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 830E41EEA54 for ; Thu, 4 Sep 2025 14:42:45 +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=1756996965; cv=none; b=qNPc/O3XxXZAOYDop4Vm/rb0dM3P7CSkYKOu1zOTqqNr5MGjAsxgfRB18l2rz36KNWDqilmkGr5yT4MXbOL9lPYneIVi7pIp8ZWpvlrIhYnQKWBRzKj3bj0Kmwzw3wcyBFfSG8kyFg/lXbKBc86+MfFtkmklVs7NiChhn/RD8J8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756996965; c=relaxed/simple; bh=8GC804Q5+f604i6VY4XMwbDtvtysGG+ibtm8moKtDCM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qU9mI6mkb34AehyxJU3GPYkTJitZmeIt8EES/ksqJpKS7r4pQbLdP8PMeeFteGK1XcZY1W8IA6Z/rW39f8ow5bd0jHdFAYgOEl63Y8/fNJXScQc54xS8q/FDKtPhfPX9MjCGEhNSeEauKaDhDlvQmunOsffinmDrLJYX2VcpTSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r8q2fLE/; 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="r8q2fLE/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D327CC4CEF0; Thu, 4 Sep 2025 14:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756996965; bh=8GC804Q5+f604i6VY4XMwbDtvtysGG+ibtm8moKtDCM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=r8q2fLE//trPGu+bY5g0eCxQw+GodsUkc/owUhrFFVEw4uYGZzv90BktnmldCWhMw 0+d05cZOmKjuHONCXtvi4zxs+H6KrBpDXjQBXe/tbWP5wvwsUrwekk8p4zaSRA5/pv GoGD9tPB3c42w6LKnUNkLltYeBlQY1+e6ptsPh7lIyvDpuvmJJDTfZmNIombsdg1dX DXmLXALDTorUarfOZ2Uf5/1o9CuAhtlHfmTmIpKXw54sLKgBTX0fD6I1wlweqAZrDx M91GxKB6EYHJWCLA22rq7ZnzTjODNCxcYos1+4hddX7nQnTijzGHUAv7dgW8hGPOcb vJNFqAztiBaxA== Date: Thu, 4 Sep 2025 10:42:43 -0400 From: Mike Snitzer To: Chuck Lever Cc: linux-nfs@vger.kernel.org, Jeff Layton Subject: Re: [RFC PATCH 1/2] NFSD: fix misaligned DIO READ to not use a start_extra_page, exposes rpcrdma bug? Message-ID: References: <20250830173852.26953-1-snitzer@kernel.org> <20250830173852.26953-2-snitzer@kernel.org> <2559f795-bdc9-4d39-aa03-e6a6d89e9f84@oracle.com> <92908105-9261-42f9-a0fd-ebfaf3e2f564@oracle.com> <18b20826-3c9f-4763-b0ac-c7f1dc2be4d4@oracle.com> Precedence: bulk X-Mailing-List: linux-nfs@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: On Tue, Sep 02, 2025 at 05:27:11PM -0400, Mike Snitzer wrote: > On Tue, Sep 02, 2025 at 05:16:10PM -0400, Chuck Lever wrote: > > > > I am testing with a physically separate client and server, so I believe > > that LOCALIO is not in play. I do see WRITEs. And other workloads (in > > particular "fsx -Z ") show READ traffic and I'm getting the > > new trace point to fire quite a bit, and it is showing misaligned > > READ requests. So it has something to do with dt. > > OK, yeah I figured you weren't doing loopback mount, only thing that > came to mind for you not seeing READ like expected. I haven't had any > problems with dt not driving READs to NFSD... > > You'll certainly need to see READs in order for NFSD's new misaligned > DIO READ handling to get tested. I was doing some additional testing of the v9 changes last night and realized why you weren't seeing any READs come through to NFSD: "flags=direct" must be added to the dt commandline. Otherwise it'll use buffered IO at the client and the READ will be serviced by the client's page cache. But like I said in another reply: when I just use v3 and RDMA (without the intermediary of flexfiles at the client) I'm not able to see the data mismatch with dt... So while its unlikely: does adding "flags=direct" cause dt to fail when NFSD handles the misaligned DIO READ? Mike