> -----Original Message----- > From: Burakov, Anatoly <anatoly.bura...@intel.com> > Sent: Tuesday, June 25, 2019 7:09 PM > To: Jerin Jacob Kollanukkaran <jer...@marvell.com>; Vamsi Krishna Attunuru > <vattun...@marvell.com>; dev@dpdk.org > Cc: ferruh.yi...@intel.com; olivier.m...@6wind.com; > arybche...@solarflare.com > Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > > On 25-Jun-19 12:30 PM, Burakov, Anatoly wrote: > > On 25-Jun-19 12:15 PM, Jerin Jacob Kollanukkaran wrote: > >>> -----Original Message----- > >>> From: dev <dev-boun...@dpdk.org> On Behalf Of Burakov, Anatoly > >>> Sent: Tuesday, June 25, 2019 3:30 PM > >>> To: Vamsi Krishna Attunuru <vattun...@marvell.com>; dev@dpdk.org > >>> Cc: ferruh.yi...@intel.com; olivier.m...@6wind.com; > >>> arybche...@solarflare.com > >>> Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > >>> > >>> On 25-Jun-19 4:56 AM, vattun...@marvell.com wrote: > >>>> From: Vamsi Attunuru <vattun...@marvell.com> > >>>> > >>>> ---- > >>>> V6 Changes: > >>>> * Added new mempool flag to ensure mbuf memory is not scattered > >>>> across page boundaries. > >>>> * Added KNI kernel module required PCI device information. > >>>> * Modified KNI example application to create mempool with new > >>>> mempool flag. > >>>> > >>> Others can chime in, but my 2 cents: this reduces the usefulness of > >>> KNI because it limits the kinds of mempools one can use them with, > >>> and makes it so that the code that works with every other PMD > >>> requires changes to work with KNI. > >> > >> # One option to make this flag as default only for packet mempool(not > >> allow allocate on page boundary). > >> In real world the overhead will be very minimal considering Huge page > >> size is 1G or 512M # Enable this flag explicitly only IOVA = VA mode > >> in library. Not need to expose to application # I don’t think, there > >> needs to be any PMD specific change to make KNI with IOVA = VA mode # > >> No preference on flags to be passed by application vs in library. > >> But IMO this change would be > >> needed in mempool support KNI in IOVA = VA mode. > >> > > > > I would be OK to just make it default behavior to not cross page > > boundaries when allocating buffers. This would solve the problem for > > KNI and for any other use case that would rely on PA-contiguous > > buffers in face of IOVA as VA mode. > > > > We could also add a flag to explicitly allow page crossing without > > also making mbufs IOVA-non-contiguous, but i'm not sure if there are > > use cases that would benefit from this. > > On another thought, such a default would break 4K pages in case for packets > bigger than page size (i.e. jumbo frames). Should we care?
The hugepage size will not be 4K. Right? Olivier, As a maintainer any thoughts of exposing/not exposing the new mepool flag to Skip the page boundaries? All, Either option is fine, Asking for feedback to processed further?
