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1775826c | 1 | /****************************************************************************** |
1775826c JF |
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 | |
080e2be7 DK |
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. | |
1775826c JF |
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 | ||
283c0972 JP |
39 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
40 | ||
1775826c | 41 | #include <linux/kernel.h> |
1775826c JF |
42 | #include <linux/sched.h> |
43 | #include <linux/errno.h> | |
72ee5112 | 44 | #include <linux/module.h> |
1775826c JF |
45 | #include <linux/mm.h> |
46 | #include <linux/bootmem.h> | |
47 | #include <linux/pagemap.h> | |
48 | #include <linux/highmem.h> | |
49 | #include <linux/mutex.h> | |
1775826c | 50 | #include <linux/list.h> |
5a0e3ad6 | 51 | #include <linux/gfp.h> |
080e2be7 DK |
52 | #include <linux/notifier.h> |
53 | #include <linux/memory.h> | |
54 | #include <linux/memory_hotplug.h> | |
1775826c | 55 | |
1775826c JF |
56 | #include <asm/page.h> |
57 | #include <asm/pgalloc.h> | |
58 | #include <asm/pgtable.h> | |
1775826c JF |
59 | #include <asm/tlb.h> |
60 | ||
ecbf29cd JF |
61 | #include <asm/xen/hypervisor.h> |
62 | #include <asm/xen/hypercall.h> | |
1ccbf534 JF |
63 | |
64 | #include <xen/xen.h> | |
ecbf29cd | 65 | #include <xen/interface/xen.h> |
1775826c | 66 | #include <xen/interface/memory.h> |
803eb047 | 67 | #include <xen/balloon.h> |
1775826c JF |
68 | #include <xen/features.h> |
69 | #include <xen/page.h> | |
70 | ||
95d2ac4a DK |
71 | /* |
72 | * balloon_process() state: | |
73 | * | |
74 | * BP_DONE: done or nothing to do, | |
75 | * BP_EAGAIN: error, go to sleep, | |
76 | * BP_ECANCELED: error, balloon operation canceled. | |
77 | */ | |
1775826c | 78 | |
95d2ac4a DK |
79 | enum bp_state { |
80 | BP_DONE, | |
81 | BP_EAGAIN, | |
82 | BP_ECANCELED | |
1775826c JF |
83 | }; |
84 | ||
1775826c | 85 | |
1775826c | 86 | static DEFINE_MUTEX(balloon_mutex); |
1775826c | 87 | |
803eb047 DDG |
88 | struct balloon_stats balloon_stats; |
89 | EXPORT_SYMBOL_GPL(balloon_stats); | |
1775826c JF |
90 | |
91 | /* We increase/decrease in batches which fit in a page */ | |
965c0aaa | 92 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; |
1775826c | 93 | |
1775826c JF |
94 | /* List of ballooned pages, threaded through the mem_map array. */ |
95 | static LIST_HEAD(ballooned_pages); | |
96 | ||
97 | /* Main work function, always executed in process context. */ | |
98 | static void balloon_process(struct work_struct *work); | |
95170b2e | 99 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); |
1775826c JF |
100 | |
101 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
102 | want the kernel to try too hard since that can trigger the oom killer. */ | |
103 | #define GFP_BALLOON \ | |
104 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
105 | ||
106 | static void scrub_page(struct page *page) | |
107 | { | |
108 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
26a3e991 | 109 | clear_highpage(page); |
1775826c JF |
110 | #endif |
111 | } | |
112 | ||
113 | /* balloon_append: add the given page to the balloon. */ | |
9be4d457 | 114 | static void __balloon_append(struct page *page) |
1775826c JF |
115 | { |
116 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
117 | if (PageHighMem(page)) { | |
118 | list_add_tail(&page->lru, &ballooned_pages); | |
119 | balloon_stats.balloon_high++; | |
1775826c JF |
120 | } else { |
121 | list_add(&page->lru, &ballooned_pages); | |
122 | balloon_stats.balloon_low++; | |
123 | } | |
9be4d457 | 124 | } |
3d65c948 | 125 | |
9be4d457 JF |
126 | static void balloon_append(struct page *page) |
127 | { | |
128 | __balloon_append(page); | |
3dcc0571 | 129 | adjust_managed_page_count(page, -1); |
1775826c JF |
130 | } |
131 | ||
132 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
b6f30679 | 133 | static struct page *balloon_retrieve(bool prefer_highmem) |
1775826c JF |
134 | { |
135 | struct page *page; | |
136 | ||
137 | if (list_empty(&ballooned_pages)) | |
138 | return NULL; | |
139 | ||
b6f30679 KRW |
140 | if (prefer_highmem) |
141 | page = list_entry(ballooned_pages.prev, struct page, lru); | |
142 | else | |
143 | page = list_entry(ballooned_pages.next, struct page, lru); | |
1775826c JF |
144 | list_del(&page->lru); |
145 | ||
3dcc0571 | 146 | if (PageHighMem(page)) |
1775826c | 147 | balloon_stats.balloon_high--; |
3dcc0571 | 148 | else |
1775826c JF |
149 | balloon_stats.balloon_low--; |
150 | ||
3dcc0571 | 151 | adjust_managed_page_count(page, 1); |
3d65c948 | 152 | |
1775826c JF |
153 | return page; |
154 | } | |
155 | ||
156 | static struct page *balloon_first_page(void) | |
157 | { | |
158 | if (list_empty(&ballooned_pages)) | |
159 | return NULL; | |
160 | return list_entry(ballooned_pages.next, struct page, lru); | |
161 | } | |
162 | ||
163 | static struct page *balloon_next_page(struct page *page) | |
164 | { | |
165 | struct list_head *next = page->lru.next; | |
166 | if (next == &ballooned_pages) | |
167 | return NULL; | |
168 | return list_entry(next, struct page, lru); | |
169 | } | |
170 | ||
95d2ac4a | 171 | static enum bp_state update_schedule(enum bp_state state) |
1775826c | 172 | { |
95d2ac4a DK |
173 | if (state == BP_DONE) { |
174 | balloon_stats.schedule_delay = 1; | |
175 | balloon_stats.retry_count = 1; | |
176 | return BP_DONE; | |
177 | } | |
178 | ||
95d2ac4a DK |
179 | ++balloon_stats.retry_count; |
180 | ||
181 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
182 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
183 | balloon_stats.schedule_delay = 1; |
184 | balloon_stats.retry_count = 1; | |
185 | return BP_ECANCELED; | |
186 | } | |
187 | ||
188 | balloon_stats.schedule_delay <<= 1; | |
189 | ||
190 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
191 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
192 | ||
193 | return BP_EAGAIN; | |
1775826c JF |
194 | } |
195 | ||
080e2be7 DK |
196 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
197 | static long current_credit(void) | |
198 | { | |
199 | return balloon_stats.target_pages - balloon_stats.current_pages - | |
200 | balloon_stats.hotplug_pages; | |
201 | } | |
202 | ||
203 | static bool balloon_is_inflated(void) | |
204 | { | |
205 | if (balloon_stats.balloon_low || balloon_stats.balloon_high || | |
206 | balloon_stats.balloon_hotplug) | |
207 | return true; | |
208 | else | |
209 | return false; | |
210 | } | |
211 | ||
212 | /* | |
213 | * reserve_additional_memory() adds memory region of size >= credit above | |
214 | * max_pfn. New region is section aligned and size is modified to be multiple | |
215 | * of section size. Those features allow optimal use of address space and | |
216 | * establish proper alignment when this function is called first time after | |
217 | * boot (last section not fully populated at boot time contains unused memory | |
218 | * pages with PG_reserved bit not set; online_pages_range() does not allow page | |
219 | * onlining in whole range if first onlined page does not have PG_reserved | |
220 | * bit set). Real size of added memory is established at page onlining stage. | |
221 | */ | |
222 | ||
223 | static enum bp_state reserve_additional_memory(long credit) | |
224 | { | |
225 | int nid, rc; | |
226 | u64 hotplug_start_paddr; | |
227 | unsigned long balloon_hotplug = credit; | |
228 | ||
229 | hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); | |
230 | balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); | |
231 | nid = memory_add_physaddr_to_nid(hotplug_start_paddr); | |
232 | ||
233 | rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); | |
234 | ||
235 | if (rc) { | |
283c0972 | 236 | pr_info("%s: add_memory() failed: %i\n", __func__, rc); |
080e2be7 DK |
237 | return BP_EAGAIN; |
238 | } | |
239 | ||
240 | balloon_hotplug -= credit; | |
241 | ||
242 | balloon_stats.hotplug_pages += credit; | |
243 | balloon_stats.balloon_hotplug = balloon_hotplug; | |
244 | ||
245 | return BP_DONE; | |
246 | } | |
247 | ||
248 | static void xen_online_page(struct page *page) | |
249 | { | |
250 | __online_page_set_limits(page); | |
251 | ||
252 | mutex_lock(&balloon_mutex); | |
253 | ||
254 | __balloon_append(page); | |
255 | ||
256 | if (balloon_stats.hotplug_pages) | |
257 | --balloon_stats.hotplug_pages; | |
258 | else | |
259 | --balloon_stats.balloon_hotplug; | |
260 | ||
261 | mutex_unlock(&balloon_mutex); | |
262 | } | |
263 | ||
264 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
265 | { | |
266 | if (val == MEM_ONLINE) | |
267 | schedule_delayed_work(&balloon_worker, 0); | |
268 | ||
269 | return NOTIFY_OK; | |
270 | } | |
271 | ||
272 | static struct notifier_block xen_memory_nb = { | |
273 | .notifier_call = xen_memory_notifier, | |
274 | .priority = 0 | |
275 | }; | |
276 | #else | |
83be7e52 | 277 | static long current_credit(void) |
1775826c | 278 | { |
bc2c0303 | 279 | unsigned long target = balloon_stats.target_pages; |
1775826c JF |
280 | |
281 | target = min(target, | |
282 | balloon_stats.current_pages + | |
283 | balloon_stats.balloon_low + | |
284 | balloon_stats.balloon_high); | |
285 | ||
83be7e52 | 286 | return target - balloon_stats.current_pages; |
1775826c JF |
287 | } |
288 | ||
080e2be7 DK |
289 | static bool balloon_is_inflated(void) |
290 | { | |
291 | if (balloon_stats.balloon_low || balloon_stats.balloon_high) | |
292 | return true; | |
293 | else | |
294 | return false; | |
295 | } | |
296 | ||
297 | static enum bp_state reserve_additional_memory(long credit) | |
298 | { | |
299 | balloon_stats.target_pages = balloon_stats.current_pages; | |
300 | return BP_DONE; | |
301 | } | |
302 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ | |
303 | ||
95d2ac4a | 304 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 305 | { |
95d2ac4a | 306 | int rc; |
2f70e0ac | 307 | unsigned long pfn, i; |
1775826c | 308 | struct page *page; |
1775826c JF |
309 | struct xen_memory_reservation reservation = { |
310 | .address_bits = 0, | |
311 | .extent_order = 0, | |
312 | .domid = DOMID_SELF | |
313 | }; | |
314 | ||
080e2be7 DK |
315 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
316 | if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) { | |
317 | nr_pages = min(nr_pages, balloon_stats.balloon_hotplug); | |
318 | balloon_stats.hotplug_pages += nr_pages; | |
319 | balloon_stats.balloon_hotplug -= nr_pages; | |
320 | return BP_DONE; | |
321 | } | |
322 | #endif | |
323 | ||
1775826c JF |
324 | if (nr_pages > ARRAY_SIZE(frame_list)) |
325 | nr_pages = ARRAY_SIZE(frame_list); | |
326 | ||
1775826c JF |
327 | page = balloon_first_page(); |
328 | for (i = 0; i < nr_pages; i++) { | |
95d2ac4a DK |
329 | if (!page) { |
330 | nr_pages = i; | |
331 | break; | |
332 | } | |
a419aef8 | 333 | frame_list[i] = page_to_pfn(page); |
1775826c JF |
334 | page = balloon_next_page(page); |
335 | } | |
336 | ||
a90971eb | 337 | set_xen_guest_handle(reservation.extent_start, frame_list); |
fde28e8f JF |
338 | reservation.nr_extents = nr_pages; |
339 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); | |
40095de1 | 340 | if (rc <= 0) |
95d2ac4a | 341 | return BP_EAGAIN; |
1775826c | 342 | |
bc2c0303 | 343 | for (i = 0; i < rc; i++) { |
b6f30679 | 344 | page = balloon_retrieve(false); |
1775826c JF |
345 | BUG_ON(page == NULL); |
346 | ||
347 | pfn = page_to_pfn(page); | |
348 | BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && | |
349 | phys_to_machine_mapping_valid(pfn)); | |
350 | ||
351 | set_phys_to_machine(pfn, frame_list[i]); | |
352 | ||
c2374bf5 | 353 | #ifdef CONFIG_XEN_HAVE_PVMMU |
1775826c | 354 | /* Link back into the page tables if not highmem. */ |
4dfe22f5 | 355 | if (xen_pv_domain() && !PageHighMem(page)) { |
1775826c JF |
356 | int ret; |
357 | ret = HYPERVISOR_update_va_mapping( | |
358 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
359 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
360 | 0); | |
361 | BUG_ON(ret); | |
362 | } | |
c2374bf5 | 363 | #endif |
1775826c JF |
364 | |
365 | /* Relinquish the page back to the allocator. */ | |
3dcc0571 | 366 | __free_reserved_page(page); |
1775826c JF |
367 | } |
368 | ||
bc2c0303 | 369 | balloon_stats.current_pages += rc; |
1775826c | 370 | |
95d2ac4a | 371 | return BP_DONE; |
1775826c JF |
372 | } |
373 | ||
b6f30679 | 374 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) |
1775826c | 375 | { |
95d2ac4a | 376 | enum bp_state state = BP_DONE; |
2f70e0ac | 377 | unsigned long pfn, i; |
1775826c | 378 | struct page *page; |
1775826c JF |
379 | int ret; |
380 | struct xen_memory_reservation reservation = { | |
381 | .address_bits = 0, | |
382 | .extent_order = 0, | |
383 | .domid = DOMID_SELF | |
384 | }; | |
385 | ||
080e2be7 DK |
386 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
387 | if (balloon_stats.hotplug_pages) { | |
388 | nr_pages = min(nr_pages, balloon_stats.hotplug_pages); | |
389 | balloon_stats.hotplug_pages -= nr_pages; | |
390 | balloon_stats.balloon_hotplug += nr_pages; | |
391 | return BP_DONE; | |
392 | } | |
393 | #endif | |
394 | ||
1775826c JF |
395 | if (nr_pages > ARRAY_SIZE(frame_list)) |
396 | nr_pages = ARRAY_SIZE(frame_list); | |
397 | ||
398 | for (i = 0; i < nr_pages; i++) { | |
fce92683 LN |
399 | page = alloc_page(gfp); |
400 | if (page == NULL) { | |
1775826c | 401 | nr_pages = i; |
95d2ac4a | 402 | state = BP_EAGAIN; |
1775826c JF |
403 | break; |
404 | } | |
405 | ||
406 | pfn = page_to_pfn(page); | |
407 | frame_list[i] = pfn_to_mfn(pfn); | |
408 | ||
409 | scrub_page(page); | |
1058a75f | 410 | |
c2374bf5 | 411 | #ifdef CONFIG_XEN_HAVE_PVMMU |
4dfe22f5 | 412 | if (xen_pv_domain() && !PageHighMem(page)) { |
ff4ce8c3 IC |
413 | ret = HYPERVISOR_update_va_mapping( |
414 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
415 | __pte_ma(0), 0); | |
416 | BUG_ON(ret); | |
e882dc9c | 417 | } |
c2374bf5 | 418 | #endif |
1775826c JF |
419 | } |
420 | ||
421 | /* Ensure that ballooned highmem pages don't have kmaps. */ | |
422 | kmap_flush_unused(); | |
423 | flush_tlb_all(); | |
424 | ||
1775826c JF |
425 | /* No more mappings: invalidate P2M and add to balloon. */ |
426 | for (i = 0; i < nr_pages; i++) { | |
427 | pfn = mfn_to_pfn(frame_list[i]); | |
6eaa412f | 428 | __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); |
1775826c JF |
429 | balloon_append(pfn_to_page(pfn)); |
430 | } | |
431 | ||
a90971eb | 432 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
433 | reservation.nr_extents = nr_pages; |
434 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
435 | BUG_ON(ret != nr_pages); | |
436 | ||
437 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 438 | |
95d2ac4a | 439 | return state; |
1775826c JF |
440 | } |
441 | ||
442 | /* | |
443 | * We avoid multiple worker processes conflicting via the balloon mutex. | |
444 | * We may of course race updates of the target counts (which are protected | |
445 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
446 | * recover from these in time. | |
447 | */ | |
448 | static void balloon_process(struct work_struct *work) | |
449 | { | |
95d2ac4a | 450 | enum bp_state state = BP_DONE; |
1775826c JF |
451 | long credit; |
452 | ||
453 | mutex_lock(&balloon_mutex); | |
454 | ||
455 | do { | |
83be7e52 | 456 | credit = current_credit(); |
95d2ac4a | 457 | |
080e2be7 DK |
458 | if (credit > 0) { |
459 | if (balloon_is_inflated()) | |
460 | state = increase_reservation(credit); | |
461 | else | |
462 | state = reserve_additional_memory(credit); | |
463 | } | |
95d2ac4a | 464 | |
1775826c | 465 | if (credit < 0) |
b6f30679 | 466 | state = decrease_reservation(-credit, GFP_BALLOON); |
95d2ac4a DK |
467 | |
468 | state = update_schedule(state); | |
1775826c JF |
469 | |
470 | #ifndef CONFIG_PREEMPT | |
471 | if (need_resched()) | |
472 | schedule(); | |
473 | #endif | |
95d2ac4a | 474 | } while (credit && state == BP_DONE); |
1775826c JF |
475 | |
476 | /* Schedule more work if there is some still to be done. */ | |
95d2ac4a DK |
477 | if (state == BP_EAGAIN) |
478 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
1775826c JF |
479 | |
480 | mutex_unlock(&balloon_mutex); | |
481 | } | |
482 | ||
483 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
803eb047 | 484 | void balloon_set_new_target(unsigned long target) |
1775826c JF |
485 | { |
486 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 487 | balloon_stats.target_pages = target; |
95170b2e | 488 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 489 | } |
803eb047 | 490 | EXPORT_SYMBOL_GPL(balloon_set_new_target); |
1775826c | 491 | |
b6f30679 KRW |
492 | /** |
493 | * alloc_xenballooned_pages - get pages that have been ballooned out | |
494 | * @nr_pages: Number of pages to get | |
495 | * @pages: pages returned | |
72e9cf2a | 496 | * @highmem: allow highmem pages |
b6f30679 KRW |
497 | * @return 0 on success, error otherwise |
498 | */ | |
693394b8 | 499 | int alloc_xenballooned_pages(int nr_pages, struct page **pages, bool highmem) |
1775826c | 500 | { |
b6f30679 | 501 | int pgno = 0; |
e882dc9c | 502 | struct page *page; |
b6f30679 KRW |
503 | mutex_lock(&balloon_mutex); |
504 | while (pgno < nr_pages) { | |
693394b8 | 505 | page = balloon_retrieve(highmem); |
72e9cf2a | 506 | if (page && (highmem || !PageHighMem(page))) { |
b6f30679 KRW |
507 | pages[pgno++] = page; |
508 | } else { | |
509 | enum bp_state st; | |
693394b8 SS |
510 | if (page) |
511 | balloon_append(page); | |
512 | st = decrease_reservation(nr_pages - pgno, | |
513 | highmem ? GFP_HIGHUSER : GFP_USER); | |
b6f30679 KRW |
514 | if (st != BP_DONE) |
515 | goto out_undo; | |
516 | } | |
1775826c | 517 | } |
b6f30679 KRW |
518 | mutex_unlock(&balloon_mutex); |
519 | return 0; | |
520 | out_undo: | |
521 | while (pgno) | |
522 | balloon_append(pages[--pgno]); | |
523 | /* Free the memory back to the kernel soon */ | |
524 | schedule_delayed_work(&balloon_worker, 0); | |
525 | mutex_unlock(&balloon_mutex); | |
526 | return -ENOMEM; | |
1775826c | 527 | } |
b6f30679 | 528 | EXPORT_SYMBOL(alloc_xenballooned_pages); |
1775826c | 529 | |
b6f30679 KRW |
530 | /** |
531 | * free_xenballooned_pages - return pages retrieved with get_ballooned_pages | |
532 | * @nr_pages: Number of pages | |
533 | * @pages: pages to return | |
534 | */ | |
e882dc9c | 535 | void free_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 536 | { |
b6f30679 | 537 | int i; |
1775826c | 538 | |
b6f30679 | 539 | mutex_lock(&balloon_mutex); |
1775826c | 540 | |
b6f30679 KRW |
541 | for (i = 0; i < nr_pages; i++) { |
542 | if (pages[i]) | |
543 | balloon_append(pages[i]); | |
544 | } | |
545 | ||
546 | /* The balloon may be too large now. Shrink it if needed. */ | |
83be7e52 | 547 | if (current_credit()) |
b6f30679 | 548 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 549 | |
b6f30679 KRW |
550 | mutex_unlock(&balloon_mutex); |
551 | } | |
552 | EXPORT_SYMBOL(free_xenballooned_pages); | |
1775826c | 553 | |
8b5d44a5 DV |
554 | static void __init balloon_add_region(unsigned long start_pfn, |
555 | unsigned long pages) | |
1775826c | 556 | { |
4dfe22f5 | 557 | unsigned long pfn, extra_pfn_end; |
1775826c JF |
558 | struct page *page; |
559 | ||
8b5d44a5 DV |
560 | /* |
561 | * If the amount of usable memory has been limited (e.g., with | |
562 | * the 'mem' command line parameter), don't add pages beyond | |
563 | * this limit. | |
564 | */ | |
565 | extra_pfn_end = min(max_pfn, start_pfn + pages); | |
566 | ||
567 | for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { | |
568 | page = pfn_to_page(pfn); | |
569 | /* totalram_pages and totalhigh_pages do not | |
570 | include the boot-time balloon extension, so | |
571 | don't subtract from it. */ | |
572 | __balloon_append(page); | |
573 | } | |
574 | } | |
575 | ||
576 | static int __init balloon_init(void) | |
577 | { | |
578 | int i; | |
579 | ||
53d5522c | 580 | if (!xen_domain()) |
1775826c JF |
581 | return -ENODEV; |
582 | ||
283c0972 | 583 | pr_info("Initialising balloon driver\n"); |
1775826c | 584 | |
aa24411b DV |
585 | balloon_stats.current_pages = xen_pv_domain() |
586 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
587 | : max_pfn; | |
1775826c JF |
588 | balloon_stats.target_pages = balloon_stats.current_pages; |
589 | balloon_stats.balloon_low = 0; | |
590 | balloon_stats.balloon_high = 0; | |
1775826c | 591 | |
95d2ac4a DK |
592 | balloon_stats.schedule_delay = 1; |
593 | balloon_stats.max_schedule_delay = 32; | |
594 | balloon_stats.retry_count = 1; | |
40095de1 | 595 | balloon_stats.max_retry_count = RETRY_UNLIMITED; |
1775826c | 596 | |
080e2be7 DK |
597 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
598 | balloon_stats.hotplug_pages = 0; | |
599 | balloon_stats.balloon_hotplug = 0; | |
600 | ||
601 | set_online_page_callback(&xen_online_page); | |
602 | register_memory_notifier(&xen_memory_nb); | |
603 | #endif | |
604 | ||
2a4c92fa | 605 | /* |
b1cbf9b1 | 606 | * Initialize the balloon with pages from the extra memory |
8b5d44a5 | 607 | * regions (see arch/x86/xen/setup.c). |
2a4c92fa | 608 | */ |
8b5d44a5 DV |
609 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) |
610 | if (xen_extra_mem[i].size) | |
611 | balloon_add_region(PFN_UP(xen_extra_mem[i].start), | |
612 | PFN_DOWN(xen_extra_mem[i].size)); | |
1775826c | 613 | |
1775826c JF |
614 | return 0; |
615 | } | |
616 | ||
617 | subsys_initcall(balloon_init); | |
618 | ||
1775826c | 619 | MODULE_LICENSE("GPL"); |