On Tue, Dec 1, 2020 at 2:55 PM Minchan Kim <[email protected]> wrote: > On Tue, Dec 01, 2020 at 11:48:15AM -0800, John Stultz wrote: > > On Tue, Dec 1, 2020 at 9:51 AM Minchan Kim <[email protected]> wrote: > > > > Thanks for reworking and resending this! > > > > ... > > > +static int __init chunk_heap_init(void) > > > +{ > > > + struct cma *default_cma = dev_get_cma_area(NULL); > > > + struct dma_heap_export_info exp_info; > > > + struct chunk_heap *chunk_heap; > > > + > > > + if (!default_cma) > > > + return 0; > > > + > > > + chunk_heap = kzalloc(sizeof(*chunk_heap), GFP_KERNEL); > > > + if (!chunk_heap) > > > + return -ENOMEM; > > > + > > > + chunk_heap->order = CHUNK_HEAP_ORDER; > > > + chunk_heap->cma = default_cma; > > > + > > > + exp_info.name = cma_get_name(default_cma); > > > > So, this would create a chunk heap name with the default CMA name, > > which would be indistinguishable from the heap name used for the plain > > CMA heap. > > > > Probably a good idea to prefix it with "chunk-" so the heap device > > names are unique? > > That will give an impression to user that they are using different CMA > area but that's not true. IMHO, let's be honest at this moment.
I disagree. The dmabuf heaps provide an abstraction for allocating a type of memory, and while your heap is pulling from CMA, you aren't "just" allocating CMA as the existing CMA heap would suffice for that. Since you need a slightly different method to allocate high order pages in bulk, we really should have a unique way to name the allocator interface. That's why I'd suggest the "chunk-" prefix to the heap name. thanks -john
