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

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

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?

-- 
Thanks,
Anatoly