Re: [RFC/RFT PATCH 1/3] memblock: update initialization of reserved pages
From: Anshuman Khandual <hidden>
Date: 2021-04-08 05:15:34
Also in:
kvmarm, linux-mm, lkml
On 4/7/21 10:56 PM, Mike Rapoport wrote:
From: Mike Rapoport <redacted> 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.
quoted hunk ↗ jump to hunk
Signed-off-by: Mike Rapoport <redacted> --- 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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