>From: Vamsi Krishna Attunuru >Sent: Thursday, July 4, 2019 12:13 PM >To: dev@dpdk.org >Cc: ferruh.yi...@intel.com; olivier.m...@6wind.com; arybche...@solarflare.com; >Jerin Jacob Kollanukkaran <jer...@marvell.com>; Burakov, Anatoly ><anatoly.bura...@intel.com> >Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > >Hi All, > >Just to summarize, below items have arisen from the initial review. >1) Can the new mempool flag be made default to all the pools and will there be >case that new flag functionality would fail for some page sizes.?
If the minimum huge page size is 2MB and normal huge page size is 512MB or 1G. So I think, new flags can be default as skipping the page boundaries for Mempool objects has nearly zero overhead. But I leave decision to maintainers. >2) Adding HW device info(pci dev info) to KNI device structure, will it break >KNI on virtual devices in VA or PA mode.? Iommu_domain will be created only for PCI devices and the system runs in IOVA_VA mode. Virtual devices(IOVA_DC(don't care) or IOVA_PA devices still it works without PCI device structure) It is a useful feature where KNI can run without root privilege and it is pending for long time. Request to review and close this > >Can someone suggest if any changes required to address above issues. ________________________________________ From: dev <mailto:dev-boun...@dpdk.org> on behalf of Vamsi Krishna Attunuru <mailto:vattun...@marvell.com> Sent: Monday, July 1, 2019 7:21:22 PM To: Jerin Jacob Kollanukkaran; Burakov, Anatoly; mailto:dev@dpdk.org Cc: mailto:ferruh.yi...@intel.com; mailto:olivier.m...@6wind.com; mailto:arybche...@solarflare.com Subject: [EXT] Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI External Email ---------------------------------------------------------------------- ping.. ________________________________ From: Jerin Jacob Kollanukkaran Sent: Thursday, June 27, 2019 3:04:58 PM To: Burakov, Anatoly; Vamsi Krishna Attunuru; mailto:dev@dpdk.org Cc: mailto:ferruh.yi...@intel.com; mailto:olivier.m...@6wind.com; mailto:arybche...@solarflare.com Subject: RE: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > -----Original Message----- > From: Burakov, Anatoly <mailto:anatoly.bura...@intel.com> > Sent: Tuesday, June 25, 2019 7:09 PM > To: Jerin Jacob Kollanukkaran <mailto:jer...@marvell.com>; Vamsi Krishna > Attunuru > <mailto:vattun...@marvell.com>; mailto:dev@dpdk.org > Cc: mailto:ferruh.yi...@intel.com; mailto:olivier.m...@6wind.com; > mailto: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 <mailto:dev-boun...@dpdk.org> On Behalf Of Burakov, Anatoly > >>> Sent: Tuesday, June 25, 2019 3:30 PM > >>> To: Vamsi Krishna Attunuru <mailto:vattun...@marvell.com>; > >>> mailto:dev@dpdk.org > >>> Cc: mailto:ferruh.yi...@intel.com; mailto:olivier.m...@6wind.com; > >>> mailto:arybche...@solarflare.com > >>> Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > >>> > >>> On 25-Jun-19 4:56 AM, mailto:vattun...@marvell.com wrote: > >>>> From: Vamsi Attunuru <mailto: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?
