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

[Wang, Haiyue]

> -----Original Message-----
> From: Thomas Monjalon <thomas at monjalon.net>
> Sent: Saturday, June 5, 2021 15:49
> To: Wang, Haiyue <haiyue.wang at intel.com>
> Cc: dev at dpdk.org; Elena Agostini <eagostini at nvidia.com>; andrew.rybchenko at oktetlabs.ru; Yigit, Ferruh
> <ferruh.yigit at intel.com>; jerinj at marvell.com
> Subject: Re: [dpdk-dev] [PATCH] gpudev: introduce memory API
> 
> 04/06/2021 20:04, Wang, Haiyue:
> > From: Thomas Monjalon <thomas at monjalon.net>
> > > 04/06/2021 15:25, Wang, Haiyue:
> > > > From: Thomas Monjalon <thomas at 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 mean that take the current external memory register as an example, it is not
a real proto-type.

The GPU memory management library can provide the this kind of API for GPU driver
to register its memory at probe time or start time ?  

> I may have missed something.
> 



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