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linux-next/mm/memory_hotplug.c
KAMEZAWA Hiroyuki ebd15302dc [PATCH] memory hotadd fixes: enhance collision check
This patch is for collision check enhancement for memory hot add.

It's better to do resouce collision check before doing memory hot add,
which will touch memory management structures.

And add_section() should check section exists or not before calling
sparse_add_one_section(). (sparse_add_one_section() will do another
check anyway. but checking in memory_hotplug.c will be easy to understand.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: keith mannthey <kmannth@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-06 08:57:49 -07:00

307 lines
7.3 KiB
C

/*
* linux/mm/memory_hotplug.c
*
* Copyright (C)
*/
#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/pagevec.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
#include <linux/highmem.h>
#include <linux/vmalloc.h>
#include <linux/ioport.h>
#include <asm/tlbflush.h>
extern void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
unsigned long size);
static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
{
struct pglist_data *pgdat = zone->zone_pgdat;
int nr_pages = PAGES_PER_SECTION;
int nid = pgdat->node_id;
int zone_type;
zone_type = zone - pgdat->node_zones;
if (!populated_zone(zone)) {
int ret = 0;
ret = init_currently_empty_zone(zone, phys_start_pfn, nr_pages);
if (ret < 0)
return ret;
}
memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn);
zonetable_add(zone, nid, zone_type, phys_start_pfn, nr_pages);
return 0;
}
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
int nr_pages);
static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
{
int nr_pages = PAGES_PER_SECTION;
int ret;
if (pfn_valid(phys_start_pfn))
return -EEXIST;
ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
if (ret < 0)
return ret;
ret = __add_zone(zone, phys_start_pfn);
if (ret < 0)
return ret;
return register_new_memory(__pfn_to_section(phys_start_pfn));
}
/*
* Reasonably generic function for adding memory. It is
* expected that archs that support memory hotplug will
* call this function after deciding the zone to which to
* add the new pages.
*/
int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
unsigned long nr_pages)
{
unsigned long i;
int err = 0;
int start_sec, end_sec;
/* 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);
for (i = start_sec; i <= end_sec; i++) {
err = __add_section(zone, i << PFN_SECTION_SHIFT);
/*
* EEXIST is finally dealed with by ioresource collision
* check. see add_memory() => register_memory_resource()
* Warning will be printed if there is collision.
*/
if (err && (err != -EEXIST))
break;
err = 0;
}
return err;
}
EXPORT_SYMBOL_GPL(__add_pages);
static void grow_zone_span(struct zone *zone,
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long old_zone_end_pfn;
zone_span_writelock(zone);
old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
if (start_pfn < zone->zone_start_pfn)
zone->zone_start_pfn = start_pfn;
zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
zone->zone_start_pfn;
zone_span_writeunlock(zone);
}
static void grow_pgdat_span(struct pglist_data *pgdat,
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long old_pgdat_end_pfn =
pgdat->node_start_pfn + pgdat->node_spanned_pages;
if (start_pfn < pgdat->node_start_pfn)
pgdat->node_start_pfn = start_pfn;
pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
pgdat->node_start_pfn;
}
int online_pages(unsigned long pfn, unsigned long nr_pages)
{
unsigned long i;
unsigned long flags;
unsigned long onlined_pages = 0;
struct resource res;
u64 section_end;
unsigned long start_pfn;
struct zone *zone;
int need_zonelists_rebuild = 0;
/*
* This doesn't need a lock to do pfn_to_page().
* The section can't be removed here because of the
* memory_block->state_sem.
*/
zone = page_zone(pfn_to_page(pfn));
pgdat_resize_lock(zone->zone_pgdat, &flags);
grow_zone_span(zone, pfn, pfn + nr_pages);
grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
pgdat_resize_unlock(zone->zone_pgdat, &flags);
/*
* If this zone is not populated, then it is not in zonelist.
* This means the page allocator ignores this zone.
* So, zonelist must be updated after online.
*/
if (!populated_zone(zone))
need_zonelists_rebuild = 1;
res.start = (u64)pfn << PAGE_SHIFT;
res.end = res.start + ((u64)nr_pages << PAGE_SHIFT) - 1;
res.flags = IORESOURCE_MEM; /* we just need system ram */
section_end = res.end;
while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
start_pfn = (unsigned long)(res.start >> PAGE_SHIFT);
nr_pages = (unsigned long)
((res.end + 1 - res.start) >> PAGE_SHIFT);
if (PageReserved(pfn_to_page(start_pfn))) {
/* this region's page is not onlined now */
for (i = 0; i < nr_pages; i++) {
struct page *page = pfn_to_page(start_pfn + i);
online_page(page);
onlined_pages++;
}
}
res.start = res.end + 1;
res.end = section_end;
}
zone->present_pages += onlined_pages;
zone->zone_pgdat->node_present_pages += onlined_pages;
setup_per_zone_pages_min();
if (need_zonelists_rebuild)
build_all_zonelists();
vm_total_pages = nr_free_pagecache_pages();
return 0;
}
static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
{
struct pglist_data *pgdat;
unsigned long zones_size[MAX_NR_ZONES] = {0};
unsigned long zholes_size[MAX_NR_ZONES] = {0};
unsigned long start_pfn = start >> PAGE_SHIFT;
pgdat = arch_alloc_nodedata(nid);
if (!pgdat)
return NULL;
arch_refresh_nodedata(nid, pgdat);
/* we can use NODE_DATA(nid) from here */
/* init node's zones as empty zones, we don't have any present pages.*/
free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
return pgdat;
}
static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
{
arch_refresh_nodedata(nid, NULL);
arch_free_nodedata(pgdat);
return;
}
/* add this memory to iomem resource */
static struct resource *register_memory_resource(u64 start, u64 size)
{
struct resource *res;
res = kzalloc(sizeof(struct resource), GFP_KERNEL);
BUG_ON(!res);
res->name = "System RAM";
res->start = start;
res->end = start + size - 1;
res->flags = IORESOURCE_MEM;
if (request_resource(&iomem_resource, res) < 0) {
printk("System RAM resource %llx - %llx cannot be added\n",
(unsigned long long)res->start, (unsigned long long)res->end);
kfree(res);
res = NULL;
}
return res;
}
static void release_memory_resource(struct resource *res)
{
if (!res)
return;
release_resource(res);
kfree(res);
return;
}
int add_memory(int nid, u64 start, u64 size)
{
pg_data_t *pgdat = NULL;
int new_pgdat = 0;
struct resource *res;
int ret;
res = register_memory_resource(start, size);
if (!res)
return -EEXIST;
if (!node_online(nid)) {
pgdat = hotadd_new_pgdat(nid, start);
if (!pgdat)
return -ENOMEM;
new_pgdat = 1;
ret = kswapd_run(nid);
if (ret)
goto error;
}
/* call arch's memory hotadd */
ret = arch_add_memory(nid, start, size);
if (ret < 0)
goto error;
/* we online node here. we can't roll back from here. */
node_set_online(nid);
if (new_pgdat) {
ret = register_one_node(nid);
/*
* If sysfs file of new node can't create, cpu on the node
* can't be hot-added. There is no rollback way now.
* So, check by BUG_ON() to catch it reluctantly..
*/
BUG_ON(ret);
}
return ret;
error:
/* rollback pgdat allocation and others */
if (new_pgdat)
rollback_node_hotadd(nid, pgdat);
if (res)
release_memory_resource(res);
return ret;
}
EXPORT_SYMBOL_GPL(add_memory);