From: Bruce Fields <bfields@fieldses.org>
To: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 04/11] SUNRPC: Do not override wspace tests in svc_handle_xprt
Date: Tue, 12 Aug 2014 16:04:46 -0400 [thread overview]
Message-ID: <20140812200446.GD25914@fieldses.org> (raw)
In-Reply-To: <CAHQdGtTL9nd_GJyV7Fn9F+YMAHk4EGU5=6OXCke35ymr7jzrrA@mail.gmail.com>
On Tue, Aug 12, 2014 at 03:31:43PM -0400, Trond Myklebust wrote:
> On Tue, Aug 12, 2014 at 3:16 PM, Bruce Fields <bfields@fieldses.org> wrote:
> > On Sun, Aug 03, 2014 at 01:03:06PM -0400, Trond Myklebust wrote:
> >> We already determined that there was enough wspace when we
> >> called svc_xprt_enqueue.
> >
> > So xpo_has_wspace may have returned true then, but I don't see what
> > guarantees it still would now. Couldn't another server thread have also
> > run svc_recv() and the atomic_add(rqstp->rq_reserved,
> > &xprt->xpt_reserved) between the svc_xprt_enqueue call and now?
>
> The point is that all this is just a heuristic: the TCP send window
> can collapse at any time. So rather than waste cycles doing multiple
> redundant tests that ultimately mean nothing when you call sendmsg(),
> do it once and be damned...
OK, makes sense.
--b.
next prev parent reply other threads:[~2014-08-12 20:04 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-03 17:03 [PATCH 00/11] SUNRPC server scalability improvements Trond Myklebust
2014-08-03 17:03 ` [PATCH 01/11] SUNRPC: Reduce contention in svc_xprt_enqueue() Trond Myklebust
2014-08-03 17:03 ` [PATCH 02/11] SUNRPC: svc_tcp_write_space: don't clear SOCK_NOSPACE prematurely Trond Myklebust
2014-08-03 17:03 ` [PATCH 03/11] SUNRPC: Allow svc_reserve() to notify TCP socket that space has been freed Trond Myklebust
2014-08-03 17:03 ` [PATCH 04/11] SUNRPC: Do not override wspace tests in svc_handle_xprt Trond Myklebust
2014-08-03 17:03 ` [PATCH 05/11] lockd: Ensure that lockd_start_svc sets the server rq_task Trond Myklebust
2014-08-03 17:03 ` [PATCH 06/11] nfs: Ensure that nfs_callback_start_svc " Trond Myklebust
2014-08-03 17:03 ` [PATCH 07/11] SUNRPC: Do not grab pool->sp_lock unnecessarily in svc_get_next_xprt Trond Myklebust
2014-08-03 17:03 ` [PATCH 08/11] SUNRPC: get rid of the request wait queue Trond Myklebust
2014-08-03 17:03 ` [PATCH 09/11] SUNRPC: Fix broken kthread_should_stop test in svc_get_next_xprt Trond Myklebust
2014-08-03 17:03 ` [PATCH 10/11] SUNRPC: More optimisations of svc_xprt_enqueue() Trond Myklebust
2014-08-03 17:03 ` [PATCH 11/11] SUNRPC: Optimise away svc_recv_available Trond Myklebust
2014-08-12 19:53 ` [PATCH 08/11] SUNRPC: get rid of the request wait queue Bruce Fields
2014-08-12 20:09 ` Trond Myklebust
2014-08-12 20:23 ` Bruce Fields
2014-08-12 20:54 ` Trond Myklebust
2014-08-12 21:29 ` Bruce Fields
2014-08-12 21:34 ` Trond Myklebust
2014-08-12 19:16 ` [PATCH 04/11] SUNRPC: Do not override wspace tests in svc_handle_xprt Bruce Fields
2014-08-12 19:31 ` Trond Myklebust
2014-08-12 20:04 ` Bruce Fields [this message]
2014-08-04 13:36 ` [PATCH 00/11] SUNRPC server scalability improvements Bruce Fields
2014-08-05 20:42 ` Bruce Fields
2014-08-05 21:24 ` Trond Myklebust
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