Commit 4b94ffdc authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds

x86, mm: introduce vmem_altmap to augment vmemmap_populate()

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.
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Reported-by: default avatarkbuild test robot <lkp@intel.com>
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>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9476df7d
......@@ -30,6 +30,7 @@
#include <linux/module.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/memremap.h>
#include <linux/nmi.h>
#include <linux/gfp.h>
#include <linux/kcore.h>
......@@ -714,6 +715,12 @@ 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)) {
......@@ -1017,13 +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;
}
......@@ -1235,7 +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;
......@@ -1258,7 +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;
......@@ -1279,7 +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;
......@@ -1293,11 +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);
......
......@@ -178,7 +178,8 @@ 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,
......@@ -387,7 +388,8 @@ 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);
......
......@@ -4,21 +4,53 @@
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;
};
unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
#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
/**
* 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
......@@ -34,5 +66,4 @@ static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
return NULL;
}
#endif
#endif /* _LINUX_MEMREMAP_H_ */
......@@ -2217,7 +2217,14 @@ 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);
struct vmem_altmap;
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);
......
......@@ -166,6 +166,7 @@ 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)
......@@ -183,6 +184,7 @@ 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);
......@@ -190,6 +192,8 @@ 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 */
......@@ -203,11 +207,23 @@ 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;
......@@ -220,14 +236,27 @@ 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) {
......@@ -273,4 +302,43 @@ void *devm_memremap_pages(struct device *dev, struct resource *res)
return ERR_PTR(error);
}
EXPORT_SYMBOL(devm_memremap_pages);
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;
}
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
{
altmap->alloc -= nr_pfns;
}
#ifdef CONFIG_SPARSEMEM_VMEMMAP
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 /* CONFIG_SPARSEMEM_VMEMMAP */
#endif /* CONFIG_ZONE_DEVICE */
......@@ -17,6 +17,7 @@
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/memory.h>
#include <linux/memremap.h>
#include <linux/memory_hotplug.h>
#include <linux/highmem.h>
#include <linux/vmalloc.h>
......@@ -506,10 +507,25 @@ 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));
......@@ -731,7 +747,8 @@ 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;
......@@ -748,7 +765,7 @@ 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;
}
......@@ -767,9 +784,32 @@ 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
......@@ -777,23 +817,12 @@ 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;
}
......
......@@ -43,6 +43,7 @@
#include <linux/vmalloc.h>
#include <linux/vmstat.h>
#include <linux/mempolicy.h>
#include <linux/memremap.h>
#include <linux/stop_machine.h>
#include <linux/sort.h>
#include <linux/pfn.h>
......@@ -4485,8 +4486,9 @@ 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;
......@@ -4494,6 +4496,13 @@ 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++) {
/*
......
......@@ -20,6 +20,7 @@
#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>
......@@ -70,7 +71,7 @@ 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 +88,77 @@ void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node)
return ptr;
}
static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
{
return altmap->base_pfn + altmap->reserve + altmap->alloc
+ altmap->align;
}
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;
}
/**
* 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;
}
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 +175,7 @@ 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 */
......
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