@@ -122,6 +122,7 @@ static inline void *__va(unsigned long x)
*/
#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
#define pfn_to_virt(pfn) __va((pfn) << PAGE_SHIFT)
+#define __pfn_to_phys(pfn) PFN_PHYS(pfn)
extern int m68k_virt_to_node_shift;
@@ -21,6 +21,7 @@ extern unsigned long memory_end;
#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
#define pfn_to_virt(pfn) __va((pfn) << PAGE_SHIFT)
+#define __pfn_to_phys(pfn) PFN_PHYS(pfn)
#define virt_to_page(addr) (mem_map + (((unsigned long)(addr)-PAGE_OFFSET) >> PAGE_SHIFT))
#define page_to_virt(page) __va(((((page) - mem_map) << PAGE_SHIFT) + PAGE_OFFSET))
@@ -107,6 +107,7 @@ static inline int get_order(unsigned long size)
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
#define pfn_to_page(pfn) (mem_map + ((pfn) - __pfn_disp))
#define page_to_pfn(page) ((unsigned long)((page) - mem_map) + __pfn_disp)
+#define __pfn_to_phys(pfn) PFN_PHYS(pfn)
#define pfn_valid(pfn) \
({ \
@@ -714,6 +714,12 @@ static void __meminit free_pagetable(struct page *page, int order)
{
unsigned long magic;
unsigned int nr_pages = 1 << order;
+ struct vmem_altmap *altmap = to_vmem_altmap((unsigned long) page);
+
+ if (altmap) {
+ vmem_altmap_free(altmap, nr_pages);
+ return;
+ }
/* bootmem page has reserved flag */
if (PageReserved(page)) {
@@ -1018,13 +1024,19 @@ int __ref arch_remove_memory(u64 start, u64 size)
{
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct page *page = pfn_to_page(start_pfn);
+ struct vmem_altmap *altmap;
struct zone *zone;
int ret;
- zone = page_zone(pfn_to_page(start_pfn));
- kernel_physical_mapping_remove(start, start + size);
+ /* With altmap the first mapped page is offset from @start */
+ altmap = to_vmem_altmap((unsigned long) page);
+ if (altmap)
+ page += vmem_altmap_offset(altmap);
+ zone = page_zone(page);
ret = __remove_pages(zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
+ kernel_physical_mapping_remove(start, start + size);
return ret;
}
@@ -1236,7 +1248,7 @@ static void __meminitdata *p_start, *p_end;
static int __meminitdata node_start;
static int __meminit vmemmap_populate_hugepages(unsigned long start,
- unsigned long end, int node)
+ unsigned long end, int node, struct vmem_altmap *altmap)
{
unsigned long addr;
unsigned long next;
@@ -1259,7 +1271,7 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start,
if (pmd_none(*pmd)) {
void *p;
- p = vmemmap_alloc_block_buf(PMD_SIZE, node);
+ p = __vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
if (p) {
pte_t entry;
@@ -1280,7 +1292,8 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start,
addr_end = addr + PMD_SIZE;
p_end = p + PMD_SIZE;
continue;
- }
+ } else if (altmap)
+ return -ENOMEM; /* no fallback */
} else if (pmd_large(*pmd)) {
vmemmap_verify((pte_t *)pmd, node, addr, next);
continue;
@@ -1294,11 +1307,16 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start,
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
{
+ struct vmem_altmap *altmap = to_vmem_altmap(start);
int err;
if (cpu_has_pse)
- err = vmemmap_populate_hugepages(start, end, node);
- else
+ err = vmemmap_populate_hugepages(start, end, node, altmap);
+ else if (altmap) {
+ pr_err_once("%s: no cpu support for altmap allocations\n",
+ __func__);
+ err = -ENOMEM;
+ } else
err = vmemmap_populate_basepages(start, end, node);
if (!err)
sync_global_pgds(start, end - 1, 0);
@@ -143,7 +143,8 @@ static struct pmem_device *pmem_alloc(struct device *dev,
pmem->pfn_flags = PFN_DEV;
if (pmem_should_map_pages(dev)) {
- pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res);
+ pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res,
+ NULL);
pmem->pfn_flags |= PFN_MAP;
} else
pmem->virt_addr = (void __pmem *) devm_memremap(dev,
@@ -355,7 +356,8 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
/* establish pfn range for lookup, and switch to direct map */
pmem = dev_get_drvdata(dev);
devm_memunmap(dev, (void __force *) pmem->virt_addr);
- pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res);
+ pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res,
+ NULL);
pmem->pfn_flags |= PFN_MAP;
if (IS_ERR(pmem->virt_addr)) {
rc = PTR_ERR(pmem->virt_addr);
@@ -275,7 +275,8 @@ extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern bool is_memblock_offlined(struct memory_block *mem);
extern void remove_memory(int nid, u64 start, u64 size);
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn);
-extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
+extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
+ unsigned long map_offset);
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
@@ -677,20 +677,89 @@ static inline enum zone_type page_zonenum(const struct page *page)
struct resource;
struct device;
/**
+ * struct vmem_altmap - pre-allocated storage for vmemmap_populate
+ * @base_pfn: base of the entire dev_pagemap mapping
+ * @reserve: pages mapped, but reserved for driver use (relative to @base)
+ * @free: free pages set aside in the mapping for memmap storage
+ * @align: pages reserved to meet allocation alignments
+ * @alloc: track pages consumed, private to vmemmap_populate()
+ */
+struct vmem_altmap {
+ const unsigned long base_pfn;
+ const unsigned long reserve;
+ unsigned long free;
+ unsigned long align;
+ unsigned long alloc;
+};
+
+static inline unsigned long 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;
+}
+
+static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
+{
+ /* number of pfns from base where pfn_to_page() is valid */
+ return altmap->reserve + altmap->free;
+}
+
+static inline unsigned long vmem_altmap_next_pfn(struct vmem_altmap *altmap)
+{
+ return altmap->base_pfn + altmap->reserve + altmap->alloc
+ + altmap->align;
+}
+
+/**
+ * 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 inline unsigned long 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;
+}
+
+static inline void vmem_altmap_free(struct vmem_altmap *altmap,
+ unsigned long nr_pfns)
+{
+ altmap->alloc -= nr_pfns;
+}
+
+/**
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
+ * @altmap: pre-allocated/reserved memory for vmemmap allocations
* @dev: host device of the mapping for debug
*/
struct dev_pagemap {
- /* TODO: vmem_altmap and percpu_ref count */
+ struct vmem_altmap *altmap;
+ const struct resource *res;
struct device *dev;
};
#ifdef CONFIG_ZONE_DEVICE
-void *devm_memremap_pages(struct device *dev, struct resource *res);
+void *devm_memremap_pages(struct device *dev, struct resource *res,
+ struct vmem_altmap *altmap);
struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
#else
static inline void *devm_memremap_pages(struct device *dev,
- struct resource *res)
+ struct resource *res, struct vmem_altmap *altmap)
{
/*
* Fail attempts to call devm_memremap_pages() without
@@ -707,6 +776,15 @@ static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
}
#endif
+#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE)
+struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start);
+#else
+static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
+{
+ return NULL;
+}
+#endif
+
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define SECTION_IN_PAGE_FLAGS
#endif
@@ -2311,7 +2389,13 @@ pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
void *vmemmap_alloc_block(unsigned long size, int node);
-void *vmemmap_alloc_block_buf(unsigned long size, int node);
+void *__vmemmap_alloc_block_buf(unsigned long size, int node,
+ struct vmem_altmap *altmap);
+static inline void *vmemmap_alloc_block_buf(unsigned long size, int node)
+{
+ return __vmemmap_alloc_block_buf(size, node, NULL);
+}
+
void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
int vmemmap_populate_basepages(unsigned long start, unsigned long end,
int node);
@@ -158,6 +158,7 @@ struct page_map {
struct resource res;
struct percpu_ref *ref;
struct dev_pagemap pgmap;
+ struct vmem_altmap altmap;
};
static void pgmap_radix_release(struct resource *res)
@@ -175,6 +176,7 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
struct page_map *page_map = data;
struct resource *res = &page_map->res;
resource_size_t align_start, align_size;
+ struct dev_pagemap *pgmap = &page_map->pgmap;
pgmap_radix_release(res);
@@ -182,6 +184,8 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(resource_size(res), SECTION_SIZE);
arch_remove_memory(align_start, align_size);
+ dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
+ "%s: failed to free all reserved pages\n", __func__);
}
/* assumes rcu_read_lock() held at entry */
@@ -195,11 +199,23 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
return page_map ? &page_map->pgmap : NULL;
}
-void *devm_memremap_pages(struct device *dev, struct resource *res)
+/**
+ * devm_memremap_pages - remap and provide memmap backing for the given resource
+ * @dev: hosting device for @res
+ * @res: "host memory" address range
+ * @altmap: optional descriptor for allocating the memmap from @res
+ *
+ * Note, the expectation is that @res is a host memory range that could
+ * feasibly be treated as a "System RAM" range, i.e. not a device mmio
+ * range, but this is not enforced.
+ */
+void *devm_memremap_pages(struct device *dev, struct resource *res,
+ struct vmem_altmap *altmap)
{
int is_ram = region_intersects(res->start, resource_size(res),
"System RAM");
resource_size_t key, align_start, align_size;
+ struct dev_pagemap *pgmap;
struct page_map *page_map;
int error, nid;
@@ -212,14 +228,27 @@ void *devm_memremap_pages(struct device *dev, struct resource *res)
if (is_ram == REGION_INTERSECTS)
return __va(res->start);
+ if (altmap && !IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) {
+ dev_err(dev, "%s: altmap requires CONFIG_SPARSEMEM_VMEMMAP=y\n",
+ __func__);
+ return ERR_PTR(-ENXIO);
+ }
+
page_map = devres_alloc_node(devm_memremap_pages_release,
sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
if (!page_map)
return ERR_PTR(-ENOMEM);
+ pgmap = &page_map->pgmap;
memcpy(&page_map->res, res, sizeof(*res));
- page_map->pgmap.dev = dev;
+ pgmap->dev = dev;
+ if (altmap) {
+ memcpy(&page_map->altmap, altmap, sizeof(*altmap));
+ pgmap->altmap = &page_map->altmap;
+ }
+ pgmap->res = &page_map->res;
+
mutex_lock(&pgmap_lock);
error = 0;
for (key = res->start; key <= res->end; key += SECTION_SIZE) {
@@ -266,3 +295,31 @@ void *devm_memremap_pages(struct device *dev, struct resource *res)
}
EXPORT_SYMBOL(devm_memremap_pages);
#endif /* CONFIG_ZONE_DEVICE */
+
+#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE)
+struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
+{
+ /*
+ * 'memmap_start' is the virtual address for the first "struct
+ * page" in this range of the vmemmap array. In the case of
+ * CONFIG_SPARSE_VMEMMAP a page_to_pfn conversion is simple
+ * pointer arithmetic, so we can perform this to_vmem_altmap()
+ * conversion without concern for the initialization state of
+ * the struct page fields.
+ */
+ struct page *page = (struct page *) memmap_start;
+ struct dev_pagemap *pgmap;
+
+ /*
+ * Uncoditionally retrieve a dev_pagemap associated with the
+ * given physical address, this is only for use in the
+ * arch_{add|remove}_memory() for setting up and tearing down
+ * the memmap.
+ */
+ rcu_read_lock();
+ pgmap = find_dev_pagemap(__pfn_to_phys(page_to_pfn(page)));
+ rcu_read_unlock();
+
+ return pgmap ? pgmap->altmap : NULL;
+}
+#endif /* defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE) */
@@ -505,10 +505,25 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
unsigned long i;
int err = 0;
int start_sec, end_sec;
+ struct vmem_altmap *altmap;
+
/* during initialize mem_map, align hot-added range to section */
start_sec = pfn_to_section_nr(phys_start_pfn);
end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
+ altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
+ if (altmap) {
+ /*
+ * Validate altmap is within bounds of the total request
+ */
+ if (altmap->base_pfn != phys_start_pfn
+ || vmem_altmap_offset(altmap) > nr_pages) {
+ pr_warn_once("memory add fail, invalid altmap\n");
+ return -EINVAL;
+ }
+ altmap->alloc = 0;
+ }
+
for (i = start_sec; i <= end_sec; i++) {
err = __add_section(nid, zone, section_nr_to_pfn(i));
@@ -730,7 +745,8 @@ static void __remove_zone(struct zone *zone, unsigned long start_pfn)
pgdat_resize_unlock(zone->zone_pgdat, &flags);
}
-static int __remove_section(struct zone *zone, struct mem_section *ms)
+static int __remove_section(struct zone *zone, struct mem_section *ms,
+ unsigned long map_offset)
{
unsigned long start_pfn;
int scn_nr;
@@ -747,7 +763,7 @@ static int __remove_section(struct zone *zone, struct mem_section *ms)
start_pfn = section_nr_to_pfn(scn_nr);
__remove_zone(zone, start_pfn);
- sparse_remove_one_section(zone, ms);
+ sparse_remove_one_section(zone, ms, map_offset);
return 0;
}
@@ -766,9 +782,32 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
unsigned long nr_pages)
{
unsigned long i;
- int sections_to_remove;
- resource_size_t start, size;
- int ret = 0;
+ unsigned long map_offset = 0;
+ int sections_to_remove, ret = 0;
+
+ /* In the ZONE_DEVICE case device driver owns the memory region */
+ if (is_dev_zone(zone)) {
+ struct page *page = pfn_to_page(phys_start_pfn);
+ struct vmem_altmap *altmap;
+
+ altmap = to_vmem_altmap((unsigned long) page);
+ if (altmap)
+ map_offset = vmem_altmap_offset(altmap);
+ } else {
+ resource_size_t start, size;
+
+ start = phys_start_pfn << PAGE_SHIFT;
+ size = nr_pages * PAGE_SIZE;
+
+ ret = release_mem_region_adjustable(&iomem_resource, start,
+ size);
+ if (ret) {
+ resource_size_t endres = start + size - 1;
+
+ pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
+ &start, &endres, ret);
+ }
+ }
/*
* We can only remove entire sections
@@ -776,23 +815,12 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
BUG_ON(nr_pages % PAGES_PER_SECTION);
- start = phys_start_pfn << PAGE_SHIFT;
- size = nr_pages * PAGE_SIZE;
-
- /* in the ZONE_DEVICE case device driver owns the memory region */
- if (!is_dev_zone(zone))
- ret = release_mem_region_adjustable(&iomem_resource, start, size);
- if (ret) {
- resource_size_t endres = start + size - 1;
-
- pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
- &start, &endres, ret);
- }
-
sections_to_remove = nr_pages / PAGES_PER_SECTION;
for (i = 0; i < sections_to_remove; i++) {
unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
- ret = __remove_section(zone, __pfn_to_section(pfn));
+
+ ret = __remove_section(zone, __pfn_to_section(pfn), map_offset);
+ map_offset = 0;
if (ret)
break;
}
@@ -4502,8 +4502,9 @@ static inline unsigned long wait_table_bits(unsigned long size)
void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
unsigned long start_pfn, enum memmap_context context)
{
- pg_data_t *pgdat = NODE_DATA(nid);
+ struct vmem_altmap *altmap = to_vmem_altmap(__pfn_to_phys(start_pfn));
unsigned long end_pfn = start_pfn + size;
+ pg_data_t *pgdat = NODE_DATA(nid);
unsigned long pfn;
struct zone *z;
unsigned long nr_initialised = 0;
@@ -4511,6 +4512,13 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
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;
+
z = &pgdat->node_zones[zone];
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
/*
@@ -70,7 +70,7 @@ void * __meminit vmemmap_alloc_block(unsigned long size, int node)
}
/* need to make sure size is all the same during early stage */
-void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node)
+static void * __meminit alloc_block_buf(unsigned long size, int node)
{
void *ptr;
@@ -87,6 +87,39 @@ void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node)
return ptr;
}
+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;
+}
+
+/* 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);
+}
+
void __meminit vmemmap_verify(pte_t *pte, int node,
unsigned long start, unsigned long end)
{
@@ -103,7 +136,7 @@ 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 = vmemmap_alloc_block_buf(PAGE_SIZE, node);
+ void *p = alloc_block_buf(PAGE_SIZE, node);
if (!p)
return NULL;
entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
@@ -748,7 +748,7 @@ static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
if (!memmap)
return;
- for (i = 0; i < PAGES_PER_SECTION; i++) {
+ for (i = 0; i < nr_pages; i++) {
if (PageHWPoison(&memmap[i])) {
atomic_long_sub(1, &num_poisoned_pages);
ClearPageHWPoison(&memmap[i]);
@@ -788,7 +788,8 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap)
free_map_bootmem(memmap);
}
-void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
+void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
+ unsigned long map_offset)
{
struct page *memmap = NULL;
unsigned long *usemap = NULL, flags;
@@ -804,7 +805,8 @@ void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
}
pgdat_resize_unlock(pgdat, &flags);
- clear_hwpoisoned_pages(memmap, PAGES_PER_SECTION);
+ clear_hwpoisoned_pages(memmap + map_offset,
+ PAGES_PER_SECTION - map_offset);
free_section_usemap(memmap, usemap);
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
In support of providing struct page for large persistent memory capacities, use struct vmem_altmap to change the default policy for allocating memory for the memmap array. The default vmemmap_populate() allocates page table storage area from the page allocator. Given persistent memory capacities relative to DRAM it may not be feasible to store the memmap in 'System Memory'. Instead vmem_altmap represents pre-allocated "device pages" to satisfy vmemmap_alloc_block_buf() requests. Cc: x86@kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- arch/m68k/include/asm/page_mm.h | 1 arch/m68k/include/asm/page_no.h | 1 arch/mn10300/include/asm/page.h | 1 arch/x86/mm/init_64.c | 32 +++++++++++--- drivers/nvdimm/pmem.c | 6 ++- include/linux/memory_hotplug.h | 3 + include/linux/mm.h | 92 +++++++++++++++++++++++++++++++++++++-- kernel/memremap.c | 61 +++++++++++++++++++++++++- mm/memory_hotplug.c | 66 ++++++++++++++++++++-------- mm/page_alloc.c | 10 ++++ mm/sparse-vmemmap.c | 37 +++++++++++++++- mm/sparse.c | 8 ++- 12 files changed, 277 insertions(+), 41 deletions(-)