blob: d86fd2f5353fcb05d39c27887f64b81e148a2bc6 [file] [log] [blame]
Joonsoo Kimeefa864b2014-12-12 16:55:46 -08001#include <linux/mm.h>
2#include <linux/mmzone.h>
3#include <linux/bootmem.h>
4#include <linux/page_ext.h>
5#include <linux/memory.h>
6#include <linux/vmalloc.h>
7#include <linux/kmemleak.h>
Joonsoo Kim48c96a32014-12-12 16:56:01 -08008#include <linux/page_owner.h>
Joonsoo Kimeefa864b2014-12-12 16:55:46 -08009
10/*
11 * struct page extension
12 *
13 * This is the feature to manage memory for extended data per page.
14 *
15 * Until now, we must modify struct page itself to store extra data per page.
16 * This requires rebuilding the kernel and it is really time consuming process.
17 * And, sometimes, rebuild is impossible due to third party module dependency.
18 * At last, enlarging struct page could cause un-wanted system behaviour change.
19 *
20 * This feature is intended to overcome above mentioned problems. This feature
21 * allocates memory for extended data per page in certain place rather than
22 * the struct page itself. This memory can be accessed by the accessor
23 * functions provided by this code. During the boot process, it checks whether
24 * allocation of huge chunk of memory is needed or not. If not, it avoids
25 * allocating memory at all. With this advantage, we can include this feature
26 * into the kernel in default and can avoid rebuild and solve related problems.
27 *
28 * To help these things to work well, there are two callbacks for clients. One
29 * is the need callback which is mandatory if user wants to avoid useless
30 * memory allocation at boot-time. The other is optional, init callback, which
31 * is used to do proper initialization after memory is allocated.
32 *
33 * The need callback is used to decide whether extended memory allocation is
34 * needed or not. Sometimes users want to deactivate some features in this
35 * boot and extra memory would be unneccessary. In this case, to avoid
36 * allocating huge chunk of memory, each clients represent their need of
37 * extra memory through the need callback. If one of the need callbacks
38 * returns true, it means that someone needs extra memory so that
39 * page extension core should allocates memory for page extension. If
40 * none of need callbacks return true, memory isn't needed at all in this boot
41 * and page extension core can skip to allocate memory. As result,
42 * none of memory is wasted.
43 *
44 * The init callback is used to do proper initialization after page extension
45 * is completely initialized. In sparse memory system, extra memory is
46 * allocated some time later than memmap is allocated. In other words, lifetime
47 * of memory for page extension isn't same with memmap for struct page.
48 * Therefore, clients can't store extra data until page extension is
49 * initialized, even if pages are allocated and used freely. This could
50 * cause inadequate state of extra data per page, so, to prevent it, client
51 * can utilize this callback to initialize the state of it correctly.
52 */
53
54static struct page_ext_operations *page_ext_ops[] = {
Joonsoo Kime30825f2014-12-12 16:55:49 -080055 &debug_guardpage_ops,
56#ifdef CONFIG_PAGE_POISONING
57 &page_poisoning_ops,
58#endif
Joonsoo Kim48c96a32014-12-12 16:56:01 -080059#ifdef CONFIG_PAGE_OWNER
60 &page_owner_ops,
61#endif
Joonsoo Kimeefa864b2014-12-12 16:55:46 -080062};
63
64static unsigned long total_usage;
65
66static bool __init invoke_need_callbacks(void)
67{
68 int i;
69 int entries = ARRAY_SIZE(page_ext_ops);
70
71 for (i = 0; i < entries; i++) {
72 if (page_ext_ops[i]->need && page_ext_ops[i]->need())
73 return true;
74 }
75
76 return false;
77}
78
79static void __init invoke_init_callbacks(void)
80{
81 int i;
82 int entries = ARRAY_SIZE(page_ext_ops);
83
84 for (i = 0; i < entries; i++) {
85 if (page_ext_ops[i]->init)
86 page_ext_ops[i]->init();
87 }
88}
89
90#if !defined(CONFIG_SPARSEMEM)
91
92
93void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
94{
95 pgdat->node_page_ext = NULL;
96}
97
98struct page_ext *lookup_page_ext(struct page *page)
99{
100 unsigned long pfn = page_to_pfn(page);
101 unsigned long offset;
102 struct page_ext *base;
103
104 base = NODE_DATA(page_to_nid(page))->node_page_ext;
105#ifdef CONFIG_DEBUG_VM
106 /*
107 * The sanity checks the page allocator does upon freeing a
108 * page can reach here before the page_ext arrays are
109 * allocated when feeding a range of pages to the allocator
110 * for the first time during bootup or memory hotplug.
111 */
112 if (unlikely(!base))
113 return NULL;
114#endif
115 offset = pfn - round_down(node_start_pfn(page_to_nid(page)),
116 MAX_ORDER_NR_PAGES);
117 return base + offset;
118}
119
120static int __init alloc_node_page_ext(int nid)
121{
122 struct page_ext *base;
123 unsigned long table_size;
124 unsigned long nr_pages;
125
126 nr_pages = NODE_DATA(nid)->node_spanned_pages;
127 if (!nr_pages)
128 return 0;
129
130 /*
131 * Need extra space if node range is not aligned with
132 * MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
133 * checks buddy's status, range could be out of exact node range.
134 */
135 if (!IS_ALIGNED(node_start_pfn(nid), MAX_ORDER_NR_PAGES) ||
136 !IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
137 nr_pages += MAX_ORDER_NR_PAGES;
138
139 table_size = sizeof(struct page_ext) * nr_pages;
140
141 base = memblock_virt_alloc_try_nid_nopanic(
142 table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
143 BOOTMEM_ALLOC_ACCESSIBLE, nid);
144 if (!base)
145 return -ENOMEM;
146 NODE_DATA(nid)->node_page_ext = base;
147 total_usage += table_size;
148 return 0;
149}
150
151void __init page_ext_init_flatmem(void)
152{
153
154 int nid, fail;
155
156 if (!invoke_need_callbacks())
157 return;
158
159 for_each_online_node(nid) {
160 fail = alloc_node_page_ext(nid);
161 if (fail)
162 goto fail;
163 }
164 pr_info("allocated %ld bytes of page_ext\n", total_usage);
165 invoke_init_callbacks();
166 return;
167
168fail:
169 pr_crit("allocation of page_ext failed.\n");
170 panic("Out of memory");
171}
172
173#else /* CONFIG_FLAT_NODE_MEM_MAP */
174
175struct page_ext *lookup_page_ext(struct page *page)
176{
177 unsigned long pfn = page_to_pfn(page);
178 struct mem_section *section = __pfn_to_section(pfn);
179#ifdef CONFIG_DEBUG_VM
180 /*
181 * The sanity checks the page allocator does upon freeing a
182 * page can reach here before the page_ext arrays are
183 * allocated when feeding a range of pages to the allocator
184 * for the first time during bootup or memory hotplug.
185 */
186 if (!section->page_ext)
187 return NULL;
188#endif
189 return section->page_ext + pfn;
190}
191
192static void *__meminit alloc_page_ext(size_t size, int nid)
193{
194 gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
195 void *addr = NULL;
196
197 addr = alloc_pages_exact_nid(nid, size, flags);
198 if (addr) {
199 kmemleak_alloc(addr, size, 1, flags);
200 return addr;
201 }
202
203 if (node_state(nid, N_HIGH_MEMORY))
204 addr = vzalloc_node(size, nid);
205 else
206 addr = vzalloc(size);
207
208 return addr;
209}
210
211static int __meminit init_section_page_ext(unsigned long pfn, int nid)
212{
213 struct mem_section *section;
214 struct page_ext *base;
215 unsigned long table_size;
216
217 section = __pfn_to_section(pfn);
218
219 if (section->page_ext)
220 return 0;
221
222 table_size = sizeof(struct page_ext) * PAGES_PER_SECTION;
223 base = alloc_page_ext(table_size, nid);
224
225 /*
226 * The value stored in section->page_ext is (base - pfn)
227 * and it does not point to the memory block allocated above,
228 * causing kmemleak false positives.
229 */
230 kmemleak_not_leak(base);
231
232 if (!base) {
233 pr_err("page ext allocation failure\n");
234 return -ENOMEM;
235 }
236
237 /*
238 * The passed "pfn" may not be aligned to SECTION. For the calculation
239 * we need to apply a mask.
240 */
241 pfn &= PAGE_SECTION_MASK;
242 section->page_ext = base - pfn;
243 total_usage += table_size;
244 return 0;
245}
246#ifdef CONFIG_MEMORY_HOTPLUG
247static void free_page_ext(void *addr)
248{
249 if (is_vmalloc_addr(addr)) {
250 vfree(addr);
251 } else {
252 struct page *page = virt_to_page(addr);
253 size_t table_size;
254
255 table_size = sizeof(struct page_ext) * PAGES_PER_SECTION;
256
257 BUG_ON(PageReserved(page));
258 free_pages_exact(addr, table_size);
259 }
260}
261
262static void __free_page_ext(unsigned long pfn)
263{
264 struct mem_section *ms;
265 struct page_ext *base;
266
267 ms = __pfn_to_section(pfn);
268 if (!ms || !ms->page_ext)
269 return;
270 base = ms->page_ext + pfn;
271 free_page_ext(base);
272 ms->page_ext = NULL;
273}
274
275static int __meminit online_page_ext(unsigned long start_pfn,
276 unsigned long nr_pages,
277 int nid)
278{
279 unsigned long start, end, pfn;
280 int fail = 0;
281
282 start = SECTION_ALIGN_DOWN(start_pfn);
283 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
284
285 if (nid == -1) {
286 /*
287 * In this case, "nid" already exists and contains valid memory.
288 * "start_pfn" passed to us is a pfn which is an arg for
289 * online__pages(), and start_pfn should exist.
290 */
291 nid = pfn_to_nid(start_pfn);
292 VM_BUG_ON(!node_state(nid, N_ONLINE));
293 }
294
295 for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
296 if (!pfn_present(pfn))
297 continue;
298 fail = init_section_page_ext(pfn, nid);
299 }
300 if (!fail)
301 return 0;
302
303 /* rollback */
304 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
305 __free_page_ext(pfn);
306
307 return -ENOMEM;
308}
309
310static int __meminit offline_page_ext(unsigned long start_pfn,
311 unsigned long nr_pages, int nid)
312{
313 unsigned long start, end, pfn;
314
315 start = SECTION_ALIGN_DOWN(start_pfn);
316 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
317
318 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
319 __free_page_ext(pfn);
320 return 0;
321
322}
323
324static int __meminit page_ext_callback(struct notifier_block *self,
325 unsigned long action, void *arg)
326{
327 struct memory_notify *mn = arg;
328 int ret = 0;
329
330 switch (action) {
331 case MEM_GOING_ONLINE:
332 ret = online_page_ext(mn->start_pfn,
333 mn->nr_pages, mn->status_change_nid);
334 break;
335 case MEM_OFFLINE:
336 offline_page_ext(mn->start_pfn,
337 mn->nr_pages, mn->status_change_nid);
338 break;
339 case MEM_CANCEL_ONLINE:
340 offline_page_ext(mn->start_pfn,
341 mn->nr_pages, mn->status_change_nid);
342 break;
343 case MEM_GOING_OFFLINE:
344 break;
345 case MEM_ONLINE:
346 case MEM_CANCEL_OFFLINE:
347 break;
348 }
349
350 return notifier_from_errno(ret);
351}
352
353#endif
354
355void __init page_ext_init(void)
356{
357 unsigned long pfn;
358 int nid;
359
360 if (!invoke_need_callbacks())
361 return;
362
363 for_each_node_state(nid, N_MEMORY) {
364 unsigned long start_pfn, end_pfn;
365
366 start_pfn = node_start_pfn(nid);
367 end_pfn = node_end_pfn(nid);
368 /*
369 * start_pfn and end_pfn may not be aligned to SECTION and the
370 * page->flags of out of node pages are not initialized. So we
371 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
372 */
373 for (pfn = start_pfn; pfn < end_pfn;
374 pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
375
376 if (!pfn_valid(pfn))
377 continue;
378 /*
379 * Nodes's pfns can be overlapping.
380 * We know some arch can have a nodes layout such as
381 * -------------pfn-------------->
382 * N0 | N1 | N2 | N0 | N1 | N2|....
383 */
384 if (pfn_to_nid(pfn) != nid)
385 continue;
386 if (init_section_page_ext(pfn, nid))
387 goto oom;
388 }
389 }
390 hotplug_memory_notifier(page_ext_callback, 0);
391 pr_info("allocated %ld bytes of page_ext\n", total_usage);
392 invoke_init_callbacks();
393 return;
394
395oom:
396 panic("Out of memory");
397}
398
399void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
400{
401}
402
403#endif