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From: Fields Bruce <bfields@fieldses.org>
To: Trond Myklebust <trondmy@primarydata.com>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 09/10] SUNRPC: Change TCP socket space reservation
Date: Wed, 6 Jul 2016 16:30:55 -0400	[thread overview]
Message-ID: <20160706203055.GH18856@fieldses.org> (raw)
In-Reply-To: <3774A9EF-883F-45E2-B93E-26B178FF499D@primarydata.com>

On Wed, Jul 06, 2016 at 08:11:53PM +0000, Trond Myklebust wrote:
> 
> > On Jul 6, 2016, at 15:53, J. Bruce Fields <bfields@fieldses.org>
> > wrote:
> > 
> > On Fri, Jun 24, 2016 at 10:55:51AM -0400, Trond Myklebust wrote:
> >> Instead of trying (and failing) to predict how much writeable
> >> socket space will be available to the RPC call, just fall back to
> >> the simple model of deferring processing until the socket is
> >> uncongested.
> >> 
> >> If a limit is neeeded, then set the hard per-connection limit.
> > 
> > I was hoping this would be an opportunity to get rid of even more
> > code, but there's still the udp case.  Do we actually need that?
> > 
> 
> I wasn’t really too concerned about UDP; I consider it to be legacy
> code.

Sure, but by the same token maybe it's not worth carrying the extra code
for a udp-only optimization; quick untested diff looks like:

 fs/nfsd/nfs3proc.c              |  1 -
 fs/nfsd/nfs4state.c             |  1 -
 fs/nfsd/nfs4xdr.c               |  1 -
 fs/nfsd/nfsproc.c               |  1 -
 include/linux/sunrpc/svc.h      | 16 ----------------
 include/linux/sunrpc/svc_xprt.h |  1 -
 net/sunrpc/svc.c                |  6 ------
 net/sunrpc/svc_xprt.c           | 37 -------------------------------------
 net/sunrpc/svcsock.c            | 13 +------------
 9 files changed, 1 insertion(+), 76 deletions(-)

> That said, I’d argue the existing system make a little more sense in
> the case of UDP as you don’t have any equivalent of the TCP window
> size. That means the socket buffer sizes are predictable, and so are
> more easily modelled as a pipeline.

OK, could be.

--b.

  reply	other threads:[~2016-07-06 20:31 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-24 14:55 [PATCH 01/10] SUNRPC: Fix tracepoint storage issues with svc_recv and svc_rqst_status Trond Myklebust
2016-06-24 14:55 ` [PATCH 02/10] SUNRPC: Don't allocate a full sockaddr_storage for tracing Trond Myklebust
2016-06-24 14:55   ` [PATCH 03/10] SUNRPC: Add a tracepoint for server socket out-of-space conditions Trond Myklebust
2016-06-24 14:55     ` [PATCH 04/10] SUNRPC: Add tracepoints for dropped and deferred requests Trond Myklebust
2016-06-24 14:55       ` [PATCH 05/10] SUNRPC: lock the socket while detaching it Trond Myklebust
2016-06-24 14:55         ` [PATCH 06/10] SUNRPC: Call the default socket callbacks instead of open coding Trond Myklebust
2016-06-24 14:55           ` [PATCH 07/10] SUNRPC: Micro optimisation for svc_data_ready Trond Myklebust
2016-06-24 14:55             ` [PATCH 08/10] SUNRPC: Add a server side per-connection limit Trond Myklebust
2016-06-24 14:55               ` [PATCH 09/10] SUNRPC: Change TCP socket space reservation Trond Myklebust
2016-06-24 14:55                 ` [PATCH 10/10] SUNRPC: Remove unused callback xpo_adjust_wspace() Trond Myklebust
2016-06-24 21:18                 ` [PATCH 09/10] SUNRPC: Change TCP socket space reservation J. Bruce Fields
2016-06-24 21:31                   ` Trond Myklebust
2016-07-06 20:17                     ` Fields Bruce
2016-07-06 19:53                 ` J. Bruce Fields
2016-07-06 20:11                   ` Trond Myklebust
2016-07-06 20:30                     ` Fields Bruce [this message]
2016-06-24 21:15               ` [PATCH 08/10] SUNRPC: Add a server side per-connection limit J. Bruce Fields
2016-06-24 21:24                 ` Trond Myklebust
2016-07-06 16:16               ` J. Bruce Fields
2016-06-24 21:06         ` [PATCH 05/10] SUNRPC: lock the socket while detaching it J. Bruce Fields
2016-06-24 21:21           ` Trond Myklebust
2016-06-24 18:28 ` [PATCH 01/10] SUNRPC: Fix tracepoint storage issues with svc_recv and svc_rqst_status J. Bruce Fields

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