From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ananyev, Konstantin" Subject: Re: [PATCH v2] example/ipv4_multicast: fix app hanging when using clone Date: Wed, 14 Nov 2018 11:19:09 +0000 Message-ID: <2601191342CEEE43887BDE71AB977258010CEB795B@IRSMSX106.ger.corp.intel.com> References: <20181112204650.7175-1-herakliusz.lipiec@intel.com> <20181113114929.9269-1-herakliusz.lipiec@intel.com> <3E2E5017C928014B90FD7864A64F0B5514F74985@SHSMSX103.ccr.corp.intel.com> <2601191342CEEE43887BDE71AB977258010CEB7388@IRSMSX106.ger.corp.intel.com> <3E2E5017C928014B90FD7864A64F0B5514F74E83@SHSMSX103.ccr.corp.intel.com> <2601191342CEEE43887BDE71AB977258010CEB74B4@IRSMSX106.ger.corp.intel.com> <3E2E5017C928014B90FD7864A64F0B5514F74F8F@SHSMSX103.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "thomas@monjalon.net" , "Burakov, Anatoly" , "stable@dpdk.org" To: "Wang, Dong1" , "Lipiec, Herakliusz" , "dev@dpdk.org" Return-path: In-Reply-To: <3E2E5017C928014B90FD7864A64F0B5514F74F8F@SHSMSX103.ccr.corp.intel.com> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" > -----Original Message----- > From: Wang, Dong1 > Sent: Wednesday, November 14, 2018 11:06 AM > To: Ananyev, Konstantin ; Lipiec, Heraklius= z ; dev@dpdk.org > Cc: thomas@monjalon.net; Burakov, Anatoly ; st= able@dpdk.org > Subject: RE: [PATCH v2] example/ipv4_multicast: fix app hanging when usin= g clone >=20 > Hi Konstantin & Herakliusz, >=20 > In mcast_out_pkt(), new header added and to be the first segment. Driver = will check first segment's ol_flags when sending mbuf. It will check for *TX* flags. TX flags are not set in cloned mbuf (only RX ones). > So why new first segment didn't inherit old one's ol_flags?=20 Because they are RX flags and they don't' really belong to new packet we are going to send. Also, as that bug shows it is error prone. > This function already copied other mbuf fields from old one. And from my perspective it is not needed and better be removed. Though it is a subject of different patch probably. >=20 > Since this is an example and reference code, hope developer can reuse it = smoothly. If they didn't notice ol_flags not be copied because > ol_flags is not changed in this example, they may take some time to debug= their application. For that scenario it is not needed. Surely when user linking two packets manually (as we are doing here) it is = his responsibility to update the mbuf fileds properly. I think this is obvious thing and probably already mentioned in the docs. Konstantin >=20 > This is a tiny change to the patch, I hope it cloud be done. >=20 > Thanks, > Dong >=20 > -----Original Message----- > From: Ananyev, Konstantin > Sent: Wednesday, November 14, 2018 18:18 > To: Wang, Dong1 ; Lipiec, Herakliusz ; dev@dpdk.org > Cc: thomas@monjalon.net; Burakov, Anatoly ; st= able@dpdk.org > Subject: RE: [PATCH v2] example/ipv4_multicast: fix app hanging when usin= g clone >=20 >=20 > > > > Hi Konstantin, > > > > In this example, no flags be set by user, so no need to copy flags from= original mbuf. >=20 > Then why to bother? >=20 > > I'm thinking about some DPDK developers may create their own > > application based on this example, they add some flags before packet b= e cloned. >=20 > Hmm you receive a packet change l2 header and transmit it. > What flags you might need to copy from original header considering that o= nly RX flags would be set at present moment? > If you let say want to insert vlan tag (or so), then you'll have to set n= ew TX flags. > Again, for timestamp you'll need to copy the timestamp value too, which w= e don't support in that example. > Konstantin >=20 > > > > Regards, > > Dong > > > > -----Original Message----- > > From: Ananyev, Konstantin > > Sent: Wednesday, November 14, 2018 17:03 > > To: Wang, Dong1 ; Lipiec, Herakliusz > > ; dev@dpdk.org > > Cc: thomas@monjalon.net; Burakov, Anatoly ; > > stable@dpdk.org > > Subject: RE: [PATCH v2] example/ipv4_multicast: fix app hanging when > > using clone > > > > Hi Dong, > > > > > Hi Herakliusz, > > > > > > Since pkt->ol_flags might set some other bits except > > > IND_ATTACHED_MBUF, how about set its value to original pkt->ol_flag > > > > It could be done, but not sure what is the point? > > Which flags you think we need to copy from cloned mbuf (segment #2) to = new header? > > Konstantin > > > > > > > > Regards, > > > Dong > > > > > > -----Original Message----- > > > From: Lipiec, Herakliusz > > > Sent: Tuesday, November 13, 2018 19:49 > > > To: dev@dpdk.org > > > Cc: Ananyev, Konstantin ; Wang, Dong1 > > > ; thomas@monjalon.net; Burakov, Anatoly > > > ; Lipiec, Herakliusz > > > ; stable@dpdk.org > > > Subject: [PATCH v2] example/ipv4_multicast: fix app hanging when > > > using clone > > > > > > The ipv4_multicast sample application was dropping packets when > > > using mbuf clone. When creating an L2 header and copying metadata > > > from the source packet, the ol_flags were also copied along with all > > > the other metadata. Because the cloned packet had IND_ATTACHED_MBUF > > flag set in its ol_flags, this caused the packets to never be freed whe= n using rte_pktmbuf_free. > > > Since copying ol_flags from the cloned packet is not necessary in the= first place, just don't do it. > > > > > > Fixes: af75078fece3 ("first public release") > > > CC: stable@dpdk.org > > > > > > Reported-by: Wang Dong > > > Signed-off-by: Herakliusz Lipiec > > > --- > > > doc/guides/sample_app_ug/ipv4_multicast.rst | 1 - > > > examples/ipv4_multicast/main.c | 2 -- > > > 2 files changed, 3 deletions(-) > > > > > > diff --git a/doc/guides/sample_app_ug/ipv4_multicast.rst > > > b/doc/guides/sample_app_ug/ipv4_multicast.rst > > > index ce1474ec7..f6efa7f6f 100644 > > > --- a/doc/guides/sample_app_ug/ipv4_multicast.rst > > > +++ b/doc/guides/sample_app_ug/ipv4_multicast.rst > > > @@ -319,7 +319,6 @@ It is the mcast_out_pkt() function that performs = the packet duplication (either > > > hdr->pkt.in_port =3D pkt->pkt.in_port; > > > hdr->pkt.vlan_macip =3D pkt->pkt.vlan_macip; > > > hdr->pkt.hash =3D pkt->pkt.hash; > > > - hdr->ol_flags =3D pkt->ol_flags; > > > rte_mbuf_sanity_check(hdr, RTE_MBUF_PKT, 1); > > > > > > return hdr; > > > diff --git a/examples/ipv4_multicast/main.c > > > b/examples/ipv4_multicast/main.c index 4073a4907..428ca4694 100644 > > > --- a/examples/ipv4_multicast/main.c > > > +++ b/examples/ipv4_multicast/main.c > > > @@ -266,8 +266,6 @@ mcast_out_pkt(struct rte_mbuf *pkt, int use_clone= ) > > > hdr->tx_offload =3D pkt->tx_offload; > > > hdr->hash =3D pkt->hash; > > > > > > - hdr->ol_flags =3D pkt->ol_flags; > > > - > > > __rte_mbuf_sanity_check(hdr, 1); > > > return hdr; > > > } > > > -- > > > 2.17.1