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![Michal Hocko](/assets/img/avatar_default.png)
Commitf52407ce2d
("memory hotplug: alloc page from other node in memory online") has introduced N_HIGH_MEMORY checks to only use NUMA aware allocations when there is some memory present because the respective node might not have any memory yet at the time and so it could fail or even OOM. Things have changed since then though. Zonelists are now always initialized before we do any allocations even for hotplug (see959ecc48fc
("mm/memory_hotplug.c: fix building of node hotplug zonelist")). Therefore these checks are not really needed. In fact caller of the allocator should never care about whether the node is populated because that might change at any time. Link: http://lkml.kernel.org/r/20170721143915.14161-10-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Toshi Kani <toshi.kani@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
318 lines
8 KiB
C
318 lines
8 KiB
C
/*
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* Virtual Memory Map support
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*
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* (C) 2007 sgi. Christoph Lameter.
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*
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* Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
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* virt_to_page, page_address() to be implemented as a base offset
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* calculation without memory access.
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*
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* However, virtual mappings need a page table and TLBs. Many Linux
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* architectures already map their physical space using 1-1 mappings
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* via TLBs. For those arches the virtual memory map is essentially
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* for free if we use the same page size as the 1-1 mappings. In that
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* case the overhead consists of a few additional pages that are
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* allocated to create a view of memory for vmemmap.
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*
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* The architecture is expected to provide a vmemmap_populate() function
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* to instantiate the mapping.
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*/
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/bootmem.h>
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#include <linux/memremap.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <linux/sched.h>
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#include <asm/dma.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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/*
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* Allocate a block of memory to be used to back the virtual memory map
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* or to back the page tables that are used to create the mapping.
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* Uses the main allocators if they are available, else bootmem.
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*/
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static void * __ref __earlyonly_bootmem_alloc(int node,
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unsigned long size,
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unsigned long align,
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unsigned long goal)
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{
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return memblock_virt_alloc_try_nid(size, align, goal,
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BOOTMEM_ALLOC_ACCESSIBLE, node);
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}
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static void *vmemmap_buf;
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static void *vmemmap_buf_end;
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void * __meminit vmemmap_alloc_block(unsigned long size, int node)
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{
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/* If the main allocator is up use that, fallback to bootmem. */
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if (slab_is_available()) {
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struct page *page;
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page = alloc_pages_node(node,
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GFP_KERNEL | __GFP_ZERO | __GFP_RETRY_MAYFAIL,
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get_order(size));
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if (page)
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return page_address(page);
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return NULL;
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} else
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return __earlyonly_bootmem_alloc(node, size, size,
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__pa(MAX_DMA_ADDRESS));
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}
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/* need to make sure size is all the same during early stage */
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static void * __meminit alloc_block_buf(unsigned long size, int node)
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{
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void *ptr;
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if (!vmemmap_buf)
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return vmemmap_alloc_block(size, node);
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/* take the from buf */
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ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size);
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if (ptr + size > vmemmap_buf_end)
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return vmemmap_alloc_block(size, node);
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vmemmap_buf = ptr + size;
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return ptr;
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}
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static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
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{
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return altmap->base_pfn + altmap->reserve + altmap->alloc
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+ altmap->align;
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}
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static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
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{
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unsigned long allocated = altmap->alloc + altmap->align;
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if (altmap->free > allocated)
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return altmap->free - allocated;
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return 0;
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}
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/**
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* vmem_altmap_alloc - allocate pages from the vmem_altmap reservation
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* @altmap - reserved page pool for the allocation
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* @nr_pfns - size (in pages) of the allocation
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*
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* Allocations are aligned to the size of the request
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*/
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static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap,
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unsigned long nr_pfns)
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{
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unsigned long pfn = vmem_altmap_next_pfn(altmap);
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unsigned long nr_align;
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nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
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nr_align = ALIGN(pfn, nr_align) - pfn;
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if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
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return ULONG_MAX;
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altmap->alloc += nr_pfns;
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altmap->align += nr_align;
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return pfn + nr_align;
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}
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static void * __meminit altmap_alloc_block_buf(unsigned long size,
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struct vmem_altmap *altmap)
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{
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unsigned long pfn, nr_pfns;
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void *ptr;
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if (size & ~PAGE_MASK) {
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pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
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__func__, size);
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return NULL;
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}
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nr_pfns = size >> PAGE_SHIFT;
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pfn = vmem_altmap_alloc(altmap, nr_pfns);
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if (pfn < ULONG_MAX)
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ptr = __va(__pfn_to_phys(pfn));
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else
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ptr = NULL;
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pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
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__func__, pfn, altmap->alloc, altmap->align, nr_pfns);
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return ptr;
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}
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/* need to make sure size is all the same during early stage */
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void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node,
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struct vmem_altmap *altmap)
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{
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if (altmap)
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return altmap_alloc_block_buf(size, altmap);
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return alloc_block_buf(size, node);
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}
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void __meminit vmemmap_verify(pte_t *pte, int node,
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unsigned long start, unsigned long end)
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{
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unsigned long pfn = pte_pfn(*pte);
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int actual_node = early_pfn_to_nid(pfn);
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if (node_distance(actual_node, node) > LOCAL_DISTANCE)
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pr_warn("[%lx-%lx] potential offnode page_structs\n",
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start, end - 1);
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}
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pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
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{
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pte_t *pte = pte_offset_kernel(pmd, addr);
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if (pte_none(*pte)) {
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pte_t entry;
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void *p = alloc_block_buf(PAGE_SIZE, node);
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if (!p)
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return NULL;
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entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
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set_pte_at(&init_mm, addr, pte, entry);
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}
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return pte;
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}
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pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
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{
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pmd_t *pmd = pmd_offset(pud, addr);
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if (pmd_none(*pmd)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pmd_populate_kernel(&init_mm, pmd, p);
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}
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return pmd;
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}
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pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
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{
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pud_t *pud = pud_offset(p4d, addr);
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if (pud_none(*pud)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pud_populate(&init_mm, pud, p);
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}
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return pud;
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}
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p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
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{
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p4d_t *p4d = p4d_offset(pgd, addr);
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if (p4d_none(*p4d)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return NULL;
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p4d_populate(&init_mm, p4d, p);
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}
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return p4d;
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}
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pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
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{
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pgd_t *pgd = pgd_offset_k(addr);
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if (pgd_none(*pgd)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pgd_populate(&init_mm, pgd, p);
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}
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return pgd;
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}
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int __meminit vmemmap_populate_basepages(unsigned long start,
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unsigned long end, int node)
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{
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unsigned long addr = start;
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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for (; addr < end; addr += PAGE_SIZE) {
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pgd = vmemmap_pgd_populate(addr, node);
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if (!pgd)
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return -ENOMEM;
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p4d = vmemmap_p4d_populate(pgd, addr, node);
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if (!p4d)
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return -ENOMEM;
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pud = vmemmap_pud_populate(p4d, addr, node);
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if (!pud)
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return -ENOMEM;
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pmd = vmemmap_pmd_populate(pud, addr, node);
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if (!pmd)
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return -ENOMEM;
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pte = vmemmap_pte_populate(pmd, addr, node);
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if (!pte)
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return -ENOMEM;
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vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
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}
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return 0;
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}
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struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
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{
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unsigned long start;
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unsigned long end;
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struct page *map;
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map = pfn_to_page(pnum * PAGES_PER_SECTION);
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start = (unsigned long)map;
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end = (unsigned long)(map + PAGES_PER_SECTION);
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if (vmemmap_populate(start, end, nid))
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return NULL;
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return map;
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}
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void __init sparse_mem_maps_populate_node(struct page **map_map,
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unsigned long pnum_begin,
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unsigned long pnum_end,
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unsigned long map_count, int nodeid)
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{
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unsigned long pnum;
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unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
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void *vmemmap_buf_start;
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size = ALIGN(size, PMD_SIZE);
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vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,
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PMD_SIZE, __pa(MAX_DMA_ADDRESS));
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if (vmemmap_buf_start) {
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vmemmap_buf = vmemmap_buf_start;
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vmemmap_buf_end = vmemmap_buf_start + size * map_count;
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}
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for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
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struct mem_section *ms;
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if (!present_section_nr(pnum))
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continue;
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map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
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if (map_map[pnum])
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continue;
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ms = __nr_to_section(pnum);
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pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
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__func__);
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ms->section_mem_map = 0;
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}
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if (vmemmap_buf_start) {
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/* need to free left buf */
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memblock_free_early(__pa(vmemmap_buf),
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vmemmap_buf_end - vmemmap_buf);
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vmemmap_buf = NULL;
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vmemmap_buf_end = NULL;
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}
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}
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