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authorFathi Boudra <fathi.boudra@linaro.org>2013-04-28 09:33:08 +0300
committerFathi Boudra <fathi.boudra@linaro.org>2013-04-28 09:33:08 +0300
commit3b4bd47f8f4ed3aaf7c81c9b5d2d37ad79fadf4a (patch)
treeb9996006addfd7ae70a39672b76843b49aebc189 /mm/memory_hotplug.c
downloadlinux-linaro-highbank-master.tar.gz
Imported Upstream version 3.9.0HEADupstream/3.9.0upstreammaster
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c1868
1 files changed, 1868 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
new file mode 100644
index 00000000..9597eec8
--- /dev/null
+++ b/mm/memory_hotplug.c
@@ -0,0 +1,1868 @@
+/*
+ * 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/export.h>
+#include <linux/pagevec.h>
+#include <linux/writeback.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 <linux/delay.h>
+#include <linux/migrate.h>
+#include <linux/page-isolation.h>
+#include <linux/pfn.h>
+#include <linux/suspend.h>
+#include <linux/mm_inline.h>
+#include <linux/firmware-map.h>
+#include <linux/stop_machine.h>
+
+#include <asm/tlbflush.h>
+
+#include "internal.h"
+
+/*
+ * online_page_callback contains pointer to current page onlining function.
+ * Initially it is generic_online_page(). If it is required it could be
+ * changed by calling set_online_page_callback() for callback registration
+ * and restore_online_page_callback() for generic callback restore.
+ */
+
+static void generic_online_page(struct page *page);
+
+static online_page_callback_t online_page_callback = generic_online_page;
+
+DEFINE_MUTEX(mem_hotplug_mutex);
+
+void lock_memory_hotplug(void)
+{
+ mutex_lock(&mem_hotplug_mutex);
+
+ /* for exclusive hibernation if CONFIG_HIBERNATION=y */
+ lock_system_sleep();
+}
+
+void unlock_memory_hotplug(void)
+{
+ unlock_system_sleep();
+ mutex_unlock(&mem_hotplug_mutex);
+}
+
+
+/* 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 | IORESOURCE_BUSY;
+ if (request_resource(&iomem_resource, res) < 0) {
+ printk("System RAM resource %pR cannot be added\n", res);
+ kfree(res);
+ res = NULL;
+ }
+ return res;
+}
+
+static void release_memory_resource(struct resource *res)
+{
+ if (!res)
+ return;
+ release_resource(res);
+ kfree(res);
+ return;
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+void get_page_bootmem(unsigned long info, struct page *page,
+ unsigned long type)
+{
+ page->lru.next = (struct list_head *) type;
+ SetPagePrivate(page);
+ set_page_private(page, info);
+ atomic_inc(&page->_count);
+}
+
+/* reference to __meminit __free_pages_bootmem is valid
+ * so use __ref to tell modpost not to generate a warning */
+void __ref put_page_bootmem(struct page *page)
+{
+ unsigned long type;
+ static DEFINE_MUTEX(ppb_lock);
+
+ type = (unsigned long) page->lru.next;
+ BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+ type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
+
+ if (atomic_dec_return(&page->_count) == 1) {
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ INIT_LIST_HEAD(&page->lru);
+
+ /*
+ * Please refer to comment for __free_pages_bootmem()
+ * for why we serialize here.
+ */
+ mutex_lock(&ppb_lock);
+ __free_pages_bootmem(page, 0);
+ mutex_unlock(&ppb_lock);
+ totalram_pages++;
+ }
+
+}
+
+#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
+#ifndef CONFIG_SPARSEMEM_VMEMMAP
+static void register_page_bootmem_info_section(unsigned long start_pfn)
+{
+ unsigned long *usemap, mapsize, section_nr, i;
+ struct mem_section *ms;
+ struct page *page, *memmap;
+
+ section_nr = pfn_to_section_nr(start_pfn);
+ ms = __nr_to_section(section_nr);
+
+ /* Get section's memmap address */
+ memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
+
+ /*
+ * Get page for the memmap's phys address
+ * XXX: need more consideration for sparse_vmemmap...
+ */
+ page = virt_to_page(memmap);
+ mapsize = sizeof(struct page) * PAGES_PER_SECTION;
+ mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
+
+ /* remember memmap's page */
+ for (i = 0; i < mapsize; i++, page++)
+ get_page_bootmem(section_nr, page, SECTION_INFO);
+
+ usemap = __nr_to_section(section_nr)->pageblock_flags;
+ page = virt_to_page(usemap);
+
+ mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
+
+ for (i = 0; i < mapsize; i++, page++)
+ get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
+
+}
+#else /* CONFIG_SPARSEMEM_VMEMMAP */
+static void register_page_bootmem_info_section(unsigned long start_pfn)
+{
+ unsigned long *usemap, mapsize, section_nr, i;
+ struct mem_section *ms;
+ struct page *page, *memmap;
+
+ if (!pfn_valid(start_pfn))
+ return;
+
+ section_nr = pfn_to_section_nr(start_pfn);
+ ms = __nr_to_section(section_nr);
+
+ memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
+
+ register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
+
+ usemap = __nr_to_section(section_nr)->pageblock_flags;
+ page = virt_to_page(usemap);
+
+ mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
+
+ for (i = 0; i < mapsize; i++, page++)
+ get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
+}
+#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
+
+void register_page_bootmem_info_node(struct pglist_data *pgdat)
+{
+ unsigned long i, pfn, end_pfn, nr_pages;
+ int node = pgdat->node_id;
+ struct page *page;
+ struct zone *zone;
+
+ nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
+ page = virt_to_page(pgdat);
+
+ for (i = 0; i < nr_pages; i++, page++)
+ get_page_bootmem(node, page, NODE_INFO);
+
+ zone = &pgdat->node_zones[0];
+ for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
+ if (zone->wait_table) {
+ nr_pages = zone->wait_table_hash_nr_entries
+ * sizeof(wait_queue_head_t);
+ nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
+ page = virt_to_page(zone->wait_table);
+
+ for (i = 0; i < nr_pages; i++, page++)
+ get_page_bootmem(node, page, NODE_INFO);
+ }
+ }
+
+ pfn = pgdat->node_start_pfn;
+ end_pfn = pgdat_end_pfn(pgdat);
+
+ /* register_section info */
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ /*
+ * Some platforms can assign the same pfn to multiple nodes - on
+ * node0 as well as nodeN. To avoid registering a pfn against
+ * multiple nodes we check that this pfn does not already
+ * reside in some other node.
+ */
+ if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
+ register_page_bootmem_info_section(pfn);
+ }
+}
+#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
+
+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 (!zone->spanned_pages || 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 resize_zone(struct zone *zone, unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ zone_span_writelock(zone);
+
+ if (end_pfn - start_pfn) {
+ zone->zone_start_pfn = start_pfn;
+ zone->spanned_pages = end_pfn - start_pfn;
+ } else {
+ /*
+ * make it consist as free_area_init_core(),
+ * if spanned_pages = 0, then keep start_pfn = 0
+ */
+ zone->zone_start_pfn = 0;
+ zone->spanned_pages = 0;
+ }
+
+ zone_span_writeunlock(zone);
+}
+
+static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ enum zone_type zid = zone_idx(zone);
+ int nid = zone->zone_pgdat->node_id;
+ unsigned long pfn;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn++)
+ set_page_links(pfn_to_page(pfn), zid, nid, pfn);
+}
+
+/* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
+ * alloc_bootmem_node_nopanic() */
+static int __ref ensure_zone_is_initialized(struct zone *zone,
+ unsigned long start_pfn, unsigned long num_pages)
+{
+ if (!zone_is_initialized(zone))
+ return init_currently_empty_zone(zone, start_pfn, num_pages,
+ MEMMAP_HOTPLUG);
+ return 0;
+}
+
+static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
+ unsigned long start_pfn, unsigned long end_pfn)
+{
+ int ret;
+ unsigned long flags;
+ unsigned long z1_start_pfn;
+
+ ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
+ if (ret)
+ return ret;
+
+ pgdat_resize_lock(z1->zone_pgdat, &flags);
+
+ /* can't move pfns which are higher than @z2 */
+ if (end_pfn > zone_end_pfn(z2))
+ goto out_fail;
+ /* the move out part mast at the left most of @z2 */
+ if (start_pfn > z2->zone_start_pfn)
+ goto out_fail;
+ /* must included/overlap */
+ if (end_pfn <= z2->zone_start_pfn)
+ goto out_fail;
+
+ /* use start_pfn for z1's start_pfn if z1 is empty */
+ if (z1->spanned_pages)
+ z1_start_pfn = z1->zone_start_pfn;
+ else
+ z1_start_pfn = start_pfn;
+
+ resize_zone(z1, z1_start_pfn, end_pfn);
+ resize_zone(z2, end_pfn, zone_end_pfn(z2));
+
+ pgdat_resize_unlock(z1->zone_pgdat, &flags);
+
+ fix_zone_id(z1, start_pfn, end_pfn);
+
+ return 0;
+out_fail:
+ pgdat_resize_unlock(z1->zone_pgdat, &flags);
+ return -1;
+}
+
+static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
+ unsigned long start_pfn, unsigned long end_pfn)
+{
+ int ret;
+ unsigned long flags;
+ unsigned long z2_end_pfn;
+
+ ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
+ if (ret)
+ return ret;
+
+ pgdat_resize_lock(z1->zone_pgdat, &flags);
+
+ /* can't move pfns which are lower than @z1 */
+ if (z1->zone_start_pfn > start_pfn)
+ goto out_fail;
+ /* the move out part mast at the right most of @z1 */
+ if (zone_end_pfn(z1) > end_pfn)
+ goto out_fail;
+ /* must included/overlap */
+ if (start_pfn >= zone_end_pfn(z1))
+ goto out_fail;
+
+ /* use end_pfn for z2's end_pfn if z2 is empty */
+ if (z2->spanned_pages)
+ z2_end_pfn = zone_end_pfn(z2);
+ else
+ z2_end_pfn = end_pfn;
+
+ resize_zone(z1, z1->zone_start_pfn, start_pfn);
+ resize_zone(z2, start_pfn, z2_end_pfn);
+
+ pgdat_resize_unlock(z1->zone_pgdat, &flags);
+
+ fix_zone_id(z2, start_pfn, end_pfn);
+
+ return 0;
+out_fail:
+ pgdat_resize_unlock(z1->zone_pgdat, &flags);
+ return -1;
+}
+
+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 (!pgdat->node_spanned_pages || 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;
+}
+
+static int __meminit __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;
+ unsigned long flags;
+ int ret;
+
+ zone_type = zone - pgdat->node_zones;
+ ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
+ if (ret)
+ return ret;
+
+ pgdat_resize_lock(zone->zone_pgdat, &flags);
+ grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
+ grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
+ phys_start_pfn + nr_pages);
+ pgdat_resize_unlock(zone->zone_pgdat, &flags);
+ memmap_init_zone(nr_pages, nid, zone_type,
+ phys_start_pfn, MEMMAP_HOTPLUG);
+ return 0;
+}
+
+static int __meminit __add_section(int nid, 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(nid, __pfn_to_section(phys_start_pfn));
+}
+
+/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
+static int find_smallest_section_pfn(int nid, struct zone *zone,
+ unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ struct mem_section *ms;
+
+ for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
+ ms = __pfn_to_section(start_pfn);
+
+ if (unlikely(!valid_section(ms)))
+ continue;
+
+ if (unlikely(pfn_to_nid(start_pfn) != nid))
+ continue;
+
+ if (zone && zone != page_zone(pfn_to_page(start_pfn)))
+ continue;
+
+ return start_pfn;
+ }
+
+ return 0;
+}
+
+/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
+static int find_biggest_section_pfn(int nid, struct zone *zone,
+ unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ struct mem_section *ms;
+ unsigned long pfn;
+
+ /* pfn is the end pfn of a memory section. */
+ pfn = end_pfn - 1;
+ for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
+ ms = __pfn_to_section(pfn);
+
+ if (unlikely(!valid_section(ms)))
+ continue;
+
+ if (unlikely(pfn_to_nid(pfn) != nid))
+ continue;
+
+ if (zone && zone != page_zone(pfn_to_page(pfn)))
+ continue;
+
+ return pfn;
+ }
+
+ return 0;
+}
+
+static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ unsigned long zone_start_pfn = zone->zone_start_pfn;
+ unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+ unsigned long pfn;
+ struct mem_section *ms;
+ int nid = zone_to_nid(zone);
+
+ zone_span_writelock(zone);
+ if (zone_start_pfn == start_pfn) {
+ /*
+ * If the section is smallest section in the zone, it need
+ * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
+ * In this case, we find second smallest valid mem_section
+ * for shrinking zone.
+ */
+ pfn = find_smallest_section_pfn(nid, zone, end_pfn,
+ zone_end_pfn);
+ if (pfn) {
+ zone->zone_start_pfn = pfn;
+ zone->spanned_pages = zone_end_pfn - pfn;
+ }
+ } else if (zone_end_pfn == end_pfn) {
+ /*
+ * If the section is biggest section in the zone, it need
+ * shrink zone->spanned_pages.
+ * In this case, we find second biggest valid mem_section for
+ * shrinking zone.
+ */
+ pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
+ start_pfn);
+ if (pfn)
+ zone->spanned_pages = pfn - zone_start_pfn + 1;
+ }
+
+ /*
+ * The section is not biggest or smallest mem_section in the zone, it
+ * only creates a hole in the zone. So in this case, we need not
+ * change the zone. But perhaps, the zone has only hole data. Thus
+ * it check the zone has only hole or not.
+ */
+ pfn = zone_start_pfn;
+ for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
+ ms = __pfn_to_section(pfn);
+
+ if (unlikely(!valid_section(ms)))
+ continue;
+
+ if (page_zone(pfn_to_page(pfn)) != zone)
+ continue;
+
+ /* If the section is current section, it continues the loop */
+ if (start_pfn == pfn)
+ continue;
+
+ /* If we find valid section, we have nothing to do */
+ zone_span_writeunlock(zone);
+ return;
+ }
+
+ /* The zone has no valid section */
+ zone->zone_start_pfn = 0;
+ zone->spanned_pages = 0;
+ zone_span_writeunlock(zone);
+}
+
+static void shrink_pgdat_span(struct pglist_data *pgdat,
+ unsigned long start_pfn, unsigned long end_pfn)
+{
+ unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
+ unsigned long pgdat_end_pfn =
+ pgdat->node_start_pfn + pgdat->node_spanned_pages;
+ unsigned long pfn;
+ struct mem_section *ms;
+ int nid = pgdat->node_id;
+
+ if (pgdat_start_pfn == start_pfn) {
+ /*
+ * If the section is smallest section in the pgdat, it need
+ * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
+ * In this case, we find second smallest valid mem_section
+ * for shrinking zone.
+ */
+ pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
+ pgdat_end_pfn);
+ if (pfn) {
+ pgdat->node_start_pfn = pfn;
+ pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
+ }
+ } else if (pgdat_end_pfn == end_pfn) {
+ /*
+ * If the section is biggest section in the pgdat, it need
+ * shrink pgdat->node_spanned_pages.
+ * In this case, we find second biggest valid mem_section for
+ * shrinking zone.
+ */
+ pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
+ start_pfn);
+ if (pfn)
+ pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
+ }
+
+ /*
+ * If the section is not biggest or smallest mem_section in the pgdat,
+ * it only creates a hole in the pgdat. So in this case, we need not
+ * change the pgdat.
+ * But perhaps, the pgdat has only hole data. Thus it check the pgdat
+ * has only hole or not.
+ */
+ pfn = pgdat_start_pfn;
+ for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
+ ms = __pfn_to_section(pfn);
+
+ if (unlikely(!valid_section(ms)))
+ continue;
+
+ if (pfn_to_nid(pfn) != nid)
+ continue;
+
+ /* If the section is current section, it continues the loop */
+ if (start_pfn == pfn)
+ continue;
+
+ /* If we find valid section, we have nothing to do */
+ return;
+ }
+
+ /* The pgdat has no valid section */
+ pgdat->node_start_pfn = 0;
+ pgdat->node_spanned_pages = 0;
+}
+
+static void __remove_zone(struct zone *zone, unsigned long start_pfn)
+{
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ int nr_pages = PAGES_PER_SECTION;
+ int zone_type;
+ unsigned long flags;
+
+ zone_type = zone - pgdat->node_zones;
+
+ pgdat_resize_lock(zone->zone_pgdat, &flags);
+ shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
+ shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
+ pgdat_resize_unlock(zone->zone_pgdat, &flags);
+}
+
+static int __remove_section(struct zone *zone, struct mem_section *ms)
+{
+ unsigned long start_pfn;
+ int scn_nr;
+ int ret = -EINVAL;
+
+ if (!valid_section(ms))
+ return ret;
+
+ ret = unregister_memory_section(ms);
+ if (ret)
+ return ret;
+
+ scn_nr = __section_nr(ms);
+ start_pfn = section_nr_to_pfn(scn_nr);
+ __remove_zone(zone, start_pfn);
+
+ sparse_remove_one_section(zone, ms);
+ return 0;
+}
+
+/*
+ * 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 __ref __add_pages(int nid, 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(nid, zone, i << PFN_SECTION_SHIFT);
+
+ /*
+ * EEXIST is finally dealt 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);
+
+/**
+ * __remove_pages() - remove sections of pages from a zone
+ * @zone: zone from which pages need to be removed
+ * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
+ * @nr_pages: number of pages to remove (must be multiple of section size)
+ *
+ * Generic helper function to remove section mappings and sysfs entries
+ * for the section of the memory we are removing. Caller needs to make
+ * sure that pages are marked reserved and zones are adjust properly by
+ * calling offline_pages().
+ */
+int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long i, ret = 0;
+ int sections_to_remove;
+
+ /*
+ * We can only remove entire sections
+ */
+ BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
+ BUG_ON(nr_pages % PAGES_PER_SECTION);
+
+ release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
+
+ sections_to_remove = nr_pages / PAGES_PER_SECTION;
+ for (i = 0; i < sections_to_remove; i++) {
+ unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+ ret = __remove_section(zone, __pfn_to_section(pfn));
+ if (ret)
+ break;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__remove_pages);
+
+int set_online_page_callback(online_page_callback_t callback)
+{
+ int rc = -EINVAL;
+
+ lock_memory_hotplug();
+
+ if (online_page_callback == generic_online_page) {
+ online_page_callback = callback;
+ rc = 0;
+ }
+
+ unlock_memory_hotplug();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(set_online_page_callback);
+
+int restore_online_page_callback(online_page_callback_t callback)
+{
+ int rc = -EINVAL;
+
+ lock_memory_hotplug();
+
+ if (online_page_callback == callback) {
+ online_page_callback = generic_online_page;
+ rc = 0;
+ }
+
+ unlock_memory_hotplug();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(restore_online_page_callback);
+
+void __online_page_set_limits(struct page *page)
+{
+ unsigned long pfn = page_to_pfn(page);
+
+ if (pfn >= num_physpages)
+ num_physpages = pfn + 1;
+}
+EXPORT_SYMBOL_GPL(__online_page_set_limits);
+
+void __online_page_increment_counters(struct page *page)
+{
+ totalram_pages++;
+
+#ifdef CONFIG_HIGHMEM
+ if (PageHighMem(page))
+ totalhigh_pages++;
+#endif
+}
+EXPORT_SYMBOL_GPL(__online_page_increment_counters);
+
+void __online_page_free(struct page *page)
+{
+ ClearPageReserved(page);
+ init_page_count(page);
+ __free_page(page);
+}
+EXPORT_SYMBOL_GPL(__online_page_free);
+
+static void generic_online_page(struct page *page)
+{
+ __online_page_set_limits(page);
+ __online_page_increment_counters(page);
+ __online_page_free(page);
+}
+
+static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
+ void *arg)
+{
+ unsigned long i;
+ unsigned long onlined_pages = *(unsigned long *)arg;
+ struct page *page;
+ if (PageReserved(pfn_to_page(start_pfn)))
+ for (i = 0; i < nr_pages; i++) {
+ page = pfn_to_page(start_pfn + i);
+ (*online_page_callback)(page);
+ onlined_pages++;
+ }
+ *(unsigned long *)arg = onlined_pages;
+ return 0;
+}
+
+#ifdef CONFIG_MOVABLE_NODE
+/*
+ * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
+ * normal memory.
+ */
+static bool can_online_high_movable(struct zone *zone)
+{
+ return true;
+}
+#else /* CONFIG_MOVABLE_NODE */
+/* ensure every online node has NORMAL memory */
+static bool can_online_high_movable(struct zone *zone)
+{
+ return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
+}
+#endif /* CONFIG_MOVABLE_NODE */
+
+/* check which state of node_states will be changed when online memory */
+static void node_states_check_changes_online(unsigned long nr_pages,
+ struct zone *zone, struct memory_notify *arg)
+{
+ int nid = zone_to_nid(zone);
+ enum zone_type zone_last = ZONE_NORMAL;
+
+ /*
+ * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
+ * contains nodes which have zones of 0...ZONE_NORMAL,
+ * set zone_last to ZONE_NORMAL.
+ *
+ * If we don't have HIGHMEM nor movable node,
+ * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
+ * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
+ */
+ if (N_MEMORY == N_NORMAL_MEMORY)
+ zone_last = ZONE_MOVABLE;
+
+ /*
+ * if the memory to be online is in a zone of 0...zone_last, and
+ * the zones of 0...zone_last don't have memory before online, we will
+ * need to set the node to node_states[N_NORMAL_MEMORY] after
+ * the memory is online.
+ */
+ if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
+ arg->status_change_nid_normal = nid;
+ else
+ arg->status_change_nid_normal = -1;
+
+#ifdef CONFIG_HIGHMEM
+ /*
+ * If we have movable node, node_states[N_HIGH_MEMORY]
+ * contains nodes which have zones of 0...ZONE_HIGHMEM,
+ * set zone_last to ZONE_HIGHMEM.
+ *
+ * If we don't have movable node, node_states[N_NORMAL_MEMORY]
+ * contains nodes which have zones of 0...ZONE_MOVABLE,
+ * set zone_last to ZONE_MOVABLE.
+ */
+ zone_last = ZONE_HIGHMEM;
+ if (N_MEMORY == N_HIGH_MEMORY)
+ zone_last = ZONE_MOVABLE;
+
+ if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
+ arg->status_change_nid_high = nid;
+ else
+ arg->status_change_nid_high = -1;
+#else
+ arg->status_change_nid_high = arg->status_change_nid_normal;
+#endif
+
+ /*
+ * if the node don't have memory befor online, we will need to
+ * set the node to node_states[N_MEMORY] after the memory
+ * is online.
+ */
+ if (!node_state(nid, N_MEMORY))
+ arg->status_change_nid = nid;
+ else
+ arg->status_change_nid = -1;
+}
+
+static void node_states_set_node(int node, struct memory_notify *arg)
+{
+ if (arg->status_change_nid_normal >= 0)
+ node_set_state(node, N_NORMAL_MEMORY);
+
+ if (arg->status_change_nid_high >= 0)
+ node_set_state(node, N_HIGH_MEMORY);
+
+ node_set_state(node, N_MEMORY);
+}
+
+
+int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
+{
+ unsigned long onlined_pages = 0;
+ struct zone *zone;
+ int need_zonelists_rebuild = 0;
+ int nid;
+ int ret;
+ struct memory_notify arg;
+
+ lock_memory_hotplug();
+ /*
+ * This doesn't need a lock to do pfn_to_page().
+ * The section can't be removed here because of the
+ * memory_block->state_mutex.
+ */
+ zone = page_zone(pfn_to_page(pfn));
+
+ if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
+ !can_online_high_movable(zone)) {
+ unlock_memory_hotplug();
+ return -1;
+ }
+
+ if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
+ if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
+ unlock_memory_hotplug();
+ return -1;
+ }
+ }
+ if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
+ if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
+ unlock_memory_hotplug();
+ return -1;
+ }
+ }
+
+ /* Previous code may changed the zone of the pfn range */
+ zone = page_zone(pfn_to_page(pfn));
+
+ arg.start_pfn = pfn;
+ arg.nr_pages = nr_pages;
+ node_states_check_changes_online(nr_pages, zone, &arg);
+
+ nid = page_to_nid(pfn_to_page(pfn));
+
+ ret = memory_notify(MEM_GOING_ONLINE, &arg);
+ ret = notifier_to_errno(ret);
+ if (ret) {
+ memory_notify(MEM_CANCEL_ONLINE, &arg);
+ unlock_memory_hotplug();
+ return ret;
+ }
+ /*
+ * 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.
+ */
+ mutex_lock(&zonelists_mutex);
+ if (!populated_zone(zone)) {
+ need_zonelists_rebuild = 1;
+ build_all_zonelists(NULL, zone);
+ }
+
+ ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
+ online_pages_range);
+ if (ret) {
+ if (need_zonelists_rebuild)
+ zone_pcp_reset(zone);
+ mutex_unlock(&zonelists_mutex);
+ printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
+ (unsigned long long) pfn << PAGE_SHIFT,
+ (((unsigned long long) pfn + nr_pages)
+ << PAGE_SHIFT) - 1);
+ memory_notify(MEM_CANCEL_ONLINE, &arg);
+ unlock_memory_hotplug();
+ return ret;
+ }
+
+ zone->managed_pages += onlined_pages;
+ zone->present_pages += onlined_pages;
+ zone->zone_pgdat->node_present_pages += onlined_pages;
+ if (onlined_pages) {
+ node_states_set_node(zone_to_nid(zone), &arg);
+ if (need_zonelists_rebuild)
+ build_all_zonelists(NULL, NULL);
+ else
+ zone_pcp_update(zone);
+ }
+
+ mutex_unlock(&zonelists_mutex);
+
+ init_per_zone_wmark_min();
+
+ if (onlined_pages)
+ kswapd_run(zone_to_nid(zone));
+
+ vm_total_pages = nr_free_pagecache_pages();
+
+ writeback_set_ratelimit();
+
+ if (onlined_pages)
+ memory_notify(MEM_ONLINE, &arg);
+ unlock_memory_hotplug();
+
+ return 0;
+}
+#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+
+/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+static pg_data_t __ref *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 = NODE_DATA(nid);
+ if (!pgdat) {
+ 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, zones_size, start_pfn, zholes_size);
+
+ /*
+ * The node we allocated has no zone fallback lists. For avoiding
+ * to access not-initialized zonelist, build here.
+ */
+ mutex_lock(&zonelists_mutex);
+ build_all_zonelists(pgdat, NULL);
+ mutex_unlock(&zonelists_mutex);
+
+ return pgdat;
+}
+
+static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
+{
+ arch_refresh_nodedata(nid, NULL);
+ arch_free_nodedata(pgdat);
+ return;
+}
+
+
+/*
+ * called by cpu_up() to online a node without onlined memory.
+ */
+int mem_online_node(int nid)
+{
+ pg_data_t *pgdat;
+ int ret;
+
+ lock_memory_hotplug();
+ pgdat = hotadd_new_pgdat(nid, 0);
+ if (!pgdat) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ node_set_online(nid);
+ ret = register_one_node(nid);
+ BUG_ON(ret);
+
+out:
+ unlock_memory_hotplug();
+ return ret;
+}
+
+/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+int __ref add_memory(int nid, u64 start, u64 size)
+{
+ pg_data_t *pgdat = NULL;
+ bool new_pgdat;
+ bool new_node;
+ struct resource *res;
+ int ret;
+
+ lock_memory_hotplug();
+
+ res = register_memory_resource(start, size);
+ ret = -EEXIST;
+ if (!res)
+ goto out;
+
+ { /* Stupid hack to suppress address-never-null warning */
+ void *p = NODE_DATA(nid);
+ new_pgdat = !p;
+ }
+ new_node = !node_online(nid);
+ if (new_node) {
+ pgdat = hotadd_new_pgdat(nid, start);
+ ret = -ENOMEM;
+ if (!pgdat)
+ 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_node) {
+ 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);
+ }
+
+ /* create new memmap entry */
+ firmware_map_add_hotplug(start, start + size, "System RAM");
+
+ goto out;
+
+error:
+ /* rollback pgdat allocation and others */
+ if (new_pgdat)
+ rollback_node_hotadd(nid, pgdat);
+ release_memory_resource(res);
+
+out:
+ unlock_memory_hotplug();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(add_memory);
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/*
+ * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
+ * set and the size of the free page is given by page_order(). Using this,
+ * the function determines if the pageblock contains only free pages.
+ * Due to buddy contraints, a free page at least the size of a pageblock will
+ * be located at the start of the pageblock
+ */
+static inline int pageblock_free(struct page *page)
+{
+ return PageBuddy(page) && page_order(page) >= pageblock_order;
+}
+
+/* Return the start of the next active pageblock after a given page */
+static struct page *next_active_pageblock(struct page *page)
+{
+ /* Ensure the starting page is pageblock-aligned */
+ BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
+
+ /* If the entire pageblock is free, move to the end of free page */
+ if (pageblock_free(page)) {
+ int order;
+ /* be careful. we don't have locks, page_order can be changed.*/
+ order = page_order(page);
+ if ((order < MAX_ORDER) && (order >= pageblock_order))
+ return page + (1 << order);
+ }
+
+ return page + pageblock_nr_pages;
+}
+
+/* Checks if this range of memory is likely to be hot-removable. */
+int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
+{
+ struct page *page = pfn_to_page(start_pfn);
+ struct page *end_page = page + nr_pages;
+
+ /* Check the starting page of each pageblock within the range */
+ for (; page < end_page; page = next_active_pageblock(page)) {
+ if (!is_pageblock_removable_nolock(page))
+ return 0;
+ cond_resched();
+ }
+
+ /* All pageblocks in the memory block are likely to be hot-removable */
+ return 1;
+}
+
+/*
+ * Confirm all pages in a range [start, end) is belongs to the same zone.
+ */
+static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
+{
+ unsigned long pfn;
+ struct zone *zone = NULL;
+ struct page *page;
+ int i;
+ for (pfn = start_pfn;
+ pfn < end_pfn;
+ pfn += MAX_ORDER_NR_PAGES) {
+ i = 0;
+ /* This is just a CONFIG_HOLES_IN_ZONE check.*/
+ while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
+ i++;
+ if (i == MAX_ORDER_NR_PAGES)
+ continue;
+ page = pfn_to_page(pfn + i);
+ if (zone && page_zone(page) != zone)
+ return 0;
+ zone = page_zone(page);
+ }
+ return 1;
+}
+
+/*
+ * Scanning pfn is much easier than scanning lru list.
+ * Scan pfn from start to end and Find LRU page.
+ */
+static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
+{
+ unsigned long pfn;
+ struct page *page;
+ for (pfn = start; pfn < end; pfn++) {
+ if (pfn_valid(pfn)) {
+ page = pfn_to_page(pfn);
+ if (PageLRU(page))
+ return pfn;
+ }
+ }
+ return 0;
+}
+
+#define NR_OFFLINE_AT_ONCE_PAGES (256)
+static int
+do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
+{
+ unsigned long pfn;
+ struct page *page;
+ int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
+ int not_managed = 0;
+ int ret = 0;
+ LIST_HEAD(source);
+
+ for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
+ if (!pfn_valid(pfn))
+ continue;
+ page = pfn_to_page(pfn);
+ if (!get_page_unless_zero(page))
+ continue;
+ /*
+ * We can skip free pages. And we can only deal with pages on
+ * LRU.
+ */
+ ret = isolate_lru_page(page);
+ if (!ret) { /* Success */
+ put_page(page);
+ list_add_tail(&page->lru, &source);
+ move_pages--;
+ inc_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
+
+ } else {
+#ifdef CONFIG_DEBUG_VM
+ printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
+ pfn);
+ dump_page(page);
+#endif
+ put_page(page);
+ /* Because we don't have big zone->lock. we should
+ check this again here. */
+ if (page_count(page)) {
+ not_managed++;
+ ret = -EBUSY;
+ break;
+ }
+ }
+ }
+ if (!list_empty(&source)) {
+ if (not_managed) {
+ putback_lru_pages(&source);
+ goto out;
+ }
+
+ /*
+ * alloc_migrate_target should be improooooved!!
+ * migrate_pages returns # of failed pages.
+ */
+ ret = migrate_pages(&source, alloc_migrate_target, 0,
+ MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
+ if (ret)
+ putback_lru_pages(&source);
+ }
+out:
+ return ret;
+}
+
+/*
+ * remove from free_area[] and mark all as Reserved.
+ */
+static int
+offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
+ void *data)
+{
+ __offline_isolated_pages(start, start + nr_pages);
+ return 0;
+}
+
+static void
+offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
+{
+ walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
+ offline_isolated_pages_cb);
+}
+
+/*
+ * Check all pages in range, recoreded as memory resource, are isolated.
+ */
+static int
+check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
+ void *data)
+{
+ int ret;
+ long offlined = *(long *)data;
+ ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
+ offlined = nr_pages;
+ if (!ret)
+ *(long *)data += offlined;
+ return ret;
+}
+
+static long
+check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
+{
+ long offlined = 0;
+ int ret;
+
+ ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
+ check_pages_isolated_cb);
+ if (ret < 0)
+ offlined = (long)ret;
+ return offlined;
+}
+
+#ifdef CONFIG_MOVABLE_NODE
+/*
+ * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
+ * normal memory.
+ */
+static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
+{
+ return true;
+}
+#else /* CONFIG_MOVABLE_NODE */
+/* ensure the node has NORMAL memory if it is still online */
+static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
+{
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ unsigned long present_pages = 0;
+ enum zone_type zt;
+
+ for (zt = 0; zt <= ZONE_NORMAL; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
+
+ if (present_pages > nr_pages)
+ return true;
+
+ present_pages = 0;
+ for (; zt <= ZONE_MOVABLE; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
+
+ /*
+ * we can't offline the last normal memory until all
+ * higher memory is offlined.
+ */
+ return present_pages == 0;
+}
+#endif /* CONFIG_MOVABLE_NODE */
+
+/* check which state of node_states will be changed when offline memory */
+static void node_states_check_changes_offline(unsigned long nr_pages,
+ struct zone *zone, struct memory_notify *arg)
+{
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ unsigned long present_pages = 0;
+ enum zone_type zt, zone_last = ZONE_NORMAL;
+
+ /*
+ * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
+ * contains nodes which have zones of 0...ZONE_NORMAL,
+ * set zone_last to ZONE_NORMAL.
+ *
+ * If we don't have HIGHMEM nor movable node,
+ * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
+ * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
+ */
+ if (N_MEMORY == N_NORMAL_MEMORY)
+ zone_last = ZONE_MOVABLE;
+
+ /*
+ * check whether node_states[N_NORMAL_MEMORY] will be changed.
+ * If the memory to be offline is in a zone of 0...zone_last,
+ * and it is the last present memory, 0...zone_last will
+ * become empty after offline , thus we can determind we will
+ * need to clear the node from node_states[N_NORMAL_MEMORY].
+ */
+ for (zt = 0; zt <= zone_last; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
+ if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
+ arg->status_change_nid_normal = zone_to_nid(zone);
+ else
+ arg->status_change_nid_normal = -1;
+
+#ifdef CONFIG_HIGHMEM
+ /*
+ * If we have movable node, node_states[N_HIGH_MEMORY]
+ * contains nodes which have zones of 0...ZONE_HIGHMEM,
+ * set zone_last to ZONE_HIGHMEM.
+ *
+ * If we don't have movable node, node_states[N_NORMAL_MEMORY]
+ * contains nodes which have zones of 0...ZONE_MOVABLE,
+ * set zone_last to ZONE_MOVABLE.
+ */
+ zone_last = ZONE_HIGHMEM;
+ if (N_MEMORY == N_HIGH_MEMORY)
+ zone_last = ZONE_MOVABLE;
+
+ for (; zt <= zone_last; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
+ if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
+ arg->status_change_nid_high = zone_to_nid(zone);
+ else
+ arg->status_change_nid_high = -1;
+#else
+ arg->status_change_nid_high = arg->status_change_nid_normal;
+#endif
+
+ /*
+ * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
+ */
+ zone_last = ZONE_MOVABLE;
+
+ /*
+ * check whether node_states[N_HIGH_MEMORY] will be changed
+ * If we try to offline the last present @nr_pages from the node,
+ * we can determind we will need to clear the node from
+ * node_states[N_HIGH_MEMORY].
+ */
+ for (; zt <= zone_last; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
+ if (nr_pages >= present_pages)
+ arg->status_change_nid = zone_to_nid(zone);
+ else
+ arg->status_change_nid = -1;
+}
+
+static void node_states_clear_node(int node, struct memory_notify *arg)
+{
+ if (arg->status_change_nid_normal >= 0)
+ node_clear_state(node, N_NORMAL_MEMORY);
+
+ if ((N_MEMORY != N_NORMAL_MEMORY) &&
+ (arg->status_change_nid_high >= 0))
+ node_clear_state(node, N_HIGH_MEMORY);
+
+ if ((N_MEMORY != N_HIGH_MEMORY) &&
+ (arg->status_change_nid >= 0))
+ node_clear_state(node, N_MEMORY);
+}
+
+static int __ref __offline_pages(unsigned long start_pfn,
+ unsigned long end_pfn, unsigned long timeout)
+{
+ unsigned long pfn, nr_pages, expire;
+ long offlined_pages;
+ int ret, drain, retry_max, node;
+ struct zone *zone;
+ struct memory_notify arg;
+
+ BUG_ON(start_pfn >= end_pfn);
+ /* at least, alignment against pageblock is necessary */
+ if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
+ return -EINVAL;
+ if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
+ return -EINVAL;
+ /* This makes hotplug much easier...and readable.
+ we assume this for now. .*/
+ if (!test_pages_in_a_zone(start_pfn, end_pfn))
+ return -EINVAL;
+
+ lock_memory_hotplug();
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ node = zone_to_nid(zone);
+ nr_pages = end_pfn - start_pfn;
+
+ ret = -EINVAL;
+ if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
+ goto out;
+
+ /* set above range as isolated */
+ ret = start_isolate_page_range(start_pfn, end_pfn,
+ MIGRATE_MOVABLE, true);
+ if (ret)
+ goto out;
+
+ arg.start_pfn = start_pfn;
+ arg.nr_pages = nr_pages;
+ node_states_check_changes_offline(nr_pages, zone, &arg);
+
+ ret = memory_notify(MEM_GOING_OFFLINE, &arg);
+ ret = notifier_to_errno(ret);
+ if (ret)
+ goto failed_removal;
+
+ pfn = start_pfn;
+ expire = jiffies + timeout;
+ drain = 0;
+ retry_max = 5;
+repeat:
+ /* start memory hot removal */
+ ret = -EAGAIN;
+ if (time_after(jiffies, expire))
+ goto failed_removal;
+ ret = -EINTR;
+ if (signal_pending(current))
+ goto failed_removal;
+ ret = 0;
+ if (drain) {
+ lru_add_drain_all();
+ cond_resched();
+ drain_all_pages();
+ }
+
+ pfn = scan_lru_pages(start_pfn, end_pfn);
+ if (pfn) { /* We have page on LRU */
+ ret = do_migrate_range(pfn, end_pfn);
+ if (!ret) {
+ drain = 1;
+ goto repeat;
+ } else {
+ if (ret < 0)
+ if (--retry_max == 0)
+ goto failed_removal;
+ yield();
+ drain = 1;
+ goto repeat;
+ }
+ }
+ /* drain all zone's lru pagevec, this is asynchronous... */
+ lru_add_drain_all();
+ yield();
+ /* drain pcp pages, this is synchronous. */
+ drain_all_pages();
+ /* check again */
+ offlined_pages = check_pages_isolated(start_pfn, end_pfn);
+ if (offlined_pages < 0) {
+ ret = -EBUSY;
+ goto failed_removal;
+ }
+ printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
+ /* Ok, all of our target is isolated.
+ We cannot do rollback at this point. */
+ offline_isolated_pages(start_pfn, end_pfn);
+ /* reset pagetype flags and makes migrate type to be MOVABLE */
+ undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
+ /* removal success */
+ zone->managed_pages -= offlined_pages;
+ zone->present_pages -= offlined_pages;
+ zone->zone_pgdat->node_present_pages -= offlined_pages;
+ totalram_pages -= offlined_pages;
+
+ init_per_zone_wmark_min();
+
+ if (!populated_zone(zone)) {
+ zone_pcp_reset(zone);
+ mutex_lock(&zonelists_mutex);
+ build_all_zonelists(NULL, NULL);
+ mutex_unlock(&zonelists_mutex);
+ } else
+ zone_pcp_update(zone);
+
+ node_states_clear_node(node, &arg);
+ if (arg.status_change_nid >= 0)
+ kswapd_stop(node);
+
+ vm_total_pages = nr_free_pagecache_pages();
+ writeback_set_ratelimit();
+
+ memory_notify(MEM_OFFLINE, &arg);
+ unlock_memory_hotplug();
+ return 0;
+
+failed_removal:
+ printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
+ (unsigned long long) start_pfn << PAGE_SHIFT,
+ ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
+ memory_notify(MEM_CANCEL_OFFLINE, &arg);
+ /* pushback to free area */
+ undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
+
+out:
+ unlock_memory_hotplug();
+ return ret;
+}
+
+int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
+{
+ return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
+}
+
+/**
+ * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
+ * @start_pfn: start pfn of the memory range
+ * @end_pfn: end pft of the memory range
+ * @arg: argument passed to func
+ * @func: callback for each memory section walked
+ *
+ * This function walks through all present mem sections in range
+ * [start_pfn, end_pfn) and call func on each mem section.
+ *
+ * Returns the return value of func.
+ */
+static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
+ void *arg, int (*func)(struct memory_block *, void *))
+{
+ struct memory_block *mem = NULL;
+ struct mem_section *section;
+ unsigned long pfn, section_nr;
+ int ret;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ section_nr = pfn_to_section_nr(pfn);
+ if (!present_section_nr(section_nr))
+ continue;
+
+ section = __nr_to_section(section_nr);
+ /* same memblock? */
+ if (mem)
+ if ((section_nr >= mem->start_section_nr) &&
+ (section_nr <= mem->end_section_nr))
+ continue;
+
+ mem = find_memory_block_hinted(section, mem);
+ if (!mem)
+ continue;
+
+ ret = func(mem, arg);
+ if (ret) {
+ kobject_put(&mem->dev.kobj);
+ return ret;
+ }
+ }
+
+ if (mem)
+ kobject_put(&mem->dev.kobj);
+
+ return 0;
+}
+
+/**
+ * offline_memory_block_cb - callback function for offlining memory block
+ * @mem: the memory block to be offlined
+ * @arg: buffer to hold error msg
+ *
+ * Always return 0, and put the error msg in arg if any.
+ */
+static int offline_memory_block_cb(struct memory_block *mem, void *arg)
+{
+ int *ret = arg;
+ int error = offline_memory_block(mem);
+
+ if (error != 0 && *ret == 0)
+ *ret = error;
+
+ return 0;
+}
+
+static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
+{
+ int ret = !is_memblock_offlined(mem);
+
+ if (unlikely(ret))
+ pr_warn("removing memory fails, because memory "
+ "[%#010llx-%#010llx] is onlined\n",
+ PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
+ PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);
+
+ return ret;
+}
+
+static int check_cpu_on_node(void *data)
+{
+ struct pglist_data *pgdat = data;
+ int cpu;
+
+ for_each_present_cpu(cpu) {
+ if (cpu_to_node(cpu) == pgdat->node_id)
+ /*
+ * the cpu on this node isn't removed, and we can't
+ * offline this node.
+ */
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+static void unmap_cpu_on_node(void *data)
+{
+#ifdef CONFIG_ACPI_NUMA
+ struct pglist_data *pgdat = data;
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ if (cpu_to_node(cpu) == pgdat->node_id)
+ numa_clear_node(cpu);
+#endif
+}
+
+static int check_and_unmap_cpu_on_node(void *data)
+{
+ int ret = check_cpu_on_node(data);
+
+ if (ret)
+ return ret;
+
+ /*
+ * the node will be offlined when we come here, so we can clear
+ * the cpu_to_node() now.
+ */
+
+ unmap_cpu_on_node(data);
+ return 0;
+}
+
+/* offline the node if all memory sections of this node are removed */
+void try_offline_node(int nid)
+{
+ pg_data_t *pgdat = NODE_DATA(nid);
+ unsigned long start_pfn = pgdat->node_start_pfn;
+ unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
+ unsigned long pfn;
+ struct page *pgdat_page = virt_to_page(pgdat);
+ int i;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ unsigned long section_nr = pfn_to_section_nr(pfn);
+
+ if (!present_section_nr(section_nr))
+ continue;
+
+ if (pfn_to_nid(pfn) != nid)
+ continue;
+
+ /*
+ * some memory sections of this node are not removed, and we
+ * can't offline node now.
+ */
+ return;
+ }
+
+ if (stop_machine(check_and_unmap_cpu_on_node, pgdat, NULL))
+ return;
+
+ /*
+ * all memory/cpu of this node are removed, we can offline this
+ * node now.
+ */
+ node_set_offline(nid);
+ unregister_one_node(nid);
+
+ if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
+ /* node data is allocated from boot memory */
+ return;
+
+ /* free waittable in each zone */
+ for (i = 0; i < MAX_NR_ZONES; i++) {
+ struct zone *zone = pgdat->node_zones + i;
+
+ if (zone->wait_table)
+ vfree(zone->wait_table);
+ }
+
+ /*
+ * Since there is no way to guarentee the address of pgdat/zone is not
+ * on stack of any kernel threads or used by other kernel objects
+ * without reference counting or other symchronizing method, do not
+ * reset node_data and free pgdat here. Just reset it to 0 and reuse
+ * the memory when the node is online again.
+ */
+ memset(pgdat, 0, sizeof(*pgdat));
+}
+EXPORT_SYMBOL(try_offline_node);
+
+int __ref remove_memory(int nid, u64 start, u64 size)
+{
+ unsigned long start_pfn, end_pfn;
+ int ret = 0;
+ int retry = 1;
+
+ start_pfn = PFN_DOWN(start);
+ end_pfn = PFN_UP(start + size - 1);
+
+ /*
+ * When CONFIG_MEMCG is on, one memory block may be used by other
+ * blocks to store page cgroup when onlining pages. But we don't know
+ * in what order pages are onlined. So we iterate twice to offline
+ * memory:
+ * 1st iterate: offline every non primary memory block.
+ * 2nd iterate: offline primary (i.e. first added) memory block.
+ */
+repeat:
+ walk_memory_range(start_pfn, end_pfn, &ret,
+ offline_memory_block_cb);
+ if (ret) {
+ if (!retry)
+ return ret;
+
+ retry = 0;
+ ret = 0;
+ goto repeat;
+ }
+
+ lock_memory_hotplug();
+
+ /*
+ * we have offlined all memory blocks like this:
+ * 1. lock memory hotplug
+ * 2. offline a memory block
+ * 3. unlock memory hotplug
+ *
+ * repeat step1-3 to offline the memory block. All memory blocks
+ * must be offlined before removing memory. But we don't hold the
+ * lock in the whole operation. So we should check whether all
+ * memory blocks are offlined.
+ */
+
+ ret = walk_memory_range(start_pfn, end_pfn, NULL,
+ is_memblock_offlined_cb);
+ if (ret) {
+ unlock_memory_hotplug();
+ return ret;
+ }
+
+ /* remove memmap entry */
+ firmware_map_remove(start, start + size, "System RAM");
+
+ arch_remove_memory(start, size);
+
+ try_offline_node(nid);
+
+ unlock_memory_hotplug();
+
+ return 0;
+}
+#else
+int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
+{
+ return -EINVAL;
+}
+int remove_memory(int nid, u64 start, u64 size)
+{
+ return -EINVAL;
+}
+#endif /* CONFIG_MEMORY_HOTREMOVE */
+EXPORT_SYMBOL_GPL(remove_memory);