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("1.2.1.1-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 statustics */ 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 static struct workqueue_struct *vmballoon_wq; 219 220 /* 221 * Send "start" command to the host, communicating supported version 222 * of the protocol. 223 */ 224 static bool vmballoon_send_start(struct vmballoon *b) 225 { 226 unsigned long status, dummy; 227 228 STATS_INC(b->stats.start); 229 230 status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_PROTOCOL_VERSION, dummy); 231 if (status == VMW_BALLOON_SUCCESS) 232 return true; 233 234 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 235 STATS_INC(b->stats.start_fail); 236 return false; 237 } 238 239 static bool vmballoon_check_status(struct vmballoon *b, unsigned long status) 240 { 241 switch (status) { 242 case VMW_BALLOON_SUCCESS: 243 return true; 244 245 case VMW_BALLOON_ERROR_RESET: 246 b->reset_required = true; 247 /* fall through */ 248 249 default: 250 return false; 251 } 252 } 253 254 /* 255 * Communicate guest type to the host so that it can adjust ballooning 256 * algorithm to the one most appropriate for the guest. This command 257 * is normally issued after sending "start" command and is part of 258 * standard reset sequence. 259 */ 260 static bool vmballoon_send_guest_id(struct vmballoon *b) 261 { 262 unsigned long status, dummy; 263 264 status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy); 265 266 STATS_INC(b->stats.guest_type); 267 268 if (vmballoon_check_status(b, status)) 269 return true; 270 271 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 272 STATS_INC(b->stats.guest_type_fail); 273 return false; 274 } 275 276 /* 277 * Retrieve desired balloon size from the host. 278 */ 279 static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target) 280 { 281 unsigned long status; 282 unsigned long target; 283 unsigned long limit; 284 u32 limit32; 285 286 /* 287 * si_meminfo() is cheap. Moreover, we want to provide dynamic 288 * max balloon size later. So let us call si_meminfo() every 289 * iteration. 290 */ 291 si_meminfo(&b->sysinfo); 292 limit = b->sysinfo.totalram; 293 294 /* Ensure limit fits in 32-bits */ 295 limit32 = (u32)limit; 296 if (limit != limit32) 297 return false; 298 299 /* update stats */ 300 STATS_INC(b->stats.target); 301 302 status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target); 303 if (vmballoon_check_status(b, status)) { 304 *new_target = target; 305 return true; 306 } 307 308 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 309 STATS_INC(b->stats.target_fail); 310 return false; 311 } 312 313 /* 314 * Notify the host about allocated page so that host can use it without 315 * fear that guest will need it. Host may reject some pages, we need to 316 * check the return value and maybe submit a different page. 317 */ 318 static bool vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn) 319 { 320 unsigned long status, dummy; 321 u32 pfn32; 322 323 pfn32 = (u32)pfn; 324 if (pfn32 != pfn) 325 return false; 326 327 STATS_INC(b->stats.lock); 328 329 status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy); 330 if (vmballoon_check_status(b, status)) 331 return true; 332 333 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 334 STATS_INC(b->stats.lock_fail); 335 return false; 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 bool locked = false; 414 415 do { 416 if (!can_sleep) 417 STATS_INC(b->stats.alloc); 418 else 419 STATS_INC(b->stats.sleep_alloc); 420 421 flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP; 422 page = alloc_page(flags); 423 if (!page) { 424 if (!can_sleep) 425 STATS_INC(b->stats.alloc_fail); 426 else 427 STATS_INC(b->stats.sleep_alloc_fail); 428 return -ENOMEM; 429 } 430 431 /* inform monitor */ 432 locked = vmballoon_send_lock_page(b, page_to_pfn(page)); 433 if (!locked) { 434 STATS_INC(b->stats.refused_alloc); 435 436 if (b->reset_required) { 437 __free_page(page); 438 return -EIO; 439 } 440 441 /* 442 * Place page on the list of non-balloonable pages 443 * and retry allocation, unless we already accumulated 444 * too many of them, in which case take a breather. 445 */ 446 list_add(&page->lru, &b->refused_pages); 447 if (++b->n_refused_pages >= VMW_BALLOON_MAX_REFUSED) 448 return -EIO; 449 } 450 } while (!locked); 451 452 /* track allocated page */ 453 list_add(&page->lru, &b->pages); 454 455 /* update balloon size */ 456 b->size++; 457 458 return 0; 459 } 460 461 /* 462 * Release the page allocated for the balloon. Note that we first notify 463 * the host so it can make sure the page will be available for the guest 464 * to use, if needed. 465 */ 466 static int vmballoon_release_page(struct vmballoon *b, struct page *page) 467 { 468 if (!vmballoon_send_unlock_page(b, page_to_pfn(page))) 469 return -EIO; 470 471 list_del(&page->lru); 472 473 /* deallocate page */ 474 __free_page(page); 475 STATS_INC(b->stats.free); 476 477 /* update balloon size */ 478 b->size--; 479 480 return 0; 481 } 482 483 /* 484 * Release pages that were allocated while attempting to inflate the 485 * balloon but were refused by the host for one reason or another. 486 */ 487 static void vmballoon_release_refused_pages(struct vmballoon *b) 488 { 489 struct page *page, *next; 490 491 list_for_each_entry_safe(page, next, &b->refused_pages, lru) { 492 list_del(&page->lru); 493 __free_page(page); 494 STATS_INC(b->stats.refused_free); 495 } 496 497 b->n_refused_pages = 0; 498 } 499 500 /* 501 * Inflate the balloon towards its target size. Note that we try to limit 502 * the rate of allocation to make sure we are not choking the rest of the 503 * system. 504 */ 505 static void vmballoon_inflate(struct vmballoon *b) 506 { 507 unsigned int goal; 508 unsigned int rate; 509 unsigned int i; 510 unsigned int allocations = 0; 511 int error = 0; 512 bool alloc_can_sleep = false; 513 514 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 515 516 /* 517 * First try NOSLEEP page allocations to inflate balloon. 518 * 519 * If we do not throttle nosleep allocations, we can drain all 520 * free pages in the guest quickly (if the balloon target is high). 521 * As a side-effect, draining free pages helps to inform (force) 522 * the guest to start swapping if balloon target is not met yet, 523 * which is a desired behavior. However, balloon driver can consume 524 * all available CPU cycles if too many pages are allocated in a 525 * second. Therefore, we throttle nosleep allocations even when 526 * the guest is not under memory pressure. OTOH, if we have already 527 * predicted that the guest is under memory pressure, then we 528 * slowdown page allocations considerably. 529 */ 530 531 goal = b->target - b->size; 532 /* 533 * Start with no sleep allocation rate which may be higher 534 * than sleeping allocation rate. 535 */ 536 rate = b->slow_allocation_cycles ? 537 b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX; 538 539 pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n", 540 __func__, goal, rate, b->rate_alloc); 541 542 for (i = 0; i < goal; i++) { 543 544 error = vmballoon_reserve_page(b, alloc_can_sleep); 545 if (error) { 546 if (error != -ENOMEM) { 547 /* 548 * Not a page allocation failure, stop this 549 * cycle. Maybe we'll get new target from 550 * the host soon. 551 */ 552 break; 553 } 554 555 if (alloc_can_sleep) { 556 /* 557 * CANSLEEP page allocation failed, so guest 558 * is under severe memory pressure. Quickly 559 * decrease allocation rate. 560 */ 561 b->rate_alloc = max(b->rate_alloc / 2, 562 VMW_BALLOON_RATE_ALLOC_MIN); 563 break; 564 } 565 566 /* 567 * NOSLEEP page allocation failed, so the guest is 568 * under memory pressure. Let us slow down page 569 * allocations for next few cycles so that the guest 570 * gets out of memory pressure. Also, if we already 571 * allocated b->rate_alloc pages, let's pause, 572 * otherwise switch to sleeping allocations. 573 */ 574 b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES; 575 576 if (i >= b->rate_alloc) 577 break; 578 579 alloc_can_sleep = true; 580 /* Lower rate for sleeping allocations. */ 581 rate = b->rate_alloc; 582 } 583 584 if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) { 585 cond_resched(); 586 allocations = 0; 587 } 588 589 if (i >= rate) { 590 /* We allocated enough pages, let's take a break. */ 591 break; 592 } 593 } 594 595 /* 596 * We reached our goal without failures so try increasing 597 * allocation rate. 598 */ 599 if (error == 0 && i >= b->rate_alloc) { 600 unsigned int mult = i / b->rate_alloc; 601 602 b->rate_alloc = 603 min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC, 604 VMW_BALLOON_RATE_ALLOC_MAX); 605 } 606 607 vmballoon_release_refused_pages(b); 608 } 609 610 /* 611 * Decrease the size of the balloon allowing guest to use more memory. 612 */ 613 static void vmballoon_deflate(struct vmballoon *b) 614 { 615 struct page *page, *next; 616 unsigned int i = 0; 617 unsigned int goal; 618 int error; 619 620 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 621 622 /* limit deallocation rate */ 623 goal = min(b->size - b->target, b->rate_free); 624 625 pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free); 626 627 /* free pages to reach target */ 628 list_for_each_entry_safe(page, next, &b->pages, lru) { 629 error = vmballoon_release_page(b, page); 630 if (error) { 631 /* quickly decrease rate in case of error */ 632 b->rate_free = max(b->rate_free / 2, 633 VMW_BALLOON_RATE_FREE_MIN); 634 return; 635 } 636 637 if (++i >= goal) 638 break; 639 } 640 641 /* slowly increase rate if there were no errors */ 642 b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC, 643 VMW_BALLOON_RATE_FREE_MAX); 644 } 645 646 /* 647 * Balloon work function: reset protocol, if needed, get the new size and 648 * adjust balloon as needed. Repeat in 1 sec. 649 */ 650 static void vmballoon_work(struct work_struct *work) 651 { 652 struct delayed_work *dwork = to_delayed_work(work); 653 struct vmballoon *b = container_of(dwork, struct vmballoon, dwork); 654 unsigned int target; 655 656 STATS_INC(b->stats.timer); 657 658 if (b->reset_required) 659 vmballoon_reset(b); 660 661 if (b->slow_allocation_cycles > 0) 662 b->slow_allocation_cycles--; 663 664 if (vmballoon_send_get_target(b, &target)) { 665 /* update target, adjust size */ 666 b->target = target; 667 668 if (b->size < target) 669 vmballoon_inflate(b); 670 else if (b->size > target) 671 vmballoon_deflate(b); 672 } 673 674 queue_delayed_work(vmballoon_wq, dwork, round_jiffies_relative(HZ)); 675 } 676 677 /* 678 * DEBUGFS Interface 679 */ 680 #ifdef CONFIG_DEBUG_FS 681 682 static int vmballoon_debug_show(struct seq_file *f, void *offset) 683 { 684 struct vmballoon *b = f->private; 685 struct vmballoon_stats *stats = &b->stats; 686 687 /* format size info */ 688 seq_printf(f, 689 "target: %8d pages\n" 690 "current: %8d pages\n", 691 b->target, b->size); 692 693 /* format rate info */ 694 seq_printf(f, 695 "rateNoSleepAlloc: %8d pages/sec\n" 696 "rateSleepAlloc: %8d pages/sec\n" 697 "rateFree: %8d pages/sec\n", 698 VMW_BALLOON_NOSLEEP_ALLOC_MAX, 699 b->rate_alloc, b->rate_free); 700 701 seq_printf(f, 702 "\n" 703 "timer: %8u\n" 704 "start: %8u (%4u failed)\n" 705 "guestType: %8u (%4u failed)\n" 706 "lock: %8u (%4u failed)\n" 707 "unlock: %8u (%4u failed)\n" 708 "target: %8u (%4u failed)\n" 709 "primNoSleepAlloc: %8u (%4u failed)\n" 710 "primCanSleepAlloc: %8u (%4u failed)\n" 711 "primFree: %8u\n" 712 "errAlloc: %8u\n" 713 "errFree: %8u\n", 714 stats->timer, 715 stats->start, stats->start_fail, 716 stats->guest_type, stats->guest_type_fail, 717 stats->lock, stats->lock_fail, 718 stats->unlock, stats->unlock_fail, 719 stats->target, stats->target_fail, 720 stats->alloc, stats->alloc_fail, 721 stats->sleep_alloc, stats->sleep_alloc_fail, 722 stats->free, 723 stats->refused_alloc, stats->refused_free); 724 725 return 0; 726 } 727 728 static int vmballoon_debug_open(struct inode *inode, struct file *file) 729 { 730 return single_open(file, vmballoon_debug_show, inode->i_private); 731 } 732 733 static const struct file_operations vmballoon_debug_fops = { 734 .owner = THIS_MODULE, 735 .open = vmballoon_debug_open, 736 .read = seq_read, 737 .llseek = seq_lseek, 738 .release = single_release, 739 }; 740 741 static int __init vmballoon_debugfs_init(struct vmballoon *b) 742 { 743 int error; 744 745 b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b, 746 &vmballoon_debug_fops); 747 if (IS_ERR(b->dbg_entry)) { 748 error = PTR_ERR(b->dbg_entry); 749 pr_err("failed to create debugfs entry, error: %d\n", error); 750 return error; 751 } 752 753 return 0; 754 } 755 756 static void __exit vmballoon_debugfs_exit(struct vmballoon *b) 757 { 758 debugfs_remove(b->dbg_entry); 759 } 760 761 #else 762 763 static inline int vmballoon_debugfs_init(struct vmballoon *b) 764 { 765 return 0; 766 } 767 768 static inline void vmballoon_debugfs_exit(struct vmballoon *b) 769 { 770 } 771 772 #endif /* CONFIG_DEBUG_FS */ 773 774 static int __init vmballoon_init(void) 775 { 776 int error; 777 778 /* 779 * Check if we are running on VMware's hypervisor and bail out 780 * if we are not. 781 */ 782 if (x86_hyper != &x86_hyper_vmware) 783 return -ENODEV; 784 785 vmballoon_wq = create_freezeable_workqueue("vmmemctl"); 786 if (!vmballoon_wq) { 787 pr_err("failed to create workqueue\n"); 788 return -ENOMEM; 789 } 790 791 INIT_LIST_HEAD(&balloon.pages); 792 INIT_LIST_HEAD(&balloon.refused_pages); 793 794 /* initialize rates */ 795 balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX; 796 balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX; 797 798 INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work); 799 800 /* 801 * Start balloon. 802 */ 803 if (!vmballoon_send_start(&balloon)) { 804 pr_err("failed to send start command to the host\n"); 805 error = -EIO; 806 goto fail; 807 } 808 809 if (!vmballoon_send_guest_id(&balloon)) { 810 pr_err("failed to send guest ID to the host\n"); 811 error = -EIO; 812 goto fail; 813 } 814 815 error = vmballoon_debugfs_init(&balloon); 816 if (error) 817 goto fail; 818 819 queue_delayed_work(vmballoon_wq, &balloon.dwork, 0); 820 821 return 0; 822 823 fail: 824 destroy_workqueue(vmballoon_wq); 825 return error; 826 } 827 module_init(vmballoon_init); 828 829 static void __exit vmballoon_exit(void) 830 { 831 cancel_delayed_work_sync(&balloon.dwork); 832 destroy_workqueue(vmballoon_wq); 833 834 vmballoon_debugfs_exit(&balloon); 835 836 /* 837 * Deallocate all reserved memory, and reset connection with monitor. 838 * Reset connection before deallocating memory to avoid potential for 839 * additional spurious resets from guest touching deallocated pages. 840 */ 841 vmballoon_send_start(&balloon); 842 vmballoon_pop(&balloon); 843 } 844 module_exit(vmballoon_exit); 845