Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 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> |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 44 | #include <linux/list.h> |
| 45 | #include <linux/sysdev.h> |
| 46 | |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 47 | #include <asm/page.h> |
| 48 | #include <asm/pgalloc.h> |
| 49 | #include <asm/pgtable.h> |
| 50 | #include <asm/uaccess.h> |
| 51 | #include <asm/tlb.h> |
| 52 | |
Jeremy Fitzhardinge | ecbf29c | 2008-12-16 12:37:07 -0800 | [diff] [blame] | 53 | #include <asm/xen/hypervisor.h> |
| 54 | #include <asm/xen/hypercall.h> |
| 55 | #include <xen/interface/xen.h> |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 56 | #include <xen/interface/memory.h> |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | 167e6cf | 2008-07-24 16:27:52 -0700 | [diff] [blame] | 63 | #define BALLOON_CLASS_NAME "xen_memory" |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 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 |
Jeremy Fitzhardinge | 26a3e99 | 2008-11-17 09:35:00 -0800 | [diff] [blame] | 127 | clear_highpage(page); |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 128 | #endif |
| 129 | } |
| 130 | |
| 131 | /* balloon_append: add the given page to the balloon. */ |
| 132 | static void balloon_append(struct page *page) |
| 133 | { |
| 134 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ |
| 135 | if (PageHighMem(page)) { |
| 136 | list_add_tail(&page->lru, &ballooned_pages); |
| 137 | balloon_stats.balloon_high++; |
| 138 | dec_totalhigh_pages(); |
| 139 | } else { |
| 140 | list_add(&page->lru, &ballooned_pages); |
| 141 | balloon_stats.balloon_low++; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ |
| 146 | static struct page *balloon_retrieve(void) |
| 147 | { |
| 148 | struct page *page; |
| 149 | |
| 150 | if (list_empty(&ballooned_pages)) |
| 151 | return NULL; |
| 152 | |
| 153 | page = list_entry(ballooned_pages.next, struct page, lru); |
| 154 | list_del(&page->lru); |
| 155 | |
| 156 | if (PageHighMem(page)) { |
| 157 | balloon_stats.balloon_high--; |
| 158 | inc_totalhigh_pages(); |
| 159 | } |
| 160 | else |
| 161 | balloon_stats.balloon_low--; |
| 162 | |
| 163 | return page; |
| 164 | } |
| 165 | |
| 166 | static struct page *balloon_first_page(void) |
| 167 | { |
| 168 | if (list_empty(&ballooned_pages)) |
| 169 | return NULL; |
| 170 | return list_entry(ballooned_pages.next, struct page, lru); |
| 171 | } |
| 172 | |
| 173 | static struct page *balloon_next_page(struct page *page) |
| 174 | { |
| 175 | struct list_head *next = page->lru.next; |
| 176 | if (next == &ballooned_pages) |
| 177 | return NULL; |
| 178 | return list_entry(next, struct page, lru); |
| 179 | } |
| 180 | |
| 181 | static void balloon_alarm(unsigned long unused) |
| 182 | { |
| 183 | schedule_work(&balloon_worker); |
| 184 | } |
| 185 | |
| 186 | static unsigned long current_target(void) |
| 187 | { |
| 188 | unsigned long target = min(balloon_stats.target_pages, balloon_stats.hard_limit); |
| 189 | |
| 190 | target = min(target, |
| 191 | balloon_stats.current_pages + |
| 192 | balloon_stats.balloon_low + |
| 193 | balloon_stats.balloon_high); |
| 194 | |
| 195 | return target; |
| 196 | } |
| 197 | |
| 198 | static int increase_reservation(unsigned long nr_pages) |
| 199 | { |
| 200 | unsigned long pfn, i, flags; |
| 201 | struct page *page; |
| 202 | long rc; |
| 203 | struct xen_memory_reservation reservation = { |
| 204 | .address_bits = 0, |
| 205 | .extent_order = 0, |
| 206 | .domid = DOMID_SELF |
| 207 | }; |
| 208 | |
| 209 | if (nr_pages > ARRAY_SIZE(frame_list)) |
| 210 | nr_pages = ARRAY_SIZE(frame_list); |
| 211 | |
| 212 | spin_lock_irqsave(&balloon_lock, flags); |
| 213 | |
| 214 | page = balloon_first_page(); |
| 215 | for (i = 0; i < nr_pages; i++) { |
| 216 | BUG_ON(page == NULL); |
| 217 | frame_list[i] = page_to_pfn(page);; |
| 218 | page = balloon_next_page(page); |
| 219 | } |
| 220 | |
Isaku Yamahata | a90971e | 2008-05-26 23:31:14 +0100 | [diff] [blame] | 221 | set_xen_guest_handle(reservation.extent_start, frame_list); |
Jeremy Fitzhardinge | fde28e8 | 2008-07-24 16:28:00 -0700 | [diff] [blame] | 222 | reservation.nr_extents = nr_pages; |
| 223 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 224 | if (rc < nr_pages) { |
| 225 | if (rc > 0) { |
| 226 | int ret; |
| 227 | |
| 228 | /* We hit the Xen hard limit: reprobe. */ |
| 229 | reservation.nr_extents = rc; |
| 230 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, |
Jeremy Fitzhardinge | fde28e8 | 2008-07-24 16:28:00 -0700 | [diff] [blame] | 231 | &reservation); |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 232 | BUG_ON(ret != rc); |
| 233 | } |
| 234 | if (rc >= 0) |
| 235 | balloon_stats.hard_limit = (balloon_stats.current_pages + rc - |
| 236 | balloon_stats.driver_pages); |
| 237 | goto out; |
| 238 | } |
| 239 | |
| 240 | for (i = 0; i < nr_pages; i++) { |
| 241 | page = balloon_retrieve(); |
| 242 | BUG_ON(page == NULL); |
| 243 | |
| 244 | pfn = page_to_pfn(page); |
| 245 | BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && |
| 246 | phys_to_machine_mapping_valid(pfn)); |
| 247 | |
| 248 | set_phys_to_machine(pfn, frame_list[i]); |
| 249 | |
| 250 | /* Link back into the page tables if not highmem. */ |
| 251 | if (pfn < max_low_pfn) { |
| 252 | int ret; |
| 253 | ret = HYPERVISOR_update_va_mapping( |
| 254 | (unsigned long)__va(pfn << PAGE_SHIFT), |
| 255 | mfn_pte(frame_list[i], PAGE_KERNEL), |
| 256 | 0); |
| 257 | BUG_ON(ret); |
| 258 | } |
| 259 | |
| 260 | /* Relinquish the page back to the allocator. */ |
| 261 | ClearPageReserved(page); |
| 262 | init_page_count(page); |
| 263 | __free_page(page); |
| 264 | } |
| 265 | |
| 266 | balloon_stats.current_pages += nr_pages; |
| 267 | totalram_pages = balloon_stats.current_pages; |
| 268 | |
| 269 | out: |
| 270 | spin_unlock_irqrestore(&balloon_lock, flags); |
| 271 | |
| 272 | return 0; |
| 273 | } |
| 274 | |
| 275 | static int decrease_reservation(unsigned long nr_pages) |
| 276 | { |
| 277 | unsigned long pfn, i, flags; |
| 278 | struct page *page; |
| 279 | int need_sleep = 0; |
| 280 | int ret; |
| 281 | struct xen_memory_reservation reservation = { |
| 282 | .address_bits = 0, |
| 283 | .extent_order = 0, |
| 284 | .domid = DOMID_SELF |
| 285 | }; |
| 286 | |
| 287 | if (nr_pages > ARRAY_SIZE(frame_list)) |
| 288 | nr_pages = ARRAY_SIZE(frame_list); |
| 289 | |
| 290 | for (i = 0; i < nr_pages; i++) { |
| 291 | if ((page = alloc_page(GFP_BALLOON)) == NULL) { |
| 292 | nr_pages = i; |
| 293 | need_sleep = 1; |
| 294 | break; |
| 295 | } |
| 296 | |
| 297 | pfn = page_to_pfn(page); |
| 298 | frame_list[i] = pfn_to_mfn(pfn); |
| 299 | |
| 300 | scrub_page(page); |
Dan Magenheimer | 1058a75 | 2009-01-22 14:36:08 -0800 | [diff] [blame] | 301 | |
| 302 | ret = HYPERVISOR_update_va_mapping( |
| 303 | (unsigned long)__va(pfn << PAGE_SHIFT), |
| 304 | __pte_ma(0), 0); |
| 305 | BUG_ON(ret); |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 306 | } |
| 307 | |
| 308 | /* Ensure that ballooned highmem pages don't have kmaps. */ |
| 309 | kmap_flush_unused(); |
| 310 | flush_tlb_all(); |
| 311 | |
| 312 | spin_lock_irqsave(&balloon_lock, flags); |
| 313 | |
| 314 | /* No more mappings: invalidate P2M and add to balloon. */ |
| 315 | for (i = 0; i < nr_pages; i++) { |
| 316 | pfn = mfn_to_pfn(frame_list[i]); |
| 317 | set_phys_to_machine(pfn, INVALID_P2M_ENTRY); |
| 318 | balloon_append(pfn_to_page(pfn)); |
| 319 | } |
| 320 | |
Isaku Yamahata | a90971e | 2008-05-26 23:31:14 +0100 | [diff] [blame] | 321 | set_xen_guest_handle(reservation.extent_start, frame_list); |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 322 | reservation.nr_extents = nr_pages; |
| 323 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); |
| 324 | BUG_ON(ret != nr_pages); |
| 325 | |
| 326 | balloon_stats.current_pages -= nr_pages; |
| 327 | totalram_pages = balloon_stats.current_pages; |
| 328 | |
| 329 | spin_unlock_irqrestore(&balloon_lock, flags); |
| 330 | |
| 331 | return need_sleep; |
| 332 | } |
| 333 | |
| 334 | /* |
| 335 | * We avoid multiple worker processes conflicting via the balloon mutex. |
| 336 | * We may of course race updates of the target counts (which are protected |
| 337 | * by the balloon lock), or with changes to the Xen hard limit, but we will |
| 338 | * recover from these in time. |
| 339 | */ |
| 340 | static void balloon_process(struct work_struct *work) |
| 341 | { |
| 342 | int need_sleep = 0; |
| 343 | long credit; |
| 344 | |
| 345 | mutex_lock(&balloon_mutex); |
| 346 | |
| 347 | do { |
| 348 | credit = current_target() - balloon_stats.current_pages; |
| 349 | if (credit > 0) |
| 350 | need_sleep = (increase_reservation(credit) != 0); |
| 351 | if (credit < 0) |
| 352 | need_sleep = (decrease_reservation(-credit) != 0); |
| 353 | |
| 354 | #ifndef CONFIG_PREEMPT |
| 355 | if (need_resched()) |
| 356 | schedule(); |
| 357 | #endif |
| 358 | } while ((credit != 0) && !need_sleep); |
| 359 | |
| 360 | /* Schedule more work if there is some still to be done. */ |
| 361 | if (current_target() != balloon_stats.current_pages) |
| 362 | mod_timer(&balloon_timer, jiffies + HZ); |
| 363 | |
| 364 | mutex_unlock(&balloon_mutex); |
| 365 | } |
| 366 | |
| 367 | /* Resets the Xen limit, sets new target, and kicks off processing. */ |
Adrian Bunk | 955d6f1 | 2008-05-26 23:31:17 +0100 | [diff] [blame] | 368 | static void balloon_set_new_target(unsigned long target) |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 369 | { |
| 370 | /* No need for lock. Not read-modify-write updates. */ |
| 371 | balloon_stats.hard_limit = ~0UL; |
| 372 | balloon_stats.target_pages = target; |
| 373 | schedule_work(&balloon_worker); |
| 374 | } |
| 375 | |
| 376 | static struct xenbus_watch target_watch = |
| 377 | { |
| 378 | .node = "memory/target" |
| 379 | }; |
| 380 | |
| 381 | /* React to a change in the target key */ |
| 382 | static void watch_target(struct xenbus_watch *watch, |
| 383 | const char **vec, unsigned int len) |
| 384 | { |
| 385 | unsigned long long new_target; |
| 386 | int err; |
| 387 | |
| 388 | err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target); |
| 389 | if (err != 1) { |
| 390 | /* This is ok (for domain0 at least) - so just return */ |
| 391 | return; |
| 392 | } |
| 393 | |
| 394 | /* The given memory/target value is in KiB, so it needs converting to |
| 395 | * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10. |
| 396 | */ |
| 397 | balloon_set_new_target(new_target >> (PAGE_SHIFT - 10)); |
| 398 | } |
| 399 | |
| 400 | static int balloon_init_watcher(struct notifier_block *notifier, |
| 401 | unsigned long event, |
| 402 | void *data) |
| 403 | { |
| 404 | int err; |
| 405 | |
| 406 | err = register_xenbus_watch(&target_watch); |
| 407 | if (err) |
| 408 | printk(KERN_ERR "Failed to set balloon watcher\n"); |
| 409 | |
| 410 | return NOTIFY_DONE; |
| 411 | } |
| 412 | |
| 413 | static struct notifier_block xenstore_notifier; |
| 414 | |
| 415 | static int __init balloon_init(void) |
| 416 | { |
| 417 | unsigned long pfn; |
| 418 | struct page *page; |
| 419 | |
Jeremy Fitzhardinge | 6e83358 | 2008-08-19 13:16:17 -0700 | [diff] [blame] | 420 | if (!xen_pv_domain()) |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 421 | return -ENODEV; |
| 422 | |
| 423 | pr_info("xen_balloon: Initialising balloon driver.\n"); |
| 424 | |
| 425 | balloon_stats.current_pages = min(xen_start_info->nr_pages, max_pfn); |
| 426 | totalram_pages = balloon_stats.current_pages; |
| 427 | balloon_stats.target_pages = balloon_stats.current_pages; |
| 428 | balloon_stats.balloon_low = 0; |
| 429 | balloon_stats.balloon_high = 0; |
| 430 | balloon_stats.driver_pages = 0UL; |
| 431 | balloon_stats.hard_limit = ~0UL; |
| 432 | |
| 433 | init_timer(&balloon_timer); |
| 434 | balloon_timer.data = 0; |
| 435 | balloon_timer.function = balloon_alarm; |
| 436 | |
| 437 | register_balloon(&balloon_sysdev); |
| 438 | |
| 439 | /* Initialise the balloon with excess memory space. */ |
| 440 | for (pfn = xen_start_info->nr_pages; pfn < max_pfn; pfn++) { |
| 441 | page = pfn_to_page(pfn); |
| 442 | if (!PageReserved(page)) |
| 443 | balloon_append(page); |
| 444 | } |
| 445 | |
| 446 | target_watch.callback = watch_target; |
| 447 | xenstore_notifier.notifier_call = balloon_init_watcher; |
| 448 | |
| 449 | register_xenstore_notifier(&xenstore_notifier); |
| 450 | |
| 451 | return 0; |
| 452 | } |
| 453 | |
| 454 | subsys_initcall(balloon_init); |
| 455 | |
| 456 | static void balloon_exit(void) |
| 457 | { |
| 458 | /* XXX - release balloon here */ |
| 459 | return; |
| 460 | } |
| 461 | |
| 462 | module_exit(balloon_exit); |
| 463 | |
Jeremy Fitzhardinge | 167e6cf | 2008-07-24 16:27:52 -0700 | [diff] [blame] | 464 | #define BALLOON_SHOW(name, format, args...) \ |
| 465 | static ssize_t show_##name(struct sys_device *dev, \ |
| 466 | struct sysdev_attribute *attr, \ |
| 467 | char *buf) \ |
| 468 | { \ |
| 469 | return sprintf(buf, format, ##args); \ |
| 470 | } \ |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 471 | static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL) |
| 472 | |
| 473 | BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages)); |
| 474 | BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low)); |
| 475 | BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high)); |
| 476 | BALLOON_SHOW(hard_limit_kb, |
| 477 | (balloon_stats.hard_limit!=~0UL) ? "%lu\n" : "???\n", |
| 478 | (balloon_stats.hard_limit!=~0UL) ? PAGES2KB(balloon_stats.hard_limit) : 0); |
| 479 | BALLOON_SHOW(driver_kb, "%lu\n", PAGES2KB(balloon_stats.driver_pages)); |
| 480 | |
Jeremy Fitzhardinge | 167e6cf | 2008-07-24 16:27:52 -0700 | [diff] [blame] | 481 | static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr, |
| 482 | char *buf) |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 483 | { |
| 484 | return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages)); |
| 485 | } |
| 486 | |
| 487 | static ssize_t store_target_kb(struct sys_device *dev, |
Andi Kleen | 4a0b2b4 | 2008-07-01 18:48:41 +0200 | [diff] [blame] | 488 | struct sysdev_attribute *attr, |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 489 | const char *buf, |
| 490 | size_t count) |
| 491 | { |
Jeremy Fitzhardinge | 167e6cf | 2008-07-24 16:27:52 -0700 | [diff] [blame] | 492 | char *endchar; |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 493 | unsigned long long target_bytes; |
| 494 | |
| 495 | if (!capable(CAP_SYS_ADMIN)) |
| 496 | return -EPERM; |
| 497 | |
Jeremy Fitzhardinge | 167e6cf | 2008-07-24 16:27:52 -0700 | [diff] [blame] | 498 | target_bytes = memparse(buf, &endchar); |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 499 | |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 500 | balloon_set_new_target(target_bytes >> PAGE_SHIFT); |
| 501 | |
| 502 | return count; |
| 503 | } |
| 504 | |
| 505 | static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR, |
| 506 | show_target_kb, store_target_kb); |
| 507 | |
| 508 | static struct sysdev_attribute *balloon_attrs[] = { |
| 509 | &attr_target_kb, |
| 510 | }; |
| 511 | |
| 512 | static struct attribute *balloon_info_attrs[] = { |
| 513 | &attr_current_kb.attr, |
| 514 | &attr_low_kb.attr, |
| 515 | &attr_high_kb.attr, |
| 516 | &attr_hard_limit_kb.attr, |
| 517 | &attr_driver_kb.attr, |
| 518 | NULL |
| 519 | }; |
| 520 | |
| 521 | static struct attribute_group balloon_info_group = { |
| 522 | .name = "info", |
| 523 | .attrs = balloon_info_attrs, |
| 524 | }; |
| 525 | |
| 526 | static struct sysdev_class balloon_sysdev_class = { |
| 527 | .name = BALLOON_CLASS_NAME, |
| 528 | }; |
| 529 | |
| 530 | static int register_balloon(struct sys_device *sysdev) |
| 531 | { |
| 532 | int i, error; |
| 533 | |
| 534 | error = sysdev_class_register(&balloon_sysdev_class); |
| 535 | if (error) |
| 536 | return error; |
| 537 | |
| 538 | sysdev->id = 0; |
| 539 | sysdev->cls = &balloon_sysdev_class; |
| 540 | |
| 541 | error = sysdev_register(sysdev); |
| 542 | if (error) { |
| 543 | sysdev_class_unregister(&balloon_sysdev_class); |
| 544 | return error; |
| 545 | } |
| 546 | |
| 547 | for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) { |
| 548 | error = sysdev_create_file(sysdev, balloon_attrs[i]); |
| 549 | if (error) |
| 550 | goto fail; |
| 551 | } |
| 552 | |
| 553 | error = sysfs_create_group(&sysdev->kobj, &balloon_info_group); |
| 554 | if (error) |
| 555 | goto fail; |
| 556 | |
| 557 | return 0; |
| 558 | |
| 559 | fail: |
| 560 | while (--i >= 0) |
| 561 | sysdev_remove_file(sysdev, balloon_attrs[i]); |
| 562 | sysdev_unregister(sysdev); |
| 563 | sysdev_class_unregister(&balloon_sysdev_class); |
| 564 | return error; |
| 565 | } |
| 566 | |
Jeremy Fitzhardinge | 1775826 | 2008-04-02 10:54:13 -0700 | [diff] [blame] | 567 | MODULE_LICENSE("GPL"); |