From: Dan Gora <dg@adax.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2 02/10] kni: separate releasing netdev from freeing KNI interface
Date: Wed, 10 Oct 2018 15:18:14 -0300 [thread overview]
Message-ID: <CAGyogRbH9Yeg2v=pRvThf8t1CFSFbDbOWuCpsEUn-96eUsPhXA@mail.gmail.com> (raw)
In-Reply-To: <0596f426-0fc5-a222-ea68-4407669f9b22@intel.com>
On Wed, Oct 10, 2018 at 2:25 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>
> On 9/4/2018 1:36 AM, Dan Gora wrote:
> > Hi Ferruh,
> >
> > I remembered now the motivation behind separating rte_kni_release()
> > and rte_kni_free().
> >
> > The problem is that the DPDK thread which calls rte_kni_release()
> > _cannot_ be the same thread which handles callbacks from the KNI
> > driver via rte_kni_handle_request(). This is because the thread which
> > calls rte_kni_release() will be stuck down in
> > ioctl(RTE_KNI_IOCTL_RELEASE) when the kernel calls the
> > RTE_KNI_REQ_CFG_NETWORK_IF callback to the DPDK application. Since
> > that thread cannot call rte_kni_handle_request(), the callback would
> > then just timeout unless some other thread calls
> > rte_kni_handle_request().
> >
> > So then you are in a bit of a chicken and egg situation. You _have_
> > to have a separate thread calling rte_kni_handle_request periodically,
> > but that thread also _cannot_ run after rte_kni_release returns
> > (actually it's worse than that because it's actually after the
> > ioctl(RTE_KNI_IOCTL_RELEASE) returns and the fifos are freed).
>
> I see, so we have problem in both end, -userspace side and kernel side.
>
> Agreed that separating release & free may help, but I am not sure about adding a
> new API for KNI.
>
> Very simply, what about prevent kni_net_release() send callback to userspace?
No, because how is the DPDK application going to know when the user
does 'ip link set down dev <kniX>'? It's important for the DPDK
application to know when the KNI interface is marked down.
> This is already not working and removing it resolves the issues you mentioned.
Huh? How is it not working? Of course it works.
> Sample application calls rte_eth_dev_stop() after release itself, so behavior
> will be same.
Huh?
> But the issues in kernel you mentioned, using `dev` after free_netdev() called
> should be addressed.
Yes, that's why I fixed them in the patches that I sent.
d
next prev parent reply other threads:[~2018-10-10 18:18 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 22:45 [dpdk-dev] [PATCH 00/10] kni: Interface detach and link status fixes Dan Gora
2018-06-29 1:54 ` Dan Gora
2018-06-29 1:54 ` [dpdk-dev] [PATCH v2 01/10] kni: remove unused variables from struct kni_dev Dan Gora
2018-08-29 10:29 ` Ferruh Yigit
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 02/10] kni: separate releasing netdev from freeing KNI interface Dan Gora
2018-08-29 10:59 ` Ferruh Yigit
2018-09-04 0:20 ` Dan Gora
2018-09-04 0:36 ` Dan Gora
2018-10-10 17:24 ` Ferruh Yigit
2018-10-10 18:18 ` Dan Gora [this message]
2018-10-10 22:51 ` Ferruh Yigit
2018-10-10 23:38 ` Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 03/10] kni: don't touch struct kni_dev after freeing Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 04/10] kni: add rte_kni_free to KNI library Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 05/10] kni: don't run rte_kni_handle_request after interface release Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 06/10] kni: increase length of timeout for KNI responses Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 07/10] kni: update kni test for rte_kni_free Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 08/10] kni: add rte_kni_free to KNI example app Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 09/10] kni: add rte_kni_free to KNI vdev driver Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 10/10] kni: add API to set link status on kernel interface Dan Gora
2018-08-29 11:48 ` Ferruh Yigit
2018-08-29 21:10 ` Dan Gora
2018-08-29 22:01 ` Stephen Hemminger
2018-08-29 15:54 ` Stephen Hemminger
2018-08-29 21:02 ` Dan Gora
2018-08-29 22:00 ` Stephen Hemminger
2018-08-29 22:12 ` Dan Gora
2018-08-29 22:41 ` Dan Gora
2018-08-29 23:10 ` Stephen Hemminger
2018-08-30 9:49 ` Igor Ryzhov
2018-08-30 10:32 ` Igor Ryzhov
2018-08-30 21:41 ` Dan Gora
2018-08-30 22:09 ` Stephen Hemminger
2018-08-30 22:11 ` Dan Gora
2018-09-04 0:47 ` Dan Gora
2018-09-05 12:57 ` Stephen Hemminger
2018-09-11 21:45 ` Dan Gora
2018-09-11 21:52 ` Stephen Hemminger
2018-09-11 22:07 ` Dan Gora
2018-09-11 23:14 ` Stephen Hemminger
2018-09-12 4:02 ` Jason Wang
2018-09-11 23:14 ` [dpdk-dev] [PATCH 0/2] " Dan Gora
2018-09-11 23:14 ` [dpdk-dev] [PATCH 1/2] " Dan Gora
2018-09-11 23:18 ` Dan Gora
2018-07-20 11:36 ` [dpdk-dev] [PATCH 00/10] kni: Interface detach and link status fixes Ferruh Yigit
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