Commit | Line | Data |
---|---|---|
1e214a5c SL |
1 | /* |
2 | * Virtio balloon implementation, inspired by Dor Laor and Marcelo | |
6b35e407 RR |
3 | * Tosatti's implementations. |
4 | * | |
5 | * Copyright 2008 Rusty Russell IBM Corporation | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
1e214a5c | 21 | |
6b35e407 RR |
22 | #include <linux/virtio.h> |
23 | #include <linux/virtio_balloon.h> | |
24 | #include <linux/swap.h> | |
25 | #include <linux/kthread.h> | |
26 | #include <linux/freezer.h> | |
6659a0f0 | 27 | #include <linux/delay.h> |
5a0e3ad6 | 28 | #include <linux/slab.h> |
b5a2c4f1 | 29 | #include <linux/module.h> |
e2250429 | 30 | #include <linux/balloon_compaction.h> |
5a10b7db | 31 | #include <linux/oom.h> |
6b35e407 | 32 | |
3ccc9372 MT |
33 | /* |
34 | * Balloon device works in 4K page units. So each page is pointed to by | |
35 | * multiple balloon pages. All memory counters in this driver are in balloon | |
36 | * page units. | |
37 | */ | |
e2250429 RA |
38 | #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) |
39 | #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 | |
5a10b7db RM |
40 | #define OOM_VBALLOON_DEFAULT_PAGES 256 |
41 | #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 | |
42 | ||
43 | static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; | |
44 | module_param(oom_pages, int, S_IRUSR | S_IWUSR); | |
45 | MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); | |
3ccc9372 | 46 | |
6b35e407 RR |
47 | struct virtio_balloon |
48 | { | |
49 | struct virtio_device *vdev; | |
9564e138 | 50 | struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; |
6b35e407 RR |
51 | |
52 | /* Where the ballooning thread waits for config to change. */ | |
53 | wait_queue_head_t config_change; | |
54 | ||
55 | /* The thread servicing the balloon. */ | |
56 | struct task_struct *thread; | |
57 | ||
58 | /* Waiting for host to ack the pages we released. */ | |
9c378abc | 59 | wait_queue_head_t acked; |
6b35e407 | 60 | |
3ccc9372 | 61 | /* Number of balloon pages we've told the Host we're not using. */ |
6b35e407 | 62 | unsigned int num_pages; |
3ccc9372 | 63 | /* |
e2250429 RA |
64 | * The pages we've told the Host we're not using are enqueued |
65 | * at vb_dev_info->pages list. | |
3ccc9372 MT |
66 | * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE |
67 | * to num_pages above. | |
68 | */ | |
9d1ba805 | 69 | struct balloon_dev_info vb_dev_info; |
e2250429 RA |
70 | |
71 | /* Synchronize access/update to this struct virtio_balloon elements */ | |
72 | struct mutex balloon_lock; | |
6b35e407 RR |
73 | |
74 | /* The array of pfns we tell the Host about. */ | |
75 | unsigned int num_pfns; | |
e2250429 | 76 | u32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX]; |
9564e138 AL |
77 | |
78 | /* Memory statistics */ | |
1f34c71a | 79 | int need_stats_update; |
9564e138 | 80 | struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; |
5a10b7db RM |
81 | |
82 | /* To register callback in oom notifier call chain */ | |
83 | struct notifier_block nb; | |
6b35e407 RR |
84 | }; |
85 | ||
86 | static struct virtio_device_id id_table[] = { | |
87 | { VIRTIO_ID_BALLOON, VIRTIO_DEV_ANY_ID }, | |
88 | { 0 }, | |
89 | }; | |
90 | ||
1b4aa2fa HB |
91 | static u32 page_to_balloon_pfn(struct page *page) |
92 | { | |
93 | unsigned long pfn = page_to_pfn(page); | |
94 | ||
95 | BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); | |
96 | /* Convert pfn from Linux page size to balloon page size. */ | |
3ccc9372 MT |
97 | return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE; |
98 | } | |
99 | ||
100 | static struct page *balloon_pfn_to_page(u32 pfn) | |
101 | { | |
102 | BUG_ON(pfn % VIRTIO_BALLOON_PAGES_PER_PAGE); | |
103 | return pfn_to_page(pfn / VIRTIO_BALLOON_PAGES_PER_PAGE); | |
1b4aa2fa HB |
104 | } |
105 | ||
6b35e407 RR |
106 | static void balloon_ack(struct virtqueue *vq) |
107 | { | |
9c378abc | 108 | struct virtio_balloon *vb = vq->vdev->priv; |
6b35e407 | 109 | |
9c378abc | 110 | wake_up(&vb->acked); |
6b35e407 RR |
111 | } |
112 | ||
113 | static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) | |
114 | { | |
115 | struct scatterlist sg; | |
9c378abc | 116 | unsigned int len; |
6b35e407 RR |
117 | |
118 | sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); | |
119 | ||
6b35e407 | 120 | /* We should always be able to add one buffer to an empty queue. */ |
4951cc90 | 121 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 122 | virtqueue_kick(vq); |
6b35e407 RR |
123 | |
124 | /* When host has read buffer, this completes via balloon_ack */ | |
9c378abc | 125 | wait_event(vb->acked, virtqueue_get_buf(vq, &len)); |
6b35e407 RR |
126 | } |
127 | ||
3ccc9372 MT |
128 | static void set_page_pfns(u32 pfns[], struct page *page) |
129 | { | |
130 | unsigned int i; | |
131 | ||
132 | /* Set balloon pfns pointing at this page. | |
133 | * Note that the first pfn points at start of the page. */ | |
134 | for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++) | |
135 | pfns[i] = page_to_balloon_pfn(page) + i; | |
136 | } | |
137 | ||
6b35e407 RR |
138 | static void fill_balloon(struct virtio_balloon *vb, size_t num) |
139 | { | |
9d1ba805 | 140 | struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info; |
e2250429 | 141 | |
6b35e407 RR |
142 | /* We can only do one array worth at a time. */ |
143 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
144 | ||
e2250429 | 145 | mutex_lock(&vb->balloon_lock); |
3ccc9372 MT |
146 | for (vb->num_pfns = 0; vb->num_pfns < num; |
147 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
148 | struct page *page = balloon_page_enqueue(vb_dev_info); |
149 | ||
6b35e407 | 150 | if (!page) { |
800ba5ea | 151 | dev_info_ratelimited(&vb->vdev->dev, |
b7dfde95 LT |
152 | "Out of puff! Can't get %u pages\n", |
153 | VIRTIO_BALLOON_PAGES_PER_PAGE); | |
6b35e407 RR |
154 | /* Sleep for at least 1/5 of a second before retry. */ |
155 | msleep(200); | |
156 | break; | |
157 | } | |
3ccc9372 MT |
158 | set_page_pfns(vb->pfns + vb->num_pfns, page); |
159 | vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE; | |
3dcc0571 | 160 | adjust_managed_page_count(page, -1); |
6b35e407 RR |
161 | } |
162 | ||
e2250429 RA |
163 | /* Did we get any? */ |
164 | if (vb->num_pfns != 0) | |
165 | tell_host(vb, vb->inflate_vq); | |
166 | mutex_unlock(&vb->balloon_lock); | |
6b35e407 RR |
167 | } |
168 | ||
169 | static void release_pages_by_pfn(const u32 pfns[], unsigned int num) | |
170 | { | |
171 | unsigned int i; | |
172 | ||
3ccc9372 MT |
173 | /* Find pfns pointing at start of each page, get pages and free them. */ |
174 | for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
3dcc0571 | 175 | struct page *page = balloon_pfn_to_page(pfns[i]); |
3dcc0571 | 176 | adjust_managed_page_count(page, 1); |
d6d86c0a | 177 | put_page(page); /* balloon reference */ |
6b35e407 RR |
178 | } |
179 | } | |
180 | ||
1fd9c672 | 181 | static unsigned leak_balloon(struct virtio_balloon *vb, size_t num) |
6b35e407 | 182 | { |
1fd9c672 | 183 | unsigned num_freed_pages; |
6b35e407 | 184 | struct page *page; |
9d1ba805 | 185 | struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info; |
6b35e407 RR |
186 | |
187 | /* We can only do one array worth at a time. */ | |
188 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
189 | ||
e2250429 | 190 | mutex_lock(&vb->balloon_lock); |
3ccc9372 MT |
191 | for (vb->num_pfns = 0; vb->num_pfns < num; |
192 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
193 | page = balloon_page_dequeue(vb_dev_info); |
194 | if (!page) | |
195 | break; | |
3ccc9372 MT |
196 | set_page_pfns(vb->pfns + vb->num_pfns, page); |
197 | vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE; | |
6b35e407 RR |
198 | } |
199 | ||
1fd9c672 | 200 | num_freed_pages = vb->num_pfns; |
bf50e69f DH |
201 | /* |
202 | * Note that if | |
203 | * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); | |
204 | * is true, we *have* to do it in this order | |
205 | */ | |
8c6bab4f LC |
206 | if (vb->num_pfns != 0) |
207 | tell_host(vb, vb->deflate_vq); | |
e2250429 | 208 | mutex_unlock(&vb->balloon_lock); |
bf50e69f | 209 | release_pages_by_pfn(vb->pfns, vb->num_pfns); |
1fd9c672 | 210 | return num_freed_pages; |
6b35e407 RR |
211 | } |
212 | ||
9564e138 AL |
213 | static inline void update_stat(struct virtio_balloon *vb, int idx, |
214 | u16 tag, u64 val) | |
215 | { | |
216 | BUG_ON(idx >= VIRTIO_BALLOON_S_NR); | |
217 | vb->stats[idx].tag = tag; | |
218 | vb->stats[idx].val = val; | |
219 | } | |
220 | ||
221 | #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) | |
222 | ||
223 | static void update_balloon_stats(struct virtio_balloon *vb) | |
224 | { | |
225 | unsigned long events[NR_VM_EVENT_ITEMS]; | |
226 | struct sysinfo i; | |
227 | int idx = 0; | |
228 | ||
229 | all_vm_events(events); | |
230 | si_meminfo(&i); | |
231 | ||
232 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, | |
233 | pages_to_bytes(events[PSWPIN])); | |
234 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, | |
235 | pages_to_bytes(events[PSWPOUT])); | |
236 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); | |
237 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); | |
238 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, | |
239 | pages_to_bytes(i.freeram)); | |
240 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, | |
241 | pages_to_bytes(i.totalram)); | |
242 | } | |
243 | ||
244 | /* | |
245 | * While most virtqueues communicate guest-initiated requests to the hypervisor, | |
246 | * the stats queue operates in reverse. The driver initializes the virtqueue | |
247 | * with a single buffer. From that point forward, all conversations consist of | |
248 | * a hypervisor request (a call to this function) which directs us to refill | |
1f34c71a AL |
249 | * the virtqueue with a fresh stats buffer. Since stats collection can sleep, |
250 | * we notify our kthread which does the actual work via stats_handle_request(). | |
9564e138 | 251 | */ |
1f34c71a | 252 | static void stats_request(struct virtqueue *vq) |
9564e138 | 253 | { |
9c378abc | 254 | struct virtio_balloon *vb = vq->vdev->priv; |
9564e138 | 255 | |
1f34c71a AL |
256 | vb->need_stats_update = 1; |
257 | wake_up(&vb->config_change); | |
258 | } | |
259 | ||
260 | static void stats_handle_request(struct virtio_balloon *vb) | |
261 | { | |
262 | struct virtqueue *vq; | |
263 | struct scatterlist sg; | |
9c378abc | 264 | unsigned int len; |
9564e138 | 265 | |
1f34c71a | 266 | vb->need_stats_update = 0; |
9564e138 AL |
267 | update_balloon_stats(vb); |
268 | ||
1f34c71a | 269 | vq = vb->stats_vq; |
9c378abc MT |
270 | if (!virtqueue_get_buf(vq, &len)) |
271 | return; | |
9564e138 | 272 | sg_init_one(&sg, vb->stats, sizeof(vb->stats)); |
4951cc90 | 273 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 274 | virtqueue_kick(vq); |
9564e138 AL |
275 | } |
276 | ||
6b35e407 RR |
277 | static void virtballoon_changed(struct virtio_device *vdev) |
278 | { | |
279 | struct virtio_balloon *vb = vdev->priv; | |
280 | ||
281 | wake_up(&vb->config_change); | |
282 | } | |
283 | ||
bdc1681c | 284 | static inline s64 towards_target(struct virtio_balloon *vb) |
6b35e407 | 285 | { |
1a87228f DG |
286 | __le32 v; |
287 | s64 target; | |
288 | ||
855e0c52 RR |
289 | virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages, &v); |
290 | ||
1a87228f DG |
291 | target = le32_to_cpu(v); |
292 | return target - vb->num_pages; | |
6b35e407 RR |
293 | } |
294 | ||
295 | static void update_balloon_size(struct virtio_balloon *vb) | |
296 | { | |
297 | __le32 actual = cpu_to_le32(vb->num_pages); | |
298 | ||
3459f11a | 299 | virtio_cwrite(vb->vdev, struct virtio_balloon_config, actual, |
855e0c52 | 300 | &actual); |
6b35e407 RR |
301 | } |
302 | ||
5a10b7db RM |
303 | /* |
304 | * virtballoon_oom_notify - release pages when system is under severe | |
305 | * memory pressure (called from out_of_memory()) | |
306 | * @self : notifier block struct | |
307 | * @dummy: not used | |
308 | * @parm : returned - number of freed pages | |
309 | * | |
310 | * The balancing of memory by use of the virtio balloon should not cause | |
311 | * the termination of processes while there are pages in the balloon. | |
312 | * If virtio balloon manages to release some memory, it will make the | |
313 | * system return and retry the allocation that forced the OOM killer | |
314 | * to run. | |
315 | */ | |
316 | static int virtballoon_oom_notify(struct notifier_block *self, | |
317 | unsigned long dummy, void *parm) | |
318 | { | |
319 | struct virtio_balloon *vb; | |
320 | unsigned long *freed; | |
321 | unsigned num_freed_pages; | |
322 | ||
323 | vb = container_of(self, struct virtio_balloon, nb); | |
324 | if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
325 | return NOTIFY_OK; | |
326 | ||
327 | freed = parm; | |
328 | num_freed_pages = leak_balloon(vb, oom_pages); | |
329 | update_balloon_size(vb); | |
330 | *freed += num_freed_pages; | |
331 | ||
332 | return NOTIFY_OK; | |
333 | } | |
334 | ||
6b35e407 RR |
335 | static int balloon(void *_vballoon) |
336 | { | |
337 | struct virtio_balloon *vb = _vballoon; | |
338 | ||
339 | set_freezable(); | |
340 | while (!kthread_should_stop()) { | |
bdc1681c | 341 | s64 diff; |
6b35e407 RR |
342 | |
343 | try_to_freeze(); | |
344 | wait_event_interruptible(vb->config_change, | |
345 | (diff = towards_target(vb)) != 0 | |
1f34c71a | 346 | || vb->need_stats_update |
84a139a9 MT |
347 | || kthread_should_stop() |
348 | || freezing(current)); | |
1f34c71a AL |
349 | if (vb->need_stats_update) |
350 | stats_handle_request(vb); | |
6b35e407 RR |
351 | if (diff > 0) |
352 | fill_balloon(vb, diff); | |
353 | else if (diff < 0) | |
354 | leak_balloon(vb, -diff); | |
355 | update_balloon_size(vb); | |
1f74ef0f RR |
356 | |
357 | /* | |
358 | * For large balloon changes, we could spend a lot of time | |
359 | * and always have work to do. Be nice if preempt disabled. | |
360 | */ | |
361 | cond_resched(); | |
6b35e407 RR |
362 | } |
363 | return 0; | |
364 | } | |
365 | ||
be91c33d | 366 | static int init_vqs(struct virtio_balloon *vb) |
6b35e407 | 367 | { |
9564e138 | 368 | struct virtqueue *vqs[3]; |
1f34c71a | 369 | vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; |
9564e138 AL |
370 | const char *names[] = { "inflate", "deflate", "stats" }; |
371 | int err, nvqs; | |
6b35e407 | 372 | |
be91c33d AS |
373 | /* |
374 | * We expect two virtqueues: inflate and deflate, and | |
375 | * optionally stat. | |
376 | */ | |
9564e138 | 377 | nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; |
be91c33d | 378 | err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names); |
d2a7ddda | 379 | if (err) |
be91c33d | 380 | return err; |
6b35e407 | 381 | |
d2a7ddda MT |
382 | vb->inflate_vq = vqs[0]; |
383 | vb->deflate_vq = vqs[1]; | |
9564e138 AL |
384 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { |
385 | struct scatterlist sg; | |
386 | vb->stats_vq = vqs[2]; | |
387 | ||
388 | /* | |
389 | * Prime this virtqueue with one buffer so the hypervisor can | |
4951cc90 | 390 | * use it to signal us later (it can't be broken yet!). |
9564e138 AL |
391 | */ |
392 | sg_init_one(&sg, vb->stats, sizeof vb->stats); | |
92549abc | 393 | if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL) |
f96fde41 | 394 | < 0) |
9564e138 | 395 | BUG(); |
946cfe0e | 396 | virtqueue_kick(vb->stats_vq); |
9564e138 | 397 | } |
be91c33d AS |
398 | return 0; |
399 | } | |
400 | ||
e2250429 RA |
401 | #ifdef CONFIG_BALLOON_COMPACTION |
402 | /* | |
403 | * virtballoon_migratepage - perform the balloon page migration on behalf of | |
404 | * a compation thread. (called under page lock) | |
9d1ba805 | 405 | * @vb_dev_info: the balloon device |
e2250429 RA |
406 | * @newpage: page that will replace the isolated page after migration finishes. |
407 | * @page : the isolated (old) page that is about to be migrated to newpage. | |
408 | * @mode : compaction mode -- not used for balloon page migration. | |
409 | * | |
410 | * After a ballooned page gets isolated by compaction procedures, this is the | |
411 | * function that performs the page migration on behalf of a compaction thread | |
412 | * The page migration for virtio balloon is done in a simple swap fashion which | |
413 | * follows these two macro steps: | |
414 | * 1) insert newpage into vb->pages list and update the host about it; | |
415 | * 2) update the host about the old page removed from vb->pages list; | |
416 | * | |
417 | * This function preforms the balloon page migration task. | |
418 | * Called through balloon_mapping->a_ops->migratepage | |
419 | */ | |
9d1ba805 | 420 | static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, |
e2250429 RA |
421 | struct page *newpage, struct page *page, enum migrate_mode mode) |
422 | { | |
9d1ba805 KK |
423 | struct virtio_balloon *vb = container_of(vb_dev_info, |
424 | struct virtio_balloon, vb_dev_info); | |
e2250429 RA |
425 | unsigned long flags; |
426 | ||
e2250429 RA |
427 | /* |
428 | * In order to avoid lock contention while migrating pages concurrently | |
429 | * to leak_balloon() or fill_balloon() we just give up the balloon_lock | |
430 | * this turn, as it is easier to retry the page migration later. | |
431 | * This also prevents fill_balloon() getting stuck into a mutex | |
432 | * recursion in the case it ends up triggering memory compaction | |
433 | * while it is attempting to inflate the ballon. | |
434 | */ | |
435 | if (!mutex_trylock(&vb->balloon_lock)) | |
436 | return -EAGAIN; | |
437 | ||
d6d86c0a KK |
438 | get_page(newpage); /* balloon reference */ |
439 | ||
e2250429 RA |
440 | /* balloon's page migration 1st step -- inflate "newpage" */ |
441 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); | |
9d1ba805 | 442 | balloon_page_insert(vb_dev_info, newpage); |
e2250429 | 443 | vb_dev_info->isolated_pages--; |
09316c09 | 444 | __count_vm_event(BALLOON_MIGRATE); |
e2250429 RA |
445 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); |
446 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
447 | set_page_pfns(vb->pfns, newpage); | |
448 | tell_host(vb, vb->inflate_vq); | |
449 | ||
d6d86c0a | 450 | /* balloon's page migration 2nd step -- deflate "page" */ |
e2250429 RA |
451 | balloon_page_delete(page); |
452 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
453 | set_page_pfns(vb->pfns, page); | |
454 | tell_host(vb, vb->deflate_vq); | |
455 | ||
456 | mutex_unlock(&vb->balloon_lock); | |
457 | ||
d6d86c0a KK |
458 | put_page(page); /* balloon reference */ |
459 | ||
460 | return MIGRATEPAGE_SUCCESS; | |
e2250429 | 461 | } |
e2250429 RA |
462 | #endif /* CONFIG_BALLOON_COMPACTION */ |
463 | ||
be91c33d AS |
464 | static int virtballoon_probe(struct virtio_device *vdev) |
465 | { | |
466 | struct virtio_balloon *vb; | |
467 | int err; | |
468 | ||
469 | vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL); | |
470 | if (!vb) { | |
471 | err = -ENOMEM; | |
472 | goto out; | |
473 | } | |
474 | ||
be91c33d | 475 | vb->num_pages = 0; |
e2250429 | 476 | mutex_init(&vb->balloon_lock); |
be91c33d | 477 | init_waitqueue_head(&vb->config_change); |
9c378abc | 478 | init_waitqueue_head(&vb->acked); |
be91c33d AS |
479 | vb->vdev = vdev; |
480 | vb->need_stats_update = 0; | |
481 | ||
9d1ba805 KK |
482 | balloon_devinfo_init(&vb->vb_dev_info); |
483 | #ifdef CONFIG_BALLOON_COMPACTION | |
484 | vb->vb_dev_info.migratepage = virtballoon_migratepage; | |
485 | #endif | |
e2250429 | 486 | |
be91c33d AS |
487 | err = init_vqs(vb); |
488 | if (err) | |
9d1ba805 | 489 | goto out_free_vb; |
6b35e407 | 490 | |
5a10b7db RM |
491 | vb->nb.notifier_call = virtballoon_oom_notify; |
492 | vb->nb.priority = VIRTBALLOON_OOM_NOTIFY_PRIORITY; | |
493 | err = register_oom_notifier(&vb->nb); | |
494 | if (err < 0) | |
495 | goto out_oom_notify; | |
496 | ||
6b35e407 RR |
497 | vb->thread = kthread_run(balloon, vb, "vballoon"); |
498 | if (IS_ERR(vb->thread)) { | |
499 | err = PTR_ERR(vb->thread); | |
d2a7ddda | 500 | goto out_del_vqs; |
6b35e407 RR |
501 | } |
502 | ||
6b35e407 RR |
503 | return 0; |
504 | ||
d2a7ddda | 505 | out_del_vqs: |
5a10b7db RM |
506 | unregister_oom_notifier(&vb->nb); |
507 | out_oom_notify: | |
d2a7ddda | 508 | vdev->config->del_vqs(vdev); |
6b35e407 RR |
509 | out_free_vb: |
510 | kfree(vb); | |
511 | out: | |
512 | return err; | |
513 | } | |
514 | ||
c877bab5 | 515 | static void remove_common(struct virtio_balloon *vb) |
6b35e407 | 516 | { |
6b35e407 RR |
517 | /* There might be pages left in the balloon: free them. */ |
518 | while (vb->num_pages) | |
519 | leak_balloon(vb, vb->num_pages); | |
b8ae0eb3 | 520 | update_balloon_size(vb); |
6b35e407 RR |
521 | |
522 | /* Now we reset the device so we can clean up the queues. */ | |
c877bab5 | 523 | vb->vdev->config->reset(vb->vdev); |
6b35e407 | 524 | |
c877bab5 AS |
525 | vb->vdev->config->del_vqs(vb->vdev); |
526 | } | |
527 | ||
8590dbc7 | 528 | static void virtballoon_remove(struct virtio_device *vdev) |
c877bab5 AS |
529 | { |
530 | struct virtio_balloon *vb = vdev->priv; | |
531 | ||
5a10b7db | 532 | unregister_oom_notifier(&vb->nb); |
c877bab5 AS |
533 | kthread_stop(vb->thread); |
534 | remove_common(vb); | |
6b35e407 RR |
535 | kfree(vb); |
536 | } | |
537 | ||
89107000 | 538 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
539 | static int virtballoon_freeze(struct virtio_device *vdev) |
540 | { | |
4eb05d56 AS |
541 | struct virtio_balloon *vb = vdev->priv; |
542 | ||
e562966d AS |
543 | /* |
544 | * The kthread is already frozen by the PM core before this | |
545 | * function is called. | |
546 | */ | |
547 | ||
c877bab5 | 548 | remove_common(vb); |
e562966d AS |
549 | return 0; |
550 | } | |
551 | ||
c45b4166 | 552 | static int virtballoon_restore(struct virtio_device *vdev) |
4eb05d56 AS |
553 | { |
554 | struct virtio_balloon *vb = vdev->priv; | |
555 | int ret; | |
556 | ||
557 | ret = init_vqs(vdev->priv); | |
558 | if (ret) | |
559 | return ret; | |
560 | ||
486d2e63 MT |
561 | virtio_device_ready(vdev); |
562 | ||
4eb05d56 AS |
563 | fill_balloon(vb, towards_target(vb)); |
564 | update_balloon_size(vb); | |
565 | return 0; | |
566 | } | |
e562966d AS |
567 | #endif |
568 | ||
9564e138 AL |
569 | static unsigned int features[] = { |
570 | VIRTIO_BALLOON_F_MUST_TELL_HOST, | |
571 | VIRTIO_BALLOON_F_STATS_VQ, | |
5a10b7db | 572 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM, |
9564e138 | 573 | }; |
c45a6816 | 574 | |
d817cd52 | 575 | static struct virtio_driver virtio_balloon_driver = { |
c45a6816 RR |
576 | .feature_table = features, |
577 | .feature_table_size = ARRAY_SIZE(features), | |
6b35e407 RR |
578 | .driver.name = KBUILD_MODNAME, |
579 | .driver.owner = THIS_MODULE, | |
580 | .id_table = id_table, | |
581 | .probe = virtballoon_probe, | |
8590dbc7 | 582 | .remove = virtballoon_remove, |
6b35e407 | 583 | .config_changed = virtballoon_changed, |
89107000 | 584 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
585 | .freeze = virtballoon_freeze, |
586 | .restore = virtballoon_restore, | |
e562966d | 587 | #endif |
6b35e407 RR |
588 | }; |
589 | ||
b2a17029 | 590 | module_virtio_driver(virtio_balloon_driver); |
6b35e407 RR |
591 | MODULE_DEVICE_TABLE(virtio, id_table); |
592 | MODULE_DESCRIPTION("Virtio balloon driver"); | |
593 | MODULE_LICENSE("GPL"); |