Commit | Line | Data |
---|---|---|
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 | 45 | #include <linux/errno.h> |
8480ed9c JG |
46 | #include <linux/freezer.h> |
47 | #include <linux/kthread.h> | |
1775826c | 48 | #include <linux/mm.h> |
57c8a661 | 49 | #include <linux/memblock.h> |
1775826c JF |
50 | #include <linux/pagemap.h> |
51 | #include <linux/highmem.h> | |
52 | #include <linux/mutex.h> | |
1775826c | 53 | #include <linux/list.h> |
5a0e3ad6 | 54 | #include <linux/gfp.h> |
080e2be7 DK |
55 | #include <linux/notifier.h> |
56 | #include <linux/memory.h> | |
57 | #include <linux/memory_hotplug.h> | |
cd9151e2 | 58 | #include <linux/percpu-defs.h> |
55b3da98 | 59 | #include <linux/slab.h> |
1cf6a6c8 | 60 | #include <linux/sysctl.h> |
40fdea02 | 61 | #include <linux/moduleparam.h> |
b537bf42 | 62 | #include <linux/jiffies.h> |
1775826c | 63 | |
1775826c | 64 | #include <asm/page.h> |
1775826c JF |
65 | #include <asm/tlb.h> |
66 | ||
ecbf29cd JF |
67 | #include <asm/xen/hypervisor.h> |
68 | #include <asm/xen/hypercall.h> | |
1ccbf534 JF |
69 | |
70 | #include <xen/xen.h> | |
ecbf29cd | 71 | #include <xen/interface/xen.h> |
1775826c | 72 | #include <xen/interface/memory.h> |
803eb047 | 73 | #include <xen/balloon.h> |
1775826c JF |
74 | #include <xen/features.h> |
75 | #include <xen/page.h> | |
ae4c51a5 | 76 | #include <xen/mem-reservation.h> |
1775826c | 77 | |
40fdea02 JG |
78 | #undef MODULE_PARAM_PREFIX |
79 | #define MODULE_PARAM_PREFIX "xen." | |
80 | ||
81 | static uint __read_mostly balloon_boot_timeout = 180; | |
82 | module_param(balloon_boot_timeout, uint, 0444); | |
83 | ||
1cf6a6c8 | 84 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
501586ea | 85 | static int xen_hotplug_unpopulated; |
1cf6a6c8 | 86 | |
1cf6a6c8 DV |
87 | static struct ctl_table balloon_table[] = { |
88 | { | |
89 | .procname = "hotplug_unpopulated", | |
90 | .data = &xen_hotplug_unpopulated, | |
91 | .maxlen = sizeof(int), | |
92 | .mode = 0644, | |
93 | .proc_handler = proc_dointvec_minmax, | |
eec4844f MC |
94 | .extra1 = SYSCTL_ZERO, |
95 | .extra2 = SYSCTL_ONE, | |
1cf6a6c8 DV |
96 | }, |
97 | { } | |
98 | }; | |
99 | ||
501586ea AB |
100 | #else |
101 | #define xen_hotplug_unpopulated 0 | |
1cf6a6c8 DV |
102 | #endif |
103 | ||
30756c62 JG |
104 | /* |
105 | * Use one extent per PAGE_SIZE to avoid to break down the page into | |
106 | * multiple frame. | |
107 | */ | |
108 | #define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1) | |
109 | ||
95d2ac4a | 110 | /* |
8480ed9c | 111 | * balloon_thread() state: |
95d2ac4a DK |
112 | * |
113 | * BP_DONE: done or nothing to do, | |
b2ac6aa8 | 114 | * BP_WAIT: wait to be rescheduled, |
95d2ac4a DK |
115 | * BP_EAGAIN: error, go to sleep, |
116 | * BP_ECANCELED: error, balloon operation canceled. | |
117 | */ | |
1775826c | 118 | |
40fdea02 | 119 | static enum bp_state { |
95d2ac4a | 120 | BP_DONE, |
b2ac6aa8 | 121 | BP_WAIT, |
95d2ac4a DK |
122 | BP_EAGAIN, |
123 | BP_ECANCELED | |
40fdea02 | 124 | } balloon_state = BP_DONE; |
1775826c | 125 | |
8480ed9c JG |
126 | /* Main waiting point for xen-balloon thread. */ |
127 | static DECLARE_WAIT_QUEUE_HEAD(balloon_thread_wq); | |
1775826c | 128 | |
1775826c | 129 | static DEFINE_MUTEX(balloon_mutex); |
1775826c | 130 | |
803eb047 DDG |
131 | struct balloon_stats balloon_stats; |
132 | EXPORT_SYMBOL_GPL(balloon_stats); | |
1775826c JF |
133 | |
134 | /* We increase/decrease in batches which fit in a page */ | |
3990dd27 | 135 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)]; |
cd9151e2 | 136 | |
1775826c | 137 | |
1775826c JF |
138 | /* List of ballooned pages, threaded through the mem_map array. */ |
139 | static LIST_HEAD(ballooned_pages); | |
1cf6a6c8 | 140 | static DECLARE_WAIT_QUEUE_HEAD(balloon_wq); |
1775826c | 141 | |
1775826c JF |
142 | /* When ballooning out (allocating memory to return to Xen) we don't really |
143 | want the kernel to try too hard since that can trigger the oom killer. */ | |
144 | #define GFP_BALLOON \ | |
145 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
146 | ||
1775826c | 147 | /* balloon_append: add the given page to the balloon. */ |
dde3285f | 148 | static void balloon_append(struct page *page) |
1775826c | 149 | { |
59b52f10 DH |
150 | __SetPageOffline(page); |
151 | ||
1775826c JF |
152 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ |
153 | if (PageHighMem(page)) { | |
154 | list_add_tail(&page->lru, &ballooned_pages); | |
155 | balloon_stats.balloon_high++; | |
1775826c JF |
156 | } else { |
157 | list_add(&page->lru, &ballooned_pages); | |
158 | balloon_stats.balloon_low++; | |
159 | } | |
1cf6a6c8 | 160 | wake_up(&balloon_wq); |
9be4d457 | 161 | } |
3d65c948 | 162 | |
1775826c | 163 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ |
81b286e0 | 164 | static struct page *balloon_retrieve(bool require_lowmem) |
1775826c JF |
165 | { |
166 | struct page *page; | |
167 | ||
168 | if (list_empty(&ballooned_pages)) | |
169 | return NULL; | |
170 | ||
81b286e0 DV |
171 | page = list_entry(ballooned_pages.next, struct page, lru); |
172 | if (require_lowmem && PageHighMem(page)) | |
173 | return NULL; | |
1775826c JF |
174 | list_del(&page->lru); |
175 | ||
3dcc0571 | 176 | if (PageHighMem(page)) |
1775826c | 177 | balloon_stats.balloon_high--; |
3dcc0571 | 178 | else |
1775826c JF |
179 | balloon_stats.balloon_low--; |
180 | ||
04ccbdc3 | 181 | __ClearPageOffline(page); |
1775826c JF |
182 | return page; |
183 | } | |
184 | ||
1775826c JF |
185 | static struct page *balloon_next_page(struct page *page) |
186 | { | |
187 | struct list_head *next = page->lru.next; | |
188 | if (next == &ballooned_pages) | |
189 | return NULL; | |
190 | return list_entry(next, struct page, lru); | |
191 | } | |
192 | ||
40fdea02 | 193 | static void update_schedule(void) |
1775826c | 194 | { |
40fdea02 JG |
195 | if (balloon_state == BP_WAIT || balloon_state == BP_ECANCELED) |
196 | return; | |
fd8b7951 | 197 | |
40fdea02 | 198 | if (balloon_state == BP_DONE) { |
95d2ac4a DK |
199 | balloon_stats.schedule_delay = 1; |
200 | balloon_stats.retry_count = 1; | |
40fdea02 | 201 | return; |
95d2ac4a DK |
202 | } |
203 | ||
95d2ac4a DK |
204 | ++balloon_stats.retry_count; |
205 | ||
206 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
207 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
208 | balloon_stats.schedule_delay = 1; |
209 | balloon_stats.retry_count = 1; | |
40fdea02 JG |
210 | balloon_state = BP_ECANCELED; |
211 | return; | |
95d2ac4a DK |
212 | } |
213 | ||
214 | balloon_stats.schedule_delay <<= 1; | |
215 | ||
216 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
217 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
218 | ||
40fdea02 | 219 | balloon_state = BP_EAGAIN; |
1775826c JF |
220 | } |
221 | ||
080e2be7 | 222 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
842775f1 RL |
223 | static void release_memory_resource(struct resource *resource) |
224 | { | |
225 | if (!resource) | |
226 | return; | |
227 | ||
228 | /* | |
229 | * No need to reset region to identity mapped since we now | |
230 | * know that no I/O can be in this region | |
231 | */ | |
232 | release_resource(resource); | |
233 | kfree(resource); | |
234 | } | |
235 | ||
55b3da98 DV |
236 | static struct resource *additional_memory_resource(phys_addr_t size) |
237 | { | |
12366410 ID |
238 | struct resource *res; |
239 | int ret; | |
55b3da98 DV |
240 | |
241 | res = kzalloc(sizeof(*res), GFP_KERNEL); | |
242 | if (!res) | |
243 | return NULL; | |
244 | ||
245 | res->name = "System RAM"; | |
782b8664 | 246 | res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; |
55b3da98 | 247 | |
12366410 ID |
248 | ret = allocate_resource(&iomem_resource, res, |
249 | size, 0, -1, | |
250 | PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); | |
251 | if (ret < 0) { | |
252 | pr_err("Cannot allocate new System RAM resource\n"); | |
253 | kfree(res); | |
254 | return NULL; | |
55b3da98 DV |
255 | } |
256 | ||
257 | return res; | |
258 | } | |
259 | ||
b2ac6aa8 | 260 | static enum bp_state reserve_additional_memory(void) |
080e2be7 | 261 | { |
b2ac6aa8 | 262 | long credit; |
55b3da98 | 263 | struct resource *resource; |
080e2be7 | 264 | int nid, rc; |
55b3da98 | 265 | unsigned long balloon_hotplug; |
080e2be7 | 266 | |
1cf6a6c8 DV |
267 | credit = balloon_stats.target_pages + balloon_stats.target_unpopulated |
268 | - balloon_stats.total_pages; | |
b2ac6aa8 DV |
269 | |
270 | /* | |
271 | * Already hotplugged enough pages? Wait for them to be | |
272 | * onlined. | |
273 | */ | |
274 | if (credit <= 0) | |
275 | return BP_WAIT; | |
276 | ||
55b3da98 DV |
277 | balloon_hotplug = round_up(credit, PAGES_PER_SECTION); |
278 | ||
279 | resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE); | |
280 | if (!resource) | |
281 | goto err; | |
282 | ||
283 | nid = memory_add_physaddr_to_nid(resource->start); | |
080e2be7 | 284 | |
3c56b3a1 | 285 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
286 | /* |
287 | * We don't support PV MMU when Linux and Xen is using | |
288 | * different page granularity. | |
289 | */ | |
290 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
291 | ||
3c56b3a1 JG |
292 | /* |
293 | * add_memory() will build page tables for the new memory so | |
294 | * the p2m must contain invalid entries so the correct | |
295 | * non-present PTEs will be written. | |
296 | * | |
297 | * If a failure occurs, the original (identity) p2m entries | |
298 | * are not restored since this region is now known not to | |
299 | * conflict with any devices. | |
300 | */ | |
301 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
302 | unsigned long pfn, i; | |
303 | ||
55b3da98 | 304 | pfn = PFN_DOWN(resource->start); |
3c56b3a1 JG |
305 | for (i = 0; i < balloon_hotplug; i++) { |
306 | if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { | |
307 | pr_warn("set_phys_to_machine() failed, no memory added\n"); | |
55b3da98 | 308 | goto err; |
3c56b3a1 JG |
309 | } |
310 | } | |
311 | } | |
312 | #endif | |
313 | ||
703fc13a VK |
314 | /* |
315 | * add_memory_resource() will call online_pages() which in its turn | |
316 | * will call xen_online_page() callback causing deadlock if we don't | |
317 | * release balloon_mutex here. Unlocking here is safe because the | |
318 | * callers drop the mutex before trying again. | |
319 | */ | |
320 | mutex_unlock(&balloon_mutex); | |
8df1d0e4 DH |
321 | /* add_memory_resource() requires the device_hotplug lock */ |
322 | lock_device_hotplug(); | |
26011267 | 323 | rc = add_memory_resource(nid, resource, MHP_MERGE_RESOURCE); |
8df1d0e4 | 324 | unlock_device_hotplug(); |
703fc13a VK |
325 | mutex_lock(&balloon_mutex); |
326 | ||
080e2be7 | 327 | if (rc) { |
3dcf6367 | 328 | pr_warn("Cannot add additional memory (%i)\n", rc); |
55b3da98 | 329 | goto err; |
080e2be7 DK |
330 | } |
331 | ||
de5a77d8 | 332 | balloon_stats.total_pages += balloon_hotplug; |
080e2be7 | 333 | |
b2ac6aa8 | 334 | return BP_WAIT; |
55b3da98 DV |
335 | err: |
336 | release_memory_resource(resource); | |
337 | return BP_ECANCELED; | |
080e2be7 DK |
338 | } |
339 | ||
a9cd410a | 340 | static void xen_online_page(struct page *page, unsigned int order) |
080e2be7 | 341 | { |
a9cd410a AK |
342 | unsigned long i, size = (1 << order); |
343 | unsigned long start_pfn = page_to_pfn(page); | |
344 | struct page *p; | |
080e2be7 | 345 | |
a9cd410a | 346 | pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn); |
080e2be7 | 347 | mutex_lock(&balloon_mutex); |
a9cd410a AK |
348 | for (i = 0; i < size; i++) { |
349 | p = pfn_to_page(start_pfn + i); | |
dde3285f | 350 | balloon_append(p); |
a9cd410a | 351 | } |
080e2be7 DK |
352 | mutex_unlock(&balloon_mutex); |
353 | } | |
354 | ||
355 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
356 | { | |
357 | if (val == MEM_ONLINE) | |
8480ed9c | 358 | wake_up(&balloon_thread_wq); |
080e2be7 DK |
359 | |
360 | return NOTIFY_OK; | |
361 | } | |
362 | ||
363 | static struct notifier_block xen_memory_nb = { | |
364 | .notifier_call = xen_memory_notifier, | |
365 | .priority = 0 | |
366 | }; | |
367 | #else | |
b2ac6aa8 | 368 | static enum bp_state reserve_additional_memory(void) |
1775826c | 369 | { |
c673ec61 JG |
370 | balloon_stats.target_pages = balloon_stats.current_pages + |
371 | balloon_stats.target_unpopulated; | |
1cf6a6c8 | 372 | return BP_ECANCELED; |
1775826c | 373 | } |
de5a77d8 | 374 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ |
1775826c | 375 | |
de5a77d8 | 376 | static long current_credit(void) |
080e2be7 | 377 | { |
de5a77d8 | 378 | return balloon_stats.target_pages - balloon_stats.current_pages; |
080e2be7 DK |
379 | } |
380 | ||
de5a77d8 | 381 | static bool balloon_is_inflated(void) |
080e2be7 | 382 | { |
de5a77d8 | 383 | return balloon_stats.balloon_low || balloon_stats.balloon_high; |
080e2be7 | 384 | } |
080e2be7 | 385 | |
95d2ac4a | 386 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 387 | { |
95d2ac4a | 388 | int rc; |
30756c62 | 389 | unsigned long i; |
1775826c | 390 | struct page *page; |
1775826c JF |
391 | |
392 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
393 | nr_pages = ARRAY_SIZE(frame_list); | |
394 | ||
9346c2a8 | 395 | page = list_first_entry_or_null(&ballooned_pages, struct page, lru); |
1775826c | 396 | for (i = 0; i < nr_pages; i++) { |
95d2ac4a DK |
397 | if (!page) { |
398 | nr_pages = i; | |
399 | break; | |
400 | } | |
30756c62 | 401 | |
30756c62 | 402 | frame_list[i] = page_to_xen_pfn(page); |
1775826c JF |
403 | page = balloon_next_page(page); |
404 | } | |
405 | ||
ae4c51a5 | 406 | rc = xenmem_reservation_increase(nr_pages, frame_list); |
40095de1 | 407 | if (rc <= 0) |
95d2ac4a | 408 | return BP_EAGAIN; |
1775826c | 409 | |
bc2c0303 | 410 | for (i = 0; i < rc; i++) { |
b6f30679 | 411 | page = balloon_retrieve(false); |
1775826c JF |
412 | BUG_ON(page == NULL); |
413 | ||
ae4c51a5 | 414 | xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]); |
1775826c JF |
415 | |
416 | /* Relinquish the page back to the allocator. */ | |
709613ad | 417 | free_reserved_page(page); |
1775826c JF |
418 | } |
419 | ||
bc2c0303 | 420 | balloon_stats.current_pages += rc; |
1775826c | 421 | |
95d2ac4a | 422 | return BP_DONE; |
1775826c JF |
423 | } |
424 | ||
b6f30679 | 425 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) |
1775826c | 426 | { |
95d2ac4a | 427 | enum bp_state state = BP_DONE; |
30756c62 JG |
428 | unsigned long i; |
429 | struct page *page, *tmp; | |
1775826c | 430 | int ret; |
30756c62 | 431 | LIST_HEAD(pages); |
1775826c JF |
432 | |
433 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
434 | nr_pages = ARRAY_SIZE(frame_list); | |
435 | ||
436 | for (i = 0; i < nr_pages; i++) { | |
fce92683 LN |
437 | page = alloc_page(gfp); |
438 | if (page == NULL) { | |
1775826c | 439 | nr_pages = i; |
95d2ac4a | 440 | state = BP_EAGAIN; |
1775826c JF |
441 | break; |
442 | } | |
709613ad | 443 | adjust_managed_page_count(page, -1); |
ae4c51a5 | 444 | xenmem_reservation_scrub_page(page); |
30756c62 | 445 | list_add(&page->lru, &pages); |
09ed3d5b | 446 | } |
1775826c | 447 | |
09ed3d5b WL |
448 | /* |
449 | * Ensure that ballooned highmem pages don't have kmaps. | |
450 | * | |
451 | * Do this before changing the p2m as kmap_flush_unused() | |
452 | * reads PTEs to obtain pages (and hence needs the original | |
453 | * p2m entry). | |
454 | */ | |
455 | kmap_flush_unused(); | |
456 | ||
30756c62 JG |
457 | /* |
458 | * Setup the frame, update direct mapping, invalidate P2M, | |
459 | * and add to balloon. | |
460 | */ | |
461 | i = 0; | |
462 | list_for_each_entry_safe(page, tmp, &pages, lru) { | |
30756c62 | 463 | frame_list[i++] = xen_page_to_gfn(page); |
1058a75f | 464 | |
ae4c51a5 | 465 | xenmem_reservation_va_mapping_reset(1, &page); |
30756c62 | 466 | |
30756c62 | 467 | list_del(&page->lru); |
24f69373 | 468 | |
09ed3d5b | 469 | balloon_append(page); |
1775826c JF |
470 | } |
471 | ||
24f69373 | 472 | flush_tlb_all(); |
2bad07ce | 473 | |
ae4c51a5 | 474 | ret = xenmem_reservation_decrease(nr_pages, frame_list); |
1775826c JF |
475 | BUG_ON(ret != nr_pages); |
476 | ||
477 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 478 | |
95d2ac4a | 479 | return state; |
1775826c JF |
480 | } |
481 | ||
482 | /* | |
319933a8 JG |
483 | * Stop waiting if either state is BP_DONE and ballooning action is |
484 | * needed, or if the credit has changed while state is not BP_DONE. | |
8480ed9c | 485 | */ |
40fdea02 | 486 | static bool balloon_thread_cond(long credit) |
8480ed9c | 487 | { |
40fdea02 | 488 | if (balloon_state == BP_DONE) |
8480ed9c JG |
489 | credit = 0; |
490 | ||
491 | return current_credit() != credit || kthread_should_stop(); | |
492 | } | |
493 | ||
494 | /* | |
495 | * As this is a kthread it is guaranteed to run as a single instance only. | |
1775826c JF |
496 | * We may of course race updates of the target counts (which are protected |
497 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
498 | * recover from these in time. | |
499 | */ | |
8480ed9c | 500 | static int balloon_thread(void *unused) |
1775826c | 501 | { |
1775826c | 502 | long credit; |
8480ed9c JG |
503 | unsigned long timeout; |
504 | ||
505 | set_freezable(); | |
506 | for (;;) { | |
40fdea02 | 507 | switch (balloon_state) { |
319933a8 JG |
508 | case BP_DONE: |
509 | case BP_ECANCELED: | |
8480ed9c | 510 | timeout = 3600 * HZ; |
319933a8 JG |
511 | break; |
512 | case BP_EAGAIN: | |
513 | timeout = balloon_stats.schedule_delay * HZ; | |
514 | break; | |
515 | case BP_WAIT: | |
516 | timeout = HZ; | |
517 | break; | |
518 | } | |
519 | ||
8480ed9c | 520 | credit = current_credit(); |
1775826c | 521 | |
96f5bd03 | 522 | wait_event_freezable_timeout(balloon_thread_wq, |
40fdea02 | 523 | balloon_thread_cond(credit), timeout); |
8480ed9c JG |
524 | |
525 | if (kthread_should_stop()) | |
526 | return 0; | |
1775826c | 527 | |
929423fa JG |
528 | mutex_lock(&balloon_mutex); |
529 | ||
83be7e52 | 530 | credit = current_credit(); |
95d2ac4a | 531 | |
080e2be7 DK |
532 | if (credit > 0) { |
533 | if (balloon_is_inflated()) | |
40fdea02 | 534 | balloon_state = increase_reservation(credit); |
080e2be7 | 535 | else |
40fdea02 | 536 | balloon_state = reserve_additional_memory(); |
080e2be7 | 537 | } |
95d2ac4a | 538 | |
a1078e82 JG |
539 | if (credit < 0) { |
540 | long n_pages; | |
541 | ||
542 | n_pages = min(-credit, si_mem_available()); | |
40fdea02 JG |
543 | balloon_state = decrease_reservation(n_pages, |
544 | GFP_BALLOON); | |
545 | if (balloon_state == BP_DONE && n_pages != -credit && | |
a1078e82 | 546 | n_pages < totalreserve_pages) |
40fdea02 | 547 | balloon_state = BP_EAGAIN; |
a1078e82 | 548 | } |
95d2ac4a | 549 | |
40fdea02 | 550 | update_schedule(); |
1775826c | 551 | |
929423fa JG |
552 | mutex_unlock(&balloon_mutex); |
553 | ||
554 | cond_resched(); | |
8480ed9c | 555 | } |
1775826c JF |
556 | } |
557 | ||
558 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
803eb047 | 559 | void balloon_set_new_target(unsigned long target) |
1775826c JF |
560 | { |
561 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 562 | balloon_stats.target_pages = target; |
8480ed9c | 563 | wake_up(&balloon_thread_wq); |
1775826c | 564 | } |
803eb047 | 565 | EXPORT_SYMBOL_GPL(balloon_set_new_target); |
1775826c | 566 | |
121f2fac | 567 | static int add_ballooned_pages(unsigned int nr_pages) |
1cf6a6c8 DV |
568 | { |
569 | enum bp_state st; | |
570 | ||
571 | if (xen_hotplug_unpopulated) { | |
572 | st = reserve_additional_memory(); | |
573 | if (st != BP_ECANCELED) { | |
88a479ff RPM |
574 | int rc; |
575 | ||
1cf6a6c8 | 576 | mutex_unlock(&balloon_mutex); |
88a479ff | 577 | rc = wait_event_interruptible(balloon_wq, |
1cf6a6c8 DV |
578 | !list_empty(&ballooned_pages)); |
579 | mutex_lock(&balloon_mutex); | |
88a479ff | 580 | return rc ? -ENOMEM : 0; |
1cf6a6c8 DV |
581 | } |
582 | } | |
583 | ||
a1078e82 JG |
584 | if (si_mem_available() < nr_pages) |
585 | return -ENOMEM; | |
586 | ||
1cf6a6c8 DV |
587 | st = decrease_reservation(nr_pages, GFP_USER); |
588 | if (st != BP_DONE) | |
589 | return -ENOMEM; | |
590 | ||
591 | return 0; | |
592 | } | |
593 | ||
b6f30679 | 594 | /** |
9dd060af | 595 | * xen_alloc_ballooned_pages - get pages that have been ballooned out |
b6f30679 KRW |
596 | * @nr_pages: Number of pages to get |
597 | * @pages: pages returned | |
598 | * @return 0 on success, error otherwise | |
599 | */ | |
9dd060af | 600 | int xen_alloc_ballooned_pages(unsigned int nr_pages, struct page **pages) |
1775826c | 601 | { |
121f2fac | 602 | unsigned int pgno = 0; |
e882dc9c | 603 | struct page *page; |
1cf6a6c8 DV |
604 | int ret; |
605 | ||
b6f30679 | 606 | mutex_lock(&balloon_mutex); |
1cf6a6c8 DV |
607 | |
608 | balloon_stats.target_unpopulated += nr_pages; | |
609 | ||
b6f30679 | 610 | while (pgno < nr_pages) { |
81b286e0 DV |
611 | page = balloon_retrieve(true); |
612 | if (page) { | |
b6f30679 | 613 | pages[pgno++] = page; |
4a69c909 | 614 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
615 | /* |
616 | * We don't support PV MMU when Linux and Xen is using | |
617 | * different page granularity. | |
618 | */ | |
619 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
620 | ||
b194da25 BO |
621 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
622 | ret = xen_alloc_p2m_entry(page_to_pfn(page)); | |
623 | if (ret < 0) | |
624 | goto out_undo; | |
625 | } | |
4a69c909 | 626 | #endif |
b6f30679 | 627 | } else { |
1cf6a6c8 DV |
628 | ret = add_ballooned_pages(nr_pages - pgno); |
629 | if (ret < 0) | |
b6f30679 KRW |
630 | goto out_undo; |
631 | } | |
1775826c | 632 | } |
b6f30679 KRW |
633 | mutex_unlock(&balloon_mutex); |
634 | return 0; | |
635 | out_undo: | |
b6f30679 | 636 | mutex_unlock(&balloon_mutex); |
9dd060af | 637 | xen_free_ballooned_pages(pgno, pages); |
1951fa33 | 638 | /* |
9dd060af | 639 | * NB: xen_free_ballooned_pages will only subtract pgno pages, but since |
1951fa33 RPM |
640 | * target_unpopulated is incremented with nr_pages at the start we need |
641 | * to remove the remaining ones also, or accounting will be screwed. | |
642 | */ | |
643 | balloon_stats.target_unpopulated -= nr_pages - pgno; | |
1cf6a6c8 | 644 | return ret; |
1775826c | 645 | } |
9dd060af | 646 | EXPORT_SYMBOL(xen_alloc_ballooned_pages); |
1775826c | 647 | |
b6f30679 | 648 | /** |
9dd060af | 649 | * xen_free_ballooned_pages - return pages retrieved with get_ballooned_pages |
b6f30679 KRW |
650 | * @nr_pages: Number of pages |
651 | * @pages: pages to return | |
652 | */ | |
9dd060af | 653 | void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages) |
1775826c | 654 | { |
121f2fac | 655 | unsigned int i; |
1775826c | 656 | |
b6f30679 | 657 | mutex_lock(&balloon_mutex); |
1775826c | 658 | |
b6f30679 | 659 | for (i = 0; i < nr_pages; i++) { |
59b52f10 | 660 | if (pages[i]) |
b6f30679 KRW |
661 | balloon_append(pages[i]); |
662 | } | |
663 | ||
1cf6a6c8 DV |
664 | balloon_stats.target_unpopulated -= nr_pages; |
665 | ||
b6f30679 | 666 | /* The balloon may be too large now. Shrink it if needed. */ |
83be7e52 | 667 | if (current_credit()) |
8480ed9c | 668 | wake_up(&balloon_thread_wq); |
1775826c | 669 | |
b6f30679 KRW |
670 | mutex_unlock(&balloon_mutex); |
671 | } | |
9dd060af | 672 | EXPORT_SYMBOL(xen_free_ballooned_pages); |
1775826c | 673 | |
262fc47a | 674 | static void __init balloon_add_regions(void) |
1775826c | 675 | { |
262fc47a JG |
676 | #if defined(CONFIG_XEN_PV) |
677 | unsigned long start_pfn, pages; | |
4dfe22f5 | 678 | unsigned long pfn, extra_pfn_end; |
262fc47a | 679 | unsigned int i; |
1775826c | 680 | |
262fc47a JG |
681 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { |
682 | pages = xen_extra_mem[i].n_pfns; | |
683 | if (!pages) | |
684 | continue; | |
8b5d44a5 | 685 | |
262fc47a | 686 | start_pfn = xen_extra_mem[i].start_pfn; |
de5a77d8 | 687 | |
262fc47a JG |
688 | /* |
689 | * If the amount of usable memory has been limited (e.g., with | |
690 | * the 'mem' command line parameter), don't add pages beyond | |
691 | * this limit. | |
692 | */ | |
693 | extra_pfn_end = min(max_pfn, start_pfn + pages); | |
694 | ||
695 | for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) | |
696 | balloon_append(pfn_to_page(pfn)); | |
697 | ||
698 | balloon_stats.total_pages += extra_pfn_end - start_pfn; | |
699 | } | |
4fee9ad8 | 700 | #endif |
262fc47a | 701 | } |
8b5d44a5 DV |
702 | |
703 | static int __init balloon_init(void) | |
704 | { | |
8480ed9c JG |
705 | struct task_struct *task; |
706 | ||
53d5522c | 707 | if (!xen_domain()) |
1775826c JF |
708 | return -ENODEV; |
709 | ||
283c0972 | 710 | pr_info("Initialising balloon driver\n"); |
1775826c | 711 | |
4fee9ad8 | 712 | #ifdef CONFIG_XEN_PV |
aa24411b DV |
713 | balloon_stats.current_pages = xen_pv_domain() |
714 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
c275a57f | 715 | : get_num_physpages(); |
4fee9ad8 VK |
716 | #else |
717 | balloon_stats.current_pages = get_num_physpages(); | |
718 | #endif | |
1775826c JF |
719 | balloon_stats.target_pages = balloon_stats.current_pages; |
720 | balloon_stats.balloon_low = 0; | |
721 | balloon_stats.balloon_high = 0; | |
de5a77d8 | 722 | balloon_stats.total_pages = balloon_stats.current_pages; |
1775826c | 723 | |
95d2ac4a DK |
724 | balloon_stats.schedule_delay = 1; |
725 | balloon_stats.max_schedule_delay = 32; | |
726 | balloon_stats.retry_count = 1; | |
a1078e82 | 727 | balloon_stats.max_retry_count = 4; |
1775826c | 728 | |
080e2be7 | 729 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
080e2be7 DK |
730 | set_online_page_callback(&xen_online_page); |
731 | register_memory_notifier(&xen_memory_nb); | |
9f17a75b | 732 | register_sysctl_init("xen/balloon", balloon_table); |
080e2be7 DK |
733 | #endif |
734 | ||
262fc47a | 735 | balloon_add_regions(); |
1775826c | 736 | |
8480ed9c JG |
737 | task = kthread_run(balloon_thread, NULL, "xen-balloon"); |
738 | if (IS_ERR(task)) { | |
739 | pr_err("xen-balloon thread could not be started, ballooning will not work!\n"); | |
740 | return PTR_ERR(task); | |
741 | } | |
742 | ||
96edd61d JG |
743 | /* Init the xen-balloon driver. */ |
744 | xen_balloon_init(); | |
745 | ||
1775826c JF |
746 | return 0; |
747 | } | |
1775826c | 748 | subsys_initcall(balloon_init); |
40fdea02 JG |
749 | |
750 | static int __init balloon_wait_finish(void) | |
751 | { | |
752 | long credit, last_credit = 0; | |
753 | unsigned long last_changed = 0; | |
754 | ||
755 | if (!xen_domain()) | |
756 | return -ENODEV; | |
757 | ||
758 | /* PV guests don't need to wait. */ | |
759 | if (xen_pv_domain() || !current_credit()) | |
760 | return 0; | |
761 | ||
762 | pr_notice("Waiting for initial ballooning down having finished.\n"); | |
763 | ||
764 | while ((credit = current_credit()) < 0) { | |
765 | if (credit != last_credit) { | |
766 | last_changed = jiffies; | |
767 | last_credit = credit; | |
768 | } | |
769 | if (balloon_state == BP_ECANCELED) { | |
770 | pr_warn_once("Initial ballooning failed, %ld pages need to be freed.\n", | |
771 | -credit); | |
b537bf42 | 772 | if (time_is_before_eq_jiffies(last_changed + HZ * balloon_boot_timeout)) |
40fdea02 JG |
773 | panic("Initial ballooning failed!\n"); |
774 | } | |
775 | ||
776 | schedule_timeout_interruptible(HZ / 10); | |
777 | } | |
778 | ||
779 | pr_notice("Initial ballooning down finished.\n"); | |
780 | ||
781 | return 0; | |
782 | } | |
783 | late_initcall_sync(balloon_wait_finish); |