[PATCH] memory hotplug: sysfs and add/remove functions
[linux-2.6.git] / mm / memory_hotplug.c
1 /*
2  *  linux/mm/memory_hotplug.c
3  *
4  *  Copyright (C)
5  */
6
7 #include <linux/config.h>
8 #include <linux/stddef.h>
9 #include <linux/mm.h>
10 #include <linux/swap.h>
11 #include <linux/interrupt.h>
12 #include <linux/pagemap.h>
13 #include <linux/bootmem.h>
14 #include <linux/compiler.h>
15 #include <linux/module.h>
16 #include <linux/pagevec.h>
17 #include <linux/slab.h>
18 #include <linux/sysctl.h>
19 #include <linux/cpu.h>
20 #include <linux/memory.h>
21 #include <linux/memory_hotplug.h>
22 #include <linux/highmem.h>
23 #include <linux/vmalloc.h>
24
25 #include <asm/tlbflush.h>
26
27 static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
28 {
29         struct page *page, *ret;
30         unsigned long memmap_size = sizeof(struct page) * nr_pages;
31
32         page = alloc_pages(GFP_KERNEL, get_order(memmap_size));
33         if (page)
34                 goto got_map_page;
35
36         ret = vmalloc(memmap_size);
37         if (ret)
38                 goto got_map_ptr;
39
40         return NULL;
41 got_map_page:
42         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
43 got_map_ptr:
44         memset(ret, 0, memmap_size);
45
46         return ret;
47 }
48
49 extern void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
50                           unsigned long size);
51 static void __add_zone(struct zone *zone, unsigned long phys_start_pfn)
52 {
53         struct pglist_data *pgdat = zone->zone_pgdat;
54         int nr_pages = PAGES_PER_SECTION;
55         int nid = pgdat->node_id;
56         int zone_type;
57
58         zone_type = zone - pgdat->node_zones;
59         memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn);
60         zonetable_add(zone, nid, zone_type, phys_start_pfn, nr_pages);
61 }
62
63 extern int sparse_add_one_section(struct zone *, unsigned long,
64                                   struct page *mem_map);
65 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
66 {
67         struct pglist_data *pgdat = zone->zone_pgdat;
68         int nr_pages = PAGES_PER_SECTION;
69         struct page *memmap;
70         int ret;
71
72         /*
73          * This can potentially allocate memory, and does its own
74          * internal locking.
75          */
76         sparse_index_init(pfn_to_section_nr(phys_start_pfn), pgdat->node_id);
77
78         pgdat_resize_lock(pgdat, &flags);
79         memmap = __kmalloc_section_memmap(nr_pages);
80         ret = sparse_add_one_section(zone, phys_start_pfn, memmap);
81         pgdat_resize_unlock(pgdat, &flags);
82
83         if (ret <= 0) {
84                 /* the mem_map didn't get used */
85                 if (memmap >= (struct page *)VMALLOC_START &&
86                     memmap < (struct page *)VMALLOC_END)
87                         vfree(memmap);
88                 else
89                         free_pages((unsigned long)memmap,
90                                    get_order(sizeof(struct page) * nr_pages));
91         }
92
93         if (ret < 0)
94                 return ret;
95
96         __add_zone(zone, phys_start_pfn);
97         return register_new_memory(__pfn_to_section(phys_start_pfn));
98 }
99
100 /*
101  * Reasonably generic function for adding memory.  It is
102  * expected that archs that support memory hotplug will
103  * call this function after deciding the zone to which to
104  * add the new pages.
105  */
106 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
107                  unsigned long nr_pages)
108 {
109         unsigned long i;
110         int err = 0;
111
112         for (i = 0; i < nr_pages; i += PAGES_PER_SECTION) {
113                 err = __add_section(zone, phys_start_pfn + i);
114
115                 if (err)
116                         break;
117         }
118
119         return err;
120 }
121
122 static void grow_zone_span(struct zone *zone,
123                 unsigned long start_pfn, unsigned long end_pfn)
124 {
125         unsigned long old_zone_end_pfn;
126
127         zone_span_writelock(zone);
128
129         old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
130         if (start_pfn < zone->zone_start_pfn)
131                 zone->zone_start_pfn = start_pfn;
132
133         if (end_pfn > old_zone_end_pfn)
134                 zone->spanned_pages = end_pfn - zone->zone_start_pfn;
135
136         zone_span_writeunlock(zone);
137 }
138
139 static void grow_pgdat_span(struct pglist_data *pgdat,
140                 unsigned long start_pfn, unsigned long end_pfn)
141 {
142         unsigned long old_pgdat_end_pfn =
143                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
144
145         if (start_pfn < pgdat->node_start_pfn)
146                 pgdat->node_start_pfn = start_pfn;
147
148         if (end_pfn > old_pgdat_end_pfn)
149                 pgdat->node_spanned_pages = end_pfn - pgdat->node_spanned_pages;
150 }
151
152 int online_pages(unsigned long pfn, unsigned long nr_pages)
153 {
154         unsigned long i;
155         unsigned long flags;
156         unsigned long onlined_pages = 0;
157         struct zone *zone;
158
159         /*
160          * This doesn't need a lock to do pfn_to_page().
161          * The section can't be removed here because of the
162          * memory_block->state_sem.
163          */
164         zone = page_zone(pfn_to_page(pfn));
165         pgdat_resize_lock(zone->zone_pgdat, &flags);
166         grow_zone_span(zone, pfn, pfn + nr_pages);
167         grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
168         pgdat_resize_unlock(zone->zone_pgdat, &flags);
169
170         for (i = 0; i < nr_pages; i++) {
171                 struct page *page = pfn_to_page(pfn + i);
172                 online_page(page);
173                 onlined_pages++;
174         }
175         zone->present_pages += onlined_pages;
176
177         return 0;
178 }