Re: [PATCH 3/3] mm: move mirrored memory specific code outside of memmap_init_zone

[Andrew Morton]

On Tue, 24 Jul 2018 19:55:20 -0400 Pavel Tatashin <pasha.tatas...@oracle.com> 
wrote:

> memmap_init_zone, is getting complex, because it is called from different
> contexts: hotplug, and during boot, and also because it must handle some
> architecture quirks. One of them is mirroed memory.
> 
> Move the code that decides whether to skip mirrored memory outside of
> memmap_init_zone, into a separate function.

Conflicts a bit with the page_alloc.c hunk from
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-remain-memblock_next_valid_pfn-on-arm-arm64.patch.
  Please check my fixup:

void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
                unsigned long start_pfn, enum memmap_context context,
                struct vmem_altmap *altmap)
{
        unsigned long pfn, end_pfn = start_pfn + size;
        struct page *page;

        if (highest_memmap_pfn < end_pfn - 1)
                highest_memmap_pfn = end_pfn - 1;

        /*
         * Honor reservation requested by the driver for this ZONE_DEVICE
         * memory
         */
        if (altmap && start_pfn == altmap->base_pfn)
                start_pfn += altmap->reserve;

        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
                /*
                 * There can be holes in boot-time mem_map[]s handed to this
                 * function.  They do not exist on hotplugged memory.
                 */
                if (context == MEMMAP_EARLY) {
                        if (!early_pfn_valid(pfn)) {
                                pfn = next_valid_pfn(pfn) - 1;
                                continue;
                        }
                        if (!early_pfn_in_nid(pfn, nid))
                                continue;
                        if (overlap_memmap_init(zone, &pfn))
                                continue;
                        if (defer_init(nid, pfn, end_pfn))
                                break;
                }

                page = pfn_to_page(pfn);
                __init_single_page(page, pfn, zone, nid);
                if (context == MEMMAP_HOTPLUG)
                        SetPageReserved(page);

                /*
                 * Mark the block movable so that blocks are reserved for
                 * movable at startup. This will force kernel allocations
                 * to reserve their blocks rather than leaking throughout
                 * the address space during boot when many long-lived
                 * kernel allocations are made.
                 *
                 * bitmap is created for zone's valid pfn range. but memmap
                 * can be created for invalid pages (for alignment)
                 * check here not to call set_pageblock_migratetype() against
                 * pfn out of zone.
                 */
                if (!(pfn & (pageblock_nr_pages - 1))) {
                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
                        cond_resched();
                }
        }
}