]>
Commit | Line | Data |
---|---|---|
1 | /****************************************************************************** | |
2 | * Xen balloon driver - enables returning/claiming memory to/from Xen. | |
3 | * | |
4 | * Copyright (c) 2003, B Dragovic | |
5 | * Copyright (c) 2003-2004, M Williamson, K Fraser | |
6 | * Copyright (c) 2005 Dan M. Smith, IBM Corporation | |
7 | * Copyright (c) 2010 Daniel Kiper | |
8 | * | |
9 | * Memory hotplug support was written by Daniel Kiper. Work on | |
10 | * it was sponsored by Google under Google Summer of Code 2010 | |
11 | * program. Jeremy Fitzhardinge from Citrix was the mentor for | |
12 | * this project. | |
13 | * | |
14 | * This program is free software; you can redistribute it and/or | |
15 | * modify it under the terms of the GNU General Public License version 2 | |
16 | * as published by the Free Software Foundation; or, when distributed | |
17 | * separately from the Linux kernel or incorporated into other | |
18 | * software packages, subject to the following license: | |
19 | * | |
20 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
21 | * of this source file (the "Software"), to deal in the Software without | |
22 | * restriction, including without limitation the rights to use, copy, modify, | |
23 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
24 | * and to permit persons to whom the Software is furnished to do so, subject to | |
25 | * the following conditions: | |
26 | * | |
27 | * The above copyright notice and this permission notice shall be included in | |
28 | * all copies or substantial portions of the Software. | |
29 | * | |
30 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
31 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
32 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
33 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
34 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
35 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
36 | * IN THE SOFTWARE. | |
37 | */ | |
38 | ||
39 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt | |
40 | ||
41 | #include <linux/cpu.h> | |
42 | #include <linux/kernel.h> | |
43 | #include <linux/sched.h> | |
44 | #include <linux/errno.h> | |
45 | #include <linux/module.h> | |
46 | #include <linux/mm.h> | |
47 | #include <linux/bootmem.h> | |
48 | #include <linux/pagemap.h> | |
49 | #include <linux/highmem.h> | |
50 | #include <linux/mutex.h> | |
51 | #include <linux/list.h> | |
52 | #include <linux/gfp.h> | |
53 | #include <linux/notifier.h> | |
54 | #include <linux/memory.h> | |
55 | #include <linux/memory_hotplug.h> | |
56 | #include <linux/percpu-defs.h> | |
57 | ||
58 | #include <asm/page.h> | |
59 | #include <asm/pgalloc.h> | |
60 | #include <asm/pgtable.h> | |
61 | #include <asm/tlb.h> | |
62 | ||
63 | #include <asm/xen/hypervisor.h> | |
64 | #include <asm/xen/hypercall.h> | |
65 | ||
66 | #include <xen/xen.h> | |
67 | #include <xen/interface/xen.h> | |
68 | #include <xen/interface/memory.h> | |
69 | #include <xen/balloon.h> | |
70 | #include <xen/features.h> | |
71 | #include <xen/page.h> | |
72 | ||
73 | /* | |
74 | * balloon_process() state: | |
75 | * | |
76 | * BP_DONE: done or nothing to do, | |
77 | * BP_EAGAIN: error, go to sleep, | |
78 | * BP_ECANCELED: error, balloon operation canceled. | |
79 | */ | |
80 | ||
81 | enum bp_state { | |
82 | BP_DONE, | |
83 | BP_EAGAIN, | |
84 | BP_ECANCELED | |
85 | }; | |
86 | ||
87 | ||
88 | static DEFINE_MUTEX(balloon_mutex); | |
89 | ||
90 | struct balloon_stats balloon_stats; | |
91 | EXPORT_SYMBOL_GPL(balloon_stats); | |
92 | ||
93 | /* We increase/decrease in batches which fit in a page */ | |
94 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; | |
95 | static DEFINE_PER_CPU(struct page *, balloon_scratch_page); | |
96 | ||
97 | ||
98 | /* List of ballooned pages, threaded through the mem_map array. */ | |
99 | static LIST_HEAD(ballooned_pages); | |
100 | ||
101 | /* Main work function, always executed in process context. */ | |
102 | static void balloon_process(struct work_struct *work); | |
103 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); | |
104 | ||
105 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
106 | want the kernel to try too hard since that can trigger the oom killer. */ | |
107 | #define GFP_BALLOON \ | |
108 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
109 | ||
110 | static void scrub_page(struct page *page) | |
111 | { | |
112 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
113 | clear_highpage(page); | |
114 | #endif | |
115 | } | |
116 | ||
117 | /* balloon_append: add the given page to the balloon. */ | |
118 | static void __balloon_append(struct page *page) | |
119 | { | |
120 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
121 | if (PageHighMem(page)) { | |
122 | list_add_tail(&page->lru, &ballooned_pages); | |
123 | balloon_stats.balloon_high++; | |
124 | } else { | |
125 | list_add(&page->lru, &ballooned_pages); | |
126 | balloon_stats.balloon_low++; | |
127 | } | |
128 | } | |
129 | ||
130 | static void balloon_append(struct page *page) | |
131 | { | |
132 | __balloon_append(page); | |
133 | adjust_managed_page_count(page, -1); | |
134 | } | |
135 | ||
136 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
137 | static struct page *balloon_retrieve(bool prefer_highmem) | |
138 | { | |
139 | struct page *page; | |
140 | ||
141 | if (list_empty(&ballooned_pages)) | |
142 | return NULL; | |
143 | ||
144 | if (prefer_highmem) | |
145 | page = list_entry(ballooned_pages.prev, struct page, lru); | |
146 | else | |
147 | page = list_entry(ballooned_pages.next, struct page, lru); | |
148 | list_del(&page->lru); | |
149 | ||
150 | if (PageHighMem(page)) | |
151 | balloon_stats.balloon_high--; | |
152 | else | |
153 | balloon_stats.balloon_low--; | |
154 | ||
155 | adjust_managed_page_count(page, 1); | |
156 | ||
157 | return page; | |
158 | } | |
159 | ||
160 | static struct page *balloon_next_page(struct page *page) | |
161 | { | |
162 | struct list_head *next = page->lru.next; | |
163 | if (next == &ballooned_pages) | |
164 | return NULL; | |
165 | return list_entry(next, struct page, lru); | |
166 | } | |
167 | ||
168 | static enum bp_state update_schedule(enum bp_state state) | |
169 | { | |
170 | if (state == BP_DONE) { | |
171 | balloon_stats.schedule_delay = 1; | |
172 | balloon_stats.retry_count = 1; | |
173 | return BP_DONE; | |
174 | } | |
175 | ||
176 | ++balloon_stats.retry_count; | |
177 | ||
178 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
179 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
180 | balloon_stats.schedule_delay = 1; | |
181 | balloon_stats.retry_count = 1; | |
182 | return BP_ECANCELED; | |
183 | } | |
184 | ||
185 | balloon_stats.schedule_delay <<= 1; | |
186 | ||
187 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
188 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
189 | ||
190 | return BP_EAGAIN; | |
191 | } | |
192 | ||
193 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
194 | static long current_credit(void) | |
195 | { | |
196 | return balloon_stats.target_pages - balloon_stats.current_pages - | |
197 | balloon_stats.hotplug_pages; | |
198 | } | |
199 | ||
200 | static bool balloon_is_inflated(void) | |
201 | { | |
202 | if (balloon_stats.balloon_low || balloon_stats.balloon_high || | |
203 | balloon_stats.balloon_hotplug) | |
204 | return true; | |
205 | else | |
206 | return false; | |
207 | } | |
208 | ||
209 | /* | |
210 | * reserve_additional_memory() adds memory region of size >= credit above | |
211 | * max_pfn. New region is section aligned and size is modified to be multiple | |
212 | * of section size. Those features allow optimal use of address space and | |
213 | * establish proper alignment when this function is called first time after | |
214 | * boot (last section not fully populated at boot time contains unused memory | |
215 | * pages with PG_reserved bit not set; online_pages_range() does not allow page | |
216 | * onlining in whole range if first onlined page does not have PG_reserved | |
217 | * bit set). Real size of added memory is established at page onlining stage. | |
218 | */ | |
219 | ||
220 | static enum bp_state reserve_additional_memory(long credit) | |
221 | { | |
222 | int nid, rc; | |
223 | u64 hotplug_start_paddr; | |
224 | unsigned long balloon_hotplug = credit; | |
225 | ||
226 | hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); | |
227 | balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); | |
228 | nid = memory_add_physaddr_to_nid(hotplug_start_paddr); | |
229 | ||
230 | rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); | |
231 | ||
232 | if (rc) { | |
233 | pr_info("%s: add_memory() failed: %i\n", __func__, rc); | |
234 | return BP_EAGAIN; | |
235 | } | |
236 | ||
237 | balloon_hotplug -= credit; | |
238 | ||
239 | balloon_stats.hotplug_pages += credit; | |
240 | balloon_stats.balloon_hotplug = balloon_hotplug; | |
241 | ||
242 | return BP_DONE; | |
243 | } | |
244 | ||
245 | static void xen_online_page(struct page *page) | |
246 | { | |
247 | __online_page_set_limits(page); | |
248 | ||
249 | mutex_lock(&balloon_mutex); | |
250 | ||
251 | __balloon_append(page); | |
252 | ||
253 | if (balloon_stats.hotplug_pages) | |
254 | --balloon_stats.hotplug_pages; | |
255 | else | |
256 | --balloon_stats.balloon_hotplug; | |
257 | ||
258 | mutex_unlock(&balloon_mutex); | |
259 | } | |
260 | ||
261 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
262 | { | |
263 | if (val == MEM_ONLINE) | |
264 | schedule_delayed_work(&balloon_worker, 0); | |
265 | ||
266 | return NOTIFY_OK; | |
267 | } | |
268 | ||
269 | static struct notifier_block xen_memory_nb = { | |
270 | .notifier_call = xen_memory_notifier, | |
271 | .priority = 0 | |
272 | }; | |
273 | #else | |
274 | static long current_credit(void) | |
275 | { | |
276 | unsigned long target = balloon_stats.target_pages; | |
277 | ||
278 | target = min(target, | |
279 | balloon_stats.current_pages + | |
280 | balloon_stats.balloon_low + | |
281 | balloon_stats.balloon_high); | |
282 | ||
283 | return target - balloon_stats.current_pages; | |
284 | } | |
285 | ||
286 | static bool balloon_is_inflated(void) | |
287 | { | |
288 | if (balloon_stats.balloon_low || balloon_stats.balloon_high) | |
289 | return true; | |
290 | else | |
291 | return false; | |
292 | } | |
293 | ||
294 | static enum bp_state reserve_additional_memory(long credit) | |
295 | { | |
296 | balloon_stats.target_pages = balloon_stats.current_pages; | |
297 | return BP_DONE; | |
298 | } | |
299 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ | |
300 | ||
301 | static enum bp_state increase_reservation(unsigned long nr_pages) | |
302 | { | |
303 | int rc; | |
304 | unsigned long pfn, i; | |
305 | struct page *page; | |
306 | struct xen_memory_reservation reservation = { | |
307 | .address_bits = 0, | |
308 | .extent_order = 0, | |
309 | .domid = DOMID_SELF | |
310 | }; | |
311 | ||
312 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
313 | if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) { | |
314 | nr_pages = min(nr_pages, balloon_stats.balloon_hotplug); | |
315 | balloon_stats.hotplug_pages += nr_pages; | |
316 | balloon_stats.balloon_hotplug -= nr_pages; | |
317 | return BP_DONE; | |
318 | } | |
319 | #endif | |
320 | ||
321 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
322 | nr_pages = ARRAY_SIZE(frame_list); | |
323 | ||
324 | page = list_first_entry_or_null(&ballooned_pages, struct page, lru); | |
325 | for (i = 0; i < nr_pages; i++) { | |
326 | if (!page) { | |
327 | nr_pages = i; | |
328 | break; | |
329 | } | |
330 | frame_list[i] = page_to_pfn(page); | |
331 | page = balloon_next_page(page); | |
332 | } | |
333 | ||
334 | set_xen_guest_handle(reservation.extent_start, frame_list); | |
335 | reservation.nr_extents = nr_pages; | |
336 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); | |
337 | if (rc <= 0) | |
338 | return BP_EAGAIN; | |
339 | ||
340 | for (i = 0; i < rc; i++) { | |
341 | page = balloon_retrieve(false); | |
342 | BUG_ON(page == NULL); | |
343 | ||
344 | pfn = page_to_pfn(page); | |
345 | ||
346 | #ifdef CONFIG_XEN_HAVE_PVMMU | |
347 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
348 | set_phys_to_machine(pfn, frame_list[i]); | |
349 | ||
350 | /* Link back into the page tables if not highmem. */ | |
351 | if (!PageHighMem(page)) { | |
352 | int ret; | |
353 | ret = HYPERVISOR_update_va_mapping( | |
354 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
355 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
356 | 0); | |
357 | BUG_ON(ret); | |
358 | } | |
359 | } | |
360 | #endif | |
361 | ||
362 | /* Relinquish the page back to the allocator. */ | |
363 | __free_reserved_page(page); | |
364 | } | |
365 | ||
366 | balloon_stats.current_pages += rc; | |
367 | ||
368 | return BP_DONE; | |
369 | } | |
370 | ||
371 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) | |
372 | { | |
373 | enum bp_state state = BP_DONE; | |
374 | unsigned long pfn, i; | |
375 | struct page *page; | |
376 | int ret; | |
377 | struct xen_memory_reservation reservation = { | |
378 | .address_bits = 0, | |
379 | .extent_order = 0, | |
380 | .domid = DOMID_SELF | |
381 | }; | |
382 | ||
383 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
384 | if (balloon_stats.hotplug_pages) { | |
385 | nr_pages = min(nr_pages, balloon_stats.hotplug_pages); | |
386 | balloon_stats.hotplug_pages -= nr_pages; | |
387 | balloon_stats.balloon_hotplug += nr_pages; | |
388 | return BP_DONE; | |
389 | } | |
390 | #endif | |
391 | ||
392 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
393 | nr_pages = ARRAY_SIZE(frame_list); | |
394 | ||
395 | for (i = 0; i < nr_pages; i++) { | |
396 | page = alloc_page(gfp); | |
397 | if (page == NULL) { | |
398 | nr_pages = i; | |
399 | state = BP_EAGAIN; | |
400 | break; | |
401 | } | |
402 | scrub_page(page); | |
403 | ||
404 | frame_list[i] = page_to_pfn(page); | |
405 | } | |
406 | ||
407 | /* | |
408 | * Ensure that ballooned highmem pages don't have kmaps. | |
409 | * | |
410 | * Do this before changing the p2m as kmap_flush_unused() | |
411 | * reads PTEs to obtain pages (and hence needs the original | |
412 | * p2m entry). | |
413 | */ | |
414 | kmap_flush_unused(); | |
415 | ||
416 | /* Update direct mapping, invalidate P2M, and add to balloon. */ | |
417 | for (i = 0; i < nr_pages; i++) { | |
418 | pfn = frame_list[i]; | |
419 | frame_list[i] = pfn_to_mfn(pfn); | |
420 | page = pfn_to_page(pfn); | |
421 | ||
422 | #ifdef CONFIG_XEN_HAVE_PVMMU | |
423 | /* | |
424 | * Ballooned out frames are effectively replaced with | |
425 | * a scratch frame. Ensure direct mappings and the | |
426 | * p2m are consistent. | |
427 | */ | |
428 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
429 | unsigned long p; | |
430 | struct page *scratch_page = get_balloon_scratch_page(); | |
431 | ||
432 | if (!PageHighMem(page)) { | |
433 | ret = HYPERVISOR_update_va_mapping( | |
434 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
435 | pfn_pte(page_to_pfn(scratch_page), | |
436 | PAGE_KERNEL_RO), 0); | |
437 | BUG_ON(ret); | |
438 | } | |
439 | p = page_to_pfn(scratch_page); | |
440 | __set_phys_to_machine(pfn, pfn_to_mfn(p)); | |
441 | ||
442 | put_balloon_scratch_page(); | |
443 | } | |
444 | #endif | |
445 | ||
446 | balloon_append(page); | |
447 | } | |
448 | ||
449 | flush_tlb_all(); | |
450 | ||
451 | set_xen_guest_handle(reservation.extent_start, frame_list); | |
452 | reservation.nr_extents = nr_pages; | |
453 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
454 | BUG_ON(ret != nr_pages); | |
455 | ||
456 | balloon_stats.current_pages -= nr_pages; | |
457 | ||
458 | return state; | |
459 | } | |
460 | ||
461 | /* | |
462 | * We avoid multiple worker processes conflicting via the balloon mutex. | |
463 | * We may of course race updates of the target counts (which are protected | |
464 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
465 | * recover from these in time. | |
466 | */ | |
467 | static void balloon_process(struct work_struct *work) | |
468 | { | |
469 | enum bp_state state = BP_DONE; | |
470 | long credit; | |
471 | ||
472 | mutex_lock(&balloon_mutex); | |
473 | ||
474 | do { | |
475 | credit = current_credit(); | |
476 | ||
477 | if (credit > 0) { | |
478 | if (balloon_is_inflated()) | |
479 | state = increase_reservation(credit); | |
480 | else | |
481 | state = reserve_additional_memory(credit); | |
482 | } | |
483 | ||
484 | if (credit < 0) | |
485 | state = decrease_reservation(-credit, GFP_BALLOON); | |
486 | ||
487 | state = update_schedule(state); | |
488 | ||
489 | #ifndef CONFIG_PREEMPT | |
490 | if (need_resched()) | |
491 | schedule(); | |
492 | #endif | |
493 | } while (credit && state == BP_DONE); | |
494 | ||
495 | /* Schedule more work if there is some still to be done. */ | |
496 | if (state == BP_EAGAIN) | |
497 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
498 | ||
499 | mutex_unlock(&balloon_mutex); | |
500 | } | |
501 | ||
502 | struct page *get_balloon_scratch_page(void) | |
503 | { | |
504 | struct page *ret = get_cpu_var(balloon_scratch_page); | |
505 | BUG_ON(ret == NULL); | |
506 | return ret; | |
507 | } | |
508 | ||
509 | void put_balloon_scratch_page(void) | |
510 | { | |
511 | put_cpu_var(balloon_scratch_page); | |
512 | } | |
513 | ||
514 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
515 | void balloon_set_new_target(unsigned long target) | |
516 | { | |
517 | /* No need for lock. Not read-modify-write updates. */ | |
518 | balloon_stats.target_pages = target; | |
519 | schedule_delayed_work(&balloon_worker, 0); | |
520 | } | |
521 | EXPORT_SYMBOL_GPL(balloon_set_new_target); | |
522 | ||
523 | /** | |
524 | * alloc_xenballooned_pages - get pages that have been ballooned out | |
525 | * @nr_pages: Number of pages to get | |
526 | * @pages: pages returned | |
527 | * @highmem: allow highmem pages | |
528 | * @return 0 on success, error otherwise | |
529 | */ | |
530 | int alloc_xenballooned_pages(int nr_pages, struct page **pages, bool highmem) | |
531 | { | |
532 | int pgno = 0; | |
533 | struct page *page; | |
534 | mutex_lock(&balloon_mutex); | |
535 | while (pgno < nr_pages) { | |
536 | page = balloon_retrieve(highmem); | |
537 | if (page && (highmem || !PageHighMem(page))) { | |
538 | pages[pgno++] = page; | |
539 | } else { | |
540 | enum bp_state st; | |
541 | if (page) | |
542 | balloon_append(page); | |
543 | st = decrease_reservation(nr_pages - pgno, | |
544 | highmem ? GFP_HIGHUSER : GFP_USER); | |
545 | if (st != BP_DONE) | |
546 | goto out_undo; | |
547 | } | |
548 | } | |
549 | mutex_unlock(&balloon_mutex); | |
550 | return 0; | |
551 | out_undo: | |
552 | while (pgno) | |
553 | balloon_append(pages[--pgno]); | |
554 | /* Free the memory back to the kernel soon */ | |
555 | schedule_delayed_work(&balloon_worker, 0); | |
556 | mutex_unlock(&balloon_mutex); | |
557 | return -ENOMEM; | |
558 | } | |
559 | EXPORT_SYMBOL(alloc_xenballooned_pages); | |
560 | ||
561 | /** | |
562 | * free_xenballooned_pages - return pages retrieved with get_ballooned_pages | |
563 | * @nr_pages: Number of pages | |
564 | * @pages: pages to return | |
565 | */ | |
566 | void free_xenballooned_pages(int nr_pages, struct page **pages) | |
567 | { | |
568 | int i; | |
569 | ||
570 | mutex_lock(&balloon_mutex); | |
571 | ||
572 | for (i = 0; i < nr_pages; i++) { | |
573 | if (pages[i]) | |
574 | balloon_append(pages[i]); | |
575 | } | |
576 | ||
577 | /* The balloon may be too large now. Shrink it if needed. */ | |
578 | if (current_credit()) | |
579 | schedule_delayed_work(&balloon_worker, 0); | |
580 | ||
581 | mutex_unlock(&balloon_mutex); | |
582 | } | |
583 | EXPORT_SYMBOL(free_xenballooned_pages); | |
584 | ||
585 | static void __init balloon_add_region(unsigned long start_pfn, | |
586 | unsigned long pages) | |
587 | { | |
588 | unsigned long pfn, extra_pfn_end; | |
589 | struct page *page; | |
590 | ||
591 | /* | |
592 | * If the amount of usable memory has been limited (e.g., with | |
593 | * the 'mem' command line parameter), don't add pages beyond | |
594 | * this limit. | |
595 | */ | |
596 | extra_pfn_end = min(max_pfn, start_pfn + pages); | |
597 | ||
598 | for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { | |
599 | page = pfn_to_page(pfn); | |
600 | /* totalram_pages and totalhigh_pages do not | |
601 | include the boot-time balloon extension, so | |
602 | don't subtract from it. */ | |
603 | __balloon_append(page); | |
604 | } | |
605 | } | |
606 | ||
607 | static int alloc_balloon_scratch_page(int cpu) | |
608 | { | |
609 | if (per_cpu(balloon_scratch_page, cpu) != NULL) | |
610 | return 0; | |
611 | ||
612 | per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL); | |
613 | if (per_cpu(balloon_scratch_page, cpu) == NULL) { | |
614 | pr_warn("Failed to allocate balloon_scratch_page for cpu %d\n", cpu); | |
615 | return -ENOMEM; | |
616 | } | |
617 | ||
618 | return 0; | |
619 | } | |
620 | ||
621 | ||
622 | static int balloon_cpu_notify(struct notifier_block *self, | |
623 | unsigned long action, void *hcpu) | |
624 | { | |
625 | int cpu = (long)hcpu; | |
626 | switch (action) { | |
627 | case CPU_UP_PREPARE: | |
628 | if (alloc_balloon_scratch_page(cpu)) | |
629 | return NOTIFY_BAD; | |
630 | break; | |
631 | default: | |
632 | break; | |
633 | } | |
634 | return NOTIFY_OK; | |
635 | } | |
636 | ||
637 | static struct notifier_block balloon_cpu_notifier = { | |
638 | .notifier_call = balloon_cpu_notify, | |
639 | }; | |
640 | ||
641 | static int __init balloon_init(void) | |
642 | { | |
643 | int i, cpu; | |
644 | ||
645 | if (!xen_domain()) | |
646 | return -ENODEV; | |
647 | ||
648 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
649 | register_cpu_notifier(&balloon_cpu_notifier); | |
650 | ||
651 | get_online_cpus(); | |
652 | for_each_online_cpu(cpu) { | |
653 | if (alloc_balloon_scratch_page(cpu)) { | |
654 | put_online_cpus(); | |
655 | unregister_cpu_notifier(&balloon_cpu_notifier); | |
656 | return -ENOMEM; | |
657 | } | |
658 | } | |
659 | put_online_cpus(); | |
660 | } | |
661 | ||
662 | pr_info("Initialising balloon driver\n"); | |
663 | ||
664 | balloon_stats.current_pages = xen_pv_domain() | |
665 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
666 | : get_num_physpages(); | |
667 | balloon_stats.target_pages = balloon_stats.current_pages; | |
668 | balloon_stats.balloon_low = 0; | |
669 | balloon_stats.balloon_high = 0; | |
670 | ||
671 | balloon_stats.schedule_delay = 1; | |
672 | balloon_stats.max_schedule_delay = 32; | |
673 | balloon_stats.retry_count = 1; | |
674 | balloon_stats.max_retry_count = RETRY_UNLIMITED; | |
675 | ||
676 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
677 | balloon_stats.hotplug_pages = 0; | |
678 | balloon_stats.balloon_hotplug = 0; | |
679 | ||
680 | set_online_page_callback(&xen_online_page); | |
681 | register_memory_notifier(&xen_memory_nb); | |
682 | #endif | |
683 | ||
684 | /* | |
685 | * Initialize the balloon with pages from the extra memory | |
686 | * regions (see arch/x86/xen/setup.c). | |
687 | */ | |
688 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) | |
689 | if (xen_extra_mem[i].size) | |
690 | balloon_add_region(PFN_UP(xen_extra_mem[i].start), | |
691 | PFN_DOWN(xen_extra_mem[i].size)); | |
692 | ||
693 | return 0; | |
694 | } | |
695 | ||
696 | subsys_initcall(balloon_init); | |
697 | ||
698 | static int __init balloon_clear(void) | |
699 | { | |
700 | int cpu; | |
701 | ||
702 | for_each_possible_cpu(cpu) | |
703 | per_cpu(balloon_scratch_page, cpu) = NULL; | |
704 | ||
705 | return 0; | |
706 | } | |
707 | early_initcall(balloon_clear); | |
708 | ||
709 | MODULE_LICENSE("GPL"); |