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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> | |
1775826c JF |
44 | #include <linux/list.h> |
45 | #include <linux/sysdev.h> | |
5a0e3ad6 | 46 | #include <linux/gfp.h> |
1775826c | 47 | |
1775826c JF |
48 | #include <asm/page.h> |
49 | #include <asm/pgalloc.h> | |
50 | #include <asm/pgtable.h> | |
51 | #include <asm/uaccess.h> | |
52 | #include <asm/tlb.h> | |
66946f67 | 53 | #include <asm/e820.h> |
1775826c | 54 | |
ecbf29cd JF |
55 | #include <asm/xen/hypervisor.h> |
56 | #include <asm/xen/hypercall.h> | |
1ccbf534 JF |
57 | |
58 | #include <xen/xen.h> | |
ecbf29cd | 59 | #include <xen/interface/xen.h> |
1775826c | 60 | #include <xen/interface/memory.h> |
1775826c JF |
61 | #include <xen/xenbus.h> |
62 | #include <xen/features.h> | |
63 | #include <xen/page.h> | |
64 | ||
65 | #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) | |
66 | ||
167e6cf6 | 67 | #define BALLOON_CLASS_NAME "xen_memory" |
1775826c | 68 | |
95d2ac4a DK |
69 | /* |
70 | * balloon_process() state: | |
71 | * | |
72 | * BP_DONE: done or nothing to do, | |
73 | * BP_EAGAIN: error, go to sleep, | |
74 | * BP_ECANCELED: error, balloon operation canceled. | |
75 | */ | |
76 | ||
77 | enum bp_state { | |
78 | BP_DONE, | |
79 | BP_EAGAIN, | |
80 | BP_ECANCELED | |
81 | }; | |
82 | ||
83 | #define RETRY_UNLIMITED 0 | |
84 | ||
1775826c JF |
85 | struct balloon_stats { |
86 | /* We aim for 'current allocation' == 'target allocation'. */ | |
87 | unsigned long current_pages; | |
88 | unsigned long target_pages; | |
1775826c JF |
89 | /* Number of pages in high- and low-memory balloons. */ |
90 | unsigned long balloon_low; | |
91 | unsigned long balloon_high; | |
95d2ac4a DK |
92 | unsigned long schedule_delay; |
93 | unsigned long max_schedule_delay; | |
94 | unsigned long retry_count; | |
95 | unsigned long max_retry_count; | |
1775826c JF |
96 | }; |
97 | ||
98 | static DEFINE_MUTEX(balloon_mutex); | |
99 | ||
100 | static struct sys_device balloon_sysdev; | |
101 | ||
102 | static int register_balloon(struct sys_device *sysdev); | |
103 | ||
1775826c JF |
104 | static struct balloon_stats balloon_stats; |
105 | ||
106 | /* We increase/decrease in batches which fit in a page */ | |
107 | static unsigned long frame_list[PAGE_SIZE / sizeof(unsigned long)]; | |
108 | ||
1775826c | 109 | #ifdef CONFIG_HIGHMEM |
1775826c JF |
110 | #define inc_totalhigh_pages() (totalhigh_pages++) |
111 | #define dec_totalhigh_pages() (totalhigh_pages--) | |
112 | #else | |
113 | #define inc_totalhigh_pages() do {} while(0) | |
114 | #define dec_totalhigh_pages() do {} while(0) | |
115 | #endif | |
116 | ||
117 | /* List of ballooned pages, threaded through the mem_map array. */ | |
118 | static LIST_HEAD(ballooned_pages); | |
119 | ||
120 | /* Main work function, always executed in process context. */ | |
121 | static void balloon_process(struct work_struct *work); | |
95170b2e | 122 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); |
1775826c JF |
123 | |
124 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
125 | want the kernel to try too hard since that can trigger the oom killer. */ | |
126 | #define GFP_BALLOON \ | |
127 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
128 | ||
129 | static void scrub_page(struct page *page) | |
130 | { | |
131 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
26a3e991 | 132 | clear_highpage(page); |
1775826c JF |
133 | #endif |
134 | } | |
135 | ||
136 | /* balloon_append: add the given page to the balloon. */ | |
9be4d457 | 137 | static void __balloon_append(struct page *page) |
1775826c JF |
138 | { |
139 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
140 | if (PageHighMem(page)) { | |
141 | list_add_tail(&page->lru, &ballooned_pages); | |
142 | balloon_stats.balloon_high++; | |
143 | dec_totalhigh_pages(); | |
144 | } else { | |
145 | list_add(&page->lru, &ballooned_pages); | |
146 | balloon_stats.balloon_low++; | |
147 | } | |
9be4d457 | 148 | } |
3d65c948 | 149 | |
9be4d457 JF |
150 | static void balloon_append(struct page *page) |
151 | { | |
152 | __balloon_append(page); | |
3d65c948 | 153 | totalram_pages--; |
1775826c JF |
154 | } |
155 | ||
156 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
157 | static struct page *balloon_retrieve(void) | |
158 | { | |
159 | struct page *page; | |
160 | ||
161 | if (list_empty(&ballooned_pages)) | |
162 | return NULL; | |
163 | ||
164 | page = list_entry(ballooned_pages.next, struct page, lru); | |
165 | list_del(&page->lru); | |
166 | ||
167 | if (PageHighMem(page)) { | |
168 | balloon_stats.balloon_high--; | |
169 | inc_totalhigh_pages(); | |
170 | } | |
171 | else | |
172 | balloon_stats.balloon_low--; | |
173 | ||
3d65c948 GG |
174 | totalram_pages++; |
175 | ||
1775826c JF |
176 | return page; |
177 | } | |
178 | ||
179 | static struct page *balloon_first_page(void) | |
180 | { | |
181 | if (list_empty(&ballooned_pages)) | |
182 | return NULL; | |
183 | return list_entry(ballooned_pages.next, struct page, lru); | |
184 | } | |
185 | ||
186 | static struct page *balloon_next_page(struct page *page) | |
187 | { | |
188 | struct list_head *next = page->lru.next; | |
189 | if (next == &ballooned_pages) | |
190 | return NULL; | |
191 | return list_entry(next, struct page, lru); | |
192 | } | |
193 | ||
95d2ac4a DK |
194 | static enum bp_state update_schedule(enum bp_state state) |
195 | { | |
196 | if (state == BP_DONE) { | |
197 | balloon_stats.schedule_delay = 1; | |
198 | balloon_stats.retry_count = 1; | |
199 | return BP_DONE; | |
200 | } | |
201 | ||
95d2ac4a DK |
202 | ++balloon_stats.retry_count; |
203 | ||
204 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
205 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
206 | balloon_stats.schedule_delay = 1; |
207 | balloon_stats.retry_count = 1; | |
208 | return BP_ECANCELED; | |
209 | } | |
210 | ||
211 | balloon_stats.schedule_delay <<= 1; | |
212 | ||
213 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
214 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
215 | ||
216 | return BP_EAGAIN; | |
217 | } | |
218 | ||
1775826c JF |
219 | static unsigned long current_target(void) |
220 | { | |
bc2c0303 | 221 | unsigned long target = balloon_stats.target_pages; |
1775826c JF |
222 | |
223 | target = min(target, | |
224 | balloon_stats.current_pages + | |
225 | balloon_stats.balloon_low + | |
226 | balloon_stats.balloon_high); | |
227 | ||
228 | return target; | |
229 | } | |
230 | ||
95d2ac4a | 231 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 232 | { |
95d2ac4a | 233 | int rc; |
2f70e0ac | 234 | unsigned long pfn, i; |
1775826c | 235 | struct page *page; |
1775826c JF |
236 | struct xen_memory_reservation reservation = { |
237 | .address_bits = 0, | |
238 | .extent_order = 0, | |
239 | .domid = DOMID_SELF | |
240 | }; | |
241 | ||
242 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
243 | nr_pages = ARRAY_SIZE(frame_list); | |
244 | ||
1775826c JF |
245 | page = balloon_first_page(); |
246 | for (i = 0; i < nr_pages; i++) { | |
95d2ac4a DK |
247 | if (!page) { |
248 | nr_pages = i; | |
249 | break; | |
250 | } | |
a419aef8 | 251 | frame_list[i] = page_to_pfn(page); |
1775826c JF |
252 | page = balloon_next_page(page); |
253 | } | |
254 | ||
a90971eb | 255 | set_xen_guest_handle(reservation.extent_start, frame_list); |
fde28e8f JF |
256 | reservation.nr_extents = nr_pages; |
257 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); | |
40095de1 | 258 | if (rc <= 0) |
95d2ac4a | 259 | return BP_EAGAIN; |
1775826c | 260 | |
bc2c0303 | 261 | for (i = 0; i < rc; i++) { |
1775826c JF |
262 | page = balloon_retrieve(); |
263 | BUG_ON(page == NULL); | |
264 | ||
265 | pfn = page_to_pfn(page); | |
266 | BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && | |
267 | phys_to_machine_mapping_valid(pfn)); | |
268 | ||
269 | set_phys_to_machine(pfn, frame_list[i]); | |
270 | ||
271 | /* Link back into the page tables if not highmem. */ | |
272 | if (pfn < max_low_pfn) { | |
273 | int ret; | |
274 | ret = HYPERVISOR_update_va_mapping( | |
275 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
276 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
277 | 0); | |
278 | BUG_ON(ret); | |
279 | } | |
280 | ||
281 | /* Relinquish the page back to the allocator. */ | |
282 | ClearPageReserved(page); | |
283 | init_page_count(page); | |
284 | __free_page(page); | |
285 | } | |
286 | ||
bc2c0303 | 287 | balloon_stats.current_pages += rc; |
1775826c | 288 | |
95d2ac4a | 289 | return BP_DONE; |
1775826c JF |
290 | } |
291 | ||
95d2ac4a | 292 | static enum bp_state decrease_reservation(unsigned long nr_pages) |
1775826c | 293 | { |
95d2ac4a | 294 | enum bp_state state = BP_DONE; |
2f70e0ac | 295 | unsigned long pfn, i; |
1775826c | 296 | struct page *page; |
1775826c JF |
297 | int ret; |
298 | struct xen_memory_reservation reservation = { | |
299 | .address_bits = 0, | |
300 | .extent_order = 0, | |
301 | .domid = DOMID_SELF | |
302 | }; | |
303 | ||
304 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
305 | nr_pages = ARRAY_SIZE(frame_list); | |
306 | ||
307 | for (i = 0; i < nr_pages; i++) { | |
308 | if ((page = alloc_page(GFP_BALLOON)) == NULL) { | |
309 | nr_pages = i; | |
95d2ac4a | 310 | state = BP_EAGAIN; |
1775826c JF |
311 | break; |
312 | } | |
313 | ||
314 | pfn = page_to_pfn(page); | |
315 | frame_list[i] = pfn_to_mfn(pfn); | |
316 | ||
317 | scrub_page(page); | |
1058a75f | 318 | |
ff4ce8c3 IC |
319 | if (!PageHighMem(page)) { |
320 | ret = HYPERVISOR_update_va_mapping( | |
321 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
322 | __pte_ma(0), 0); | |
323 | BUG_ON(ret); | |
324 | } | |
325 | ||
1775826c JF |
326 | } |
327 | ||
328 | /* Ensure that ballooned highmem pages don't have kmaps. */ | |
329 | kmap_flush_unused(); | |
330 | flush_tlb_all(); | |
331 | ||
1775826c JF |
332 | /* No more mappings: invalidate P2M and add to balloon. */ |
333 | for (i = 0; i < nr_pages; i++) { | |
334 | pfn = mfn_to_pfn(frame_list[i]); | |
335 | set_phys_to_machine(pfn, INVALID_P2M_ENTRY); | |
336 | balloon_append(pfn_to_page(pfn)); | |
337 | } | |
338 | ||
a90971eb | 339 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
340 | reservation.nr_extents = nr_pages; |
341 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
342 | BUG_ON(ret != nr_pages); | |
343 | ||
344 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 345 | |
95d2ac4a | 346 | return state; |
1775826c JF |
347 | } |
348 | ||
349 | /* | |
350 | * We avoid multiple worker processes conflicting via the balloon mutex. | |
351 | * We may of course race updates of the target counts (which are protected | |
352 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
353 | * recover from these in time. | |
354 | */ | |
355 | static void balloon_process(struct work_struct *work) | |
356 | { | |
95d2ac4a | 357 | enum bp_state state = BP_DONE; |
1775826c JF |
358 | long credit; |
359 | ||
360 | mutex_lock(&balloon_mutex); | |
361 | ||
362 | do { | |
363 | credit = current_target() - balloon_stats.current_pages; | |
95d2ac4a | 364 | |
1775826c | 365 | if (credit > 0) |
95d2ac4a DK |
366 | state = increase_reservation(credit); |
367 | ||
1775826c | 368 | if (credit < 0) |
95d2ac4a DK |
369 | state = decrease_reservation(-credit); |
370 | ||
371 | state = update_schedule(state); | |
1775826c JF |
372 | |
373 | #ifndef CONFIG_PREEMPT | |
374 | if (need_resched()) | |
375 | schedule(); | |
376 | #endif | |
95d2ac4a | 377 | } while (credit && state == BP_DONE); |
1775826c JF |
378 | |
379 | /* Schedule more work if there is some still to be done. */ | |
95d2ac4a DK |
380 | if (state == BP_EAGAIN) |
381 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
1775826c JF |
382 | |
383 | mutex_unlock(&balloon_mutex); | |
384 | } | |
385 | ||
386 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
955d6f17 | 387 | static void balloon_set_new_target(unsigned long target) |
1775826c JF |
388 | { |
389 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 390 | balloon_stats.target_pages = target; |
95170b2e | 391 | schedule_delayed_work(&balloon_worker, 0); |
1775826c JF |
392 | } |
393 | ||
394 | static struct xenbus_watch target_watch = | |
395 | { | |
396 | .node = "memory/target" | |
397 | }; | |
398 | ||
399 | /* React to a change in the target key */ | |
400 | static void watch_target(struct xenbus_watch *watch, | |
401 | const char **vec, unsigned int len) | |
402 | { | |
403 | unsigned long long new_target; | |
404 | int err; | |
405 | ||
406 | err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target); | |
407 | if (err != 1) { | |
408 | /* This is ok (for domain0 at least) - so just return */ | |
409 | return; | |
410 | } | |
411 | ||
412 | /* The given memory/target value is in KiB, so it needs converting to | |
413 | * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10. | |
414 | */ | |
415 | balloon_set_new_target(new_target >> (PAGE_SHIFT - 10)); | |
416 | } | |
417 | ||
418 | static int balloon_init_watcher(struct notifier_block *notifier, | |
419 | unsigned long event, | |
420 | void *data) | |
421 | { | |
422 | int err; | |
423 | ||
424 | err = register_xenbus_watch(&target_watch); | |
425 | if (err) | |
426 | printk(KERN_ERR "Failed to set balloon watcher\n"); | |
427 | ||
428 | return NOTIFY_DONE; | |
429 | } | |
430 | ||
431 | static struct notifier_block xenstore_notifier; | |
432 | ||
433 | static int __init balloon_init(void) | |
434 | { | |
66946f67 | 435 | unsigned long pfn, extra_pfn_end; |
1775826c JF |
436 | struct page *page; |
437 | ||
6e833587 | 438 | if (!xen_pv_domain()) |
1775826c JF |
439 | return -ENODEV; |
440 | ||
441 | pr_info("xen_balloon: Initialising balloon driver.\n"); | |
442 | ||
443 | balloon_stats.current_pages = min(xen_start_info->nr_pages, max_pfn); | |
1775826c JF |
444 | balloon_stats.target_pages = balloon_stats.current_pages; |
445 | balloon_stats.balloon_low = 0; | |
446 | balloon_stats.balloon_high = 0; | |
1775826c | 447 | |
95d2ac4a DK |
448 | balloon_stats.schedule_delay = 1; |
449 | balloon_stats.max_schedule_delay = 32; | |
450 | balloon_stats.retry_count = 1; | |
40095de1 | 451 | balloon_stats.max_retry_count = RETRY_UNLIMITED; |
95d2ac4a | 452 | |
1775826c JF |
453 | register_balloon(&balloon_sysdev); |
454 | ||
2a4c92fa JF |
455 | /* |
456 | * Initialise the balloon with excess memory space. We need | |
457 | * to make sure we don't add memory which doesn't exist or | |
458 | * logically exist. The E820 map can be trimmed to be smaller | |
459 | * than the amount of physical memory due to the mem= command | |
460 | * line parameter. And if this is a 32-bit non-HIGHMEM kernel | |
461 | * on a system with memory which requires highmem to access, | |
462 | * don't try to use it. | |
463 | */ | |
464 | extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()), | |
66946f67 | 465 | (unsigned long)PFN_DOWN(xen_extra_mem_start + xen_extra_mem_size)); |
9be4d457 | 466 | for (pfn = PFN_UP(xen_extra_mem_start); |
66946f67 | 467 | pfn < extra_pfn_end; |
9be4d457 | 468 | pfn++) { |
1775826c | 469 | page = pfn_to_page(pfn); |
9be4d457 JF |
470 | /* totalram_pages doesn't include the boot-time |
471 | balloon extension, so don't subtract from it. */ | |
472 | __balloon_append(page); | |
1775826c JF |
473 | } |
474 | ||
475 | target_watch.callback = watch_target; | |
476 | xenstore_notifier.notifier_call = balloon_init_watcher; | |
477 | ||
478 | register_xenstore_notifier(&xenstore_notifier); | |
479 | ||
480 | return 0; | |
481 | } | |
482 | ||
483 | subsys_initcall(balloon_init); | |
484 | ||
485 | static void balloon_exit(void) | |
486 | { | |
487 | /* XXX - release balloon here */ | |
488 | return; | |
489 | } | |
490 | ||
491 | module_exit(balloon_exit); | |
492 | ||
167e6cf6 JF |
493 | #define BALLOON_SHOW(name, format, args...) \ |
494 | static ssize_t show_##name(struct sys_device *dev, \ | |
495 | struct sysdev_attribute *attr, \ | |
496 | char *buf) \ | |
497 | { \ | |
498 | return sprintf(buf, format, ##args); \ | |
499 | } \ | |
1775826c JF |
500 | static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL) |
501 | ||
502 | BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages)); | |
503 | BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low)); | |
504 | BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high)); | |
1775826c | 505 | |
95d2ac4a DK |
506 | static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay); |
507 | static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay); | |
508 | static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count); | |
509 | static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count); | |
510 | ||
167e6cf6 JF |
511 | static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr, |
512 | char *buf) | |
1775826c JF |
513 | { |
514 | return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages)); | |
515 | } | |
516 | ||
517 | static ssize_t store_target_kb(struct sys_device *dev, | |
4a0b2b4d | 518 | struct sysdev_attribute *attr, |
1775826c JF |
519 | const char *buf, |
520 | size_t count) | |
521 | { | |
167e6cf6 | 522 | char *endchar; |
1775826c JF |
523 | unsigned long long target_bytes; |
524 | ||
525 | if (!capable(CAP_SYS_ADMIN)) | |
526 | return -EPERM; | |
527 | ||
618b2c8d | 528 | target_bytes = simple_strtoull(buf, &endchar, 0) * 1024; |
1775826c | 529 | |
1775826c JF |
530 | balloon_set_new_target(target_bytes >> PAGE_SHIFT); |
531 | ||
532 | return count; | |
533 | } | |
534 | ||
535 | static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR, | |
536 | show_target_kb, store_target_kb); | |
537 | ||
618b2c8d JF |
538 | |
539 | static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr, | |
540 | char *buf) | |
541 | { | |
542 | return sprintf(buf, "%llu\n", | |
0692698c JB |
543 | (unsigned long long)balloon_stats.target_pages |
544 | << PAGE_SHIFT); | |
618b2c8d JF |
545 | } |
546 | ||
547 | static ssize_t store_target(struct sys_device *dev, | |
548 | struct sysdev_attribute *attr, | |
549 | const char *buf, | |
550 | size_t count) | |
551 | { | |
552 | char *endchar; | |
553 | unsigned long long target_bytes; | |
554 | ||
555 | if (!capable(CAP_SYS_ADMIN)) | |
556 | return -EPERM; | |
557 | ||
558 | target_bytes = memparse(buf, &endchar); | |
559 | ||
560 | balloon_set_new_target(target_bytes >> PAGE_SHIFT); | |
561 | ||
562 | return count; | |
563 | } | |
564 | ||
565 | static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR, | |
566 | show_target, store_target); | |
567 | ||
568 | ||
1775826c JF |
569 | static struct sysdev_attribute *balloon_attrs[] = { |
570 | &attr_target_kb, | |
618b2c8d | 571 | &attr_target, |
95d2ac4a DK |
572 | &attr_schedule_delay.attr, |
573 | &attr_max_schedule_delay.attr, | |
574 | &attr_retry_count.attr, | |
575 | &attr_max_retry_count.attr | |
1775826c JF |
576 | }; |
577 | ||
578 | static struct attribute *balloon_info_attrs[] = { | |
579 | &attr_current_kb.attr, | |
580 | &attr_low_kb.attr, | |
581 | &attr_high_kb.attr, | |
1775826c JF |
582 | NULL |
583 | }; | |
584 | ||
585 | static struct attribute_group balloon_info_group = { | |
586 | .name = "info", | |
587 | .attrs = balloon_info_attrs, | |
588 | }; | |
589 | ||
590 | static struct sysdev_class balloon_sysdev_class = { | |
591 | .name = BALLOON_CLASS_NAME, | |
592 | }; | |
593 | ||
594 | static int register_balloon(struct sys_device *sysdev) | |
595 | { | |
596 | int i, error; | |
597 | ||
598 | error = sysdev_class_register(&balloon_sysdev_class); | |
599 | if (error) | |
600 | return error; | |
601 | ||
602 | sysdev->id = 0; | |
603 | sysdev->cls = &balloon_sysdev_class; | |
604 | ||
605 | error = sysdev_register(sysdev); | |
606 | if (error) { | |
607 | sysdev_class_unregister(&balloon_sysdev_class); | |
608 | return error; | |
609 | } | |
610 | ||
611 | for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) { | |
612 | error = sysdev_create_file(sysdev, balloon_attrs[i]); | |
613 | if (error) | |
614 | goto fail; | |
615 | } | |
616 | ||
617 | error = sysfs_create_group(&sysdev->kobj, &balloon_info_group); | |
618 | if (error) | |
619 | goto fail; | |
620 | ||
621 | return 0; | |
622 | ||
623 | fail: | |
624 | while (--i >= 0) | |
625 | sysdev_remove_file(sysdev, balloon_attrs[i]); | |
626 | sysdev_unregister(sysdev); | |
627 | sysdev_class_unregister(&balloon_sysdev_class); | |
628 | return error; | |
629 | } | |
630 | ||
1775826c | 631 | MODULE_LICENSE("GPL"); |