Release 4.15 mm/sparse-vmemmap.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Virtual Memory Map support
 *
 * (C) 2007 sgi. Christoph Lameter.
 *
 * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
 * virt_to_page, page_address() to be implemented as a base offset
 * calculation without memory access.
 *
 * However, virtual mappings need a page table and TLBs. Many Linux
 * architectures already map their physical space using 1-1 mappings
 * via TLBs. For those arches the virtual memory map is essentially
 * for free if we use the same page size as the 1-1 mappings. In that
 * case the overhead consists of a few additional pages that are
 * allocated to create a view of memory for vmemmap.
 *
 * The architecture is expected to provide a vmemmap_populate() function
 * to instantiate the mapping.
 */
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/bootmem.h>
#include <linux/memremap.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/sched.h>
#include <asm/dma.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>

/*
 * Allocate a block of memory to be used to back the virtual memory map
 * or to back the page tables that are used to create the mapping.
 * Uses the main allocators if they are available, else bootmem.
 */



static void * __ref __earlyonly_bootmem_alloc(int node,
				unsigned long size,
				unsigned long align,
				unsigned long goal)
{
	return memblock_virt_alloc_try_nid_raw(size, align, goal,
					    BOOTMEM_ALLOC_ACCESSIBLE, node);
}

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Kamezawa Hiroyuki
31
83.78%
1
25.00%
Santosh Shilimkar
4
10.81%
1
25.00%
Fabian Frederick
1
2.70%
1
25.00%
Pavel Tatashin
1
2.70%
1
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4
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static void *vmemmap_buf;

static void *vmemmap_buf_end;



void * __meminit vmemmap_alloc_block(unsigned long size, int node)
{
	/* If the main allocator is up use that, fallback to bootmem. */
	if (slab_is_available()) {
		gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
		int order = get_order(size);
		static bool warned;
		struct page *page;

		page = alloc_pages_node(node, gfp_mask, order);
		if (page)
			return page_address(page);

		if (!warned) {
			warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL,
				   "vmemmap alloc failure: order:%u", order);
			warned = true;
		}
		return NULL;
	} else
		return __earlyonly_bootmem_alloc(node, size, size,
				__pa(MAX_DMA_ADDRESS));
}

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Christoph Lameter
60
53.10%
1
25.00%
Michal Hocko
48
42.48%
1
25.00%
David Shaohua Li
4
3.54%
1
25.00%
Kamezawa Hiroyuki
1
0.88%
1
25.00%
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113
100.00%
4
100.00%

/* need to make sure size is all the same during early stage */


static void * __meminit alloc_block_buf(unsigned long size, int node)
{
	void *ptr;

	if (!vmemmap_buf)
		return vmemmap_alloc_block(size, node);

	/* take the from buf */
	ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size);
	if (ptr + size > vmemmap_buf_end)
		return vmemmap_alloc_block(size, node);

	vmemmap_buf = ptr + size;

	return ptr;
}

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Yinghai Lu
73
97.33%
1
50.00%
Dan J Williams
2
2.67%
1
50.00%
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75
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2
100.00%



static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
{
	return altmap->base_pfn + altmap->reserve + altmap->alloc
		+ altmap->align;
}

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30
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static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
{
	unsigned long allocated = altmap->alloc + altmap->align;

	if (altmap->free > allocated)
		return altmap->free - allocated;
	return 0;
}

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/**
 * 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 unsigned long __meminit 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;
}

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84
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static void * __meminit altmap_alloc_block_buf(unsigned long size,
		struct vmem_altmap *altmap)
{
	unsigned long pfn, nr_pfns;
	void *ptr;

	if (size & ~PAGE_MASK) {
		pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
				__func__, size);
		return NULL;
	}

	nr_pfns = size >> PAGE_SHIFT;
	pfn = vmem_altmap_alloc(altmap, nr_pfns);
	if (pfn < ULONG_MAX)
		ptr = __va(__pfn_to_phys(pfn));
	else
		ptr = NULL;
	pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
			__func__, pfn, altmap->alloc, altmap->align, nr_pfns);

	return ptr;
}

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Dan J Williams
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/* need to make sure size is all the same during early stage */


void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node,
		struct vmem_altmap *altmap)
{
	if (altmap)
		return altmap_alloc_block_buf(size, altmap);
	return alloc_block_buf(size, node);
}

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Dan J Williams
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39
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void __meminit vmemmap_verify(pte_t *pte, int node,
				unsigned long start, unsigned long end)
{
	unsigned long pfn = pte_pfn(*pte);
	int actual_node = early_pfn_to_nid(pfn);

	if (node_distance(actual_node, node) > LOCAL_DISTANCE)
		pr_warn("[%lx-%lx] potential offnode page_structs\n",
			start, end - 1);
}

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Christoph Lameter
53
86.89%
1
25.00%
David Rientjes
6
9.84%
1
25.00%
Joe Perches
2
3.28%
2
50.00%
Total
61
100.00%
4
100.00%



pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
{
	pte_t *pte = pte_offset_kernel(pmd, addr);
	if (pte_none(*pte)) {
		pte_t entry;
		void *p = alloc_block_buf(PAGE_SIZE, node);
		if (!p)
			return NULL;
		entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
		set_pte_at(&init_mm, addr, pte, entry);
	}
	return pte;
}

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Christoph Lameter
76
84.44%
1
25.00%
Andy Whitcroft
12
13.33%
1
25.00%
Al Viro
1
1.11%
1
25.00%
Dan J Williams
1
1.11%
1
25.00%
Total
90
100.00%
4
100.00%



static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node)
{
	void *p = vmemmap_alloc_block(size, node);

	if (!p)
		return NULL;
	memset(p, 0, size);

	return p;
}

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pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
{
	pmd_t *pmd = pmd_offset(pud, addr);
	if (pmd_none(*pmd)) {
		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
		if (!p)
			return NULL;
		pmd_populate_kernel(&init_mm, pmd, p);
	}
	return pmd;
}

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Christoph Lameter
64
90.14%
1
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Andy Whitcroft
5
7.04%
1
25.00%
Al Viro
1
1.41%
1
25.00%
Pavel Tatashin
1
1.41%
1
25.00%
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71
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4
100.00%



pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
{
	pud_t *pud = pud_offset(p4d, addr);
	if (pud_none(*pud)) {
		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
		if (!p)
			return NULL;
		pud_populate(&init_mm, pud, p);
	}
	return pud;
}

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Christoph Lameter
58
81.69%
1
20.00%
Andy Whitcroft
8
11.27%
1
20.00%
Kirill A. Shutemov
3
4.23%
1
20.00%
Al Viro
1
1.41%
1
20.00%
Pavel Tatashin
1
1.41%
1
20.00%
Total
71
100.00%
5
100.00%



p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
{
	p4d_t *p4d = p4d_offset(pgd, addr);
	if (p4d_none(*p4d)) {
		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
		if (!p)
			return NULL;
		p4d_populate(&init_mm, p4d, p);
	}
	return p4d;
}

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70
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Pavel Tatashin
1
1.41%
1
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71
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2
100.00%



pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
{
	pgd_t *pgd = pgd_offset_k(addr);
	if (pgd_none(*pgd)) {
		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
		if (!p)
			return NULL;
		pgd_populate(&init_mm, pgd, p);
	}
	return pgd;
}

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Andy Whitcroft
50
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Christoph Lameter
13
20.00%
1
25.00%
Al Viro
1
1.54%
1
25.00%
Pavel Tatashin
1
1.54%
1
25.00%
Total
65
100.00%
4
100.00%



int __meminit vmemmap_populate_basepages(unsigned long start,
					 unsigned long end, int node)
{
	unsigned long addr = start;
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	for (; addr < end; addr += PAGE_SIZE) {
		pgd = vmemmap_pgd_populate(addr, node);
		if (!pgd)
			return -ENOMEM;
		p4d = vmemmap_p4d_populate(pgd, addr, node);
		if (!p4d)
			return -ENOMEM;
		pud = vmemmap_pud_populate(p4d, addr, node);
		if (!pud)
			return -ENOMEM;
		pmd = vmemmap_pmd_populate(pud, addr, node);
		if (!pmd)
			return -ENOMEM;
		pte = vmemmap_pte_populate(pmd, addr, node);
		if (!pte)
			return -ENOMEM;
		vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
	}

	return 0;
}

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Andy Whitcroft
76
44.71%
1
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Christoph Lameter
64
37.65%
1
25.00%
Kirill A. Shutemov
25
14.71%
1
25.00%
Johannes Weiner
5
2.94%
1
25.00%
Total
170
100.00%
4
100.00%



struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
{
	unsigned long start;
	unsigned long end;
	struct page *map;

	map = pfn_to_page(pnum * PAGES_PER_SECTION);
	start = (unsigned long)map;
	end = (unsigned long)(map + PAGES_PER_SECTION);

	if (vmemmap_populate(start, end, nid))
		return NULL;

	return map;
}

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Johannes Weiner
36
48.65%
1
33.33%
Christoph Lameter
36
48.65%
1
33.33%
Yasunori Goto
2
2.70%
1
33.33%
Total
74
100.00%
3
100.00%



void __init sparse_mem_maps_populate_node(struct page **map_map,
					  unsigned long pnum_begin,
					  unsigned long pnum_end,
					  unsigned long map_count, int nodeid)
{
	unsigned long pnum;
	unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
	void *vmemmap_buf_start;

	size = ALIGN(size, PMD_SIZE);
	vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,
			 PMD_SIZE, __pa(MAX_DMA_ADDRESS));

	if (vmemmap_buf_start) {
		vmemmap_buf = vmemmap_buf_start;
		vmemmap_buf_end = vmemmap_buf_start + size * map_count;
	}

	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
		struct mem_section *ms;

		if (!present_section_nr(pnum))
			continue;

		map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
		if (map_map[pnum])
			continue;
		ms = __nr_to_section(pnum);
		pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
		       __func__);
		ms->section_mem_map = 0;
	}

	if (vmemmap_buf_start) {
		/* need to free left buf */
		memblock_free_early(__pa(vmemmap_buf),
				    vmemmap_buf_end - vmemmap_buf);
		vmemmap_buf = NULL;
		vmemmap_buf_end = NULL;
	}
}
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Yinghai Lu
185
98.40%
1
33.33%
Joe Perches
2
1.06%
1
33.33%
Santosh Shilimkar
1
0.53%
1
33.33%
Total
188
100.00%
3
100.00%

Overall Contributors
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CommitProp
Christoph Lameter
452
30.42%
1
4.76%
Dan J Williams
310
20.86%
1
4.76%
Yinghai Lu
269
18.10%
1
4.76%
Andy Whitcroft
151
10.16%
1
4.76%
Kirill A. Shutemov
98
6.59%
1
4.76%
Pavel Tatashin
51
3.43%
1
4.76%
Michal Hocko
48
3.23%
1
4.76%
Johannes Weiner
41
2.76%
1
4.76%
Kamezawa Hiroyuki
32
2.15%
1
4.76%
David Rientjes
6
0.40%
1
4.76%
Santosh Shilimkar
5
0.34%
1
4.76%
Joe Perches
4
0.27%
2
9.52%
David Shaohua Li
4
0.27%
1
4.76%
Al Viro
4
0.27%
1
4.76%
Tejun Heo
3
0.20%
1
4.76%
Glauber de Oliveira Costa
3
0.20%
1
4.76%
Yasunori Goto
2
0.13%
1
4.76%
Uwe Kleine-König
1
0.07%
1
4.76%
Greg Kroah-Hartman
1
0.07%
1
4.76%
Fabian Frederick
1
0.07%
1
4.76%
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