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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 | ||
cd9151e2 | 41 | #include <linux/cpu.h> |
1775826c | 42 | #include <linux/kernel.h> |
1775826c JF |
43 | #include <linux/sched.h> |
44 | #include <linux/errno.h> | |
72ee5112 | 45 | #include <linux/module.h> |
1775826c JF |
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> | |
1775826c | 51 | #include <linux/list.h> |
5a0e3ad6 | 52 | #include <linux/gfp.h> |
080e2be7 DK |
53 | #include <linux/notifier.h> |
54 | #include <linux/memory.h> | |
55 | #include <linux/memory_hotplug.h> | |
cd9151e2 | 56 | #include <linux/percpu-defs.h> |
1775826c | 57 | |
1775826c JF |
58 | #include <asm/page.h> |
59 | #include <asm/pgalloc.h> | |
60 | #include <asm/pgtable.h> | |
1775826c JF |
61 | #include <asm/tlb.h> |
62 | ||
ecbf29cd JF |
63 | #include <asm/xen/hypervisor.h> |
64 | #include <asm/xen/hypercall.h> | |
1ccbf534 JF |
65 | |
66 | #include <xen/xen.h> | |
ecbf29cd | 67 | #include <xen/interface/xen.h> |
1775826c | 68 | #include <xen/interface/memory.h> |
803eb047 | 69 | #include <xen/balloon.h> |
1775826c JF |
70 | #include <xen/features.h> |
71 | #include <xen/page.h> | |
72 | ||
95d2ac4a DK |
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 | */ | |
1775826c | 80 | |
95d2ac4a DK |
81 | enum bp_state { |
82 | BP_DONE, | |
83 | BP_EAGAIN, | |
84 | BP_ECANCELED | |
1775826c JF |
85 | }; |
86 | ||
1775826c | 87 | |
1775826c | 88 | static DEFINE_MUTEX(balloon_mutex); |
1775826c | 89 | |
803eb047 DDG |
90 | struct balloon_stats balloon_stats; |
91 | EXPORT_SYMBOL_GPL(balloon_stats); | |
1775826c JF |
92 | |
93 | /* We increase/decrease in batches which fit in a page */ | |
965c0aaa | 94 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; |
cd9151e2 | 95 | |
1775826c | 96 | |
1775826c JF |
97 | /* List of ballooned pages, threaded through the mem_map array. */ |
98 | static LIST_HEAD(ballooned_pages); | |
99 | ||
100 | /* Main work function, always executed in process context. */ | |
101 | static void balloon_process(struct work_struct *work); | |
95170b2e | 102 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); |
1775826c JF |
103 | |
104 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
105 | want the kernel to try too hard since that can trigger the oom killer. */ | |
106 | #define GFP_BALLOON \ | |
107 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
108 | ||
109 | static void scrub_page(struct page *page) | |
110 | { | |
111 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
26a3e991 | 112 | clear_highpage(page); |
1775826c JF |
113 | #endif |
114 | } | |
115 | ||
116 | /* balloon_append: add the given page to the balloon. */ | |
9be4d457 | 117 | static void __balloon_append(struct page *page) |
1775826c JF |
118 | { |
119 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
120 | if (PageHighMem(page)) { | |
121 | list_add_tail(&page->lru, &ballooned_pages); | |
122 | balloon_stats.balloon_high++; | |
1775826c JF |
123 | } else { |
124 | list_add(&page->lru, &ballooned_pages); | |
125 | balloon_stats.balloon_low++; | |
126 | } | |
9be4d457 | 127 | } |
3d65c948 | 128 | |
9be4d457 JF |
129 | static void balloon_append(struct page *page) |
130 | { | |
131 | __balloon_append(page); | |
3dcc0571 | 132 | adjust_managed_page_count(page, -1); |
1775826c JF |
133 | } |
134 | ||
135 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
b6f30679 | 136 | static struct page *balloon_retrieve(bool prefer_highmem) |
1775826c JF |
137 | { |
138 | struct page *page; | |
139 | ||
140 | if (list_empty(&ballooned_pages)) | |
141 | return NULL; | |
142 | ||
b6f30679 KRW |
143 | if (prefer_highmem) |
144 | page = list_entry(ballooned_pages.prev, struct page, lru); | |
145 | else | |
146 | page = list_entry(ballooned_pages.next, struct page, lru); | |
1775826c JF |
147 | list_del(&page->lru); |
148 | ||
3dcc0571 | 149 | if (PageHighMem(page)) |
1775826c | 150 | balloon_stats.balloon_high--; |
3dcc0571 | 151 | else |
1775826c JF |
152 | balloon_stats.balloon_low--; |
153 | ||
3dcc0571 | 154 | adjust_managed_page_count(page, 1); |
3d65c948 | 155 | |
1775826c JF |
156 | return page; |
157 | } | |
158 | ||
1775826c JF |
159 | static struct page *balloon_next_page(struct page *page) |
160 | { | |
161 | struct list_head *next = page->lru.next; | |
162 | if (next == &ballooned_pages) | |
163 | return NULL; | |
164 | return list_entry(next, struct page, lru); | |
165 | } | |
166 | ||
95d2ac4a | 167 | static enum bp_state update_schedule(enum bp_state state) |
1775826c | 168 | { |
fd8b7951 BO |
169 | if (state == BP_ECANCELED) |
170 | return BP_ECANCELED; | |
171 | ||
95d2ac4a DK |
172 | if (state == BP_DONE) { |
173 | balloon_stats.schedule_delay = 1; | |
174 | balloon_stats.retry_count = 1; | |
175 | return BP_DONE; | |
176 | } | |
177 | ||
95d2ac4a DK |
178 | ++balloon_stats.retry_count; |
179 | ||
180 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
181 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
182 | balloon_stats.schedule_delay = 1; |
183 | balloon_stats.retry_count = 1; | |
184 | return BP_ECANCELED; | |
185 | } | |
186 | ||
187 | balloon_stats.schedule_delay <<= 1; | |
188 | ||
189 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
190 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
191 | ||
192 | return BP_EAGAIN; | |
1775826c JF |
193 | } |
194 | ||
080e2be7 DK |
195 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
196 | static long current_credit(void) | |
197 | { | |
198 | return balloon_stats.target_pages - balloon_stats.current_pages - | |
199 | balloon_stats.hotplug_pages; | |
200 | } | |
201 | ||
202 | static bool balloon_is_inflated(void) | |
203 | { | |
204 | if (balloon_stats.balloon_low || balloon_stats.balloon_high || | |
205 | balloon_stats.balloon_hotplug) | |
206 | return true; | |
207 | else | |
208 | return false; | |
209 | } | |
210 | ||
211 | /* | |
212 | * reserve_additional_memory() adds memory region of size >= credit above | |
213 | * max_pfn. New region is section aligned and size is modified to be multiple | |
214 | * of section size. Those features allow optimal use of address space and | |
215 | * establish proper alignment when this function is called first time after | |
216 | * boot (last section not fully populated at boot time contains unused memory | |
217 | * pages with PG_reserved bit not set; online_pages_range() does not allow page | |
218 | * onlining in whole range if first onlined page does not have PG_reserved | |
219 | * bit set). Real size of added memory is established at page onlining stage. | |
220 | */ | |
221 | ||
222 | static enum bp_state reserve_additional_memory(long credit) | |
223 | { | |
224 | int nid, rc; | |
225 | u64 hotplug_start_paddr; | |
226 | unsigned long balloon_hotplug = credit; | |
227 | ||
228 | hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); | |
229 | balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); | |
230 | nid = memory_add_physaddr_to_nid(hotplug_start_paddr); | |
231 | ||
3c56b3a1 JG |
232 | #ifdef CONFIG_XEN_HAVE_PVMMU |
233 | /* | |
234 | * add_memory() will build page tables for the new memory so | |
235 | * the p2m must contain invalid entries so the correct | |
236 | * non-present PTEs will be written. | |
237 | * | |
238 | * If a failure occurs, the original (identity) p2m entries | |
239 | * are not restored since this region is now known not to | |
240 | * conflict with any devices. | |
241 | */ | |
242 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
243 | unsigned long pfn, i; | |
244 | ||
245 | pfn = PFN_DOWN(hotplug_start_paddr); | |
246 | for (i = 0; i < balloon_hotplug; i++) { | |
247 | if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { | |
248 | pr_warn("set_phys_to_machine() failed, no memory added\n"); | |
249 | return BP_ECANCELED; | |
250 | } | |
251 | } | |
252 | } | |
253 | #endif | |
254 | ||
080e2be7 DK |
255 | rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); |
256 | ||
257 | if (rc) { | |
3dcf6367 DV |
258 | pr_warn("Cannot add additional memory (%i)\n", rc); |
259 | return BP_ECANCELED; | |
080e2be7 DK |
260 | } |
261 | ||
262 | balloon_hotplug -= credit; | |
263 | ||
264 | balloon_stats.hotplug_pages += credit; | |
265 | balloon_stats.balloon_hotplug = balloon_hotplug; | |
266 | ||
267 | return BP_DONE; | |
268 | } | |
269 | ||
270 | static void xen_online_page(struct page *page) | |
271 | { | |
272 | __online_page_set_limits(page); | |
273 | ||
274 | mutex_lock(&balloon_mutex); | |
275 | ||
276 | __balloon_append(page); | |
277 | ||
278 | if (balloon_stats.hotplug_pages) | |
279 | --balloon_stats.hotplug_pages; | |
280 | else | |
281 | --balloon_stats.balloon_hotplug; | |
282 | ||
283 | mutex_unlock(&balloon_mutex); | |
284 | } | |
285 | ||
286 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
287 | { | |
288 | if (val == MEM_ONLINE) | |
289 | schedule_delayed_work(&balloon_worker, 0); | |
290 | ||
291 | return NOTIFY_OK; | |
292 | } | |
293 | ||
294 | static struct notifier_block xen_memory_nb = { | |
295 | .notifier_call = xen_memory_notifier, | |
296 | .priority = 0 | |
297 | }; | |
298 | #else | |
83be7e52 | 299 | static long current_credit(void) |
1775826c | 300 | { |
bc2c0303 | 301 | unsigned long target = balloon_stats.target_pages; |
1775826c JF |
302 | |
303 | target = min(target, | |
304 | balloon_stats.current_pages + | |
305 | balloon_stats.balloon_low + | |
306 | balloon_stats.balloon_high); | |
307 | ||
83be7e52 | 308 | return target - balloon_stats.current_pages; |
1775826c JF |
309 | } |
310 | ||
080e2be7 DK |
311 | static bool balloon_is_inflated(void) |
312 | { | |
313 | if (balloon_stats.balloon_low || balloon_stats.balloon_high) | |
314 | return true; | |
315 | else | |
316 | return false; | |
317 | } | |
318 | ||
319 | static enum bp_state reserve_additional_memory(long credit) | |
320 | { | |
321 | balloon_stats.target_pages = balloon_stats.current_pages; | |
322 | return BP_DONE; | |
323 | } | |
324 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ | |
325 | ||
95d2ac4a | 326 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 327 | { |
95d2ac4a | 328 | int rc; |
2f70e0ac | 329 | unsigned long pfn, i; |
1775826c | 330 | struct page *page; |
1775826c JF |
331 | struct xen_memory_reservation reservation = { |
332 | .address_bits = 0, | |
333 | .extent_order = 0, | |
334 | .domid = DOMID_SELF | |
335 | }; | |
336 | ||
080e2be7 DK |
337 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
338 | if (!balloon_stats.balloon_low && !balloon_stats.balloon_high) { | |
339 | nr_pages = min(nr_pages, balloon_stats.balloon_hotplug); | |
340 | balloon_stats.hotplug_pages += nr_pages; | |
341 | balloon_stats.balloon_hotplug -= nr_pages; | |
342 | return BP_DONE; | |
343 | } | |
344 | #endif | |
345 | ||
1775826c JF |
346 | if (nr_pages > ARRAY_SIZE(frame_list)) |
347 | nr_pages = ARRAY_SIZE(frame_list); | |
348 | ||
9346c2a8 | 349 | page = list_first_entry_or_null(&ballooned_pages, struct page, lru); |
1775826c | 350 | for (i = 0; i < nr_pages; i++) { |
95d2ac4a DK |
351 | if (!page) { |
352 | nr_pages = i; | |
353 | break; | |
354 | } | |
a419aef8 | 355 | frame_list[i] = page_to_pfn(page); |
1775826c JF |
356 | page = balloon_next_page(page); |
357 | } | |
358 | ||
a90971eb | 359 | set_xen_guest_handle(reservation.extent_start, frame_list); |
fde28e8f JF |
360 | reservation.nr_extents = nr_pages; |
361 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); | |
40095de1 | 362 | if (rc <= 0) |
95d2ac4a | 363 | return BP_EAGAIN; |
1775826c | 364 | |
bc2c0303 | 365 | for (i = 0; i < rc; i++) { |
b6f30679 | 366 | page = balloon_retrieve(false); |
1775826c JF |
367 | BUG_ON(page == NULL); |
368 | ||
369 | pfn = page_to_pfn(page); | |
1775826c | 370 | |
c2374bf5 | 371 | #ifdef CONFIG_XEN_HAVE_PVMMU |
c1d15f5c SS |
372 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
373 | set_phys_to_machine(pfn, frame_list[i]); | |
374 | ||
375 | /* Link back into the page tables if not highmem. */ | |
376 | if (!PageHighMem(page)) { | |
377 | int ret; | |
378 | ret = HYPERVISOR_update_va_mapping( | |
379 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
380 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
381 | 0); | |
382 | BUG_ON(ret); | |
383 | } | |
1775826c | 384 | } |
c2374bf5 | 385 | #endif |
1775826c JF |
386 | |
387 | /* Relinquish the page back to the allocator. */ | |
3dcc0571 | 388 | __free_reserved_page(page); |
1775826c JF |
389 | } |
390 | ||
bc2c0303 | 391 | balloon_stats.current_pages += rc; |
1775826c | 392 | |
95d2ac4a | 393 | return BP_DONE; |
1775826c JF |
394 | } |
395 | ||
b6f30679 | 396 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) |
1775826c | 397 | { |
95d2ac4a | 398 | enum bp_state state = BP_DONE; |
2f70e0ac | 399 | unsigned long pfn, i; |
1775826c | 400 | struct page *page; |
1775826c JF |
401 | int ret; |
402 | struct xen_memory_reservation reservation = { | |
403 | .address_bits = 0, | |
404 | .extent_order = 0, | |
405 | .domid = DOMID_SELF | |
406 | }; | |
407 | ||
080e2be7 DK |
408 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
409 | if (balloon_stats.hotplug_pages) { | |
410 | nr_pages = min(nr_pages, balloon_stats.hotplug_pages); | |
411 | balloon_stats.hotplug_pages -= nr_pages; | |
412 | balloon_stats.balloon_hotplug += nr_pages; | |
413 | return BP_DONE; | |
414 | } | |
415 | #endif | |
416 | ||
1775826c JF |
417 | if (nr_pages > ARRAY_SIZE(frame_list)) |
418 | nr_pages = ARRAY_SIZE(frame_list); | |
419 | ||
420 | for (i = 0; i < nr_pages; i++) { | |
fce92683 LN |
421 | page = alloc_page(gfp); |
422 | if (page == NULL) { | |
1775826c | 423 | nr_pages = i; |
95d2ac4a | 424 | state = BP_EAGAIN; |
1775826c JF |
425 | break; |
426 | } | |
09ed3d5b | 427 | scrub_page(page); |
1775826c | 428 | |
09ed3d5b WL |
429 | frame_list[i] = page_to_pfn(page); |
430 | } | |
1775826c | 431 | |
09ed3d5b WL |
432 | /* |
433 | * Ensure that ballooned highmem pages don't have kmaps. | |
434 | * | |
435 | * Do this before changing the p2m as kmap_flush_unused() | |
436 | * reads PTEs to obtain pages (and hence needs the original | |
437 | * p2m entry). | |
438 | */ | |
439 | kmap_flush_unused(); | |
440 | ||
441 | /* Update direct mapping, invalidate P2M, and add to balloon. */ | |
442 | for (i = 0; i < nr_pages; i++) { | |
443 | pfn = frame_list[i]; | |
444 | frame_list[i] = pfn_to_mfn(pfn); | |
445 | page = pfn_to_page(pfn); | |
1058a75f | 446 | |
c1d15f5c | 447 | #ifdef CONFIG_XEN_HAVE_PVMMU |
04660bb5 | 448 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
c1d15f5c SS |
449 | if (!PageHighMem(page)) { |
450 | ret = HYPERVISOR_update_va_mapping( | |
451 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
0bb599fd | 452 | __pte_ma(0), 0); |
c1d15f5c | 453 | BUG_ON(ret); |
fb9a0c44 DV |
454 | } |
455 | __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); | |
04660bb5 | 456 | } |
c1d15f5c | 457 | #endif |
24f69373 | 458 | |
09ed3d5b | 459 | balloon_append(page); |
1775826c JF |
460 | } |
461 | ||
24f69373 | 462 | flush_tlb_all(); |
2bad07ce | 463 | |
a90971eb | 464 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
465 | reservation.nr_extents = nr_pages; |
466 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
467 | BUG_ON(ret != nr_pages); | |
468 | ||
469 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 470 | |
95d2ac4a | 471 | return state; |
1775826c JF |
472 | } |
473 | ||
474 | /* | |
929423fa | 475 | * As this is a work item it is guaranteed to run as a single instance only. |
1775826c JF |
476 | * We may of course race updates of the target counts (which are protected |
477 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
478 | * recover from these in time. | |
479 | */ | |
480 | static void balloon_process(struct work_struct *work) | |
481 | { | |
95d2ac4a | 482 | enum bp_state state = BP_DONE; |
1775826c JF |
483 | long credit; |
484 | ||
1775826c JF |
485 | |
486 | do { | |
929423fa JG |
487 | mutex_lock(&balloon_mutex); |
488 | ||
83be7e52 | 489 | credit = current_credit(); |
95d2ac4a | 490 | |
080e2be7 DK |
491 | if (credit > 0) { |
492 | if (balloon_is_inflated()) | |
493 | state = increase_reservation(credit); | |
494 | else | |
495 | state = reserve_additional_memory(credit); | |
496 | } | |
95d2ac4a | 497 | |
1775826c | 498 | if (credit < 0) |
b6f30679 | 499 | state = decrease_reservation(-credit, GFP_BALLOON); |
95d2ac4a DK |
500 | |
501 | state = update_schedule(state); | |
1775826c | 502 | |
929423fa JG |
503 | mutex_unlock(&balloon_mutex); |
504 | ||
505 | cond_resched(); | |
506 | ||
95d2ac4a | 507 | } while (credit && state == BP_DONE); |
1775826c JF |
508 | |
509 | /* Schedule more work if there is some still to be done. */ | |
95d2ac4a DK |
510 | if (state == BP_EAGAIN) |
511 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
1775826c JF |
512 | } |
513 | ||
514 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
803eb047 | 515 | void balloon_set_new_target(unsigned long target) |
1775826c JF |
516 | { |
517 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 518 | balloon_stats.target_pages = target; |
95170b2e | 519 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 520 | } |
803eb047 | 521 | EXPORT_SYMBOL_GPL(balloon_set_new_target); |
1775826c | 522 | |
b6f30679 KRW |
523 | /** |
524 | * alloc_xenballooned_pages - get pages that have been ballooned out | |
525 | * @nr_pages: Number of pages to get | |
526 | * @pages: pages returned | |
72e9cf2a | 527 | * @highmem: allow highmem pages |
b6f30679 KRW |
528 | * @return 0 on success, error otherwise |
529 | */ | |
693394b8 | 530 | int alloc_xenballooned_pages(int nr_pages, struct page **pages, bool highmem) |
1775826c | 531 | { |
b6f30679 | 532 | int pgno = 0; |
e882dc9c | 533 | struct page *page; |
b6f30679 KRW |
534 | mutex_lock(&balloon_mutex); |
535 | while (pgno < nr_pages) { | |
693394b8 | 536 | page = balloon_retrieve(highmem); |
72e9cf2a | 537 | if (page && (highmem || !PageHighMem(page))) { |
b6f30679 KRW |
538 | pages[pgno++] = page; |
539 | } else { | |
540 | enum bp_state st; | |
693394b8 SS |
541 | if (page) |
542 | balloon_append(page); | |
543 | st = decrease_reservation(nr_pages - pgno, | |
544 | highmem ? GFP_HIGHUSER : GFP_USER); | |
b6f30679 KRW |
545 | if (st != BP_DONE) |
546 | goto out_undo; | |
547 | } | |
1775826c | 548 | } |
b6f30679 KRW |
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; | |
1775826c | 558 | } |
b6f30679 | 559 | EXPORT_SYMBOL(alloc_xenballooned_pages); |
1775826c | 560 | |
b6f30679 KRW |
561 | /** |
562 | * free_xenballooned_pages - return pages retrieved with get_ballooned_pages | |
563 | * @nr_pages: Number of pages | |
564 | * @pages: pages to return | |
565 | */ | |
e882dc9c | 566 | void free_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 567 | { |
b6f30679 | 568 | int i; |
1775826c | 569 | |
b6f30679 | 570 | mutex_lock(&balloon_mutex); |
1775826c | 571 | |
b6f30679 KRW |
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. */ | |
83be7e52 | 578 | if (current_credit()) |
b6f30679 | 579 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 580 | |
b6f30679 KRW |
581 | mutex_unlock(&balloon_mutex); |
582 | } | |
583 | EXPORT_SYMBOL(free_xenballooned_pages); | |
1775826c | 584 | |
8b5d44a5 DV |
585 | static void __init balloon_add_region(unsigned long start_pfn, |
586 | unsigned long pages) | |
1775826c | 587 | { |
4dfe22f5 | 588 | unsigned long pfn, extra_pfn_end; |
1775826c JF |
589 | struct page *page; |
590 | ||
8b5d44a5 DV |
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 __init balloon_init(void) | |
608 | { | |
0bb599fd | 609 | int i; |
8b5d44a5 | 610 | |
53d5522c | 611 | if (!xen_domain()) |
1775826c JF |
612 | return -ENODEV; |
613 | ||
283c0972 | 614 | pr_info("Initialising balloon driver\n"); |
1775826c | 615 | |
aa24411b DV |
616 | balloon_stats.current_pages = xen_pv_domain() |
617 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
c275a57f | 618 | : get_num_physpages(); |
1775826c JF |
619 | balloon_stats.target_pages = balloon_stats.current_pages; |
620 | balloon_stats.balloon_low = 0; | |
621 | balloon_stats.balloon_high = 0; | |
1775826c | 622 | |
95d2ac4a DK |
623 | balloon_stats.schedule_delay = 1; |
624 | balloon_stats.max_schedule_delay = 32; | |
625 | balloon_stats.retry_count = 1; | |
40095de1 | 626 | balloon_stats.max_retry_count = RETRY_UNLIMITED; |
1775826c | 627 | |
080e2be7 DK |
628 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
629 | balloon_stats.hotplug_pages = 0; | |
630 | balloon_stats.balloon_hotplug = 0; | |
631 | ||
632 | set_online_page_callback(&xen_online_page); | |
633 | register_memory_notifier(&xen_memory_nb); | |
634 | #endif | |
635 | ||
2a4c92fa | 636 | /* |
b1cbf9b1 | 637 | * Initialize the balloon with pages from the extra memory |
8b5d44a5 | 638 | * regions (see arch/x86/xen/setup.c). |
2a4c92fa | 639 | */ |
8b5d44a5 DV |
640 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) |
641 | if (xen_extra_mem[i].size) | |
642 | balloon_add_region(PFN_UP(xen_extra_mem[i].start), | |
643 | PFN_DOWN(xen_extra_mem[i].size)); | |
1775826c | 644 | |
1775826c JF |
645 | return 0; |
646 | } | |
647 | ||
648 | subsys_initcall(balloon_init); | |
649 | ||
1775826c | 650 | MODULE_LICENSE("GPL"); |