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: Dan Williams <dan.j.williams@intel.com>
Reported-by: kbuild 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 8829482..5488d21 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -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 @@
{
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 @@
{
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 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 @@
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 @@
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 @@
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);