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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>
hifive-unleashed-5.1
Oliver O'Halloran 2017-06-28 11:32:33 +10:00 committed by Michael Ellerman
parent d7d9b612f1
commit b584c25440
2 changed files with 26 additions and 5 deletions
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15
arch/powerpc/mm/init_64.c
View File

@ -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) {
/*

16
arch/powerpc/mm/mem.c
View File

@ -36,6 +36,7 @@
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/memremap.h>
#include <asm/pgalloc.h>
#include <asm/prom.h>
@ -159,11 +160,20 @@ int arch_remove_memory(u64 start, u64 size)
{
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct zone *zone;
struct vmem_altmap *altmap;
struct page *page;
int ret;
zone = page_zone(pfn_to_page(start_pfn));
ret = __remove_pages(zone, start_pfn, nr_pages);
/*
* If we have an altmap then we need to skip over any reserved PFNs
* when querying the zone.
*/
page = pfn_to_page(start_pfn);
altmap = to_vmem_altmap((unsigned long) page);
if (altmap)
page += vmem_altmap_offset(altmap);
ret = __remove_pages(page_zone(page), start_pfn, nr_pages);
if (ret)
return ret;