[PATCH] memory hotplug: sysfs and add/remove functions
This adds generic memory add/remove and supporting functions for memory
hotplug into a new file as well as a memory hotplug kernel config option.
Individual architecture patches will follow.
For now, disable memory hotplug when swsusp is enabled. There's a lot of
churn there right now. We'll fix it up properly once it calms down.
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
new file mode 100644
index 0000000..855e0fc
--- /dev/null
+++ b/mm/memory_hotplug.c
@@ -0,0 +1,178 @@
+/*
+ * 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;
+}