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("1.2.1.2-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 unsigned int *hv_status) 320 { 321 unsigned long status, dummy; 322 u32 pfn32; 323 324 pfn32 = (u32)pfn; 325 if (pfn32 != pfn) 326 return false; 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 true; 333 334 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 335 STATS_INC(b->stats.lock_fail); 336 return false; 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 bool locked = false; 416 417 do { 418 if (!can_sleep) 419 STATS_INC(b->stats.alloc); 420 else 421 STATS_INC(b->stats.sleep_alloc); 422 423 flags = can_sleep ? VMW_PAGE_ALLOC_CANSLEEP : VMW_PAGE_ALLOC_NOSLEEP; 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) { 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); 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 queue_delayed_work(vmballoon_wq, dwork, round_jiffies_relative(HZ)); 678 } 679 680 /* 681 * DEBUGFS Interface 682 */ 683 #ifdef CONFIG_DEBUG_FS 684 685 static int vmballoon_debug_show(struct seq_file *f, void *offset) 686 { 687 struct vmballoon *b = f->private; 688 struct vmballoon_stats *stats = &b->stats; 689 690 /* format size info */ 691 seq_printf(f, 692 "target: %8d pages\n" 693 "current: %8d pages\n", 694 b->target, b->size); 695 696 /* format rate info */ 697 seq_printf(f, 698 "rateNoSleepAlloc: %8d pages/sec\n" 699 "rateSleepAlloc: %8d pages/sec\n" 700 "rateFree: %8d pages/sec\n", 701 VMW_BALLOON_NOSLEEP_ALLOC_MAX, 702 b->rate_alloc, b->rate_free); 703 704 seq_printf(f, 705 "\n" 706 "timer: %8u\n" 707 "start: %8u (%4u failed)\n" 708 "guestType: %8u (%4u failed)\n" 709 "lock: %8u (%4u failed)\n" 710 "unlock: %8u (%4u failed)\n" 711 "target: %8u (%4u failed)\n" 712 "primNoSleepAlloc: %8u (%4u failed)\n" 713 "primCanSleepAlloc: %8u (%4u failed)\n" 714 "primFree: %8u\n" 715 "errAlloc: %8u\n" 716 "errFree: %8u\n", 717 stats->timer, 718 stats->start, stats->start_fail, 719 stats->guest_type, stats->guest_type_fail, 720 stats->lock, stats->lock_fail, 721 stats->unlock, stats->unlock_fail, 722 stats->target, stats->target_fail, 723 stats->alloc, stats->alloc_fail, 724 stats->sleep_alloc, stats->sleep_alloc_fail, 725 stats->free, 726 stats->refused_alloc, stats->refused_free); 727 728 return 0; 729 } 730 731 static int vmballoon_debug_open(struct inode *inode, struct file *file) 732 { 733 return single_open(file, vmballoon_debug_show, inode->i_private); 734 } 735 736 static const struct file_operations vmballoon_debug_fops = { 737 .owner = THIS_MODULE, 738 .open = vmballoon_debug_open, 739 .read = seq_read, 740 .llseek = seq_lseek, 741 .release = single_release, 742 }; 743 744 static int __init vmballoon_debugfs_init(struct vmballoon *b) 745 { 746 int error; 747 748 b->dbg_entry = debugfs_create_file("vmmemctl", S_IRUGO, NULL, b, 749 &vmballoon_debug_fops); 750 if (IS_ERR(b->dbg_entry)) { 751 error = PTR_ERR(b->dbg_entry); 752 pr_err("failed to create debugfs entry, error: %d\n", error); 753 return error; 754 } 755 756 return 0; 757 } 758 759 static void __exit vmballoon_debugfs_exit(struct vmballoon *b) 760 { 761 debugfs_remove(b->dbg_entry); 762 } 763 764 #else 765 766 static inline int vmballoon_debugfs_init(struct vmballoon *b) 767 { 768 return 0; 769 } 770 771 static inline void vmballoon_debugfs_exit(struct vmballoon *b) 772 { 773 } 774 775 #endif /* CONFIG_DEBUG_FS */ 776 777 static int __init vmballoon_init(void) 778 { 779 int error; 780 781 /* 782 * Check if we are running on VMware's hypervisor and bail out 783 * if we are not. 784 */ 785 if (x86_hyper != &x86_hyper_vmware) 786 return -ENODEV; 787 788 vmballoon_wq = create_freezable_workqueue("vmmemctl"); 789 if (!vmballoon_wq) { 790 pr_err("failed to create workqueue\n"); 791 return -ENOMEM; 792 } 793 794 INIT_LIST_HEAD(&balloon.pages); 795 INIT_LIST_HEAD(&balloon.refused_pages); 796 797 /* initialize rates */ 798 balloon.rate_alloc = VMW_BALLOON_RATE_ALLOC_MAX; 799 balloon.rate_free = VMW_BALLOON_RATE_FREE_MAX; 800 801 INIT_DELAYED_WORK(&balloon.dwork, vmballoon_work); 802 803 /* 804 * Start balloon. 805 */ 806 if (!vmballoon_send_start(&balloon)) { 807 pr_err("failed to send start command to the host\n"); 808 error = -EIO; 809 goto fail; 810 } 811 812 if (!vmballoon_send_guest_id(&balloon)) { 813 pr_err("failed to send guest ID to the host\n"); 814 error = -EIO; 815 goto fail; 816 } 817 818 error = vmballoon_debugfs_init(&balloon); 819 if (error) 820 goto fail; 821 822 queue_delayed_work(vmballoon_wq, &balloon.dwork, 0); 823 824 return 0; 825 826 fail: 827 destroy_workqueue(vmballoon_wq); 828 return error; 829 } 830 module_init(vmballoon_init); 831 832 static void __exit vmballoon_exit(void) 833 { 834 cancel_delayed_work_sync(&balloon.dwork); 835 destroy_workqueue(vmballoon_wq); 836 837 vmballoon_debugfs_exit(&balloon); 838 839 /* 840 * Deallocate all reserved memory, and reset connection with monitor. 841 * Reset connection before deallocating memory to avoid potential for 842 * additional spurious resets from guest touching deallocated pages. 843 */ 844 vmballoon_send_start(&balloon); 845 vmballoon_pop(&balloon); 846 } 847 module_exit(vmballoon_exit); 848