On 4/7/21 10:56 PM, Mike Rapoport wrote:
> From: Mike Rapoport <r...@linux.ibm.com>
>
> The struct pages representing a reserved memory region are initialized
> using reserve_bootmem_range() function. This function is called for each
> reserved region just before the memory is freed from memblock to the buddy
> page allocator.
>
> The struct pages for MEMBLOCK_NOMAP regions are kept with the default
> values set by the memory map initialization which makes it necessary to
> have a special treatment for such pages in pfn_valid() and
> pfn_valid_within().
>
> Split out initialization of the reserved pages to a function with a
> meaningful name and treat the MEMBLOCK_NOMAP regions the same way as the
> reserved regions and mark struct pages for the NOMAP regions as
> PageReserved.
This would definitely need updating the comment for MEMBLOCK_NOMAP definition
in include/linux/memblock.h just to make the semantics is clear, though arm64
is currently the only user for MEMBLOCK_NOMAP.
>
> Signed-off-by: Mike Rapoport <r...@linux.ibm.com>
> ---
> mm/memblock.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memblock.c b/mm/memblock.c
> index afaefa8fc6ab..6b7ea9d86310 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -2002,6 +2002,26 @@ static unsigned long __init
> __free_memory_core(phys_addr_t start,
> return end_pfn - start_pfn;
> }
>
> +static void __init memmap_init_reserved_pages(void)
> +{
> + struct memblock_region *region;
> + phys_addr_t start, end;
> + u64 i;
> +
> + /* initialize struct pages for the reserved regions */
> + for_each_reserved_mem_range(i, &start, &end)
> + reserve_bootmem_region(start, end);
> +
> + /* and also treat struct pages for the NOMAP regions as PageReserved */
> + for_each_mem_region(region) {
> + if (memblock_is_nomap(region)) {
> + start = region->base;
> + end = start + region->size;
> + reserve_bootmem_region(start, end);
> + }
> + }
> +}
> +
> static unsigned long __init free_low_memory_core_early(void)
> {
> unsigned long count = 0;
> @@ -2010,8 +2030,7 @@ static unsigned long __init
> free_low_memory_core_early(void)
>
> memblock_clear_hotplug(0, -1);
>
> - for_each_reserved_mem_range(i, &start, &end)
> - reserve_bootmem_region(start, end);
> + memmap_init_reserved_pages();
>
> /*
> * We need to use NUMA_NO_NODE instead of NODE_DATA(0)->node_id
>
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