1 /* 2 * VMware Balloon driver. 3 * 4 * Copyright (C) 2000-2010, VMware, Inc. All Rights Reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the 8 * Free Software Foundation; version 2 of the License and no later version. 9 * 10 * This program is distributed in the hope that it will be useful, but 11 * WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 13 * NON INFRINGEMENT. See the GNU General Public License for more 14 * details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Maintained by: Dmitry Torokhov <dtor@vmware.com> 21 */ 22 23 /* 24 * This is VMware physical memory management driver for Linux. The driver 25 * acts like a "balloon" that can be inflated to reclaim physical pages by 26 * reserving them in the guest and invalidating them in the monitor, 27 * freeing up the underlying machine pages so they can be allocated to 28 * other guests. The balloon can also be deflated to allow the guest to 29 * use more physical memory. Higher level policies can control the sizes 30 * of balloons in VMs in order to manage physical memory resources. 31 */ 32 33 //#define DEBUG 34 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 35 36 #include <linux/types.h> 37 #include <linux/kernel.h> 38 #include <linux/mm.h> 39 #include <linux/sched.h> 40 #include <linux/module.h> 41 #include <linux/workqueue.h> 42 #include <linux/debugfs.h> 43 #include <linux/seq_file.h> 44 #include <asm/hypervisor.h> 45 46 MODULE_AUTHOR("VMware, Inc."); 47 MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver"); 48 MODULE_VERSION("1.2.1.3-k"); 49 MODULE_ALIAS("dmi:*:svnVMware*:*"); 50 MODULE_ALIAS("vmware_vmmemctl"); 51 MODULE_LICENSE("GPL"); 52 53 /* 54 * Various constants controlling rate of inflaint/deflating balloon, 55 * measured in pages. 56 */ 57 58 /* 59 * Rate of allocating memory when there is no memory pressure 60 * (driver performs non-sleeping allocations). 61 */ 62 #define VMW_BALLOON_NOSLEEP_ALLOC_MAX 16384U 63 64 /* 65 * Rates of memory allocaton when guest experiences memory pressure 66 * (driver performs sleeping allocations). 67 */ 68 #define VMW_BALLOON_RATE_ALLOC_MIN 512U 69 #define VMW_BALLOON_RATE_ALLOC_MAX 2048U 70 #define VMW_BALLOON_RATE_ALLOC_INC 16U 71 72 /* 73 * Rates for releasing pages while deflating balloon. 74 */ 75 #define VMW_BALLOON_RATE_FREE_MIN 512U 76 #define VMW_BALLOON_RATE_FREE_MAX 16384U 77 #define VMW_BALLOON_RATE_FREE_INC 16U 78 79 /* 80 * When guest is under memory pressure, use a reduced page allocation 81 * rate for next several cycles. 82 */ 83 #define VMW_BALLOON_SLOW_CYCLES 4 84 85 /* 86 * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't 87 * allow wait (__GFP_WAIT) for NOSLEEP page allocations. Use 88 * __GFP_NOWARN, to suppress page allocation failure warnings. 89 */ 90 #define VMW_PAGE_ALLOC_NOSLEEP (__GFP_HIGHMEM|__GFP_NOWARN) 91 92 /* 93 * Use GFP_HIGHUSER when executing in a separate kernel thread 94 * context and allocation can sleep. This is less stressful to 95 * the guest memory system, since it allows the thread to block 96 * while memory is reclaimed, and won't take pages from emergency 97 * low-memory pools. 98 */ 99 #define VMW_PAGE_ALLOC_CANSLEEP (GFP_HIGHUSER) 100 101 /* Maximum number of page allocations without yielding processor */ 102 #define VMW_BALLOON_YIELD_THRESHOLD 1024 103 104 /* Maximum number of refused pages we accumulate during inflation cycle */ 105 #define VMW_BALLOON_MAX_REFUSED 16 106 107 /* 108 * Hypervisor communication port definitions. 109 */ 110 #define VMW_BALLOON_HV_PORT 0x5670 111 #define VMW_BALLOON_HV_MAGIC 0x456c6d6f 112 #define VMW_BALLOON_PROTOCOL_VERSION 2 113 #define VMW_BALLOON_GUEST_ID 1 /* Linux */ 114 115 #define VMW_BALLOON_CMD_START 0 116 #define VMW_BALLOON_CMD_GET_TARGET 1 117 #define VMW_BALLOON_CMD_LOCK 2 118 #define VMW_BALLOON_CMD_UNLOCK 3 119 #define VMW_BALLOON_CMD_GUEST_ID 4 120 121 /* error codes */ 122 #define VMW_BALLOON_SUCCESS 0 123 #define VMW_BALLOON_FAILURE -1 124 #define VMW_BALLOON_ERROR_CMD_INVALID 1 125 #define VMW_BALLOON_ERROR_PPN_INVALID 2 126 #define VMW_BALLOON_ERROR_PPN_LOCKED 3 127 #define VMW_BALLOON_ERROR_PPN_UNLOCKED 4 128 #define VMW_BALLOON_ERROR_PPN_PINNED 5 129 #define VMW_BALLOON_ERROR_PPN_NOTNEEDED 6 130 #define VMW_BALLOON_ERROR_RESET 7 131 #define VMW_BALLOON_ERROR_BUSY 8 132 133 #define VMWARE_BALLOON_CMD(cmd, data, result) \ 134 ({ \ 135 unsigned long __stat, __dummy1, __dummy2; \ 136 __asm__ __volatile__ ("inl %%dx" : \ 137 "=a"(__stat), \ 138 "=c"(__dummy1), \ 139 "=d"(__dummy2), \ 140 "=b"(result) : \ 141 "0"(VMW_BALLOON_HV_MAGIC), \ 142 "1"(VMW_BALLOON_CMD_##cmd), \ 143 "2"(VMW_BALLOON_HV_PORT), \ 144 "3"(data) : \ 145 "memory"); \ 146 result &= -1UL; \ 147 __stat & -1UL; \ 148 }) 149 150 #ifdef CONFIG_DEBUG_FS 151 struct vmballoon_stats { 152 unsigned int timer; 153 154 /* allocation statistics */ 155 unsigned int alloc; 156 unsigned int alloc_fail; 157 unsigned int sleep_alloc; 158 unsigned int sleep_alloc_fail; 159 unsigned int refused_alloc; 160 unsigned int refused_free; 161 unsigned int free; 162 163 /* monitor operations */ 164 unsigned int lock; 165 unsigned int lock_fail; 166 unsigned int unlock; 167 unsigned int unlock_fail; 168 unsigned int target; 169 unsigned int target_fail; 170 unsigned int start; 171 unsigned int start_fail; 172 unsigned int guest_type; 173 unsigned int guest_type_fail; 174 }; 175 176 #define STATS_INC(stat) (stat)++ 177 #else 178 #define STATS_INC(stat) 179 #endif 180 181 struct vmballoon { 182 183 /* list of reserved physical pages */ 184 struct list_head pages; 185 186 /* transient list of non-balloonable pages */ 187 struct list_head refused_pages; 188 unsigned int n_refused_pages; 189 190 /* balloon size in pages */ 191 unsigned int size; 192 unsigned int target; 193 194 /* reset flag */ 195 bool reset_required; 196 197 /* adjustment rates (pages per second) */ 198 unsigned int rate_alloc; 199 unsigned int rate_free; 200 201 /* slowdown page allocations for next few cycles */ 202 unsigned int slow_allocation_cycles; 203 204 #ifdef CONFIG_DEBUG_FS 205 /* statistics */ 206 struct vmballoon_stats stats; 207 208 /* debugfs file exporting statistics */ 209 struct dentry *dbg_entry; 210 #endif 211 212 struct sysinfo sysinfo; 213 214 struct delayed_work dwork; 215 }; 216 217 static struct vmballoon balloon; 218 219 /* 220 * Send "start" command to the host, communicating supported version 221 * of the protocol. 222 */ 223 static bool vmballoon_send_start(struct vmballoon *b) 224 { 225 unsigned long status, dummy; 226 227 STATS_INC(b->stats.start); 228 229 status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_PROTOCOL_VERSION, dummy); 230 if (status == VMW_BALLOON_SUCCESS) 231 return true; 232 233 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 234 STATS_INC(b->stats.start_fail); 235 return false; 236 } 237 238 static bool vmballoon_check_status(struct vmballoon *b, unsigned long status) 239 { 240 switch (status) { 241 case VMW_BALLOON_SUCCESS: 242 return true; 243 244 case VMW_BALLOON_ERROR_RESET: 245 b->reset_required = true; 246 /* fall through */ 247 248 default: 249 return false; 250 } 251 } 252 253 /* 254 * Communicate guest type to the host so that it can adjust ballooning 255 * algorithm to the one most appropriate for the guest. This command 256 * is normally issued after sending "start" command and is part of 257 * standard reset sequence. 258 */ 259 static bool vmballoon_send_guest_id(struct vmballoon *b) 260 { 261 unsigned long status, dummy; 262 263 status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy); 264 265 STATS_INC(b->stats.guest_type); 266 267 if (vmballoon_check_status(b, status)) 268 return true; 269 270 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 271 STATS_INC(b->stats.guest_type_fail); 272 return false; 273 } 274 275 /* 276 * Retrieve desired balloon size from the host. 277 */ 278 static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target) 279 { 280 unsigned long status; 281 unsigned long target; 282 unsigned long limit; 283 u32 limit32; 284 285 /* 286 * si_meminfo() is cheap. Moreover, we want to provide dynamic 287 * max balloon size later. So let us call si_meminfo() every 288 * iteration. 289 */ 290 si_meminfo(&b->sysinfo); 291 limit = b->sysinfo.totalram; 292 293 /* Ensure limit fits in 32-bits */ 294 limit32 = (u32)limit; 295 if (limit != limit32) 296 return false; 297 298 /* update stats */ 299 STATS_INC(b->stats.target); 300 301 status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target); 302 if (vmballoon_check_status(b, status)) { 303 *new_target = target; 304 return true; 305 } 306 307 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 308 STATS_INC(b->stats.target_fail); 309 return false; 310 } 311 312 /* 313 * Notify the host about allocated page so that host can use it without 314 * fear that guest will need it. Host may reject some pages, we need to 315 * check the return value and maybe submit a different page. 316 */ 317 static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn, 318 unsigned int *hv_status) 319 { 320 unsigned long status, dummy; 321 u32 pfn32; 322 323 pfn32 = (u32)pfn; 324 if (pfn32 != pfn) 325 return -1; 326 327 STATS_INC(b->stats.lock); 328 329 *hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy); 330 if (vmballoon_check_status(b, status)) 331 return 0; 332 333 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 334 STATS_INC(b->stats.lock_fail); 335 return 1; 336 } 337 338 /* 339 * Notify the host that guest intends to release given page back into 340 * the pool of available (to the guest) pages. 341 */ 342 static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn) 343 { 344 unsigned long status, dummy; 345 u32 pfn32; 346 347 pfn32 = (u32)pfn; 348 if (pfn32 != pfn) 349 return false; 350 351 STATS_INC(b->stats.unlock); 352 353 status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy); 354 if (vmballoon_check_status(b, status)) 355 return true; 356 357 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 358 STATS_INC(b->stats.unlock_fail); 359 return false; 360 } 361 362 /* 363 * Quickly release all pages allocated for the balloon. This function is 364 * called when host decides to "reset" balloon for one reason or another. 365 * Unlike normal "deflate" we do not (shall not) notify host of the pages 366 * being released. 367 */ 368 static void vmballoon_pop(struct vmballoon *b) 369 { 370 struct page *page, *next; 371 unsigned int count = 0; 372 373 list_for_each_entry_safe(page, next, &b->pages, lru) { 374 list_del(&page->lru); 375 __free_page(page); 376 STATS_INC(b->stats.free); 377 b->size--; 378 379 if (++count >= b->rate_free) { 380 count = 0; 381 cond_resched(); 382 } 383 } 384 } 385 386 /* 387 * Perform standard reset sequence by popping the balloon (in case it 388 * is not empty) and then restarting protocol. This operation normally 389 * happens when host responds with VMW_BALLOON_ERROR_RESET to a command. 390 */ 391 static void vmballoon_reset(struct vmballoon *b) 392 { 393 /* free all pages, skipping monitor unlock */ 394 vmballoon_pop(b); 395 396 if (vmballoon_send_start(b)) { 397 b->reset_required = false; 398 if (!vmballoon_send_guest_id(b)) 399 pr_err("failed to send guest ID to the host\n"); 400 } 401 } 402 403 /* 404 * Allocate (or reserve) a page for the balloon and notify the host. If host 405 * refuses the page put it on "refuse" list and allocate another one until host 406 * is satisfied. "Refused" pages are released at the end of inflation cycle 407 * (when we allocate b->rate_alloc pages). 408 */ 409 static int vmballoon_reserve_page(struct vmballoon *b, bool can_sleep) 410 { 411 struct page *page; 412 gfp_t flags; 413 unsigned int hv_status; 414 int locked; 415 flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP; 416 417 do { 418 if (!can_sleep) 419 STATS_INC(b->stats.alloc); 420 else 421 STATS_INC(b->stats.sleep_alloc); 422 423 page = alloc_page(flags); 424 if (!page) { 425 if (!can_sleep) 426 STATS_INC(b->stats.alloc_fail); 427 else 428 STATS_INC(b->stats.sleep_alloc_fail); 429 return -ENOMEM; 430 } 431 432 /* inform monitor */ 433 locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status); 434 if (locked > 0) { 435 STATS_INC(b->stats.refused_alloc); 436 437 if (hv_status == VMW_BALLOON_ERROR_RESET || 438 hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED) { 439 __free_page(page); 440 return -EIO; 441 } 442 443 /* 444 * Place page on the list of non-balloonable pages 445 * and retry allocation, unless we already accumulated 446 * too many of them, in which case take a breather. 447 */ 448 list_add(&page->lru, &b->refused_pages); 449 if (++b->n_refused_pages >= VMW_BALLOON_MAX_REFUSED) 450 return -EIO; 451 } 452 } while (locked != 0); 453 454 /* track allocated page */ 455 list_add(&page->lru, &b->pages); 456 457 /* update balloon size */ 458 b->size++; 459 460 return 0; 461 } 462 463 /* 464 * Release the page allocated for the balloon. Note that we first notify 465 * the host so it can make sure the page will be available for the guest 466 * to use, if needed. 467 */ 468 static int vmballoon_release_page(struct vmballoon *b, struct page *page) 469 { 470 if (!vmballoon_send_unlock_page(b, page_to_pfn(page))) 471 return -EIO; 472 473 list_del(&page->lru); 474 475 /* deallocate page */ 476 __free_page(page); 477 STATS_INC(b->stats.free); 478 479 /* update balloon size */ 480 b->size--; 481 482 return 0; 483 } 484 485 /* 486 * Release pages that were allocated while attempting to inflate the 487 * balloon but were refused by the host for one reason or another. 488 */ 489 static void vmballoon_release_refused_pages(struct vmballoon *b) 490 { 491 struct page *page, *next; 492 493 list_for_each_entry_safe(page, next, &b->refused_pages, lru) { 494 list_del(&page->lru); 495 __free_page(page); 496 STATS_INC(b->stats.refused_free); 497 } 498 499 b->n_refused_pages = 0; 500 } 501 502 /* 503 * Inflate the balloon towards its target size. Note that we try to limit 504 * the rate of allocation to make sure we are not choking the rest of the 505 * system. 506 */ 507 static void vmballoon_inflate(struct vmballoon *b) 508 { 509 unsigned int goal; 510 unsigned int rate; 511 unsigned int i; 512 unsigned int allocations = 0; 513 int error = 0; 514 bool alloc_can_sleep = false; 515 516 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 517 518 /* 519 * First try NOSLEEP page allocations to inflate balloon. 520 * 521 * If we do not throttle nosleep allocations, we can drain all 522 * free pages in the guest quickly (if the balloon target is high). 523 * As a side-effect, draining free pages helps to inform (force) 524 * the guest to start swapping if balloon target is not met yet, 525 * which is a desired behavior. However, balloon driver can consume 526 * all available CPU cycles if too many pages are allocated in a 527 * second. Therefore, we throttle nosleep allocations even when 528 * the guest is not under memory pressure. OTOH, if we have already 529 * predicted that the guest is under memory pressure, then we 530 * slowdown page allocations considerably. 531 */ 532 533 goal = b->target - b->size; 534 /* 535 * Start with no sleep allocation rate which may be higher 536 * than sleeping allocation rate. 537 */ 538 rate = b->slow_allocation_cycles ? 539 b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX; 540 541 pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n", 542 __func__, goal, rate, b->rate_alloc); 543 544 for (i = 0; i < goal; i++) { 545 546 error = vmballoon_reserve_page(b, alloc_can_sleep); 547 if (error) { 548 if (error != -ENOMEM) { 549 /* 550 * Not a page allocation failure, stop this 551 * cycle. Maybe we'll get new target from 552 * the host soon. 553 */ 554 break; 555 } 556 557 if (alloc_can_sleep) { 558 /* 559 * CANSLEEP page allocation failed, so guest 560 * is under severe memory pressure. Quickly 561 * decrease allocation rate. 562 */ 563 b->rate_alloc = max(b->rate_alloc / 2, 564 VMW_BALLOON_RATE_ALLOC_MIN); 565 break; 566 } 567 568 /* 569 * NOSLEEP page allocation failed, so the guest is 570 * under memory pressure. Let us slow down page 571 * allocations for next few cycles so that the guest 572 * gets out of memory pressure. Also, if we already 573 * allocated b->rate_alloc pages, let's pause, 574 * otherwise switch to sleeping allocations. 575 */ 576 b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES; 577 578 if (i >= b->rate_alloc) 579 break; 580 581 alloc_can_sleep = true; 582 /* Lower rate for sleeping allocations. */ 583 rate = b->rate_alloc; 584 } 585 586 if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) { 587 cond_resched(); 588 allocations = 0; 589 } 590 591 if (i >= rate) { 592 /* We allocated enough pages, let's take a break. */ 593 break; 594 } 595 } 596 597 /* 598 * We reached our goal without failures so try increasing 599 * allocation rate. 600 */ 601 if (error == 0 && i >= b->rate_alloc) { 602 unsigned int mult = i / b->rate_alloc; 603 604 b->rate_alloc = 605 min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC, 606 VMW_BALLOON_RATE_ALLOC_MAX); 607 } 608 609 vmballoon_release_refused_pages(b); 610 } 611 612 /* 613 * Decrease the size of the balloon allowing guest to use more memory. 614 */ 615 static void vmballoon_deflate(struct vmballoon *b) 616 { 617 struct page *page, *next; 618 unsigned int i = 0; 619 unsigned int goal; 620 int error; 621 622 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 623 624 /* limit deallocation rate */ 625 goal = min(b->size - b->target, b->rate_free); 626 627 pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free); 628 629 /* free pages to reach target */ 630 list_for_each_entry_safe(page, next, &b->pages, lru) { 631 error = vmballoon_release_page(b, page); 632 if (error) { 633 /* quickly decrease rate in case of error */ 634 b->rate_free = max(b->rate_free / 2, 635 VMW_BALLOON_RATE_FREE_MIN); 636 return; 637 } 638 639 if (++i >= goal) 640 break; 641 } 642 643 /* slowly increase rate if there were no errors */ 644 b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC, 645 VMW_BALLOON_RATE_FREE_MAX); 646 } 647 648 /* 649 * Balloon work function: reset protocol, if needed, get the new size and 650 * adjust balloon as needed. Repeat in 1 sec. 651 */ 652 static void vmballoon_work(struct work_struct *work) 653 { 654 struct delayed_work *dwork = to_delayed_work(work); 655 struct vmballoon *b = container_of(dwork, struct vmballoon, dwork); 656 unsigned int target; 657 658 STATS_INC(b->stats.timer); 659 660 if (b->reset_required) 661 vmballoon_reset(b); 662 663 if (b->slow_allocation_cycles > 0) 664 b->slow_allocation_cycles--; 665 666 if (vmballoon_send_get_target(b, &target)) { 667 /* update target, adjust size */ 668 b->target = target; 669 670 if (b->size < target) 671 vmballoon_inflate(b); 672 else if (b->size > target) 673 vmballoon_deflate(b); 674 } 675 676 /* 677 * We are using a freezable workqueue so that balloon operations are 678 * stopped while the system transitions to/from sleep/hibernation. 679 */ 680 queue_delayed_work(system_freezable_wq, 681 dwork, round_jiffies_relative(HZ)); 682 } 683 684 /* 685 * DEBUGFS Interface 686 */ 687 #ifdef CONFIG_DEBUG_FS 688 689 static int vmballoon_debug_show(struct seq_file *f, void *offset) 690 { 691 struct vmballoon *b = f->private; 692 struct vmballoon_stats *stats = &b->stats; 693 694 /* format size info */ 695 seq_printf(f, 696 "target: %8d pages\n" 697 "current: %8d pages\n", 698 b->target, b->size); 699 700 /* format rate info */ 701 seq_printf(f, 702 "rateNoSleepAlloc: %8d pages/sec\n" 703 "rateSleepAlloc: %8d pages/sec\n" 704 "rateFree: %8d pages/sec\n", 705 VMW_BALLOON_NOSLEEP_ALLOC_MAX, 706 b->rate_alloc, b->rate_free); 707 708 seq_printf(f, 709 "\n" 710 "timer: %8u\n" 711 "start: %8u (%4u failed)\n" 712 "guestType: %8u (%4u failed)\n" 713 "lock: %8u (%4u failed)\n" 714 "unlock: %8u (%4u failed)\n" 715 "target: %8u (%4u failed)\n" 716 "primNoSleepAlloc: %8u (%4u failed)\n" 717 "primCanSleepAlloc: %8u (%4u failed)\n" 718 "primFree: %8u\n" 719 "errAlloc: %8u\n" 720 "errFree: %8u\n", 721 stats->timer, 722 stats->start, stats->start_fail, 723 stats->guest_type, stats->guest_type_fail, 724 stats->lock, stats->lock_fail, 725 stats->unlock, stats->unlock_fail, 726 stats->target, stats->target_fail, 727 stats->alloc, stats->alloc_fail, 728 stats->sleep_alloc, stats->sleep_alloc_fail, 729 stats->free, 730 stats->refused_alloc, stats->refused_free); 731 732 return 0; 733 } 734 735 static int vmballoon_debug_open(struct inode *inode, struct file *file) 736 { 737 return single_open(file, vmballoon_debug_show, inode->i_private); 738 } 739 740 static const struct file_operations vmballoon_debug_fops = { 741 .owner = THIS_MODULE, 742 .open = vmballoon_debug_open, 743 .read = seq_read, 744 .llseek = seq_lseek, 745 .release = single_release, 746 }; 747 748 static int __init vmballoon_debugfs_init(struct vmballoon *b) 749 { 750 int error; 751 752 b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b, 753 &vmballoon_debug_fops); 754 if (IS_ERR(b->dbg_entry)) { 755 error = PTR_ERR(b->dbg_entry); 756 pr_err("failed to create debugfs entry, error: %d\n", error); 757 return error; 758 } 759 760 return 0; 761 } 762 763 static void __exit vmballoon_debugfs_exit(struct vmballoon *b) 764 { 765 debugfs_remove(b->dbg_entry); 766 } 767 768 #else 769 770 static inline int vmballoon_debugfs_init(struct vmballoon *b) 771 { 772 return 0; 773 } 774 775 static inline void vmballoon_debugfs_exit(struct vmballoon *b) 776 { 777 } 778 779 #endif /* CONFIG_DEBUG_FS */ 780 781 static int __init vmballoon_init(void) 782 { 783 int error; 784 785 /* 786 * Check if we are running on VMware's hypervisor and bail out 787 * if we are not. 788 */ 789 if (x86_hyper != &x86_hyper_vmware) 790 return -ENODEV; 791 792 INIT_LIST_HEAD(&balloon.pages); 793 INIT_LIST_HEAD(&balloon.refused_pages); 794 795 /* initialize rates */ 796 balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX; 797 balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX; 798 799 INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work); 800 801 /* 802 * Start balloon. 803 */ 804 if (!vmballoon_send_start(&balloon)) { 805 pr_err("failed to send start command to the host\n"); 806 return -EIO; 807 } 808 809 if (!vmballoon_send_guest_id(&balloon)) { 810 pr_err("failed to send guest ID to the host\n"); 811 return -EIO; 812 } 813 814 error = vmballoon_debugfs_init(&balloon); 815 if (error) 816 return error; 817 818 queue_delayed_work(system_freezable_wq, &balloon.dwork, 0); 819 820 return 0; 821 } 822 module_init(vmballoon_init); 823 824 static void __exit vmballoon_exit(void) 825 { 826 cancel_delayed_work_sync(&balloon.dwork); 827 828 vmballoon_debugfs_exit(&balloon); 829 830 /* 831 * Deallocate all reserved memory, and reset connection with monitor. 832 * Reset connection before deallocating memory to avoid potential for 833 * additional spurious resets from guest touching deallocated pages. 834 */ 835 vmballoon_send_start(&balloon); 836 vmballoon_pop(&balloon); 837 } 838 module_exit(vmballoon_exit); 839