On Wed, 09 Dec 2015 18:38:12 -0800 Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> In support of providing struct page for large persistent memory
> capacities, use struct vmem_altmap to change the default policy for
> allocating memory for the memmap array. The default vmemmap_populate()
> allocates page table storage area from the page allocator. Given
> persistent memory capacities relative to DRAM it may not be feasible to
> store the memmap in 'System Memory'. Instead vmem_altmap represents
> pre-allocated "device pages" to satisfy vmemmap_alloc_block_buf()
> requests.
>
> ...
>
> include/linux/mm.h | 92 +++++++++++++++++++++++++++++++++++++--
mm.h is getting ridiculously huge and these additions look to be fairly
standalone. Perhaps you could take a look at creating a vmem_altmap.h
sometime if feeling bored?
> +
> +/**
> + * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation
> + * @altmap - reserved page pool for the allocation
> + * @nr_pfns - size (in pages) of the allocation
> + *
> + * Allocations are aligned to the size of the request
> + */
> +static inline unsigned long vmem_altmap_alloc(struct vmem_altmap *altmap,
> + unsigned long nr_pfns)
> +{
> + unsigned long pfn = vmem_altmap_next_pfn(altmap);
> + unsigned long nr_align;
> +
> + nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
> + nr_align = ALIGN(pfn, nr_align) - pfn;
> +
> + if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
> + return ULONG_MAX;
> + altmap->alloc += nr_pfns;
> + altmap->align += nr_align;
> + return pfn + nr_align;
> +}
This look pretty large for an inline. But it has only one callsite so
it doesn't matter. But if it only has one callsite, why is it in .h?
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