From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [rdma-next 01/33] Revert "IB/core: Add flow control to the portmapper netlink calls" Date: Tue, 1 Aug 2017 17:58:29 +0000 Message-ID: <1501610305.2475.16.camel@wdc.com> References: <20170801133832.GA11812@ctung-MOBL3.amr.corp.intel.com> <20170801141023.GM13672@mtr-leonro.local> <20170801141842.GA1808@ctung-MOBL3.amr.corp.intel.com> <20170801151511.GA13376@ctung-MOBL3.amr.corp.intel.com> <1501600807.2475.4.camel@wdc.com> <20170801162135.GA240@ctung-MOBL3.amr.corp.intel.com> <1501606508.2475.12.camel@wdc.com> <20170801171454.GA8484@ctung-MOBL3.amr.corp.intel.com> <1501608534.2475.14.camel@wdc.com> <20170801175236.GA14048@ctung-MOBL3.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20170801175236.GA14048-TZeIlv3TuzOfrEmaQUPKxl95YUYmaKo1UNDiOz3kqAs@public.gmane.org> Content-Language: en-US Content-ID: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "chien.tin.tung-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org" Cc: "cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On Tue, 2017-08-01 at 12:52 -0500, Chien Tin Tung wrote: > On Tue, Aug 01, 2017 at 05:28:54PM +0000, Bart Van Assche wrote: > > On Tue, 2017-08-01 at 12:14 -0500, Chien Tin Tung wrote: > > > On Tue, Aug 01, 2017 at 04:55:09PM +0000, Bart Van Assche wrote: > > > > Yes, I had read these e-mails but I do not agree with all of what w= as written > > > > in these e-mails. I'm not sure whether you are aware of the origina= l design > > > > goal of the netlink mechanism? It was designed on purpose to be unr= eliable > > > > such that sending information from the kernel to user space would n= ever block. > > >=20 > > > Please show me a feference to Netlink design document/email on mailin= g list > > > that specifically disallowed this? > >=20 > > As you probably know kernel developers do not write design documents. B= ut there > > is plenty of evidence on the web that the netlink mechanism was designe= d to be > > unreliable. A quote from a Linux Journal article from 2005 > > (http://www.linuxjournal.com/article/7356): "Netlink is asynchronous be= cause, > > as with any other socket API, it provides a socket queue to smooth the = burst > > of messages." >=20 > So what happens when the queue is full? you can fail at that point or yo= u > can choose the 1-shot retry with timeout as we have done. What is _wrong= _ > with the 1-shot retry? Why is the one-shot retry necessary? What aspect of the portmapper design m= akes this one-shot retry necessary? Why is this one-shot retry only necessary fo= r the portmapper and not for any other Netlink client? Bart.= -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html