Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:23223 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751715AbdITQ4P (ORCPT ); Wed, 20 Sep 2017 12:56:15 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: [PATCH] nfs: RPC_MAX_AUTH_SIZE is in bytes From: Chuck Lever In-Reply-To: <20170920164951.GG14329@fieldses.org> Date: Wed, 20 Sep 2017 12:56:07 -0400 Cc: Trond Myklebust , Anna Schumaker , Linux NFS Mailing List Message-Id: References: <20170920164213.GF14329@fieldses.org> <20170920164951.GG14329@fieldses.org> To: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Sep 20, 2017, at 12:49 PM, J. Bruce Fields wrote: > > On Wed, Sep 20, 2017 at 12:42:13PM -0400, bfields wrote: >> From: "J. Bruce Fields" >> >> The units of RPC_MAX_AUTH_SIZE is bytes, not 4-byte words. This causes >> the client to request a larger-than-necessary session replay slot size. > > By the way, the client's still asking for 3428 bytes after that, which > seems high. It's mostly the fault of NFS4_MAXLABELLEN, which is 2048. The maximum size of NFSv4 LOOKUP replies is also quite large, thanks to label support (IIRC). It would be nicer for NFS/RDMA, at least, if the maximum reply sizes of common operations were small (say, less than 1024 bytes). > I haven't spotted an improvement there yet. I haven't either. > Noticed because knfsd was hitting session drc cache limits much to early > and failing CREATE_SESSION (hence mount). The main trouble is on the > server side, so I'm relaxing the limits there (and revisiting Trond's > dynamic slot renegotiation patches). But I thought I should check for > any easy improvements here too. > > --b. > >> >> Signed-off-by: J. Bruce Fields >> --- >> fs/nfs/nfs4xdr.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c >> index 37c8af003275..14ed9791ec9c 100644 >> --- a/fs/nfs/nfs4xdr.c >> +++ b/fs/nfs/nfs4xdr.c >> @@ -1842,8 +1842,8 @@ static void encode_create_session(struct xdr_stream *xdr, >> * Assumes OPEN is the biggest non-idempotent compound. >> * 2 is the verifier. >> */ >> - max_resp_sz_cached = (NFS4_dec_open_sz + RPC_REPHDRSIZE + >> - RPC_MAX_AUTH_SIZE + 2) * XDR_UNIT; >> + max_resp_sz_cached = (NFS4_dec_open_sz + RPC_REPHDRSIZE + 2) >> + * XDR_UNIT + RPC_MAX_AUTH_SIZE; >> >> encode_op_hdr(xdr, OP_CREATE_SESSION, decode_create_session_maxsz, hdr); >> p = reserve_space(xdr, 16 + 2*28 + 20 + clnt->cl_nodelen + 12); >> -- >> 2.13.5 >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever