Commit | Line | Data |
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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 | 43 | #include <linux/sched.h> |
5b825c3a | 44 | #include <linux/cred.h> |
1775826c JF |
45 | #include <linux/errno.h> |
46 | #include <linux/mm.h> | |
57c8a661 | 47 | #include <linux/memblock.h> |
1775826c JF |
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> |
55b3da98 | 57 | #include <linux/slab.h> |
1cf6a6c8 | 58 | #include <linux/sysctl.h> |
1775826c | 59 | |
1775826c JF |
60 | #include <asm/page.h> |
61 | #include <asm/pgalloc.h> | |
62 | #include <asm/pgtable.h> | |
1775826c JF |
63 | #include <asm/tlb.h> |
64 | ||
ecbf29cd JF |
65 | #include <asm/xen/hypervisor.h> |
66 | #include <asm/xen/hypercall.h> | |
1ccbf534 JF |
67 | |
68 | #include <xen/xen.h> | |
ecbf29cd | 69 | #include <xen/interface/xen.h> |
1775826c | 70 | #include <xen/interface/memory.h> |
803eb047 | 71 | #include <xen/balloon.h> |
1775826c JF |
72 | #include <xen/features.h> |
73 | #include <xen/page.h> | |
ae4c51a5 | 74 | #include <xen/mem-reservation.h> |
1775826c | 75 | |
1cf6a6c8 DV |
76 | static int xen_hotplug_unpopulated; |
77 | ||
78 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
79 | ||
80 | static int zero; | |
81 | static int one = 1; | |
82 | ||
83 | static struct ctl_table balloon_table[] = { | |
84 | { | |
85 | .procname = "hotplug_unpopulated", | |
86 | .data = &xen_hotplug_unpopulated, | |
87 | .maxlen = sizeof(int), | |
88 | .mode = 0644, | |
89 | .proc_handler = proc_dointvec_minmax, | |
90 | .extra1 = &zero, | |
91 | .extra2 = &one, | |
92 | }, | |
93 | { } | |
94 | }; | |
95 | ||
96 | static struct ctl_table balloon_root[] = { | |
97 | { | |
98 | .procname = "balloon", | |
99 | .mode = 0555, | |
100 | .child = balloon_table, | |
101 | }, | |
102 | { } | |
103 | }; | |
104 | ||
105 | static struct ctl_table xen_root[] = { | |
106 | { | |
107 | .procname = "xen", | |
108 | .mode = 0555, | |
109 | .child = balloon_root, | |
110 | }, | |
111 | { } | |
112 | }; | |
113 | ||
114 | #endif | |
115 | ||
30756c62 JG |
116 | /* |
117 | * Use one extent per PAGE_SIZE to avoid to break down the page into | |
118 | * multiple frame. | |
119 | */ | |
120 | #define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1) | |
121 | ||
95d2ac4a DK |
122 | /* |
123 | * balloon_process() state: | |
124 | * | |
125 | * BP_DONE: done or nothing to do, | |
b2ac6aa8 | 126 | * BP_WAIT: wait to be rescheduled, |
95d2ac4a DK |
127 | * BP_EAGAIN: error, go to sleep, |
128 | * BP_ECANCELED: error, balloon operation canceled. | |
129 | */ | |
1775826c | 130 | |
95d2ac4a DK |
131 | enum bp_state { |
132 | BP_DONE, | |
b2ac6aa8 | 133 | BP_WAIT, |
95d2ac4a DK |
134 | BP_EAGAIN, |
135 | BP_ECANCELED | |
1775826c JF |
136 | }; |
137 | ||
1775826c | 138 | |
1775826c | 139 | static DEFINE_MUTEX(balloon_mutex); |
1775826c | 140 | |
803eb047 DDG |
141 | struct balloon_stats balloon_stats; |
142 | EXPORT_SYMBOL_GPL(balloon_stats); | |
1775826c JF |
143 | |
144 | /* We increase/decrease in batches which fit in a page */ | |
3990dd27 | 145 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)]; |
cd9151e2 | 146 | |
1775826c | 147 | |
1775826c JF |
148 | /* List of ballooned pages, threaded through the mem_map array. */ |
149 | static LIST_HEAD(ballooned_pages); | |
1cf6a6c8 | 150 | static DECLARE_WAIT_QUEUE_HEAD(balloon_wq); |
1775826c JF |
151 | |
152 | /* Main work function, always executed in process context. */ | |
153 | static void balloon_process(struct work_struct *work); | |
95170b2e | 154 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); |
1775826c JF |
155 | |
156 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
157 | want the kernel to try too hard since that can trigger the oom killer. */ | |
158 | #define GFP_BALLOON \ | |
159 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
160 | ||
1775826c | 161 | /* balloon_append: add the given page to the balloon. */ |
9be4d457 | 162 | static void __balloon_append(struct page *page) |
1775826c JF |
163 | { |
164 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
165 | if (PageHighMem(page)) { | |
166 | list_add_tail(&page->lru, &ballooned_pages); | |
167 | balloon_stats.balloon_high++; | |
1775826c JF |
168 | } else { |
169 | list_add(&page->lru, &ballooned_pages); | |
170 | balloon_stats.balloon_low++; | |
171 | } | |
1cf6a6c8 | 172 | wake_up(&balloon_wq); |
9be4d457 | 173 | } |
3d65c948 | 174 | |
9be4d457 JF |
175 | static void balloon_append(struct page *page) |
176 | { | |
177 | __balloon_append(page); | |
1775826c JF |
178 | } |
179 | ||
180 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
81b286e0 | 181 | static struct page *balloon_retrieve(bool require_lowmem) |
1775826c JF |
182 | { |
183 | struct page *page; | |
184 | ||
185 | if (list_empty(&ballooned_pages)) | |
186 | return NULL; | |
187 | ||
81b286e0 DV |
188 | page = list_entry(ballooned_pages.next, struct page, lru); |
189 | if (require_lowmem && PageHighMem(page)) | |
190 | return NULL; | |
1775826c JF |
191 | list_del(&page->lru); |
192 | ||
3dcc0571 | 193 | if (PageHighMem(page)) |
1775826c | 194 | balloon_stats.balloon_high--; |
3dcc0571 | 195 | else |
1775826c JF |
196 | balloon_stats.balloon_low--; |
197 | ||
198 | return page; | |
199 | } | |
200 | ||
1775826c JF |
201 | static struct page *balloon_next_page(struct page *page) |
202 | { | |
203 | struct list_head *next = page->lru.next; | |
204 | if (next == &ballooned_pages) | |
205 | return NULL; | |
206 | return list_entry(next, struct page, lru); | |
207 | } | |
208 | ||
95d2ac4a | 209 | static enum bp_state update_schedule(enum bp_state state) |
1775826c | 210 | { |
b2ac6aa8 DV |
211 | if (state == BP_WAIT) |
212 | return BP_WAIT; | |
213 | ||
fd8b7951 BO |
214 | if (state == BP_ECANCELED) |
215 | return BP_ECANCELED; | |
216 | ||
95d2ac4a DK |
217 | if (state == BP_DONE) { |
218 | balloon_stats.schedule_delay = 1; | |
219 | balloon_stats.retry_count = 1; | |
220 | return BP_DONE; | |
221 | } | |
222 | ||
95d2ac4a DK |
223 | ++balloon_stats.retry_count; |
224 | ||
225 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
226 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
227 | balloon_stats.schedule_delay = 1; |
228 | balloon_stats.retry_count = 1; | |
229 | return BP_ECANCELED; | |
230 | } | |
231 | ||
232 | balloon_stats.schedule_delay <<= 1; | |
233 | ||
234 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
235 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
236 | ||
237 | return BP_EAGAIN; | |
1775826c JF |
238 | } |
239 | ||
080e2be7 | 240 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
842775f1 RL |
241 | static void release_memory_resource(struct resource *resource) |
242 | { | |
243 | if (!resource) | |
244 | return; | |
245 | ||
246 | /* | |
247 | * No need to reset region to identity mapped since we now | |
248 | * know that no I/O can be in this region | |
249 | */ | |
250 | release_resource(resource); | |
251 | kfree(resource); | |
252 | } | |
253 | ||
55b3da98 DV |
254 | static struct resource *additional_memory_resource(phys_addr_t size) |
255 | { | |
12366410 ID |
256 | struct resource *res; |
257 | int ret; | |
55b3da98 DV |
258 | |
259 | res = kzalloc(sizeof(*res), GFP_KERNEL); | |
260 | if (!res) | |
261 | return NULL; | |
262 | ||
263 | res->name = "System RAM"; | |
782b8664 | 264 | res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; |
55b3da98 | 265 | |
12366410 ID |
266 | ret = allocate_resource(&iomem_resource, res, |
267 | size, 0, -1, | |
268 | PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); | |
269 | if (ret < 0) { | |
270 | pr_err("Cannot allocate new System RAM resource\n"); | |
271 | kfree(res); | |
272 | return NULL; | |
55b3da98 DV |
273 | } |
274 | ||
dfd74a1e RL |
275 | #ifdef CONFIG_SPARSEMEM |
276 | { | |
277 | unsigned long limit = 1UL << (MAX_PHYSMEM_BITS - PAGE_SHIFT); | |
278 | unsigned long pfn = res->start >> PAGE_SHIFT; | |
279 | ||
280 | if (pfn > limit) { | |
281 | pr_err("New System RAM resource outside addressable RAM (%lu > %lu)\n", | |
282 | pfn, limit); | |
283 | release_memory_resource(res); | |
284 | return NULL; | |
285 | } | |
286 | } | |
287 | #endif | |
288 | ||
55b3da98 DV |
289 | return res; |
290 | } | |
291 | ||
b2ac6aa8 | 292 | static enum bp_state reserve_additional_memory(void) |
080e2be7 | 293 | { |
b2ac6aa8 | 294 | long credit; |
55b3da98 | 295 | struct resource *resource; |
080e2be7 | 296 | int nid, rc; |
55b3da98 | 297 | unsigned long balloon_hotplug; |
080e2be7 | 298 | |
1cf6a6c8 DV |
299 | credit = balloon_stats.target_pages + balloon_stats.target_unpopulated |
300 | - balloon_stats.total_pages; | |
b2ac6aa8 DV |
301 | |
302 | /* | |
303 | * Already hotplugged enough pages? Wait for them to be | |
304 | * onlined. | |
305 | */ | |
306 | if (credit <= 0) | |
307 | return BP_WAIT; | |
308 | ||
55b3da98 DV |
309 | balloon_hotplug = round_up(credit, PAGES_PER_SECTION); |
310 | ||
311 | resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE); | |
312 | if (!resource) | |
313 | goto err; | |
314 | ||
315 | nid = memory_add_physaddr_to_nid(resource->start); | |
080e2be7 | 316 | |
3c56b3a1 | 317 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
318 | /* |
319 | * We don't support PV MMU when Linux and Xen is using | |
320 | * different page granularity. | |
321 | */ | |
322 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
323 | ||
3c56b3a1 JG |
324 | /* |
325 | * add_memory() will build page tables for the new memory so | |
326 | * the p2m must contain invalid entries so the correct | |
327 | * non-present PTEs will be written. | |
328 | * | |
329 | * If a failure occurs, the original (identity) p2m entries | |
330 | * are not restored since this region is now known not to | |
331 | * conflict with any devices. | |
332 | */ | |
333 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
334 | unsigned long pfn, i; | |
335 | ||
55b3da98 | 336 | pfn = PFN_DOWN(resource->start); |
3c56b3a1 JG |
337 | for (i = 0; i < balloon_hotplug; i++) { |
338 | if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { | |
339 | pr_warn("set_phys_to_machine() failed, no memory added\n"); | |
55b3da98 | 340 | goto err; |
3c56b3a1 JG |
341 | } |
342 | } | |
343 | } | |
344 | #endif | |
345 | ||
703fc13a VK |
346 | /* |
347 | * add_memory_resource() will call online_pages() which in its turn | |
348 | * will call xen_online_page() callback causing deadlock if we don't | |
349 | * release balloon_mutex here. Unlocking here is safe because the | |
350 | * callers drop the mutex before trying again. | |
351 | */ | |
352 | mutex_unlock(&balloon_mutex); | |
8df1d0e4 DH |
353 | /* add_memory_resource() requires the device_hotplug lock */ |
354 | lock_device_hotplug(); | |
f29d8e9c | 355 | rc = add_memory_resource(nid, resource); |
8df1d0e4 | 356 | unlock_device_hotplug(); |
703fc13a VK |
357 | mutex_lock(&balloon_mutex); |
358 | ||
080e2be7 | 359 | if (rc) { |
3dcf6367 | 360 | pr_warn("Cannot add additional memory (%i)\n", rc); |
55b3da98 | 361 | goto err; |
080e2be7 DK |
362 | } |
363 | ||
de5a77d8 | 364 | balloon_stats.total_pages += balloon_hotplug; |
080e2be7 | 365 | |
b2ac6aa8 | 366 | return BP_WAIT; |
55b3da98 DV |
367 | err: |
368 | release_memory_resource(resource); | |
369 | return BP_ECANCELED; | |
080e2be7 DK |
370 | } |
371 | ||
372 | static void xen_online_page(struct page *page) | |
373 | { | |
374 | __online_page_set_limits(page); | |
375 | ||
376 | mutex_lock(&balloon_mutex); | |
377 | ||
378 | __balloon_append(page); | |
379 | ||
080e2be7 DK |
380 | mutex_unlock(&balloon_mutex); |
381 | } | |
382 | ||
383 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
384 | { | |
385 | if (val == MEM_ONLINE) | |
386 | schedule_delayed_work(&balloon_worker, 0); | |
387 | ||
388 | return NOTIFY_OK; | |
389 | } | |
390 | ||
391 | static struct notifier_block xen_memory_nb = { | |
392 | .notifier_call = xen_memory_notifier, | |
393 | .priority = 0 | |
394 | }; | |
395 | #else | |
b2ac6aa8 | 396 | static enum bp_state reserve_additional_memory(void) |
1775826c | 397 | { |
de5a77d8 | 398 | balloon_stats.target_pages = balloon_stats.current_pages; |
1cf6a6c8 | 399 | return BP_ECANCELED; |
1775826c | 400 | } |
de5a77d8 | 401 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ |
1775826c | 402 | |
de5a77d8 | 403 | static long current_credit(void) |
080e2be7 | 404 | { |
de5a77d8 | 405 | return balloon_stats.target_pages - balloon_stats.current_pages; |
080e2be7 DK |
406 | } |
407 | ||
de5a77d8 | 408 | static bool balloon_is_inflated(void) |
080e2be7 | 409 | { |
de5a77d8 | 410 | return balloon_stats.balloon_low || balloon_stats.balloon_high; |
080e2be7 | 411 | } |
080e2be7 | 412 | |
95d2ac4a | 413 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 414 | { |
95d2ac4a | 415 | int rc; |
30756c62 | 416 | unsigned long i; |
1775826c | 417 | struct page *page; |
1775826c JF |
418 | |
419 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
420 | nr_pages = ARRAY_SIZE(frame_list); | |
421 | ||
9346c2a8 | 422 | page = list_first_entry_or_null(&ballooned_pages, struct page, lru); |
1775826c | 423 | for (i = 0; i < nr_pages; i++) { |
95d2ac4a DK |
424 | if (!page) { |
425 | nr_pages = i; | |
426 | break; | |
427 | } | |
30756c62 | 428 | |
30756c62 | 429 | frame_list[i] = page_to_xen_pfn(page); |
1775826c JF |
430 | page = balloon_next_page(page); |
431 | } | |
432 | ||
ae4c51a5 | 433 | rc = xenmem_reservation_increase(nr_pages, frame_list); |
40095de1 | 434 | if (rc <= 0) |
95d2ac4a | 435 | return BP_EAGAIN; |
1775826c | 436 | |
bc2c0303 | 437 | for (i = 0; i < rc; i++) { |
b6f30679 | 438 | page = balloon_retrieve(false); |
1775826c JF |
439 | BUG_ON(page == NULL); |
440 | ||
ae4c51a5 | 441 | xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]); |
1775826c JF |
442 | |
443 | /* Relinquish the page back to the allocator. */ | |
709613ad | 444 | free_reserved_page(page); |
1775826c JF |
445 | } |
446 | ||
bc2c0303 | 447 | balloon_stats.current_pages += rc; |
1775826c | 448 | |
95d2ac4a | 449 | return BP_DONE; |
1775826c JF |
450 | } |
451 | ||
b6f30679 | 452 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) |
1775826c | 453 | { |
95d2ac4a | 454 | enum bp_state state = BP_DONE; |
30756c62 JG |
455 | unsigned long i; |
456 | struct page *page, *tmp; | |
1775826c | 457 | int ret; |
30756c62 | 458 | LIST_HEAD(pages); |
1775826c JF |
459 | |
460 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
461 | nr_pages = ARRAY_SIZE(frame_list); | |
462 | ||
463 | for (i = 0; i < nr_pages; i++) { | |
fce92683 LN |
464 | page = alloc_page(gfp); |
465 | if (page == NULL) { | |
1775826c | 466 | nr_pages = i; |
95d2ac4a | 467 | state = BP_EAGAIN; |
1775826c JF |
468 | break; |
469 | } | |
709613ad | 470 | adjust_managed_page_count(page, -1); |
ae4c51a5 | 471 | xenmem_reservation_scrub_page(page); |
30756c62 | 472 | list_add(&page->lru, &pages); |
09ed3d5b | 473 | } |
1775826c | 474 | |
09ed3d5b WL |
475 | /* |
476 | * Ensure that ballooned highmem pages don't have kmaps. | |
477 | * | |
478 | * Do this before changing the p2m as kmap_flush_unused() | |
479 | * reads PTEs to obtain pages (and hence needs the original | |
480 | * p2m entry). | |
481 | */ | |
482 | kmap_flush_unused(); | |
483 | ||
30756c62 JG |
484 | /* |
485 | * Setup the frame, update direct mapping, invalidate P2M, | |
486 | * and add to balloon. | |
487 | */ | |
488 | i = 0; | |
489 | list_for_each_entry_safe(page, tmp, &pages, lru) { | |
30756c62 | 490 | frame_list[i++] = xen_page_to_gfn(page); |
1058a75f | 491 | |
ae4c51a5 | 492 | xenmem_reservation_va_mapping_reset(1, &page); |
30756c62 | 493 | |
30756c62 | 494 | list_del(&page->lru); |
24f69373 | 495 | |
09ed3d5b | 496 | balloon_append(page); |
1775826c JF |
497 | } |
498 | ||
24f69373 | 499 | flush_tlb_all(); |
2bad07ce | 500 | |
ae4c51a5 | 501 | ret = xenmem_reservation_decrease(nr_pages, frame_list); |
1775826c JF |
502 | BUG_ON(ret != nr_pages); |
503 | ||
504 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 505 | |
95d2ac4a | 506 | return state; |
1775826c JF |
507 | } |
508 | ||
509 | /* | |
929423fa | 510 | * As this is a work item it is guaranteed to run as a single instance only. |
1775826c JF |
511 | * We may of course race updates of the target counts (which are protected |
512 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
513 | * recover from these in time. | |
514 | */ | |
515 | static void balloon_process(struct work_struct *work) | |
516 | { | |
95d2ac4a | 517 | enum bp_state state = BP_DONE; |
1775826c JF |
518 | long credit; |
519 | ||
1775826c JF |
520 | |
521 | do { | |
929423fa JG |
522 | mutex_lock(&balloon_mutex); |
523 | ||
83be7e52 | 524 | credit = current_credit(); |
95d2ac4a | 525 | |
080e2be7 DK |
526 | if (credit > 0) { |
527 | if (balloon_is_inflated()) | |
528 | state = increase_reservation(credit); | |
529 | else | |
b2ac6aa8 | 530 | state = reserve_additional_memory(); |
080e2be7 | 531 | } |
95d2ac4a | 532 | |
1775826c | 533 | if (credit < 0) |
b6f30679 | 534 | state = decrease_reservation(-credit, GFP_BALLOON); |
95d2ac4a DK |
535 | |
536 | state = update_schedule(state); | |
1775826c | 537 | |
929423fa JG |
538 | mutex_unlock(&balloon_mutex); |
539 | ||
540 | cond_resched(); | |
541 | ||
95d2ac4a | 542 | } while (credit && state == BP_DONE); |
1775826c JF |
543 | |
544 | /* Schedule more work if there is some still to be done. */ | |
95d2ac4a DK |
545 | if (state == BP_EAGAIN) |
546 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
1775826c JF |
547 | } |
548 | ||
549 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
803eb047 | 550 | void balloon_set_new_target(unsigned long target) |
1775826c JF |
551 | { |
552 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 553 | balloon_stats.target_pages = target; |
95170b2e | 554 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 555 | } |
803eb047 | 556 | EXPORT_SYMBOL_GPL(balloon_set_new_target); |
1775826c | 557 | |
1cf6a6c8 DV |
558 | static int add_ballooned_pages(int nr_pages) |
559 | { | |
560 | enum bp_state st; | |
561 | ||
562 | if (xen_hotplug_unpopulated) { | |
563 | st = reserve_additional_memory(); | |
564 | if (st != BP_ECANCELED) { | |
565 | mutex_unlock(&balloon_mutex); | |
566 | wait_event(balloon_wq, | |
567 | !list_empty(&ballooned_pages)); | |
568 | mutex_lock(&balloon_mutex); | |
569 | return 0; | |
570 | } | |
571 | } | |
572 | ||
573 | st = decrease_reservation(nr_pages, GFP_USER); | |
574 | if (st != BP_DONE) | |
575 | return -ENOMEM; | |
576 | ||
577 | return 0; | |
578 | } | |
579 | ||
b6f30679 KRW |
580 | /** |
581 | * alloc_xenballooned_pages - get pages that have been ballooned out | |
582 | * @nr_pages: Number of pages to get | |
583 | * @pages: pages returned | |
584 | * @return 0 on success, error otherwise | |
585 | */ | |
81b286e0 | 586 | int alloc_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 587 | { |
b6f30679 | 588 | int pgno = 0; |
e882dc9c | 589 | struct page *page; |
1cf6a6c8 DV |
590 | int ret; |
591 | ||
b6f30679 | 592 | mutex_lock(&balloon_mutex); |
1cf6a6c8 DV |
593 | |
594 | balloon_stats.target_unpopulated += nr_pages; | |
595 | ||
b6f30679 | 596 | while (pgno < nr_pages) { |
81b286e0 DV |
597 | page = balloon_retrieve(true); |
598 | if (page) { | |
b6f30679 | 599 | pages[pgno++] = page; |
4a69c909 | 600 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
601 | /* |
602 | * We don't support PV MMU when Linux and Xen is using | |
603 | * different page granularity. | |
604 | */ | |
605 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
606 | ||
b194da25 BO |
607 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
608 | ret = xen_alloc_p2m_entry(page_to_pfn(page)); | |
609 | if (ret < 0) | |
610 | goto out_undo; | |
611 | } | |
4a69c909 | 612 | #endif |
b6f30679 | 613 | } else { |
1cf6a6c8 DV |
614 | ret = add_ballooned_pages(nr_pages - pgno); |
615 | if (ret < 0) | |
b6f30679 KRW |
616 | goto out_undo; |
617 | } | |
1775826c | 618 | } |
b6f30679 KRW |
619 | mutex_unlock(&balloon_mutex); |
620 | return 0; | |
621 | out_undo: | |
b6f30679 | 622 | mutex_unlock(&balloon_mutex); |
1cf6a6c8 DV |
623 | free_xenballooned_pages(pgno, pages); |
624 | return ret; | |
1775826c | 625 | } |
b6f30679 | 626 | EXPORT_SYMBOL(alloc_xenballooned_pages); |
1775826c | 627 | |
b6f30679 KRW |
628 | /** |
629 | * free_xenballooned_pages - return pages retrieved with get_ballooned_pages | |
630 | * @nr_pages: Number of pages | |
631 | * @pages: pages to return | |
632 | */ | |
e882dc9c | 633 | void free_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 634 | { |
b6f30679 | 635 | int i; |
1775826c | 636 | |
b6f30679 | 637 | mutex_lock(&balloon_mutex); |
1775826c | 638 | |
b6f30679 KRW |
639 | for (i = 0; i < nr_pages; i++) { |
640 | if (pages[i]) | |
641 | balloon_append(pages[i]); | |
642 | } | |
643 | ||
1cf6a6c8 DV |
644 | balloon_stats.target_unpopulated -= nr_pages; |
645 | ||
b6f30679 | 646 | /* The balloon may be too large now. Shrink it if needed. */ |
83be7e52 | 647 | if (current_credit()) |
b6f30679 | 648 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 649 | |
b6f30679 KRW |
650 | mutex_unlock(&balloon_mutex); |
651 | } | |
652 | EXPORT_SYMBOL(free_xenballooned_pages); | |
1775826c | 653 | |
4fee9ad8 | 654 | #ifdef CONFIG_XEN_PV |
8b5d44a5 DV |
655 | static void __init balloon_add_region(unsigned long start_pfn, |
656 | unsigned long pages) | |
1775826c | 657 | { |
4dfe22f5 | 658 | unsigned long pfn, extra_pfn_end; |
1775826c JF |
659 | struct page *page; |
660 | ||
8b5d44a5 DV |
661 | /* |
662 | * If the amount of usable memory has been limited (e.g., with | |
663 | * the 'mem' command line parameter), don't add pages beyond | |
664 | * this limit. | |
665 | */ | |
666 | extra_pfn_end = min(max_pfn, start_pfn + pages); | |
667 | ||
668 | for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { | |
669 | page = pfn_to_page(pfn); | |
670 | /* totalram_pages and totalhigh_pages do not | |
671 | include the boot-time balloon extension, so | |
672 | don't subtract from it. */ | |
673 | __balloon_append(page); | |
674 | } | |
de5a77d8 DV |
675 | |
676 | balloon_stats.total_pages += extra_pfn_end - start_pfn; | |
8b5d44a5 | 677 | } |
4fee9ad8 | 678 | #endif |
8b5d44a5 DV |
679 | |
680 | static int __init balloon_init(void) | |
681 | { | |
53d5522c | 682 | if (!xen_domain()) |
1775826c JF |
683 | return -ENODEV; |
684 | ||
283c0972 | 685 | pr_info("Initialising balloon driver\n"); |
1775826c | 686 | |
4fee9ad8 | 687 | #ifdef CONFIG_XEN_PV |
aa24411b DV |
688 | balloon_stats.current_pages = xen_pv_domain() |
689 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
c275a57f | 690 | : get_num_physpages(); |
4fee9ad8 VK |
691 | #else |
692 | balloon_stats.current_pages = get_num_physpages(); | |
693 | #endif | |
1775826c JF |
694 | balloon_stats.target_pages = balloon_stats.current_pages; |
695 | balloon_stats.balloon_low = 0; | |
696 | balloon_stats.balloon_high = 0; | |
de5a77d8 | 697 | balloon_stats.total_pages = balloon_stats.current_pages; |
1775826c | 698 | |
95d2ac4a DK |
699 | balloon_stats.schedule_delay = 1; |
700 | balloon_stats.max_schedule_delay = 32; | |
701 | balloon_stats.retry_count = 1; | |
40095de1 | 702 | balloon_stats.max_retry_count = RETRY_UNLIMITED; |
1775826c | 703 | |
080e2be7 | 704 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
080e2be7 DK |
705 | set_online_page_callback(&xen_online_page); |
706 | register_memory_notifier(&xen_memory_nb); | |
1cf6a6c8 | 707 | register_sysctl_table(xen_root); |
080e2be7 DK |
708 | #endif |
709 | ||
4fee9ad8 VK |
710 | #ifdef CONFIG_XEN_PV |
711 | { | |
712 | int i; | |
713 | ||
714 | /* | |
715 | * Initialize the balloon with pages from the extra memory | |
716 | * regions (see arch/x86/xen/setup.c). | |
717 | */ | |
718 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) | |
719 | if (xen_extra_mem[i].n_pfns) | |
720 | balloon_add_region(xen_extra_mem[i].start_pfn, | |
721 | xen_extra_mem[i].n_pfns); | |
722 | } | |
723 | #endif | |
1775826c | 724 | |
96edd61d JG |
725 | /* Init the xen-balloon driver. */ |
726 | xen_balloon_init(); | |
727 | ||
1775826c JF |
728 | return 0; |
729 | } | |
1775826c | 730 | subsys_initcall(balloon_init); |