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> |
3d2a3774 | 32 | #include <linux/wait.h> |
6b35e407 | 33 | |
3ccc9372 MT |
34 | /* |
35 | * Balloon device works in 4K page units. So each page is pointed to by | |
36 | * multiple balloon pages. All memory counters in this driver are in balloon | |
37 | * page units. | |
38 | */ | |
e2250429 RA |
39 | #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) |
40 | #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 | |
5a10b7db RM |
41 | #define OOM_VBALLOON_DEFAULT_PAGES 256 |
42 | #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 | |
43 | ||
44 | static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; | |
45 | module_param(oom_pages, int, S_IRUSR | S_IWUSR); | |
46 | MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); | |
3ccc9372 | 47 | |
25e65e4e | 48 | struct virtio_balloon { |
6b35e407 | 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; | |
997e1208 DL |
160 | if (!virtio_has_feature(vb->vdev, |
161 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
162 | adjust_managed_page_count(page, -1); | |
6b35e407 RR |
163 | } |
164 | ||
e2250429 RA |
165 | /* Did we get any? */ |
166 | if (vb->num_pfns != 0) | |
167 | tell_host(vb, vb->inflate_vq); | |
168 | mutex_unlock(&vb->balloon_lock); | |
6b35e407 RR |
169 | } |
170 | ||
b4d34037 | 171 | static void release_pages_balloon(struct virtio_balloon *vb) |
6b35e407 RR |
172 | { |
173 | unsigned int i; | |
174 | ||
3ccc9372 | 175 | /* Find pfns pointing at start of each page, get pages and free them. */ |
b4d34037 DL |
176 | for (i = 0; i < vb->num_pfns; i += VIRTIO_BALLOON_PAGES_PER_PAGE) { |
177 | struct page *page = balloon_pfn_to_page(vb->pfns[i]); | |
997e1208 DL |
178 | if (!virtio_has_feature(vb->vdev, |
179 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
180 | adjust_managed_page_count(page, 1); | |
d6d86c0a | 181 | put_page(page); /* balloon reference */ |
6b35e407 RR |
182 | } |
183 | } | |
184 | ||
1fd9c672 | 185 | static unsigned leak_balloon(struct virtio_balloon *vb, size_t num) |
6b35e407 | 186 | { |
1fd9c672 | 187 | unsigned num_freed_pages; |
6b35e407 | 188 | struct page *page; |
9d1ba805 | 189 | struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info; |
6b35e407 RR |
190 | |
191 | /* We can only do one array worth at a time. */ | |
192 | num = min(num, ARRAY_SIZE(vb->pfns)); | |
193 | ||
e2250429 | 194 | mutex_lock(&vb->balloon_lock); |
3ccc9372 MT |
195 | for (vb->num_pfns = 0; vb->num_pfns < num; |
196 | vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { | |
e2250429 RA |
197 | page = balloon_page_dequeue(vb_dev_info); |
198 | if (!page) | |
199 | break; | |
3ccc9372 MT |
200 | set_page_pfns(vb->pfns + vb->num_pfns, page); |
201 | vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE; | |
6b35e407 RR |
202 | } |
203 | ||
1fd9c672 | 204 | num_freed_pages = vb->num_pfns; |
bf50e69f DH |
205 | /* |
206 | * Note that if | |
207 | * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); | |
208 | * is true, we *have* to do it in this order | |
209 | */ | |
8c6bab4f LC |
210 | if (vb->num_pfns != 0) |
211 | tell_host(vb, vb->deflate_vq); | |
e2250429 | 212 | mutex_unlock(&vb->balloon_lock); |
b4d34037 | 213 | release_pages_balloon(vb); |
1fd9c672 | 214 | return num_freed_pages; |
6b35e407 RR |
215 | } |
216 | ||
9564e138 AL |
217 | static inline void update_stat(struct virtio_balloon *vb, int idx, |
218 | u16 tag, u64 val) | |
219 | { | |
220 | BUG_ON(idx >= VIRTIO_BALLOON_S_NR); | |
df81b29c MT |
221 | vb->stats[idx].tag = cpu_to_virtio16(vb->vdev, tag); |
222 | vb->stats[idx].val = cpu_to_virtio64(vb->vdev, val); | |
9564e138 AL |
223 | } |
224 | ||
225 | #define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) | |
226 | ||
227 | static void update_balloon_stats(struct virtio_balloon *vb) | |
228 | { | |
229 | unsigned long events[NR_VM_EVENT_ITEMS]; | |
230 | struct sysinfo i; | |
231 | int idx = 0; | |
232 | ||
233 | all_vm_events(events); | |
234 | si_meminfo(&i); | |
235 | ||
236 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, | |
237 | pages_to_bytes(events[PSWPIN])); | |
238 | update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, | |
239 | pages_to_bytes(events[PSWPOUT])); | |
240 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); | |
241 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); | |
242 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, | |
243 | pages_to_bytes(i.freeram)); | |
244 | update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, | |
245 | pages_to_bytes(i.totalram)); | |
246 | } | |
247 | ||
248 | /* | |
249 | * While most virtqueues communicate guest-initiated requests to the hypervisor, | |
250 | * the stats queue operates in reverse. The driver initializes the virtqueue | |
251 | * with a single buffer. From that point forward, all conversations consist of | |
252 | * a hypervisor request (a call to this function) which directs us to refill | |
1f34c71a AL |
253 | * the virtqueue with a fresh stats buffer. Since stats collection can sleep, |
254 | * we notify our kthread which does the actual work via stats_handle_request(). | |
9564e138 | 255 | */ |
1f34c71a | 256 | static void stats_request(struct virtqueue *vq) |
9564e138 | 257 | { |
9c378abc | 258 | struct virtio_balloon *vb = vq->vdev->priv; |
9564e138 | 259 | |
1f34c71a AL |
260 | vb->need_stats_update = 1; |
261 | wake_up(&vb->config_change); | |
262 | } | |
263 | ||
264 | static void stats_handle_request(struct virtio_balloon *vb) | |
265 | { | |
266 | struct virtqueue *vq; | |
267 | struct scatterlist sg; | |
9c378abc | 268 | unsigned int len; |
9564e138 | 269 | |
1f34c71a | 270 | vb->need_stats_update = 0; |
9564e138 AL |
271 | update_balloon_stats(vb); |
272 | ||
1f34c71a | 273 | vq = vb->stats_vq; |
9c378abc MT |
274 | if (!virtqueue_get_buf(vq, &len)) |
275 | return; | |
9564e138 | 276 | sg_init_one(&sg, vb->stats, sizeof(vb->stats)); |
4951cc90 | 277 | virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); |
946cfe0e | 278 | virtqueue_kick(vq); |
9564e138 AL |
279 | } |
280 | ||
6b35e407 RR |
281 | static void virtballoon_changed(struct virtio_device *vdev) |
282 | { | |
283 | struct virtio_balloon *vb = vdev->priv; | |
284 | ||
285 | wake_up(&vb->config_change); | |
286 | } | |
287 | ||
bdc1681c | 288 | static inline s64 towards_target(struct virtio_balloon *vb) |
6b35e407 | 289 | { |
1a87228f | 290 | s64 target; |
df81b29c | 291 | u32 num_pages; |
1a87228f | 292 | |
df81b29c MT |
293 | virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages, |
294 | &num_pages); | |
855e0c52 | 295 | |
df81b29c MT |
296 | /* Legacy balloon config space is LE, unlike all other devices. */ |
297 | if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) | |
298 | num_pages = le32_to_cpu((__force __le32)num_pages); | |
299 | ||
300 | target = num_pages; | |
1a87228f | 301 | return target - vb->num_pages; |
6b35e407 RR |
302 | } |
303 | ||
304 | static void update_balloon_size(struct virtio_balloon *vb) | |
305 | { | |
df81b29c MT |
306 | u32 actual = vb->num_pages; |
307 | ||
308 | /* Legacy balloon config space is LE, unlike all other devices. */ | |
309 | if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1)) | |
310 | actual = (__force u32)cpu_to_le32(actual); | |
6b35e407 | 311 | |
3459f11a | 312 | virtio_cwrite(vb->vdev, struct virtio_balloon_config, actual, |
855e0c52 | 313 | &actual); |
6b35e407 RR |
314 | } |
315 | ||
5a10b7db RM |
316 | /* |
317 | * virtballoon_oom_notify - release pages when system is under severe | |
318 | * memory pressure (called from out_of_memory()) | |
319 | * @self : notifier block struct | |
320 | * @dummy: not used | |
321 | * @parm : returned - number of freed pages | |
322 | * | |
323 | * The balancing of memory by use of the virtio balloon should not cause | |
324 | * the termination of processes while there are pages in the balloon. | |
325 | * If virtio balloon manages to release some memory, it will make the | |
326 | * system return and retry the allocation that forced the OOM killer | |
327 | * to run. | |
328 | */ | |
329 | static int virtballoon_oom_notify(struct notifier_block *self, | |
330 | unsigned long dummy, void *parm) | |
331 | { | |
332 | struct virtio_balloon *vb; | |
333 | unsigned long *freed; | |
334 | unsigned num_freed_pages; | |
335 | ||
336 | vb = container_of(self, struct virtio_balloon, nb); | |
337 | if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) | |
338 | return NOTIFY_OK; | |
339 | ||
340 | freed = parm; | |
341 | num_freed_pages = leak_balloon(vb, oom_pages); | |
342 | update_balloon_size(vb); | |
343 | *freed += num_freed_pages; | |
344 | ||
345 | return NOTIFY_OK; | |
346 | } | |
347 | ||
6b35e407 RR |
348 | static int balloon(void *_vballoon) |
349 | { | |
350 | struct virtio_balloon *vb = _vballoon; | |
3d2a3774 | 351 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
6b35e407 RR |
352 | |
353 | set_freezable(); | |
354 | while (!kthread_should_stop()) { | |
bdc1681c | 355 | s64 diff; |
6b35e407 RR |
356 | |
357 | try_to_freeze(); | |
3d2a3774 MT |
358 | |
359 | add_wait_queue(&vb->config_change, &wait); | |
360 | for (;;) { | |
361 | if ((diff = towards_target(vb)) != 0 || | |
362 | vb->need_stats_update || | |
363 | kthread_should_stop() || | |
364 | freezing(current)) | |
365 | break; | |
366 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
367 | } | |
368 | remove_wait_queue(&vb->config_change, &wait); | |
369 | ||
1f34c71a AL |
370 | if (vb->need_stats_update) |
371 | stats_handle_request(vb); | |
6b35e407 RR |
372 | if (diff > 0) |
373 | fill_balloon(vb, diff); | |
374 | else if (diff < 0) | |
375 | leak_balloon(vb, -diff); | |
376 | update_balloon_size(vb); | |
1f74ef0f RR |
377 | |
378 | /* | |
379 | * For large balloon changes, we could spend a lot of time | |
380 | * and always have work to do. Be nice if preempt disabled. | |
381 | */ | |
382 | cond_resched(); | |
6b35e407 RR |
383 | } |
384 | return 0; | |
385 | } | |
386 | ||
be91c33d | 387 | static int init_vqs(struct virtio_balloon *vb) |
6b35e407 | 388 | { |
9564e138 | 389 | struct virtqueue *vqs[3]; |
1f34c71a | 390 | vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; |
9564e138 AL |
391 | const char *names[] = { "inflate", "deflate", "stats" }; |
392 | int err, nvqs; | |
6b35e407 | 393 | |
be91c33d AS |
394 | /* |
395 | * We expect two virtqueues: inflate and deflate, and | |
396 | * optionally stat. | |
397 | */ | |
9564e138 | 398 | nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; |
be91c33d | 399 | err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names); |
d2a7ddda | 400 | if (err) |
be91c33d | 401 | return err; |
6b35e407 | 402 | |
d2a7ddda MT |
403 | vb->inflate_vq = vqs[0]; |
404 | vb->deflate_vq = vqs[1]; | |
9564e138 AL |
405 | if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { |
406 | struct scatterlist sg; | |
407 | vb->stats_vq = vqs[2]; | |
408 | ||
409 | /* | |
410 | * Prime this virtqueue with one buffer so the hypervisor can | |
4951cc90 | 411 | * use it to signal us later (it can't be broken yet!). |
9564e138 AL |
412 | */ |
413 | sg_init_one(&sg, vb->stats, sizeof vb->stats); | |
92549abc | 414 | if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL) |
f96fde41 | 415 | < 0) |
9564e138 | 416 | BUG(); |
946cfe0e | 417 | virtqueue_kick(vb->stats_vq); |
9564e138 | 418 | } |
be91c33d AS |
419 | return 0; |
420 | } | |
421 | ||
e2250429 RA |
422 | #ifdef CONFIG_BALLOON_COMPACTION |
423 | /* | |
424 | * virtballoon_migratepage - perform the balloon page migration on behalf of | |
425 | * a compation thread. (called under page lock) | |
9d1ba805 | 426 | * @vb_dev_info: the balloon device |
e2250429 RA |
427 | * @newpage: page that will replace the isolated page after migration finishes. |
428 | * @page : the isolated (old) page that is about to be migrated to newpage. | |
429 | * @mode : compaction mode -- not used for balloon page migration. | |
430 | * | |
431 | * After a ballooned page gets isolated by compaction procedures, this is the | |
432 | * function that performs the page migration on behalf of a compaction thread | |
433 | * The page migration for virtio balloon is done in a simple swap fashion which | |
434 | * follows these two macro steps: | |
435 | * 1) insert newpage into vb->pages list and update the host about it; | |
436 | * 2) update the host about the old page removed from vb->pages list; | |
437 | * | |
438 | * This function preforms the balloon page migration task. | |
439 | * Called through balloon_mapping->a_ops->migratepage | |
440 | */ | |
9d1ba805 | 441 | static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info, |
e2250429 RA |
442 | struct page *newpage, struct page *page, enum migrate_mode mode) |
443 | { | |
9d1ba805 KK |
444 | struct virtio_balloon *vb = container_of(vb_dev_info, |
445 | struct virtio_balloon, vb_dev_info); | |
e2250429 RA |
446 | unsigned long flags; |
447 | ||
e2250429 RA |
448 | /* |
449 | * In order to avoid lock contention while migrating pages concurrently | |
450 | * to leak_balloon() or fill_balloon() we just give up the balloon_lock | |
451 | * this turn, as it is easier to retry the page migration later. | |
452 | * This also prevents fill_balloon() getting stuck into a mutex | |
453 | * recursion in the case it ends up triggering memory compaction | |
454 | * while it is attempting to inflate the ballon. | |
455 | */ | |
456 | if (!mutex_trylock(&vb->balloon_lock)) | |
457 | return -EAGAIN; | |
458 | ||
d6d86c0a KK |
459 | get_page(newpage); /* balloon reference */ |
460 | ||
e2250429 RA |
461 | /* balloon's page migration 1st step -- inflate "newpage" */ |
462 | spin_lock_irqsave(&vb_dev_info->pages_lock, flags); | |
9d1ba805 | 463 | balloon_page_insert(vb_dev_info, newpage); |
e2250429 | 464 | vb_dev_info->isolated_pages--; |
09316c09 | 465 | __count_vm_event(BALLOON_MIGRATE); |
e2250429 RA |
466 | spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags); |
467 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
468 | set_page_pfns(vb->pfns, newpage); | |
469 | tell_host(vb, vb->inflate_vq); | |
470 | ||
d6d86c0a | 471 | /* balloon's page migration 2nd step -- deflate "page" */ |
e2250429 RA |
472 | balloon_page_delete(page); |
473 | vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE; | |
474 | set_page_pfns(vb->pfns, page); | |
475 | tell_host(vb, vb->deflate_vq); | |
476 | ||
477 | mutex_unlock(&vb->balloon_lock); | |
478 | ||
d6d86c0a KK |
479 | put_page(page); /* balloon reference */ |
480 | ||
481 | return MIGRATEPAGE_SUCCESS; | |
e2250429 | 482 | } |
e2250429 RA |
483 | #endif /* CONFIG_BALLOON_COMPACTION */ |
484 | ||
be91c33d AS |
485 | static int virtballoon_probe(struct virtio_device *vdev) |
486 | { | |
487 | struct virtio_balloon *vb; | |
488 | int err; | |
489 | ||
2d9becc1 MT |
490 | if (!vdev->config->get) { |
491 | dev_err(&vdev->dev, "%s failure: config access disabled\n", | |
492 | __func__); | |
493 | return -EINVAL; | |
494 | } | |
495 | ||
be91c33d AS |
496 | vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL); |
497 | if (!vb) { | |
498 | err = -ENOMEM; | |
499 | goto out; | |
500 | } | |
501 | ||
be91c33d | 502 | vb->num_pages = 0; |
e2250429 | 503 | mutex_init(&vb->balloon_lock); |
be91c33d | 504 | init_waitqueue_head(&vb->config_change); |
9c378abc | 505 | init_waitqueue_head(&vb->acked); |
be91c33d AS |
506 | vb->vdev = vdev; |
507 | vb->need_stats_update = 0; | |
508 | ||
9d1ba805 KK |
509 | balloon_devinfo_init(&vb->vb_dev_info); |
510 | #ifdef CONFIG_BALLOON_COMPACTION | |
511 | vb->vb_dev_info.migratepage = virtballoon_migratepage; | |
512 | #endif | |
e2250429 | 513 | |
be91c33d AS |
514 | err = init_vqs(vb); |
515 | if (err) | |
9d1ba805 | 516 | goto out_free_vb; |
6b35e407 | 517 | |
5a10b7db RM |
518 | vb->nb.notifier_call = virtballoon_oom_notify; |
519 | vb->nb.priority = VIRTBALLOON_OOM_NOTIFY_PRIORITY; | |
520 | err = register_oom_notifier(&vb->nb); | |
521 | if (err < 0) | |
522 | goto out_oom_notify; | |
523 | ||
88660f7f MT |
524 | virtio_device_ready(vdev); |
525 | ||
6b35e407 RR |
526 | vb->thread = kthread_run(balloon, vb, "vballoon"); |
527 | if (IS_ERR(vb->thread)) { | |
528 | err = PTR_ERR(vb->thread); | |
d2a7ddda | 529 | goto out_del_vqs; |
6b35e407 RR |
530 | } |
531 | ||
6b35e407 RR |
532 | return 0; |
533 | ||
d2a7ddda | 534 | out_del_vqs: |
5a10b7db RM |
535 | unregister_oom_notifier(&vb->nb); |
536 | out_oom_notify: | |
d2a7ddda | 537 | vdev->config->del_vqs(vdev); |
6b35e407 RR |
538 | out_free_vb: |
539 | kfree(vb); | |
540 | out: | |
541 | return err; | |
542 | } | |
543 | ||
c877bab5 | 544 | static void remove_common(struct virtio_balloon *vb) |
6b35e407 | 545 | { |
6b35e407 RR |
546 | /* There might be pages left in the balloon: free them. */ |
547 | while (vb->num_pages) | |
548 | leak_balloon(vb, vb->num_pages); | |
b8ae0eb3 | 549 | update_balloon_size(vb); |
6b35e407 RR |
550 | |
551 | /* Now we reset the device so we can clean up the queues. */ | |
c877bab5 | 552 | vb->vdev->config->reset(vb->vdev); |
6b35e407 | 553 | |
c877bab5 AS |
554 | vb->vdev->config->del_vqs(vb->vdev); |
555 | } | |
556 | ||
8590dbc7 | 557 | static void virtballoon_remove(struct virtio_device *vdev) |
c877bab5 AS |
558 | { |
559 | struct virtio_balloon *vb = vdev->priv; | |
560 | ||
5a10b7db | 561 | unregister_oom_notifier(&vb->nb); |
c877bab5 AS |
562 | kthread_stop(vb->thread); |
563 | remove_common(vb); | |
6b35e407 RR |
564 | kfree(vb); |
565 | } | |
566 | ||
89107000 | 567 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
568 | static int virtballoon_freeze(struct virtio_device *vdev) |
569 | { | |
4eb05d56 AS |
570 | struct virtio_balloon *vb = vdev->priv; |
571 | ||
e562966d AS |
572 | /* |
573 | * The kthread is already frozen by the PM core before this | |
574 | * function is called. | |
575 | */ | |
576 | ||
c877bab5 | 577 | remove_common(vb); |
e562966d AS |
578 | return 0; |
579 | } | |
580 | ||
c45b4166 | 581 | static int virtballoon_restore(struct virtio_device *vdev) |
4eb05d56 AS |
582 | { |
583 | struct virtio_balloon *vb = vdev->priv; | |
584 | int ret; | |
585 | ||
586 | ret = init_vqs(vdev->priv); | |
587 | if (ret) | |
588 | return ret; | |
589 | ||
486d2e63 MT |
590 | virtio_device_ready(vdev); |
591 | ||
4eb05d56 AS |
592 | fill_balloon(vb, towards_target(vb)); |
593 | update_balloon_size(vb); | |
594 | return 0; | |
595 | } | |
e562966d AS |
596 | #endif |
597 | ||
9564e138 AL |
598 | static unsigned int features[] = { |
599 | VIRTIO_BALLOON_F_MUST_TELL_HOST, | |
600 | VIRTIO_BALLOON_F_STATS_VQ, | |
5a10b7db | 601 | VIRTIO_BALLOON_F_DEFLATE_ON_OOM, |
9564e138 | 602 | }; |
c45a6816 | 603 | |
d817cd52 | 604 | static struct virtio_driver virtio_balloon_driver = { |
c45a6816 RR |
605 | .feature_table = features, |
606 | .feature_table_size = ARRAY_SIZE(features), | |
6b35e407 RR |
607 | .driver.name = KBUILD_MODNAME, |
608 | .driver.owner = THIS_MODULE, | |
609 | .id_table = id_table, | |
610 | .probe = virtballoon_probe, | |
8590dbc7 | 611 | .remove = virtballoon_remove, |
6b35e407 | 612 | .config_changed = virtballoon_changed, |
89107000 | 613 | #ifdef CONFIG_PM_SLEEP |
e562966d AS |
614 | .freeze = virtballoon_freeze, |
615 | .restore = virtballoon_restore, | |
e562966d | 616 | #endif |
6b35e407 RR |
617 | }; |
618 | ||
b2a17029 | 619 | module_virtio_driver(virtio_balloon_driver); |
6b35e407 RR |
620 | MODULE_DEVICE_TABLE(virtio, id_table); |
621 | MODULE_DESCRIPTION("Virtio balloon driver"); | |
622 | MODULE_LICENSE("GPL"); |