On Tue, Dec 15, 2015 at 3:28 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> 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?
>
Will do, and the pfn_t inlines can also move out.
>> +
>> +/**
>> + * 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?
I'll move it.
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