Re: [dpdk-dev] [PATCH] gpudev: introduce memory API

[Thomas Monjalon <thomas@monjalon.net>]

04/06/2021 20:04, Wang, Haiyue:
> From: Thomas Monjalon <thomas@monjalon.net>
> > 04/06/2021 15:25, Wang, Haiyue:
> > > From: Thomas Monjalon <thomas@monjalon.net>
> > > > Another question is about the function rte_gpu_free().
> > > > How do we recognize that a memory chunk is from the CPU and GPU visible,
> > > > or just from GPU?
> > > >
> > >
> > > I didn't find the rte_gpu_free_visible definition, and the rte_gpu_free's
> > > comment just says: deallocate a chunk of memory allocated with rte_gpu_malloc*
> > >
> > > Looks like the rte_gpu_free can handle this case ?
> > 
> > This is the proposal, yes.
> > 
> > > And from the definition "rte_gpu_free(uint16_t gpu_id, void *ptr)", the
> > > free needs to check whether this memory belong to the GPU or not, so it
> > > also can recognize the memory type, I think.
> > 
> > Yes that's the idea behind having a single free function.
> > We could have some metadata in front of the memory chunk.
> > My question is to confirm whether it is a good design or not,
> > and whether it should be driver specific or have a common struct in the lib.
> > 
> > Opinions?
> > 
> 
> Make the GPU memory to be registered into the common lib API with the metadata
> like address, size etc, and also some GPU specific callbacks like to handle how
> to make GPU memory visible to CPU ?
> 
> And the memory register can be like the exist external memory function:
> 
> int
> rte_extmem_register(void *va_addr, size_t len, rte_iova_t iova_addrs[],
> 		unsigned int n_pages, size_t page_sz)

How do you specify the device ID?
I may have missed something.