linux/mm/memory_hotplug.c

/*
 *  linux/mm/memory_hotplug.c
 *
 *  Copyright (C)
 */

#include <linux/config.h>
#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 <asm/tlbflush.h>

static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
{
	struct page *page, *ret;
	unsigned long memmap_size = sizeof(struct page) * nr_pages;

	page = alloc_pages(GFP_KERNEL, get_order(memmap_size));
	if (page)
		goto got_map_page;

	ret = vmalloc(memmap_size);
	if (ret)
		goto got_map_ptr;

	return NULL;
got_map_page:
	ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
got_map_ptr:
	memset(ret, 0, memmap_size);

	return ret;
}

extern void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
			  unsigned long size);
static void __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;
	memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn);
	zonetable_add(zone, nid, zone_type, phys_start_pfn, nr_pages);
}

extern int sparse_add_one_section(struct zone *, unsigned long,
				  struct page *mem_map);
static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
{
	struct pglist_data *pgdat = zone->zone_pgdat;
	int nr_pages = PAGES_PER_SECTION;
	struct page *memmap;
	int ret;

	/*
	 * This can potentially allocate memory, and does its own
	 * internal locking.
	 */
	sparse_index_init(pfn_to_section_nr(phys_start_pfn), pgdat->node_id);

	pgdat_resize_lock(pgdat, &flags);
	memmap = __kmalloc_section_memmap(nr_pages);
	ret = sparse_add_one_section(zone, phys_start_pfn, memmap);
	pgdat_resize_unlock(pgdat, &flags);

	if (ret <= 0) {
		/* the mem_map didn't get used */
		if (memmap >= (struct page *)VMALLOC_START &&
		    memmap < (struct page *)VMALLOC_END)
			vfree(memmap);
		else
			free_pages((unsigned long)memmap,
				   get_order(sizeof(struct page) * nr_pages));
	}

	if (ret < 0)
		return ret;

	__add_zone(zone, phys_start_pfn);
	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;

	for (i = 0; i < nr_pages; i += PAGES_PER_SECTION) {
		err = __add_section(zone, phys_start_pfn + i);

		if (err)
			break;
	}

	return err;
}

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;

	if (end_pfn > old_zone_end_pfn)
		zone->spanned_pages = 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;

	if (end_pfn > old_pgdat_end_pfn)
		pgdat->node_spanned_pages = end_pfn - pgdat->node_spanned_pages;
}

int online_pages(unsigned long pfn, unsigned long nr_pages)
{
	unsigned long i;
	unsigned long flags;
	unsigned long onlined_pages = 0;
	struct zone *zone;

	/*
	 * 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);

	for (i = 0; i < nr_pages; i++) {
		struct page *page = pfn_to_page(pfn + i);
		online_page(page);
		onlined_pages++;
	}
	zone->present_pages += onlined_pages;

	return 0;
}