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: Xavier Deguillard <xdeguillard@vmware.com> 21 * Philip Moltmann <moltmann@vmware.com> 22 */ 23 24 /* 25 * This is VMware physical memory management driver for Linux. The driver 26 * acts like a "balloon" that can be inflated to reclaim physical pages by 27 * reserving them in the guest and invalidating them in the monitor, 28 * freeing up the underlying machine pages so they can be allocated to 29 * other guests. The balloon can also be deflated to allow the guest to 30 * use more physical memory. Higher level policies can control the sizes 31 * of balloons in VMs in order to manage physical memory resources. 32 */ 33 34 //#define DEBUG 35 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 36 37 #include <linux/types.h> 38 #include <linux/kernel.h> 39 #include <linux/mm.h> 40 #include <linux/sched.h> 41 #include <linux/module.h> 42 #include <linux/workqueue.h> 43 #include <linux/debugfs.h> 44 #include <linux/seq_file.h> 45 #include <asm/hypervisor.h> 46 47 MODULE_AUTHOR("VMware, Inc."); 48 MODULE_DESCRIPTION("VMware Memory Control (Balloon) Driver"); 49 MODULE_VERSION("1.2.1.3-k"); 50 MODULE_ALIAS("dmi:*:svnVMware*:*"); 51 MODULE_ALIAS("vmware_vmmemctl"); 52 MODULE_LICENSE("GPL"); 53 54 /* 55 * Various constants controlling rate of inflaint/deflating balloon, 56 * measured in pages. 57 */ 58 59 /* 60 * Rate of allocating memory when there is no memory pressure 61 * (driver performs non-sleeping allocations). 62 */ 63 #define VMW_BALLOON_NOSLEEP_ALLOC_MAX 16384U 64 65 /* 66 * Rates of memory allocaton when guest experiences memory pressure 67 * (driver performs sleeping allocations). 68 */ 69 #define VMW_BALLOON_RATE_ALLOC_MIN 512U 70 #define VMW_BALLOON_RATE_ALLOC_MAX 2048U 71 #define VMW_BALLOON_RATE_ALLOC_INC 16U 72 73 /* 74 * Rates for releasing pages while deflating balloon. 75 */ 76 #define VMW_BALLOON_RATE_FREE_MIN 512U 77 #define VMW_BALLOON_RATE_FREE_MAX 16384U 78 #define VMW_BALLOON_RATE_FREE_INC 16U 79 80 /* 81 * When guest is under memory pressure, use a reduced page allocation 82 * rate for next several cycles. 83 */ 84 #define VMW_BALLOON_SLOW_CYCLES 4 85 86 /* 87 * Use __GFP_HIGHMEM to allow pages from HIGHMEM zone. We don't 88 * allow wait (__GFP_WAIT) for NOSLEEP page allocations. Use 89 * __GFP_NOWARN, to suppress page allocation failure warnings. 90 */ 91 #define VMW_PAGE_ALLOC_NOSLEEP (__GFP_HIGHMEM|__GFP_NOWARN) 92 93 /* 94 * Use GFP_HIGHUSER when executing in a separate kernel thread 95 * context and allocation can sleep. This is less stressful to 96 * the guest memory system, since it allows the thread to block 97 * while memory is reclaimed, and won't take pages from emergency 98 * low-memory pools. 99 */ 100 #define VMW_PAGE_ALLOC_CANSLEEP (GFP_HIGHUSER) 101 102 /* Maximum number of page allocations without yielding processor */ 103 #define VMW_BALLOON_YIELD_THRESHOLD 1024 104 105 /* Maximum number of refused pages we accumulate during inflation cycle */ 106 #define VMW_BALLOON_MAX_REFUSED 16 107 108 /* 109 * Hypervisor communication port definitions. 110 */ 111 #define VMW_BALLOON_HV_PORT 0x5670 112 #define VMW_BALLOON_HV_MAGIC 0x456c6d6f 113 #define VMW_BALLOON_PROTOCOL_VERSION 2 114 #define VMW_BALLOON_GUEST_ID 1 /* Linux */ 115 116 #define VMW_BALLOON_CMD_START 0 117 #define VMW_BALLOON_CMD_GET_TARGET 1 118 #define VMW_BALLOON_CMD_LOCK 2 119 #define VMW_BALLOON_CMD_UNLOCK 3 120 #define VMW_BALLOON_CMD_GUEST_ID 4 121 122 /* error codes */ 123 #define VMW_BALLOON_SUCCESS 0 124 #define VMW_BALLOON_FAILURE -1 125 #define VMW_BALLOON_ERROR_CMD_INVALID 1 126 #define VMW_BALLOON_ERROR_PPN_INVALID 2 127 #define VMW_BALLOON_ERROR_PPN_LOCKED 3 128 #define VMW_BALLOON_ERROR_PPN_UNLOCKED 4 129 #define VMW_BALLOON_ERROR_PPN_PINNED 5 130 #define VMW_BALLOON_ERROR_PPN_NOTNEEDED 6 131 #define VMW_BALLOON_ERROR_RESET 7 132 #define VMW_BALLOON_ERROR_BUSY 8 133 134 #define VMWARE_BALLOON_CMD(cmd, data, result) \ 135 ({ \ 136 unsigned long __stat, __dummy1, __dummy2; \ 137 __asm__ __volatile__ ("inl %%dx" : \ 138 "=a"(__stat), \ 139 "=c"(__dummy1), \ 140 "=d"(__dummy2), \ 141 "=b"(result) : \ 142 "0"(VMW_BALLOON_HV_MAGIC), \ 143 "1"(VMW_BALLOON_CMD_##cmd), \ 144 "2"(VMW_BALLOON_HV_PORT), \ 145 "3"(data) : \ 146 "memory"); \ 147 result &= -1UL; \ 148 __stat & -1UL; \ 149 }) 150 151 #ifdef CONFIG_DEBUG_FS 152 struct vmballoon_stats { 153 unsigned int timer; 154 155 /* allocation statistics */ 156 unsigned int alloc; 157 unsigned int alloc_fail; 158 unsigned int sleep_alloc; 159 unsigned int sleep_alloc_fail; 160 unsigned int refused_alloc; 161 unsigned int refused_free; 162 unsigned int free; 163 164 /* monitor operations */ 165 unsigned int lock; 166 unsigned int lock_fail; 167 unsigned int unlock; 168 unsigned int unlock_fail; 169 unsigned int target; 170 unsigned int target_fail; 171 unsigned int start; 172 unsigned int start_fail; 173 unsigned int guest_type; 174 unsigned int guest_type_fail; 175 }; 176 177 #define STATS_INC(stat) (stat)++ 178 #else 179 #define STATS_INC(stat) 180 #endif 181 182 struct vmballoon { 183 184 /* list of reserved physical pages */ 185 struct list_head pages; 186 187 /* transient list of non-balloonable pages */ 188 struct list_head refused_pages; 189 unsigned int n_refused_pages; 190 191 /* balloon size in pages */ 192 unsigned int size; 193 unsigned int target; 194 195 /* reset flag */ 196 bool reset_required; 197 198 /* adjustment rates (pages per second) */ 199 unsigned int rate_alloc; 200 unsigned int rate_free; 201 202 /* slowdown page allocations for next few cycles */ 203 unsigned int slow_allocation_cycles; 204 205 #ifdef CONFIG_DEBUG_FS 206 /* statistics */ 207 struct vmballoon_stats stats; 208 209 /* debugfs file exporting statistics */ 210 struct dentry *dbg_entry; 211 #endif 212 213 struct sysinfo sysinfo; 214 215 struct delayed_work dwork; 216 }; 217 218 static struct vmballoon balloon; 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 int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn, 319 unsigned int *hv_status) 320 { 321 unsigned long status, dummy; 322 u32 pfn32; 323 324 pfn32 = (u32)pfn; 325 if (pfn32 != pfn) 326 return -1; 327 328 STATS_INC(b->stats.lock); 329 330 *hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy); 331 if (vmballoon_check_status(b, status)) 332 return 0; 333 334 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 335 STATS_INC(b->stats.lock_fail); 336 return 1; 337 } 338 339 /* 340 * Notify the host that guest intends to release given page back into 341 * the pool of available (to the guest) pages. 342 */ 343 static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn) 344 { 345 unsigned long status, dummy; 346 u32 pfn32; 347 348 pfn32 = (u32)pfn; 349 if (pfn32 != pfn) 350 return false; 351 352 STATS_INC(b->stats.unlock); 353 354 status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy); 355 if (vmballoon_check_status(b, status)) 356 return true; 357 358 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 359 STATS_INC(b->stats.unlock_fail); 360 return false; 361 } 362 363 /* 364 * Quickly release all pages allocated for the balloon. This function is 365 * called when host decides to "reset" balloon for one reason or another. 366 * Unlike normal "deflate" we do not (shall not) notify host of the pages 367 * being released. 368 */ 369 static void vmballoon_pop(struct vmballoon *b) 370 { 371 struct page *page, *next; 372 unsigned int count = 0; 373 374 list_for_each_entry_safe(page, next, &b->pages, lru) { 375 list_del(&page->lru); 376 __free_page(page); 377 STATS_INC(b->stats.free); 378 b->size--; 379 380 if (++count >= b->rate_free) { 381 count = 0; 382 cond_resched(); 383 } 384 } 385 } 386 387 /* 388 * Perform standard reset sequence by popping the balloon (in case it 389 * is not empty) and then restarting protocol. This operation normally 390 * happens when host responds with VMW_BALLOON_ERROR_RESET to a command. 391 */ 392 static void vmballoon_reset(struct vmballoon *b) 393 { 394 /* free all pages, skipping monitor unlock */ 395 vmballoon_pop(b); 396 397 if (vmballoon_send_start(b)) { 398 b->reset_required = false; 399 if (!vmballoon_send_guest_id(b)) 400 pr_err("failed to send guest ID to the host\n"); 401 } 402 } 403 404 /* 405 * Allocate (or reserve) a page for the balloon and notify the host. If host 406 * refuses the page put it on "refuse" list and allocate another one until host 407 * is satisfied. "Refused" pages are released at the end of inflation cycle 408 * (when we allocate b->rate_alloc pages). 409 */ 410 static int vmballoon_reserve_page(struct vmballoon *b, bool can_sleep) 411 { 412 struct page *page; 413 gfp_t flags; 414 unsigned int hv_status; 415 int locked; 416 flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP; 417 418 do { 419 if (!can_sleep) 420 STATS_INC(b->stats.alloc); 421 else 422 STATS_INC(b->stats.sleep_alloc); 423 424 page = alloc_page(flags); 425 if (!page) { 426 if (!can_sleep) 427 STATS_INC(b->stats.alloc_fail); 428 else 429 STATS_INC(b->stats.sleep_alloc_fail); 430 return -ENOMEM; 431 } 432 433 /* inform monitor */ 434 locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status); 435 if (locked > 0) { 436 STATS_INC(b->stats.refused_alloc); 437 438 if (hv_status == VMW_BALLOON_ERROR_RESET || 439 hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED) { 440 __free_page(page); 441 return -EIO; 442 } 443 444 /* 445 * Place page on the list of non-balloonable pages 446 * and retry allocation, unless we already accumulated 447 * too many of them, in which case take a breather. 448 */ 449 list_add(&page->lru, &b->refused_pages); 450 if (++b->n_refused_pages >= VMW_BALLOON_MAX_REFUSED) 451 return -EIO; 452 } 453 } while (locked != 0); 454 455 /* track allocated page */ 456 list_add(&page->lru, &b->pages); 457 458 /* update balloon size */ 459 b->size++; 460 461 return 0; 462 } 463 464 /* 465 * Release the page allocated for the balloon. Note that we first notify 466 * the host so it can make sure the page will be available for the guest 467 * to use, if needed. 468 */ 469 static int vmballoon_release_page(struct vmballoon *b, struct page *page) 470 { 471 if (!vmballoon_send_unlock_page(b, page_to_pfn(page))) 472 return -EIO; 473 474 list_del(&page->lru); 475 476 /* deallocate page */ 477 __free_page(page); 478 STATS_INC(b->stats.free); 479 480 /* update balloon size */ 481 b->size--; 482 483 return 0; 484 } 485 486 /* 487 * Release pages that were allocated while attempting to inflate the 488 * balloon but were refused by the host for one reason or another. 489 */ 490 static void vmballoon_release_refused_pages(struct vmballoon *b) 491 { 492 struct page *page, *next; 493 494 list_for_each_entry_safe(page, next, &b->refused_pages, lru) { 495 list_del(&page->lru); 496 __free_page(page); 497 STATS_INC(b->stats.refused_free); 498 } 499 500 b->n_refused_pages = 0; 501 } 502 503 /* 504 * Inflate the balloon towards its target size. Note that we try to limit 505 * the rate of allocation to make sure we are not choking the rest of the 506 * system. 507 */ 508 static void vmballoon_inflate(struct vmballoon *b) 509 { 510 unsigned int goal; 511 unsigned int rate; 512 unsigned int i; 513 unsigned int allocations = 0; 514 int error = 0; 515 bool alloc_can_sleep = false; 516 517 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 518 519 /* 520 * First try NOSLEEP page allocations to inflate balloon. 521 * 522 * If we do not throttle nosleep allocations, we can drain all 523 * free pages in the guest quickly (if the balloon target is high). 524 * As a side-effect, draining free pages helps to inform (force) 525 * the guest to start swapping if balloon target is not met yet, 526 * which is a desired behavior. However, balloon driver can consume 527 * all available CPU cycles if too many pages are allocated in a 528 * second. Therefore, we throttle nosleep allocations even when 529 * the guest is not under memory pressure. OTOH, if we have already 530 * predicted that the guest is under memory pressure, then we 531 * slowdown page allocations considerably. 532 */ 533 534 goal = b->target - b->size; 535 /* 536 * Start with no sleep allocation rate which may be higher 537 * than sleeping allocation rate. 538 */ 539 rate = b->slow_allocation_cycles ? 540 b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX; 541 542 pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n", 543 __func__, goal, rate, b->rate_alloc); 544 545 for (i = 0; i < goal; i++) { 546 547 error = vmballoon_reserve_page(b, alloc_can_sleep); 548 if (error) { 549 if (error != -ENOMEM) { 550 /* 551 * Not a page allocation failure, stop this 552 * cycle. Maybe we'll get new target from 553 * the host soon. 554 */ 555 break; 556 } 557 558 if (alloc_can_sleep) { 559 /* 560 * CANSLEEP page allocation failed, so guest 561 * is under severe memory pressure. Quickly 562 * decrease allocation rate. 563 */ 564 b->rate_alloc = max(b->rate_alloc / 2, 565 VMW_BALLOON_RATE_ALLOC_MIN); 566 break; 567 } 568 569 /* 570 * NOSLEEP page allocation failed, so the guest is 571 * under memory pressure. Let us slow down page 572 * allocations for next few cycles so that the guest 573 * gets out of memory pressure. Also, if we already 574 * allocated b->rate_alloc pages, let's pause, 575 * otherwise switch to sleeping allocations. 576 */ 577 b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES; 578 579 if (i >= b->rate_alloc) 580 break; 581 582 alloc_can_sleep = true; 583 /* Lower rate for sleeping allocations. */ 584 rate = b->rate_alloc; 585 } 586 587 if (++allocations > VMW_BALLOON_YIELD_THRESHOLD) { 588 cond_resched(); 589 allocations = 0; 590 } 591 592 if (i >= rate) { 593 /* We allocated enough pages, let's take a break. */ 594 break; 595 } 596 } 597 598 /* 599 * We reached our goal without failures so try increasing 600 * allocation rate. 601 */ 602 if (error == 0 && i >= b->rate_alloc) { 603 unsigned int mult = i / b->rate_alloc; 604 605 b->rate_alloc = 606 min(b->rate_alloc + mult * VMW_BALLOON_RATE_ALLOC_INC, 607 VMW_BALLOON_RATE_ALLOC_MAX); 608 } 609 610 vmballoon_release_refused_pages(b); 611 } 612 613 /* 614 * Decrease the size of the balloon allowing guest to use more memory. 615 */ 616 static void vmballoon_deflate(struct vmballoon *b) 617 { 618 struct page *page, *next; 619 unsigned int i = 0; 620 unsigned int goal; 621 int error; 622 623 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 624 625 /* limit deallocation rate */ 626 goal = min(b->size - b->target, b->rate_free); 627 628 pr_debug("%s - goal: %d, rate: %d\n", __func__, goal, b->rate_free); 629 630 /* free pages to reach target */ 631 list_for_each_entry_safe(page, next, &b->pages, lru) { 632 error = vmballoon_release_page(b, page); 633 if (error) { 634 /* quickly decrease rate in case of error */ 635 b->rate_free = max(b->rate_free / 2, 636 VMW_BALLOON_RATE_FREE_MIN); 637 return; 638 } 639 640 if (++i >= goal) 641 break; 642 } 643 644 /* slowly increase rate if there were no errors */ 645 b->rate_free = min(b->rate_free + VMW_BALLOON_RATE_FREE_INC, 646 VMW_BALLOON_RATE_FREE_MAX); 647 } 648 649 /* 650 * Balloon work function: reset protocol, if needed, get the new size and 651 * adjust balloon as needed. Repeat in 1 sec. 652 */ 653 static void vmballoon_work(struct work_struct *work) 654 { 655 struct delayed_work *dwork = to_delayed_work(work); 656 struct vmballoon *b = container_of(dwork, struct vmballoon, dwork); 657 unsigned int target; 658 659 STATS_INC(b->stats.timer); 660 661 if (b->reset_required) 662 vmballoon_reset(b); 663 664 if (b->slow_allocation_cycles > 0) 665 b->slow_allocation_cycles--; 666 667 if (vmballoon_send_get_target(b, &target)) { 668 /* update target, adjust size */ 669 b->target = target; 670 671 if (b->size < target) 672 vmballoon_inflate(b); 673 else if (b->size > target) 674 vmballoon_deflate(b); 675 } 676 677 /* 678 * We are using a freezable workqueue so that balloon operations are 679 * stopped while the system transitions to/from sleep/hibernation. 680 */ 681 queue_delayed_work(system_freezable_wq, 682 dwork, round_jiffies_relative(HZ)); 683 } 684 685 /* 686 * DEBUGFS Interface 687 */ 688 #ifdef CONFIG_DEBUG_FS 689 690 static int vmballoon_debug_show(struct seq_file *f, void *offset) 691 { 692 struct vmballoon *b = f->private; 693 struct vmballoon_stats *stats = &b->stats; 694 695 /* format size info */ 696 seq_printf(f, 697 "target: %8d pages\n" 698 "current: %8d pages\n", 699 b->target, b->size); 700 701 /* format rate info */ 702 seq_printf(f, 703 "rateNoSleepAlloc: %8d pages/sec\n" 704 "rateSleepAlloc: %8d pages/sec\n" 705 "rateFree: %8d pages/sec\n", 706 VMW_BALLOON_NOSLEEP_ALLOC_MAX, 707 b->rate_alloc, b->rate_free); 708 709 seq_printf(f, 710 "\n" 711 "timer: %8u\n" 712 "start: %8u (%4u failed)\n" 713 "guestType: %8u (%4u failed)\n" 714 "lock: %8u (%4u failed)\n" 715 "unlock: %8u (%4u failed)\n" 716 "target: %8u (%4u failed)\n" 717 "primNoSleepAlloc: %8u (%4u failed)\n" 718 "primCanSleepAlloc: %8u (%4u failed)\n" 719 "primFree: %8u\n" 720 "errAlloc: %8u\n" 721 "errFree: %8u\n", 722 stats->timer, 723 stats->start, stats->start_fail, 724 stats->guest_type, stats->guest_type_fail, 725 stats->lock, stats->lock_fail, 726 stats->unlock, stats->unlock_fail, 727 stats->target, stats->target_fail, 728 stats->alloc, stats->alloc_fail, 729 stats->sleep_alloc, stats->sleep_alloc_fail, 730 stats->free, 731 stats->refused_alloc, stats->refused_free); 732 733 return 0; 734 } 735 736 static int vmballoon_debug_open(struct inode *inode, struct file *file) 737 { 738 return single_open(file, vmballoon_debug_show, inode->i_private); 739 } 740 741 static const struct file_operations vmballoon_debug_fops = { 742 .owner = THIS_MODULE, 743 .open = vmballoon_debug_open, 744 .read = seq_read, 745 .llseek = seq_lseek, 746 .release = single_release, 747 }; 748 749 static int __init vmballoon_debugfs_init(struct vmballoon *b) 750 { 751 int error; 752 753 b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b, 754 &vmballoon_debug_fops); 755 if (IS_ERR(b->dbg_entry)) { 756 error = PTR_ERR(b->dbg_entry); 757 pr_err("failed to create debugfs entry, error: %d\n", error); 758 return error; 759 } 760 761 return 0; 762 } 763 764 static void __exit vmballoon_debugfs_exit(struct vmballoon *b) 765 { 766 debugfs_remove(b->dbg_entry); 767 } 768 769 #else 770 771 static inline int vmballoon_debugfs_init(struct vmballoon *b) 772 { 773 return 0; 774 } 775 776 static inline void vmballoon_debugfs_exit(struct vmballoon *b) 777 { 778 } 779 780 #endif /* CONFIG_DEBUG_FS */ 781 782 static int __init vmballoon_init(void) 783 { 784 int error; 785 786 /* 787 * Check if we are running on VMware's hypervisor and bail out 788 * if we are not. 789 */ 790 if (x86_hyper != &x86_hyper_vmware) 791 return -ENODEV; 792 793 INIT_LIST_HEAD(&balloon.pages); 794 INIT_LIST_HEAD(&balloon.refused_pages); 795 796 /* initialize rates */ 797 balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX; 798 balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX; 799 800 INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work); 801 802 /* 803 * Start balloon. 804 */ 805 if (!vmballoon_send_start(&balloon)) { 806 pr_err("failed to send start command to the host\n"); 807 return -EIO; 808 } 809 810 if (!vmballoon_send_guest_id(&balloon)) { 811 pr_err("failed to send guest ID to the host\n"); 812 return -EIO; 813 } 814 815 error = vmballoon_debugfs_init(&balloon); 816 if (error) 817 return error; 818 819 queue_delayed_work(system_freezable_wq, &balloon.dwork, 0); 820 821 return 0; 822 } 823 module_init(vmballoon_init); 824 825 static void __exit vmballoon_exit(void) 826 { 827 cancel_delayed_work_sync(&balloon.dwork); 828 829 vmballoon_debugfs_exit(&balloon); 830 831 /* 832 * Deallocate all reserved memory, and reset connection with monitor. 833 * Reset connection before deallocating memory to avoid potential for 834 * additional spurious resets from guest touching deallocated pages. 835 */ 836 vmballoon_send_start(&balloon); 837 vmballoon_pop(&balloon); 838 } 839 module_exit(vmballoon_exit); 840