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1775826c JF |
1 | /****************************************************************************** |
2 | * balloon.c | |
3 | * | |
4 | * Xen balloon driver - enables returning/claiming memory to/from Xen. | |
5 | * | |
6 | * Copyright (c) 2003, B Dragovic | |
7 | * Copyright (c) 2003-2004, M Williamson, K Fraser | |
8 | * Copyright (c) 2005 Dan M. Smith, IBM Corporation | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License version 2 | |
12 | * as published by the Free Software Foundation; or, when distributed | |
13 | * separately from the Linux kernel or incorporated into other | |
14 | * software packages, subject to the following license: | |
15 | * | |
16 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
17 | * of this source file (the "Software"), to deal in the Software without | |
18 | * restriction, including without limitation the rights to use, copy, modify, | |
19 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
20 | * and to permit persons to whom the Software is furnished to do so, subject to | |
21 | * the following conditions: | |
22 | * | |
23 | * The above copyright notice and this permission notice shall be included in | |
24 | * all copies or substantial portions of the Software. | |
25 | * | |
26 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
27 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
28 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
29 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
30 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
31 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
32 | * IN THE SOFTWARE. | |
33 | */ | |
34 | ||
35 | #include <linux/kernel.h> | |
36 | #include <linux/module.h> | |
37 | #include <linux/sched.h> | |
38 | #include <linux/errno.h> | |
39 | #include <linux/mm.h> | |
40 | #include <linux/bootmem.h> | |
41 | #include <linux/pagemap.h> | |
42 | #include <linux/highmem.h> | |
43 | #include <linux/mutex.h> | |
44 | #include <linux/highmem.h> | |
45 | #include <linux/list.h> | |
46 | #include <linux/sysdev.h> | |
47 | ||
48 | #include <asm/xen/hypervisor.h> | |
49 | #include <asm/page.h> | |
50 | #include <asm/pgalloc.h> | |
51 | #include <asm/pgtable.h> | |
52 | #include <asm/uaccess.h> | |
53 | #include <asm/tlb.h> | |
54 | ||
55 | #include <xen/interface/memory.h> | |
56 | #include <xen/balloon.h> | |
57 | #include <xen/xenbus.h> | |
58 | #include <xen/features.h> | |
59 | #include <xen/page.h> | |
60 | ||
61 | #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) | |
62 | ||
0253398c | 63 | #define BALLOON_CLASS_NAME "xen_memory" |
1775826c JF |
64 | |
65 | struct balloon_stats { | |
66 | /* We aim for 'current allocation' == 'target allocation'. */ | |
67 | unsigned long current_pages; | |
68 | unsigned long target_pages; | |
69 | /* We may hit the hard limit in Xen. If we do then we remember it. */ | |
70 | unsigned long hard_limit; | |
71 | /* | |
72 | * Drivers may alter the memory reservation independently, but they | |
73 | * must inform the balloon driver so we avoid hitting the hard limit. | |
74 | */ | |
75 | unsigned long driver_pages; | |
76 | /* Number of pages in high- and low-memory balloons. */ | |
77 | unsigned long balloon_low; | |
78 | unsigned long balloon_high; | |
79 | }; | |
80 | ||
81 | static DEFINE_MUTEX(balloon_mutex); | |
82 | ||
83 | static struct sys_device balloon_sysdev; | |
84 | ||
85 | static int register_balloon(struct sys_device *sysdev); | |
86 | ||
87 | /* | |
88 | * Protects atomic reservation decrease/increase against concurrent increases. | |
89 | * Also protects non-atomic updates of current_pages and driver_pages, and | |
90 | * balloon lists. | |
91 | */ | |
92 | static DEFINE_SPINLOCK(balloon_lock); | |
93 | ||
94 | static struct balloon_stats balloon_stats; | |
95 | ||
96 | /* We increase/decrease in batches which fit in a page */ | |
97 | static unsigned long frame_list[PAGE_SIZE / sizeof(unsigned long)]; | |
98 | ||
99 | /* VM /proc information for memory */ | |
100 | extern unsigned long totalram_pages; | |
101 | ||
102 | #ifdef CONFIG_HIGHMEM | |
103 | extern unsigned long totalhigh_pages; | |
104 | #define inc_totalhigh_pages() (totalhigh_pages++) | |
105 | #define dec_totalhigh_pages() (totalhigh_pages--) | |
106 | #else | |
107 | #define inc_totalhigh_pages() do {} while(0) | |
108 | #define dec_totalhigh_pages() do {} while(0) | |
109 | #endif | |
110 | ||
111 | /* List of ballooned pages, threaded through the mem_map array. */ | |
112 | static LIST_HEAD(ballooned_pages); | |
113 | ||
114 | /* Main work function, always executed in process context. */ | |
115 | static void balloon_process(struct work_struct *work); | |
116 | static DECLARE_WORK(balloon_worker, balloon_process); | |
117 | static struct timer_list balloon_timer; | |
118 | ||
119 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
120 | want the kernel to try too hard since that can trigger the oom killer. */ | |
121 | #define GFP_BALLOON \ | |
122 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
123 | ||
124 | static void scrub_page(struct page *page) | |
125 | { | |
126 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
127 | if (PageHighMem(page)) { | |
128 | void *v = kmap(page); | |
129 | clear_page(v); | |
130 | kunmap(v); | |
131 | } else { | |
132 | void *v = page_address(page); | |
133 | clear_page(v); | |
134 | } | |
135 | #endif | |
136 | } | |
137 | ||
138 | /* balloon_append: add the given page to the balloon. */ | |
139 | static void balloon_append(struct page *page) | |
140 | { | |
141 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
142 | if (PageHighMem(page)) { | |
143 | list_add_tail(&page->lru, &ballooned_pages); | |
144 | balloon_stats.balloon_high++; | |
145 | dec_totalhigh_pages(); | |
146 | } else { | |
147 | list_add(&page->lru, &ballooned_pages); | |
148 | balloon_stats.balloon_low++; | |
149 | } | |
150 | } | |
151 | ||
152 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
153 | static struct page *balloon_retrieve(void) | |
154 | { | |
155 | struct page *page; | |
156 | ||
157 | if (list_empty(&ballooned_pages)) | |
158 | return NULL; | |
159 | ||
160 | page = list_entry(ballooned_pages.next, struct page, lru); | |
161 | list_del(&page->lru); | |
162 | ||
163 | if (PageHighMem(page)) { | |
164 | balloon_stats.balloon_high--; | |
165 | inc_totalhigh_pages(); | |
166 | } | |
167 | else | |
168 | balloon_stats.balloon_low--; | |
169 | ||
170 | return page; | |
171 | } | |
172 | ||
173 | static struct page *balloon_first_page(void) | |
174 | { | |
175 | if (list_empty(&ballooned_pages)) | |
176 | return NULL; | |
177 | return list_entry(ballooned_pages.next, struct page, lru); | |
178 | } | |
179 | ||
180 | static struct page *balloon_next_page(struct page *page) | |
181 | { | |
182 | struct list_head *next = page->lru.next; | |
183 | if (next == &ballooned_pages) | |
184 | return NULL; | |
185 | return list_entry(next, struct page, lru); | |
186 | } | |
187 | ||
188 | static void balloon_alarm(unsigned long unused) | |
189 | { | |
190 | schedule_work(&balloon_worker); | |
191 | } | |
192 | ||
193 | static unsigned long current_target(void) | |
194 | { | |
195 | unsigned long target = min(balloon_stats.target_pages, balloon_stats.hard_limit); | |
196 | ||
197 | target = min(target, | |
198 | balloon_stats.current_pages + | |
199 | balloon_stats.balloon_low + | |
200 | balloon_stats.balloon_high); | |
201 | ||
202 | return target; | |
203 | } | |
204 | ||
205 | static int increase_reservation(unsigned long nr_pages) | |
206 | { | |
207 | unsigned long pfn, i, flags; | |
208 | struct page *page; | |
209 | long rc; | |
210 | struct xen_memory_reservation reservation = { | |
211 | .address_bits = 0, | |
212 | .extent_order = 0, | |
213 | .domid = DOMID_SELF | |
214 | }; | |
215 | ||
216 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
217 | nr_pages = ARRAY_SIZE(frame_list); | |
218 | ||
219 | spin_lock_irqsave(&balloon_lock, flags); | |
220 | ||
221 | page = balloon_first_page(); | |
222 | for (i = 0; i < nr_pages; i++) { | |
223 | BUG_ON(page == NULL); | |
224 | frame_list[i] = page_to_pfn(page);; | |
225 | page = balloon_next_page(page); | |
226 | } | |
227 | ||
a90971eb | 228 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
229 | reservation.nr_extents = nr_pages; |
230 | rc = HYPERVISOR_memory_op( | |
231 | XENMEM_populate_physmap, &reservation); | |
232 | if (rc < nr_pages) { | |
233 | if (rc > 0) { | |
234 | int ret; | |
235 | ||
236 | /* We hit the Xen hard limit: reprobe. */ | |
237 | reservation.nr_extents = rc; | |
238 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, | |
239 | &reservation); | |
240 | BUG_ON(ret != rc); | |
241 | } | |
242 | if (rc >= 0) | |
243 | balloon_stats.hard_limit = (balloon_stats.current_pages + rc - | |
244 | balloon_stats.driver_pages); | |
245 | goto out; | |
246 | } | |
247 | ||
248 | for (i = 0; i < nr_pages; i++) { | |
249 | page = balloon_retrieve(); | |
250 | BUG_ON(page == NULL); | |
251 | ||
252 | pfn = page_to_pfn(page); | |
253 | BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && | |
254 | phys_to_machine_mapping_valid(pfn)); | |
255 | ||
256 | set_phys_to_machine(pfn, frame_list[i]); | |
257 | ||
258 | /* Link back into the page tables if not highmem. */ | |
259 | if (pfn < max_low_pfn) { | |
260 | int ret; | |
261 | ret = HYPERVISOR_update_va_mapping( | |
262 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
263 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
264 | 0); | |
265 | BUG_ON(ret); | |
266 | } | |
267 | ||
268 | /* Relinquish the page back to the allocator. */ | |
269 | ClearPageReserved(page); | |
270 | init_page_count(page); | |
271 | __free_page(page); | |
272 | } | |
273 | ||
274 | balloon_stats.current_pages += nr_pages; | |
275 | totalram_pages = balloon_stats.current_pages; | |
276 | ||
277 | out: | |
278 | spin_unlock_irqrestore(&balloon_lock, flags); | |
279 | ||
280 | return 0; | |
281 | } | |
282 | ||
283 | static int decrease_reservation(unsigned long nr_pages) | |
284 | { | |
285 | unsigned long pfn, i, flags; | |
286 | struct page *page; | |
287 | int need_sleep = 0; | |
288 | int ret; | |
289 | struct xen_memory_reservation reservation = { | |
290 | .address_bits = 0, | |
291 | .extent_order = 0, | |
292 | .domid = DOMID_SELF | |
293 | }; | |
294 | ||
295 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
296 | nr_pages = ARRAY_SIZE(frame_list); | |
297 | ||
298 | for (i = 0; i < nr_pages; i++) { | |
299 | if ((page = alloc_page(GFP_BALLOON)) == NULL) { | |
300 | nr_pages = i; | |
301 | need_sleep = 1; | |
302 | break; | |
303 | } | |
304 | ||
305 | pfn = page_to_pfn(page); | |
306 | frame_list[i] = pfn_to_mfn(pfn); | |
307 | ||
308 | scrub_page(page); | |
309 | } | |
310 | ||
311 | /* Ensure that ballooned highmem pages don't have kmaps. */ | |
312 | kmap_flush_unused(); | |
313 | flush_tlb_all(); | |
314 | ||
315 | spin_lock_irqsave(&balloon_lock, flags); | |
316 | ||
317 | /* No more mappings: invalidate P2M and add to balloon. */ | |
318 | for (i = 0; i < nr_pages; i++) { | |
319 | pfn = mfn_to_pfn(frame_list[i]); | |
320 | set_phys_to_machine(pfn, INVALID_P2M_ENTRY); | |
321 | balloon_append(pfn_to_page(pfn)); | |
322 | } | |
323 | ||
a90971eb | 324 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
325 | reservation.nr_extents = nr_pages; |
326 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
327 | BUG_ON(ret != nr_pages); | |
328 | ||
329 | balloon_stats.current_pages -= nr_pages; | |
330 | totalram_pages = balloon_stats.current_pages; | |
331 | ||
332 | spin_unlock_irqrestore(&balloon_lock, flags); | |
333 | ||
334 | return need_sleep; | |
335 | } | |
336 | ||
337 | /* | |
338 | * We avoid multiple worker processes conflicting via the balloon mutex. | |
339 | * We may of course race updates of the target counts (which are protected | |
340 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
341 | * recover from these in time. | |
342 | */ | |
343 | static void balloon_process(struct work_struct *work) | |
344 | { | |
345 | int need_sleep = 0; | |
346 | long credit; | |
347 | ||
348 | mutex_lock(&balloon_mutex); | |
349 | ||
350 | do { | |
351 | credit = current_target() - balloon_stats.current_pages; | |
352 | if (credit > 0) | |
353 | need_sleep = (increase_reservation(credit) != 0); | |
354 | if (credit < 0) | |
355 | need_sleep = (decrease_reservation(-credit) != 0); | |
356 | ||
357 | #ifndef CONFIG_PREEMPT | |
358 | if (need_resched()) | |
359 | schedule(); | |
360 | #endif | |
361 | } while ((credit != 0) && !need_sleep); | |
362 | ||
363 | /* Schedule more work if there is some still to be done. */ | |
364 | if (current_target() != balloon_stats.current_pages) | |
365 | mod_timer(&balloon_timer, jiffies + HZ); | |
366 | ||
367 | mutex_unlock(&balloon_mutex); | |
368 | } | |
369 | ||
370 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
955d6f17 | 371 | static void balloon_set_new_target(unsigned long target) |
1775826c JF |
372 | { |
373 | /* No need for lock. Not read-modify-write updates. */ | |
374 | balloon_stats.hard_limit = ~0UL; | |
375 | balloon_stats.target_pages = target; | |
376 | schedule_work(&balloon_worker); | |
377 | } | |
378 | ||
379 | static struct xenbus_watch target_watch = | |
380 | { | |
381 | .node = "memory/target" | |
382 | }; | |
383 | ||
384 | /* React to a change in the target key */ | |
385 | static void watch_target(struct xenbus_watch *watch, | |
386 | const char **vec, unsigned int len) | |
387 | { | |
388 | unsigned long long new_target; | |
389 | int err; | |
390 | ||
391 | err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target); | |
392 | if (err != 1) { | |
393 | /* This is ok (for domain0 at least) - so just return */ | |
394 | return; | |
395 | } | |
396 | ||
397 | /* The given memory/target value is in KiB, so it needs converting to | |
398 | * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10. | |
399 | */ | |
400 | balloon_set_new_target(new_target >> (PAGE_SHIFT - 10)); | |
401 | } | |
402 | ||
403 | static int balloon_init_watcher(struct notifier_block *notifier, | |
404 | unsigned long event, | |
405 | void *data) | |
406 | { | |
407 | int err; | |
408 | ||
409 | err = register_xenbus_watch(&target_watch); | |
410 | if (err) | |
411 | printk(KERN_ERR "Failed to set balloon watcher\n"); | |
412 | ||
413 | return NOTIFY_DONE; | |
414 | } | |
415 | ||
416 | static struct notifier_block xenstore_notifier; | |
417 | ||
418 | static int __init balloon_init(void) | |
419 | { | |
420 | unsigned long pfn; | |
421 | struct page *page; | |
422 | ||
423 | if (!is_running_on_xen()) | |
424 | return -ENODEV; | |
425 | ||
426 | pr_info("xen_balloon: Initialising balloon driver.\n"); | |
427 | ||
428 | balloon_stats.current_pages = min(xen_start_info->nr_pages, max_pfn); | |
429 | totalram_pages = balloon_stats.current_pages; | |
430 | balloon_stats.target_pages = balloon_stats.current_pages; | |
431 | balloon_stats.balloon_low = 0; | |
432 | balloon_stats.balloon_high = 0; | |
433 | balloon_stats.driver_pages = 0UL; | |
434 | balloon_stats.hard_limit = ~0UL; | |
435 | ||
436 | init_timer(&balloon_timer); | |
437 | balloon_timer.data = 0; | |
438 | balloon_timer.function = balloon_alarm; | |
439 | ||
440 | register_balloon(&balloon_sysdev); | |
441 | ||
442 | /* Initialise the balloon with excess memory space. */ | |
443 | for (pfn = xen_start_info->nr_pages; pfn < max_pfn; pfn++) { | |
444 | page = pfn_to_page(pfn); | |
445 | if (!PageReserved(page)) | |
446 | balloon_append(page); | |
447 | } | |
448 | ||
449 | target_watch.callback = watch_target; | |
450 | xenstore_notifier.notifier_call = balloon_init_watcher; | |
451 | ||
452 | register_xenstore_notifier(&xenstore_notifier); | |
453 | ||
454 | return 0; | |
455 | } | |
456 | ||
457 | subsys_initcall(balloon_init); | |
458 | ||
459 | static void balloon_exit(void) | |
460 | { | |
461 | /* XXX - release balloon here */ | |
462 | return; | |
463 | } | |
464 | ||
465 | module_exit(balloon_exit); | |
466 | ||
467 | static void balloon_update_driver_allowance(long delta) | |
468 | { | |
469 | unsigned long flags; | |
470 | ||
471 | spin_lock_irqsave(&balloon_lock, flags); | |
472 | balloon_stats.driver_pages += delta; | |
473 | spin_unlock_irqrestore(&balloon_lock, flags); | |
474 | } | |
475 | ||
476 | static int dealloc_pte_fn( | |
477 | pte_t *pte, struct page *pmd_page, unsigned long addr, void *data) | |
478 | { | |
479 | unsigned long mfn = pte_mfn(*pte); | |
480 | int ret; | |
481 | struct xen_memory_reservation reservation = { | |
482 | .nr_extents = 1, | |
483 | .extent_order = 0, | |
484 | .domid = DOMID_SELF | |
485 | }; | |
a90971eb | 486 | set_xen_guest_handle(reservation.extent_start, &mfn); |
1775826c JF |
487 | set_pte_at(&init_mm, addr, pte, __pte_ma(0ull)); |
488 | set_phys_to_machine(__pa(addr) >> PAGE_SHIFT, INVALID_P2M_ENTRY); | |
489 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
490 | BUG_ON(ret != 1); | |
491 | return 0; | |
492 | } | |
493 | ||
494 | static struct page **alloc_empty_pages_and_pagevec(int nr_pages) | |
495 | { | |
496 | unsigned long vaddr, flags; | |
497 | struct page *page, **pagevec; | |
498 | int i, ret; | |
499 | ||
500 | pagevec = kmalloc(sizeof(page) * nr_pages, GFP_KERNEL); | |
501 | if (pagevec == NULL) | |
502 | return NULL; | |
503 | ||
504 | for (i = 0; i < nr_pages; i++) { | |
505 | page = pagevec[i] = alloc_page(GFP_KERNEL); | |
506 | if (page == NULL) | |
507 | goto err; | |
508 | ||
509 | vaddr = (unsigned long)page_address(page); | |
510 | ||
511 | scrub_page(page); | |
512 | ||
513 | spin_lock_irqsave(&balloon_lock, flags); | |
514 | ||
515 | if (xen_feature(XENFEAT_auto_translated_physmap)) { | |
516 | unsigned long gmfn = page_to_pfn(page); | |
517 | struct xen_memory_reservation reservation = { | |
518 | .nr_extents = 1, | |
519 | .extent_order = 0, | |
520 | .domid = DOMID_SELF | |
521 | }; | |
a90971eb | 522 | set_xen_guest_handle(reservation.extent_start, &gmfn); |
1775826c JF |
523 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, |
524 | &reservation); | |
525 | if (ret == 1) | |
526 | ret = 0; /* success */ | |
527 | } else { | |
528 | ret = apply_to_page_range(&init_mm, vaddr, PAGE_SIZE, | |
529 | dealloc_pte_fn, NULL); | |
530 | } | |
531 | ||
532 | if (ret != 0) { | |
533 | spin_unlock_irqrestore(&balloon_lock, flags); | |
534 | __free_page(page); | |
535 | goto err; | |
536 | } | |
537 | ||
538 | totalram_pages = --balloon_stats.current_pages; | |
539 | ||
540 | spin_unlock_irqrestore(&balloon_lock, flags); | |
541 | } | |
542 | ||
543 | out: | |
544 | schedule_work(&balloon_worker); | |
545 | flush_tlb_all(); | |
546 | return pagevec; | |
547 | ||
548 | err: | |
549 | spin_lock_irqsave(&balloon_lock, flags); | |
550 | while (--i >= 0) | |
551 | balloon_append(pagevec[i]); | |
552 | spin_unlock_irqrestore(&balloon_lock, flags); | |
553 | kfree(pagevec); | |
554 | pagevec = NULL; | |
555 | goto out; | |
556 | } | |
557 | ||
558 | static void free_empty_pages_and_pagevec(struct page **pagevec, int nr_pages) | |
559 | { | |
560 | unsigned long flags; | |
561 | int i; | |
562 | ||
563 | if (pagevec == NULL) | |
564 | return; | |
565 | ||
566 | spin_lock_irqsave(&balloon_lock, flags); | |
567 | for (i = 0; i < nr_pages; i++) { | |
568 | BUG_ON(page_count(pagevec[i]) != 1); | |
569 | balloon_append(pagevec[i]); | |
570 | } | |
571 | spin_unlock_irqrestore(&balloon_lock, flags); | |
572 | ||
573 | kfree(pagevec); | |
574 | ||
575 | schedule_work(&balloon_worker); | |
576 | } | |
577 | ||
578 | static void balloon_release_driver_page(struct page *page) | |
579 | { | |
580 | unsigned long flags; | |
581 | ||
582 | spin_lock_irqsave(&balloon_lock, flags); | |
583 | balloon_append(page); | |
584 | balloon_stats.driver_pages--; | |
585 | spin_unlock_irqrestore(&balloon_lock, flags); | |
586 | ||
587 | schedule_work(&balloon_worker); | |
588 | } | |
589 | ||
590 | ||
591 | #define BALLOON_SHOW(name, format, args...) \ | |
592 | static ssize_t show_##name(struct sys_device *dev, \ | |
593 | char *buf) \ | |
594 | { \ | |
595 | return sprintf(buf, format, ##args); \ | |
596 | } \ | |
597 | static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL) | |
598 | ||
599 | BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages)); | |
600 | BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low)); | |
601 | BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high)); | |
602 | BALLOON_SHOW(hard_limit_kb, | |
603 | (balloon_stats.hard_limit!=~0UL) ? "%lu\n" : "???\n", | |
604 | (balloon_stats.hard_limit!=~0UL) ? PAGES2KB(balloon_stats.hard_limit) : 0); | |
605 | BALLOON_SHOW(driver_kb, "%lu\n", PAGES2KB(balloon_stats.driver_pages)); | |
606 | ||
607 | static ssize_t show_target_kb(struct sys_device *dev, char *buf) | |
608 | { | |
609 | return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages)); | |
610 | } | |
611 | ||
612 | static ssize_t store_target_kb(struct sys_device *dev, | |
4a0b2b4d | 613 | struct sysdev_attribute *attr, |
1775826c JF |
614 | const char *buf, |
615 | size_t count) | |
616 | { | |
617 | char memstring[64], *endchar; | |
618 | unsigned long long target_bytes; | |
619 | ||
620 | if (!capable(CAP_SYS_ADMIN)) | |
621 | return -EPERM; | |
622 | ||
623 | if (count <= 1) | |
624 | return -EBADMSG; /* runt */ | |
625 | if (count > sizeof(memstring)) | |
626 | return -EFBIG; /* too long */ | |
627 | strcpy(memstring, buf); | |
628 | ||
629 | target_bytes = memparse(memstring, &endchar); | |
630 | balloon_set_new_target(target_bytes >> PAGE_SHIFT); | |
631 | ||
632 | return count; | |
633 | } | |
634 | ||
635 | static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR, | |
636 | show_target_kb, store_target_kb); | |
637 | ||
638 | static struct sysdev_attribute *balloon_attrs[] = { | |
639 | &attr_target_kb, | |
640 | }; | |
641 | ||
642 | static struct attribute *balloon_info_attrs[] = { | |
643 | &attr_current_kb.attr, | |
644 | &attr_low_kb.attr, | |
645 | &attr_high_kb.attr, | |
646 | &attr_hard_limit_kb.attr, | |
647 | &attr_driver_kb.attr, | |
648 | NULL | |
649 | }; | |
650 | ||
651 | static struct attribute_group balloon_info_group = { | |
652 | .name = "info", | |
653 | .attrs = balloon_info_attrs, | |
654 | }; | |
655 | ||
656 | static struct sysdev_class balloon_sysdev_class = { | |
657 | .name = BALLOON_CLASS_NAME, | |
658 | }; | |
659 | ||
660 | static int register_balloon(struct sys_device *sysdev) | |
661 | { | |
662 | int i, error; | |
663 | ||
664 | error = sysdev_class_register(&balloon_sysdev_class); | |
665 | if (error) | |
666 | return error; | |
667 | ||
668 | sysdev->id = 0; | |
669 | sysdev->cls = &balloon_sysdev_class; | |
670 | ||
671 | error = sysdev_register(sysdev); | |
672 | if (error) { | |
673 | sysdev_class_unregister(&balloon_sysdev_class); | |
674 | return error; | |
675 | } | |
676 | ||
677 | for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) { | |
678 | error = sysdev_create_file(sysdev, balloon_attrs[i]); | |
679 | if (error) | |
680 | goto fail; | |
681 | } | |
682 | ||
683 | error = sysfs_create_group(&sysdev->kobj, &balloon_info_group); | |
684 | if (error) | |
685 | goto fail; | |
686 | ||
687 | return 0; | |
688 | ||
689 | fail: | |
690 | while (--i >= 0) | |
691 | sysdev_remove_file(sysdev, balloon_attrs[i]); | |
692 | sysdev_unregister(sysdev); | |
693 | sysdev_class_unregister(&balloon_sysdev_class); | |
694 | return error; | |
695 | } | |
696 | ||
697 | static void unregister_balloon(struct sys_device *sysdev) | |
698 | { | |
699 | int i; | |
700 | ||
701 | sysfs_remove_group(&sysdev->kobj, &balloon_info_group); | |
702 | for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) | |
703 | sysdev_remove_file(sysdev, balloon_attrs[i]); | |
704 | sysdev_unregister(sysdev); | |
705 | sysdev_class_unregister(&balloon_sysdev_class); | |
706 | } | |
707 | ||
708 | static void balloon_sysfs_exit(void) | |
709 | { | |
710 | unregister_balloon(&balloon_sysdev); | |
711 | } | |
712 | ||
713 | MODULE_LICENSE("GPL"); |