powerpc/vmemmap: Add altmap support
Adds support to powerpc for the altmap feature of ZONE_DEVICE memory. An
altmap is a driver provided region that is used to provide the backing
storage for the struct pages of ZONE_DEVICE memory. In situations where
large amount of ZONE_DEVICE memory is being added to the system the
altmap reduces pressure on main system memory by allowing the mm/
metadata to be stored on the device itself rather in main memory.
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index f855a24..5b4c25d 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -44,6 +44,7 @@
#include <linux/slab.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
+#include <linux/memremap.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
@@ -192,13 +193,17 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
for (; start < end; start += page_size) {
+ struct vmem_altmap *altmap;
void *p;
int rc;
if (vmemmap_populated(start, page_size))
continue;
- p = vmemmap_alloc_block(page_size, node);
+ /* altmap lookups only work at section boundaries */
+ altmap = to_vmem_altmap(SECTION_ALIGN_DOWN(start));
+
+ p = __vmemmap_alloc_block_buf(page_size, node, altmap);
if (!p)
return -ENOMEM;
@@ -263,6 +268,8 @@ void __ref vmemmap_free(unsigned long start, unsigned long end)
for (; start < end; start += page_size) {
unsigned long nr_pages, addr;
+ struct vmem_altmap *altmap;
+ struct page *section_base;
struct page *page;
/*
@@ -278,9 +285,13 @@ void __ref vmemmap_free(unsigned long start, unsigned long end)
continue;
page = pfn_to_page(addr >> PAGE_SHIFT);
+ section_base = pfn_to_page(vmemmap_section_start(start));
nr_pages = 1 << page_order;
- if (PageReserved(page)) {
+ altmap = to_vmem_altmap((unsigned long) section_base);
+ if (altmap) {
+ vmem_altmap_free(altmap, nr_pages);
+ } else if (PageReserved(page)) {
/* allocated from bootmem */
if (page_size < PAGE_SIZE) {
/*