Question about lima kernel MM implementation

[Qiang Yu]

>
>
> >
> > Current MM:
> > 1. drm_gem_cma_object, only support contiguous memory
>
> Please note that drm_gem_cma_object only looks at memory after the MMU
> has done the mapping. If you have a good IOMMU driver that registers
> correctly the dma_ops then you can allocate memory from anywhere and
> still import it into the lima driver via drm_gem_cma_prime_import_sg_
> table()
> hook attached to the gem_prime_import_sg_table.
>
Thanks, good to know this. But some Mali400/450 SoC doesn't have IOMMU
at all, so I can't rely on it.

Regards,
Qiang


>
> > 3. buffer is not really allocated when GEM_CREATE, but in CPU
> > page fault handler and task submit buffer validation which make
> > sure no GPU page fault
> > 4. in shrinker handler, free un-used page in the pool, if still not
> > enough, swap some idle buffer to disk
> >
> > 3&4 apply to both dma_alloc buffer and alloc_page buffer.
> >
> > Thanks,
> > Qiang
>
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>
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