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 93124281369; Wed, 7 May 2025 14:25:05 +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=1746627905; cv=none; b=kuSBq4pDDp0yvzTW1VhGo7zFealxItIOfxMKqKRhnvhZYiuuLtS27iqzO+eQtxvuUAvDzAAgbux80OgAylPzCuyutBSUHkNgsPZfHc45JPnzlsrhpuN+fr/R8YBXAPONURMmsFf9d5fbbzUdBMLBaEQrDmQRRKf3UPj09qIqS+Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746627905; c=relaxed/simple; bh=VWD7WqVDPeXj9twUcUFapIRynqKgAhDd6ooWQ/9Di0U=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lC5gfkHnNAn2YwcqoD3aHXE2gmVToT/L4AxKPI+cFzIRklnLYT3LIJJZaDSSz2aV4SOzVvAR7ekhlvJ9KbH12Iiut9+3pq8wogawwKvUnRQx9wrRyEv1MLEF6UDnsekvzAA5UsUz5PM0lNz2xD+mONVSdKhaalBHzHpltyh/P3U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fds/vJ7V; 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="fds/vJ7V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3154AC4CEE2; Wed, 7 May 2025 14:25:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746627905; bh=VWD7WqVDPeXj9twUcUFapIRynqKgAhDd6ooWQ/9Di0U=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=fds/vJ7V06A7HlNn3H3ZjvOB8u9lUFpjg6cX11BHRg1MBg933JgQk1PArkgS8nTmg AXNiguvL6VmU1UKgeOybpdyKrVl1sAA0D8Kbqy1XXh7vNEPp+JKLd6SOXU+YqpQkxy 21qc9dAXtBUnd0F1f+FgZQXmgH7hQq5kxKELMKIa3MPHWTRsTKTURSSc4LzLMPSQqb Jc9KSDCWnXziVCAU5NOZsiVbLBA23K7m+mokL2HBNj3L7XQL/ZknKCA732eQO4S9kR Y188ry4xsfHkxW+5eyyQ4p1cIPxQtDNMYnJ9/znI50eDC8WQ+gRAr1qNwAQl42UbGR 7AEvykn5yrJLw== Message-ID: Date: Wed, 7 May 2025 10:25:03 -0400 Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 14/14] SUNRPC: Bump the maximum payload size for the server To: Christoph Hellwig Cc: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey , Anna Schumaker , linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org, Chuck Lever References: <20250428193702.5186-1-cel@kernel.org> <20250428193702.5186-15-cel@kernel.org> <390ac9ce-d32d-4534-a406-52288f79ab0c@kernel.org> Content-Language: en-US From: Chuck Lever Organization: kernel.org In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/7/25 3:42 AM, Christoph Hellwig wrote: > On Tue, May 06, 2025 at 09:52:06AM -0400, Chuck Lever wrote: >>> Are you going to wire this up to a config file in nfs-utils that >>> gets set before the daemon starts? >> >> That's up to SteveD -- it might be added to /etc/nfs.conf. > > Well, you should be talking to him or even include a patch. On this list, we post nfs-utils patches separately, once the kernel API is nailed. Steve doesn't pull such changes until the kernel changes have been merged. But see below: I'm still not convinced this is a tunable that is worth going to that level of trouble for. >>> Because otherwise this is a pretty horrible user interface. >> >> This is an API that has existed forever. > > Huh? It is a brand new file added by this patch. /proc/fs/nfsd/max_block_size was added by commit 596bbe53eb3a ("[PATCH] knfsd: Allow max size of NFSd payload to be configured") in 2006. Or are you referring to something else? >> I don't even like that this maximum can be tuned. After a period of >> experimentation, I was going to set the default to a higher value and >> be done with it, because I can't think of a reason why it needs to be >> shifted up or down after that. > > Why not? A tiny desk NAS box has very different resources available > compared to say a multi-socket enterprise AI data server. I don't believe system memory size is a concern. a. max_block_size is automatically reduced on small memory systems. See nfsd_get_default_max_blksize(). b. The extra memory allocation is per thread, so a smaller server can reduce the standing memory requirements by lowering the number of nfsd threads. c. we're now removing rq_vec, so there's already less memory to allocate than before. -- Chuck Lever