba.org header.i=@samba.org header.b="Vq5WqrP5" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42; h=From:Cc:To:Date:Message-ID; bh=6ru3pRMmGQBukf0GXDQ/g5j3M3KKaVhfWOPVpl/umhc=; b=Vq5WqrP5sCnEvoutdYsokfVsMf puYtQ4sXLtLpyQw798T5IYTufDecgUn9jvpe8ZXggb1yK/ztZs/dPthYClJzNGwQ3JgXw/yhUIDFT 0CqzMHqZW4lhae7W/B3/ElhzvsaYlsI1oyeHHAxAh6PbToi/+jTxtkx9kcerKNDhnvNme1t/SYKeC 6SCrJ8AE9C9GaUJJjPz8lhIkNBfs7MZbBFT84E85g+cStBtmIBTcxnpzZdzyTcwBM5ScvpgfpV4EI ZP4zGzxUUU/s7OK423tOcX6kAAG0GoHjX5AFCuMG9wvFLjgSZ7BwjB8gO9qIbYA2T7fk3cEuLhojf Q4AbssGH+Arr+52LWDYG1qrJkZsYlz0hZA3bvFPbJgKSbKRr53Ep5q3LRb6O0Uk0YWm2Ww+q+O9kr 6XxeVXepCN7PEYIb60tRKetKkWYL/yMrlHJ0E9L1RLPSChpjCFpI+TrHA4/aP7NwO9xryYs60t1W+ RXiOAqwArVUd3Y4tynEc/O84; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__CHACHA20_POLY1305:256) (Exim) id 1ujt5h-001UId-0n; Thu, 07 Aug 2025 05:23:01 +0000 Message-ID: Date: Thu, 7 Aug 2025 07:23:00 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 00/31] netfs: [WIP] Allow the use of MSG_SPLICE_PAGES and use netmem allocator To: David Howells , Steve French Cc: Paulo Alcantara , Shyam Prasad N , Tom Talpey , Wang Zhaolong , Mina Almasry , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250806203705.2560493-1-dhowells@redhat.com> Content-Language: en-US From: Stefan Metzmacher In-Reply-To: <20250806203705.2560493-1-dhowells@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi David, > The aim is to build up a list of fragments for each request using a bvecq. > These form a segmented list and can be spliced together when assembling a > compound request. The segmented list can then be passed to sendmsg() with > MSG_SPLICE_PAGES in a single call, thereby only having a single loop (in > the TCP stack) to shovel data, not loops-over-loops. Possibly we can > dispense with corking also, provided we can tell TCP to flush the record > boundaries. (Note that this also simplifies smbd_send() for RDMA). I didn't look at the patches in detail, but I like the simplifications for the transport layer and that hopefully allows me to move smbd_send() behind sendmsg() with MSG_SPLICE_PAGES in the end. So the current situation is that we memcpy (at least) in sendmsg() and with your patches we do a memcpy higher in the stack, but then use MSG_SPLICE_PAGES in order to do it twice. Is that correct? Thanks! metze