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From: "Loftus, Ciara" <ciara.loftus@intel.com>
To: "Yigit, Ferruh" <ferruh.yigit@intel.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "stephen@networkplumber.org" <stephen@networkplumber.org>,
	"Burakov, Anatoly" <anatoly.burakov@intel.com>,
	"Singh, Aman Deep" <aman.deep.singh@intel.com>
Subject: RE: [PATCH v4] net/af_xdp: re-enable secondary process support
Date: Fri, 11 Feb 2022 15:32:55 +0000	[thread overview]
Message-ID: <PH0PR11MB4791D9D32106D800B791015A8E309@PH0PR11MB4791.namprd11.prod.outlook.com> (raw)
In-Reply-To: <9367c446-4fe7-c18e-acae-52c4f3d1e31c@intel.com>

> 
> On 2/11/2022 1:01 PM, Loftus, Ciara wrote:
> >>
> >> On 2/11/2022 9:26 AM, Loftus, Ciara wrote:
> >>>>>
> >>>>> On 2/10/2022 5:47 PM, Loftus, Ciara wrote:
> >>>>>>> Subject: Re: [PATCH v4] net/af_xdp: re-enable secondary process
> >>>> support
> >>>>>>>
> >>>>>>> On 2/10/2022 3:40 PM, Loftus, Ciara wrote:
> >>>>>>>>> Subject: Re: [PATCH v4] net/af_xdp: re-enable secondary
> process
> >>>>> support
> >>>>>>>>>
> >>>>>>>>> On 2/9/2022 9:48 AM, Ciara Loftus wrote:
> >>>>>>>>>> Secondary process support had been disabled for the AF_XDP
> >> PMD
> >>>>>>>>> because
> >>>>>>>>>> there was no logic in place to share the AF_XDP socket file
> >>>> descriptors
> >>>>>>>>>> between the processes. This commit introduces this logic using
> >> the
> >>>>> IPC
> >>>>>>>>>> APIs.
> >>>>>>>>>>
> >>>>>>>>>> Rx and Tx are disabled in the secondary process due to memory
> >>>>> mapping
> >>>>>>> of
> >>>>>>>>>> the AF_XDP rings being assigned by the kernel in the primary
> >>>> process
> >>>>>>> only.
> >>>>>>>>>> However other operations including retrieval of stats are
> >> permitted.
> >>>>>>>>>>
> >>>>>>>>>> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Hi Ciara,
> >>>>>>>>>
> >>>>>>>>> When I tried to test the patch getting following error [1], it
> doesn't
> >>>> look
> >>>>>>>>> related to this patch but can you help to fix the issue, thanks.
> >>>>>>>>>
> >>>>>>>>> [1]
> >>>>>>>>> libxdp: Couldn't find a BPF file with name xsk_def_xdp_prog.o
> >>>>>>>>> xsk_configure(): Failed to create xsk socket.
> >>>>>>>>> eth_rx_queue_setup(): Failed to configure xdp socket
> >>>>>>>>> Fail to configure port 2 rx queues
> >>>>>>>>> EAL: Error - exiting with code: 1
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> Hi Ferruh,
> >>>>>>>>
> >>>>>>>> This file should be generated when libxdp is compiled.
> >>>>>>>> Mine is located @ /usr/local/lib/bpf/xsk_def_xdp_prog.o
> >>>>>>>> Can you check if that file is there for you? It could be in
> >>>>>>> /usr/local/lib64/bpf/ on your machine.
> >>>>>>>> What kernel are you running on?
> >>>>>>>>
> >>>>>>>
> >>>>>>> It is in: /usr/local/lib64/bpf/xsk_def_xdp_prog.o
> >>>>>>>
> >>>>>>> I had to compile libxdp from source because OS package version
> was
> >> old
> >>>>>>> to work with af_xdp.
> >>>>>>> Is something required to point location of this file to af_xdp PMD?
> >>>>>>>
> >>>>>>> I run kernel:
> >>>>>>> 5.15.16-200.fc35.x86_64
> >>>>>>
> >>>>>> I read through the libxdp code to figure out what happens when
> >>>> searching
> >>>>> for the file:
> >>>>>> https://github.com/xdp-project/xdp-
> >>>>> tools/blob/v1.2.2/lib/libxdp/libxdp.c#L1055
> >>>>>>
> >>>>>> secure_getenv(XDP_OBJECT_ENVVAR) is called which according to
> the
> >>>>> README "defaults to /usr/lib/bpf (or /usr/lib64/bpf on systems using
> a
> >> split
> >>>>> library path)".
> >>>>>> If that fails, BPF_OBJECT_PATH will be searched, which points to
> >>>>> /usr/lib/bpf
> >>>>>>
> >>>>>> I discovered that on my system the getenv() call fails, but the file is
> >>>>> eventually found because luckily BPF_OBJECT_PATH points to the
> >>>>> appropriate place for me (lib):
> >>>>>> https://github.com/xdp-project/xdp-
> >> tools/blob/v1.2.2/lib/util/util.h#L24
> >>>>>> I suspect the same failure is happening for you, but since
> >>>>> BPF_OBJECT_PATH points to lib and not lib64, the file is not found.
> >>>>>> As a temporary measure can you create a symlink in
> /usr/local/lib/bpf/
> >> to
> >>>>> point to /usr/local/lib/bpf/xsk_def_xdp_prog.o
> >>>>>> I will investigate the libxdp issue further. Maybe a change is needed
> in
> >>>> the
> >>>>> library. If a change or setup recommendation is needed in DPDK I will
> >>>> create a
> >>>>> patch.
> >>>>>>
> >>>>>
> >>>>>
> >>>>> I don't have XDP_OBJECT_ENVVAR or BPF_OBJECT_PATH
> environment
> >>>>> variables set,
> >>>>> if they should be we should document them.
> >>>>>
> >>>>> When I created '/usr/local/lib/bpf/' link, the BPF file found.
> >>>>> This should be clarified/documented for users.
> >>>>
> >>>> Ok. Ideally we shouldn't have to create the symlink. I will look for a
> better
> >>>> solution and submit a patch.
> >>>> The symlink might be a temporary solution if another solution is not
> >> found.
> >>>
> >>> Can you please try setting the environment variable
> >> LIBXDP_OBJECT_PATH=/usr/local/lib64/bpf/
> >>> And see if your test works without the symlink?
> >>> This worked for me and the getenv succeeded.
> >>> If it works for you too, I'll create a patch for the docs instructing users to
> do
> >> the same.
> >>>
> >>
> >> I confirm it works, and +1 to document it.
> >>
> >>
> >> btw, when this environment variable is not set (and no symlink), af_xdp
> fails
> >> and testpmd crashes. I think af_xdp failure shouldn't cause a crash in
> >> testpmd,
> >> most probably some error checks are needed in the af_xdp driver.
> >
> > When I trigger the error case in my environment I get a graceful exit:
> >
> > libxdp: Couldn't find a BPF file with name xsk_def_xdp_prog.o
> > xsk_configure(): Failed to create xsk socket.
> > eth_rx_queue_setup(): Failed to configure xdp socket
> > Fail to configure port 0 rx queues
> > EAL: Error - exiting with code: 1
> >    Cause: Start ports failed
> >
> > Can you please provide more info on your crash?
> >
> 
> $ ./build/app/dpdk-testpmd --vdev net_af_xdp0,iface=enp24s0f1 --vdev
> net_af_xdp1,iface=enp94s0f1 -- -i
> ...
> Configuring Port 2 (socket 0)
> libxdp: Couldn't find a BPF file with name xsk_def_xdp_prog.o
> xsk_configure(): Failed to create xsk socket.
> eth_rx_queue_setup(): Failed to configure xdp socket
> Fail to configure port 2 rx queues
> EAL: Error - exiting with code: 1
>    Cause: Start ports failed
> Segmentation fault (core dumped)
> 
> (I have two physical interfaces too, af_xdp ports are port 2 & 3)

Thanks for providing more info. I have reproduced this issue.
It doesn't happen when --no-pci is used.
The issue is not related to the libxdp patch. It just occurs when xsk_configure() fails. As you said, some extra error checks/handling are probably required.
Thanks for reporting. I'll work on a fix.

Ciara

  reply	other threads:[~2022-02-11 15:33 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-10 15:32 [RFC PATCH] net/af_xdp: reenable " Ciara Loftus
2021-12-11 21:49 ` Stephen Hemminger
2022-01-12  7:54 ` [PATCH] net/af_xdp: re-enable " Ciara Loftus
2022-02-04 12:54   ` [PATCH v2] " Ciara Loftus
2022-02-04 14:18     ` Ferruh Yigit
2022-02-07  7:49       ` Loftus, Ciara
2022-02-07 10:27         ` Ferruh Yigit
2022-02-07 11:39           ` Loftus, Ciara
2022-02-08 10:58             ` Ferruh Yigit
2022-02-08 13:48     ` [PATCH v3] " Ciara Loftus
2022-02-08 17:45       ` Stephen Hemminger
2022-02-08 18:00         ` Ferruh Yigit
2022-02-08 18:42           ` Stephen Hemminger
2022-02-08 18:56             ` Ferruh Yigit
2022-02-09  7:41               ` Loftus, Ciara
2022-02-09  9:48       ` [PATCH v4] " Ciara Loftus
2022-02-09 15:29         ` Stephen Hemminger
2022-02-11 13:32           ` Ferruh Yigit
2022-02-09 17:55         ` Ferruh Yigit
2022-02-10 15:08           ` Ferruh Yigit
2022-02-10 15:19         ` Ferruh Yigit
2022-02-10 15:40           ` Loftus, Ciara
2022-02-10 16:06             ` Ferruh Yigit
2022-02-10 17:47               ` Loftus, Ciara
2022-02-10 20:12                 ` Ferruh Yigit
2022-02-11  7:28                   ` Loftus, Ciara
2022-02-11  9:26                     ` Loftus, Ciara
2022-02-11 12:29                       ` Ferruh Yigit
2022-02-11 13:01                         ` Loftus, Ciara
2022-02-11 13:07                           ` Ferruh Yigit
2022-02-11 15:32                             ` Loftus, Ciara [this message]
2022-02-16 11:23                               ` Loftus, Ciara
2022-02-11 11:31                     ` Ferruh Yigit
2022-02-17 12:44         ` David Marchand
2022-02-17 12:47           ` Ferruh Yigit
2022-02-17 12:53             ` David Marchand

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