Re: [dpdk-dev] [PATCH] librte_eal: add APIs to speedup virt2iova/phys

[Li Feng <fengli@smartx.com>]

Cool, thank you, Anatoly and Kozlyuk.

I haven't found how Windows implements the rte_mem_virt2phy.

Using an opaque structure pointer as the first argument is a good idea.

Thanks,

Feng Li

Dmitry Kozlyuk <dmitry.kozliuk@gmail.com> 于2020年4月20日周一 下午9:07写道：
>
> > On 20-Apr-20 12:09 PM, Li Feng wrote:
> > > Using pread to replace lseek + read.
> > > And add new APIs to reduce open/close/lseek system call frequency when the
> > > user needs to convert a large range of virtual address space.
> > >      - rte_mem_virt2iova_with_fd
> > >      - rte_mem_virt2phy_with_fd
> > >
> > > Currently it will be used by spdk in spdk_mem_register.
> > >
> > > Signed-off-by: Li Feng <fengli@smartx.com>
> > > ---
> >
> > These API's are IMO already on the verge of what's acceptable because of
> > the differences between PA, DPDK IOVA and external memory IOVA. I'm not
> > sure building on top of them is a good idea. It's also quite platform
> > specific - rte_mem_virt2phy could potentially work with Windows (and in
> > fact there was an RFC for it), but would this API work with Windows,
> > given that Windows doesn't have fd's? Should we perhaps replace fd's
> > with an opaque structure pointer, so that each platform-specific
> > implementation could dereference it the way it needs to, without
> > exposing internal details of the platform?
>
> These new APIs are, in fact, Linux-specific. Doubtfully will Windows ever
> benefit from it even with fd abstracted, though I can't say for FreeBSD. Given
> the linked suggestion to move rte_vfio_container_dma_map/unmap to some
> include/linux header, maybe these APIs could land there too?
>
>         http://mails.dpdk.org/archives/dev/2020-April/164404.html
>
> --
> Dmitry Kozlyuk

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