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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> |
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> | |
74 | ||
1cf6a6c8 DV |
75 | static int xen_hotplug_unpopulated; |
76 | ||
77 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
78 | ||
79 | static int zero; | |
80 | static int one = 1; | |
81 | ||
82 | static struct ctl_table balloon_table[] = { | |
83 | { | |
84 | .procname = "hotplug_unpopulated", | |
85 | .data = &xen_hotplug_unpopulated, | |
86 | .maxlen = sizeof(int), | |
87 | .mode = 0644, | |
88 | .proc_handler = proc_dointvec_minmax, | |
89 | .extra1 = &zero, | |
90 | .extra2 = &one, | |
91 | }, | |
92 | { } | |
93 | }; | |
94 | ||
95 | static struct ctl_table balloon_root[] = { | |
96 | { | |
97 | .procname = "balloon", | |
98 | .mode = 0555, | |
99 | .child = balloon_table, | |
100 | }, | |
101 | { } | |
102 | }; | |
103 | ||
104 | static struct ctl_table xen_root[] = { | |
105 | { | |
106 | .procname = "xen", | |
107 | .mode = 0555, | |
108 | .child = balloon_root, | |
109 | }, | |
110 | { } | |
111 | }; | |
112 | ||
113 | #endif | |
114 | ||
95d2ac4a DK |
115 | /* |
116 | * balloon_process() state: | |
117 | * | |
118 | * BP_DONE: done or nothing to do, | |
b2ac6aa8 | 119 | * BP_WAIT: wait to be rescheduled, |
95d2ac4a DK |
120 | * BP_EAGAIN: error, go to sleep, |
121 | * BP_ECANCELED: error, balloon operation canceled. | |
122 | */ | |
1775826c | 123 | |
95d2ac4a DK |
124 | enum bp_state { |
125 | BP_DONE, | |
b2ac6aa8 | 126 | BP_WAIT, |
95d2ac4a DK |
127 | BP_EAGAIN, |
128 | BP_ECANCELED | |
1775826c JF |
129 | }; |
130 | ||
1775826c | 131 | |
1775826c | 132 | static DEFINE_MUTEX(balloon_mutex); |
1775826c | 133 | |
803eb047 DDG |
134 | struct balloon_stats balloon_stats; |
135 | EXPORT_SYMBOL_GPL(balloon_stats); | |
1775826c JF |
136 | |
137 | /* We increase/decrease in batches which fit in a page */ | |
965c0aaa | 138 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(unsigned long)]; |
cd9151e2 | 139 | |
1775826c | 140 | |
1775826c JF |
141 | /* List of ballooned pages, threaded through the mem_map array. */ |
142 | static LIST_HEAD(ballooned_pages); | |
1cf6a6c8 | 143 | static DECLARE_WAIT_QUEUE_HEAD(balloon_wq); |
1775826c JF |
144 | |
145 | /* Main work function, always executed in process context. */ | |
146 | static void balloon_process(struct work_struct *work); | |
95170b2e | 147 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); |
1775826c JF |
148 | |
149 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
150 | want the kernel to try too hard since that can trigger the oom killer. */ | |
151 | #define GFP_BALLOON \ | |
152 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
153 | ||
154 | static void scrub_page(struct page *page) | |
155 | { | |
156 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
26a3e991 | 157 | clear_highpage(page); |
1775826c JF |
158 | #endif |
159 | } | |
160 | ||
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); | |
3dcc0571 | 178 | adjust_managed_page_count(page, -1); |
1775826c JF |
179 | } |
180 | ||
181 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
81b286e0 | 182 | static struct page *balloon_retrieve(bool require_lowmem) |
1775826c JF |
183 | { |
184 | struct page *page; | |
185 | ||
186 | if (list_empty(&ballooned_pages)) | |
187 | return NULL; | |
188 | ||
81b286e0 DV |
189 | page = list_entry(ballooned_pages.next, struct page, lru); |
190 | if (require_lowmem && PageHighMem(page)) | |
191 | return NULL; | |
1775826c JF |
192 | list_del(&page->lru); |
193 | ||
3dcc0571 | 194 | if (PageHighMem(page)) |
1775826c | 195 | balloon_stats.balloon_high--; |
3dcc0571 | 196 | else |
1775826c JF |
197 | balloon_stats.balloon_low--; |
198 | ||
3dcc0571 | 199 | adjust_managed_page_count(page, 1); |
3d65c948 | 200 | |
1775826c JF |
201 | return page; |
202 | } | |
203 | ||
1775826c JF |
204 | static struct page *balloon_next_page(struct page *page) |
205 | { | |
206 | struct list_head *next = page->lru.next; | |
207 | if (next == &ballooned_pages) | |
208 | return NULL; | |
209 | return list_entry(next, struct page, lru); | |
210 | } | |
211 | ||
95d2ac4a | 212 | static enum bp_state update_schedule(enum bp_state state) |
1775826c | 213 | { |
b2ac6aa8 DV |
214 | if (state == BP_WAIT) |
215 | return BP_WAIT; | |
216 | ||
fd8b7951 BO |
217 | if (state == BP_ECANCELED) |
218 | return BP_ECANCELED; | |
219 | ||
95d2ac4a DK |
220 | if (state == BP_DONE) { |
221 | balloon_stats.schedule_delay = 1; | |
222 | balloon_stats.retry_count = 1; | |
223 | return BP_DONE; | |
224 | } | |
225 | ||
95d2ac4a DK |
226 | ++balloon_stats.retry_count; |
227 | ||
228 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
229 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
230 | balloon_stats.schedule_delay = 1; |
231 | balloon_stats.retry_count = 1; | |
232 | return BP_ECANCELED; | |
233 | } | |
234 | ||
235 | balloon_stats.schedule_delay <<= 1; | |
236 | ||
237 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
238 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
239 | ||
240 | return BP_EAGAIN; | |
1775826c JF |
241 | } |
242 | ||
080e2be7 | 243 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
55b3da98 DV |
244 | static struct resource *additional_memory_resource(phys_addr_t size) |
245 | { | |
246 | struct resource *res; | |
247 | int ret; | |
248 | ||
249 | res = kzalloc(sizeof(*res), GFP_KERNEL); | |
250 | if (!res) | |
251 | return NULL; | |
252 | ||
253 | res->name = "System RAM"; | |
254 | res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; | |
255 | ||
256 | ret = allocate_resource(&iomem_resource, res, | |
257 | size, 0, -1, | |
258 | PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); | |
259 | if (ret < 0) { | |
260 | pr_err("Cannot allocate new System RAM resource\n"); | |
261 | kfree(res); | |
262 | return NULL; | |
263 | } | |
264 | ||
265 | return res; | |
266 | } | |
267 | ||
268 | static void release_memory_resource(struct resource *resource) | |
269 | { | |
270 | if (!resource) | |
271 | return; | |
272 | ||
273 | /* | |
274 | * No need to reset region to identity mapped since we now | |
275 | * know that no I/O can be in this region | |
276 | */ | |
277 | release_resource(resource); | |
278 | kfree(resource); | |
279 | } | |
080e2be7 | 280 | |
b2ac6aa8 | 281 | static enum bp_state reserve_additional_memory(void) |
080e2be7 | 282 | { |
b2ac6aa8 | 283 | long credit; |
55b3da98 | 284 | struct resource *resource; |
080e2be7 | 285 | int nid, rc; |
55b3da98 | 286 | unsigned long balloon_hotplug; |
080e2be7 | 287 | |
1cf6a6c8 DV |
288 | credit = balloon_stats.target_pages + balloon_stats.target_unpopulated |
289 | - balloon_stats.total_pages; | |
b2ac6aa8 DV |
290 | |
291 | /* | |
292 | * Already hotplugged enough pages? Wait for them to be | |
293 | * onlined. | |
294 | */ | |
295 | if (credit <= 0) | |
296 | return BP_WAIT; | |
297 | ||
55b3da98 DV |
298 | balloon_hotplug = round_up(credit, PAGES_PER_SECTION); |
299 | ||
300 | resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE); | |
301 | if (!resource) | |
302 | goto err; | |
303 | ||
304 | nid = memory_add_physaddr_to_nid(resource->start); | |
080e2be7 | 305 | |
3c56b3a1 JG |
306 | #ifdef CONFIG_XEN_HAVE_PVMMU |
307 | /* | |
308 | * add_memory() will build page tables for the new memory so | |
309 | * the p2m must contain invalid entries so the correct | |
310 | * non-present PTEs will be written. | |
311 | * | |
312 | * If a failure occurs, the original (identity) p2m entries | |
313 | * are not restored since this region is now known not to | |
314 | * conflict with any devices. | |
315 | */ | |
316 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
317 | unsigned long pfn, i; | |
318 | ||
55b3da98 | 319 | pfn = PFN_DOWN(resource->start); |
3c56b3a1 JG |
320 | for (i = 0; i < balloon_hotplug; i++) { |
321 | if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { | |
322 | pr_warn("set_phys_to_machine() failed, no memory added\n"); | |
55b3da98 | 323 | goto err; |
3c56b3a1 JG |
324 | } |
325 | } | |
326 | } | |
327 | #endif | |
328 | ||
55b3da98 | 329 | rc = add_memory_resource(nid, resource); |
080e2be7 | 330 | if (rc) { |
3dcf6367 | 331 | pr_warn("Cannot add additional memory (%i)\n", rc); |
55b3da98 | 332 | goto err; |
080e2be7 DK |
333 | } |
334 | ||
de5a77d8 | 335 | balloon_stats.total_pages += balloon_hotplug; |
080e2be7 | 336 | |
b2ac6aa8 | 337 | return BP_WAIT; |
55b3da98 DV |
338 | err: |
339 | release_memory_resource(resource); | |
340 | return BP_ECANCELED; | |
080e2be7 DK |
341 | } |
342 | ||
343 | static void xen_online_page(struct page *page) | |
344 | { | |
345 | __online_page_set_limits(page); | |
346 | ||
347 | mutex_lock(&balloon_mutex); | |
348 | ||
349 | __balloon_append(page); | |
350 | ||
080e2be7 DK |
351 | mutex_unlock(&balloon_mutex); |
352 | } | |
353 | ||
354 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
355 | { | |
356 | if (val == MEM_ONLINE) | |
357 | schedule_delayed_work(&balloon_worker, 0); | |
358 | ||
359 | return NOTIFY_OK; | |
360 | } | |
361 | ||
362 | static struct notifier_block xen_memory_nb = { | |
363 | .notifier_call = xen_memory_notifier, | |
364 | .priority = 0 | |
365 | }; | |
366 | #else | |
b2ac6aa8 | 367 | static enum bp_state reserve_additional_memory(void) |
1775826c | 368 | { |
de5a77d8 | 369 | balloon_stats.target_pages = balloon_stats.current_pages; |
1cf6a6c8 | 370 | return BP_ECANCELED; |
1775826c | 371 | } |
de5a77d8 | 372 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ |
1775826c | 373 | |
de5a77d8 | 374 | static long current_credit(void) |
080e2be7 | 375 | { |
de5a77d8 | 376 | return balloon_stats.target_pages - balloon_stats.current_pages; |
080e2be7 DK |
377 | } |
378 | ||
de5a77d8 | 379 | static bool balloon_is_inflated(void) |
080e2be7 | 380 | { |
de5a77d8 | 381 | return balloon_stats.balloon_low || balloon_stats.balloon_high; |
080e2be7 | 382 | } |
080e2be7 | 383 | |
95d2ac4a | 384 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 385 | { |
95d2ac4a | 386 | int rc; |
2f70e0ac | 387 | unsigned long pfn, i; |
1775826c | 388 | struct page *page; |
1775826c JF |
389 | struct xen_memory_reservation reservation = { |
390 | .address_bits = 0, | |
391 | .extent_order = 0, | |
392 | .domid = DOMID_SELF | |
393 | }; | |
394 | ||
395 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
396 | nr_pages = ARRAY_SIZE(frame_list); | |
397 | ||
9346c2a8 | 398 | page = list_first_entry_or_null(&ballooned_pages, struct page, lru); |
1775826c | 399 | for (i = 0; i < nr_pages; i++) { |
95d2ac4a DK |
400 | if (!page) { |
401 | nr_pages = i; | |
402 | break; | |
403 | } | |
a419aef8 | 404 | frame_list[i] = page_to_pfn(page); |
1775826c JF |
405 | page = balloon_next_page(page); |
406 | } | |
407 | ||
a90971eb | 408 | set_xen_guest_handle(reservation.extent_start, frame_list); |
fde28e8f JF |
409 | reservation.nr_extents = nr_pages; |
410 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); | |
40095de1 | 411 | if (rc <= 0) |
95d2ac4a | 412 | return BP_EAGAIN; |
1775826c | 413 | |
bc2c0303 | 414 | for (i = 0; i < rc; i++) { |
b6f30679 | 415 | page = balloon_retrieve(false); |
1775826c JF |
416 | BUG_ON(page == NULL); |
417 | ||
418 | pfn = page_to_pfn(page); | |
1775826c | 419 | |
c2374bf5 | 420 | #ifdef CONFIG_XEN_HAVE_PVMMU |
c1d15f5c SS |
421 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
422 | set_phys_to_machine(pfn, frame_list[i]); | |
423 | ||
424 | /* Link back into the page tables if not highmem. */ | |
425 | if (!PageHighMem(page)) { | |
426 | int ret; | |
427 | ret = HYPERVISOR_update_va_mapping( | |
428 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
429 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
430 | 0); | |
431 | BUG_ON(ret); | |
432 | } | |
1775826c | 433 | } |
c2374bf5 | 434 | #endif |
1775826c JF |
435 | |
436 | /* Relinquish the page back to the allocator. */ | |
3dcc0571 | 437 | __free_reserved_page(page); |
1775826c JF |
438 | } |
439 | ||
bc2c0303 | 440 | balloon_stats.current_pages += rc; |
1775826c | 441 | |
95d2ac4a | 442 | return BP_DONE; |
1775826c JF |
443 | } |
444 | ||
b6f30679 | 445 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) |
1775826c | 446 | { |
95d2ac4a | 447 | enum bp_state state = BP_DONE; |
2f70e0ac | 448 | unsigned long pfn, i; |
1775826c | 449 | struct page *page; |
1775826c JF |
450 | int ret; |
451 | struct xen_memory_reservation reservation = { | |
452 | .address_bits = 0, | |
453 | .extent_order = 0, | |
454 | .domid = DOMID_SELF | |
455 | }; | |
456 | ||
457 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
458 | nr_pages = ARRAY_SIZE(frame_list); | |
459 | ||
460 | for (i = 0; i < nr_pages; i++) { | |
fce92683 LN |
461 | page = alloc_page(gfp); |
462 | if (page == NULL) { | |
1775826c | 463 | nr_pages = i; |
95d2ac4a | 464 | state = BP_EAGAIN; |
1775826c JF |
465 | break; |
466 | } | |
09ed3d5b | 467 | scrub_page(page); |
1775826c | 468 | |
09ed3d5b WL |
469 | frame_list[i] = page_to_pfn(page); |
470 | } | |
1775826c | 471 | |
09ed3d5b WL |
472 | /* |
473 | * Ensure that ballooned highmem pages don't have kmaps. | |
474 | * | |
475 | * Do this before changing the p2m as kmap_flush_unused() | |
476 | * reads PTEs to obtain pages (and hence needs the original | |
477 | * p2m entry). | |
478 | */ | |
479 | kmap_flush_unused(); | |
480 | ||
481 | /* Update direct mapping, invalidate P2M, and add to balloon. */ | |
482 | for (i = 0; i < nr_pages; i++) { | |
483 | pfn = frame_list[i]; | |
0df4f266 | 484 | frame_list[i] = pfn_to_gfn(pfn); |
09ed3d5b | 485 | page = pfn_to_page(pfn); |
1058a75f | 486 | |
c1d15f5c | 487 | #ifdef CONFIG_XEN_HAVE_PVMMU |
04660bb5 | 488 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
c1d15f5c SS |
489 | if (!PageHighMem(page)) { |
490 | ret = HYPERVISOR_update_va_mapping( | |
491 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
0bb599fd | 492 | __pte_ma(0), 0); |
c1d15f5c | 493 | BUG_ON(ret); |
fb9a0c44 DV |
494 | } |
495 | __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); | |
04660bb5 | 496 | } |
c1d15f5c | 497 | #endif |
24f69373 | 498 | |
09ed3d5b | 499 | balloon_append(page); |
1775826c JF |
500 | } |
501 | ||
24f69373 | 502 | flush_tlb_all(); |
2bad07ce | 503 | |
a90971eb | 504 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
505 | reservation.nr_extents = nr_pages; |
506 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
507 | BUG_ON(ret != nr_pages); | |
508 | ||
509 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 510 | |
95d2ac4a | 511 | return state; |
1775826c JF |
512 | } |
513 | ||
514 | /* | |
929423fa | 515 | * As this is a work item it is guaranteed to run as a single instance only. |
1775826c JF |
516 | * We may of course race updates of the target counts (which are protected |
517 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
518 | * recover from these in time. | |
519 | */ | |
520 | static void balloon_process(struct work_struct *work) | |
521 | { | |
95d2ac4a | 522 | enum bp_state state = BP_DONE; |
1775826c JF |
523 | long credit; |
524 | ||
1775826c JF |
525 | |
526 | do { | |
929423fa JG |
527 | mutex_lock(&balloon_mutex); |
528 | ||
83be7e52 | 529 | credit = current_credit(); |
95d2ac4a | 530 | |
080e2be7 DK |
531 | if (credit > 0) { |
532 | if (balloon_is_inflated()) | |
533 | state = increase_reservation(credit); | |
534 | else | |
b2ac6aa8 | 535 | state = reserve_additional_memory(); |
080e2be7 | 536 | } |
95d2ac4a | 537 | |
1775826c | 538 | if (credit < 0) |
b6f30679 | 539 | state = decrease_reservation(-credit, GFP_BALLOON); |
95d2ac4a DK |
540 | |
541 | state = update_schedule(state); | |
1775826c | 542 | |
929423fa JG |
543 | mutex_unlock(&balloon_mutex); |
544 | ||
545 | cond_resched(); | |
546 | ||
95d2ac4a | 547 | } while (credit && state == BP_DONE); |
1775826c JF |
548 | |
549 | /* Schedule more work if there is some still to be done. */ | |
95d2ac4a DK |
550 | if (state == BP_EAGAIN) |
551 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
1775826c JF |
552 | } |
553 | ||
554 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
803eb047 | 555 | void balloon_set_new_target(unsigned long target) |
1775826c JF |
556 | { |
557 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 558 | balloon_stats.target_pages = target; |
95170b2e | 559 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 560 | } |
803eb047 | 561 | EXPORT_SYMBOL_GPL(balloon_set_new_target); |
1775826c | 562 | |
1cf6a6c8 DV |
563 | static int add_ballooned_pages(int nr_pages) |
564 | { | |
565 | enum bp_state st; | |
566 | ||
567 | if (xen_hotplug_unpopulated) { | |
568 | st = reserve_additional_memory(); | |
569 | if (st != BP_ECANCELED) { | |
570 | mutex_unlock(&balloon_mutex); | |
571 | wait_event(balloon_wq, | |
572 | !list_empty(&ballooned_pages)); | |
573 | mutex_lock(&balloon_mutex); | |
574 | return 0; | |
575 | } | |
576 | } | |
577 | ||
578 | st = decrease_reservation(nr_pages, GFP_USER); | |
579 | if (st != BP_DONE) | |
580 | return -ENOMEM; | |
581 | ||
582 | return 0; | |
583 | } | |
584 | ||
b6f30679 KRW |
585 | /** |
586 | * alloc_xenballooned_pages - get pages that have been ballooned out | |
587 | * @nr_pages: Number of pages to get | |
588 | * @pages: pages returned | |
589 | * @return 0 on success, error otherwise | |
590 | */ | |
81b286e0 | 591 | int alloc_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 592 | { |
b6f30679 | 593 | int pgno = 0; |
e882dc9c | 594 | struct page *page; |
1cf6a6c8 DV |
595 | int ret; |
596 | ||
b6f30679 | 597 | mutex_lock(&balloon_mutex); |
1cf6a6c8 DV |
598 | |
599 | balloon_stats.target_unpopulated += nr_pages; | |
600 | ||
b6f30679 | 601 | while (pgno < nr_pages) { |
81b286e0 DV |
602 | page = balloon_retrieve(true); |
603 | if (page) { | |
b6f30679 KRW |
604 | pages[pgno++] = page; |
605 | } else { | |
1cf6a6c8 DV |
606 | ret = add_ballooned_pages(nr_pages - pgno); |
607 | if (ret < 0) | |
b6f30679 KRW |
608 | goto out_undo; |
609 | } | |
1775826c | 610 | } |
b6f30679 KRW |
611 | mutex_unlock(&balloon_mutex); |
612 | return 0; | |
613 | out_undo: | |
b6f30679 | 614 | mutex_unlock(&balloon_mutex); |
1cf6a6c8 DV |
615 | free_xenballooned_pages(pgno, pages); |
616 | return ret; | |
1775826c | 617 | } |
b6f30679 | 618 | EXPORT_SYMBOL(alloc_xenballooned_pages); |
1775826c | 619 | |
b6f30679 KRW |
620 | /** |
621 | * free_xenballooned_pages - return pages retrieved with get_ballooned_pages | |
622 | * @nr_pages: Number of pages | |
623 | * @pages: pages to return | |
624 | */ | |
e882dc9c | 625 | void free_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 626 | { |
b6f30679 | 627 | int i; |
1775826c | 628 | |
b6f30679 | 629 | mutex_lock(&balloon_mutex); |
1775826c | 630 | |
b6f30679 KRW |
631 | for (i = 0; i < nr_pages; i++) { |
632 | if (pages[i]) | |
633 | balloon_append(pages[i]); | |
634 | } | |
635 | ||
1cf6a6c8 DV |
636 | balloon_stats.target_unpopulated -= nr_pages; |
637 | ||
b6f30679 | 638 | /* The balloon may be too large now. Shrink it if needed. */ |
83be7e52 | 639 | if (current_credit()) |
b6f30679 | 640 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 641 | |
b6f30679 KRW |
642 | mutex_unlock(&balloon_mutex); |
643 | } | |
644 | EXPORT_SYMBOL(free_xenballooned_pages); | |
1775826c | 645 | |
8b5d44a5 DV |
646 | static void __init balloon_add_region(unsigned long start_pfn, |
647 | unsigned long pages) | |
1775826c | 648 | { |
4dfe22f5 | 649 | unsigned long pfn, extra_pfn_end; |
1775826c JF |
650 | struct page *page; |
651 | ||
8b5d44a5 DV |
652 | /* |
653 | * If the amount of usable memory has been limited (e.g., with | |
654 | * the 'mem' command line parameter), don't add pages beyond | |
655 | * this limit. | |
656 | */ | |
657 | extra_pfn_end = min(max_pfn, start_pfn + pages); | |
658 | ||
659 | for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { | |
660 | page = pfn_to_page(pfn); | |
661 | /* totalram_pages and totalhigh_pages do not | |
662 | include the boot-time balloon extension, so | |
663 | don't subtract from it. */ | |
664 | __balloon_append(page); | |
665 | } | |
de5a77d8 DV |
666 | |
667 | balloon_stats.total_pages += extra_pfn_end - start_pfn; | |
8b5d44a5 DV |
668 | } |
669 | ||
670 | static int __init balloon_init(void) | |
671 | { | |
0bb599fd | 672 | int i; |
8b5d44a5 | 673 | |
53d5522c | 674 | if (!xen_domain()) |
1775826c JF |
675 | return -ENODEV; |
676 | ||
283c0972 | 677 | pr_info("Initialising balloon driver\n"); |
1775826c | 678 | |
aa24411b DV |
679 | balloon_stats.current_pages = xen_pv_domain() |
680 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
c275a57f | 681 | : get_num_physpages(); |
1775826c JF |
682 | balloon_stats.target_pages = balloon_stats.current_pages; |
683 | balloon_stats.balloon_low = 0; | |
684 | balloon_stats.balloon_high = 0; | |
de5a77d8 | 685 | balloon_stats.total_pages = balloon_stats.current_pages; |
1775826c | 686 | |
95d2ac4a DK |
687 | balloon_stats.schedule_delay = 1; |
688 | balloon_stats.max_schedule_delay = 32; | |
689 | balloon_stats.retry_count = 1; | |
40095de1 | 690 | balloon_stats.max_retry_count = RETRY_UNLIMITED; |
1775826c | 691 | |
080e2be7 | 692 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
080e2be7 DK |
693 | set_online_page_callback(&xen_online_page); |
694 | register_memory_notifier(&xen_memory_nb); | |
1cf6a6c8 | 695 | register_sysctl_table(xen_root); |
080e2be7 DK |
696 | #endif |
697 | ||
2a4c92fa | 698 | /* |
b1cbf9b1 | 699 | * Initialize the balloon with pages from the extra memory |
8b5d44a5 | 700 | * regions (see arch/x86/xen/setup.c). |
2a4c92fa | 701 | */ |
8b5d44a5 | 702 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) |
626d7508 JG |
703 | if (xen_extra_mem[i].n_pfns) |
704 | balloon_add_region(xen_extra_mem[i].start_pfn, | |
705 | xen_extra_mem[i].n_pfns); | |
1775826c | 706 | |
1775826c JF |
707 | return 0; |
708 | } | |
709 | ||
710 | subsys_initcall(balloon_init); | |
711 | ||
1775826c | 712 | MODULE_LICENSE("GPL"); |