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("1.3.0.0-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_GUEST_ID 1 /* Linux */ 114 115 enum vmwballoon_capabilities { 116 /* 117 * Bit 0 is reserved and not associated to any capability. 118 */ 119 VMW_BALLOON_BASIC_CMDS = (1 << 1), 120 VMW_BALLOON_BATCHED_CMDS = (1 << 2) 121 }; 122 123 #define VMW_BALLOON_CAPABILITIES (VMW_BALLOON_BASIC_CMDS) 124 125 #define VMW_BALLOON_CMD_START 0 126 #define VMW_BALLOON_CMD_GET_TARGET 1 127 #define VMW_BALLOON_CMD_LOCK 2 128 #define VMW_BALLOON_CMD_UNLOCK 3 129 #define VMW_BALLOON_CMD_GUEST_ID 4 130 131 /* error codes */ 132 #define VMW_BALLOON_SUCCESS 0 133 #define VMW_BALLOON_FAILURE -1 134 #define VMW_BALLOON_ERROR_CMD_INVALID 1 135 #define VMW_BALLOON_ERROR_PPN_INVALID 2 136 #define VMW_BALLOON_ERROR_PPN_LOCKED 3 137 #define VMW_BALLOON_ERROR_PPN_UNLOCKED 4 138 #define VMW_BALLOON_ERROR_PPN_PINNED 5 139 #define VMW_BALLOON_ERROR_PPN_NOTNEEDED 6 140 #define VMW_BALLOON_ERROR_RESET 7 141 #define VMW_BALLOON_ERROR_BUSY 8 142 143 #define VMW_BALLOON_SUCCESS_WITH_CAPABILITIES (0x03000000) 144 145 #define VMWARE_BALLOON_CMD(cmd, data, result) \ 146 ({ \ 147 unsigned long __status, __dummy1, __dummy2; \ 148 __asm__ __volatile__ ("inl %%dx" : \ 149 "=a"(__status), \ 150 "=c"(__dummy1), \ 151 "=d"(__dummy2), \ 152 "=b"(result) : \ 153 "0"(VMW_BALLOON_HV_MAGIC), \ 154 "1"(VMW_BALLOON_CMD_##cmd), \ 155 "2"(VMW_BALLOON_HV_PORT), \ 156 "3"(data) : \ 157 "memory"); \ 158 if (VMW_BALLOON_CMD_##cmd == VMW_BALLOON_CMD_START) \ 159 result = __dummy1; \ 160 result &= -1UL; \ 161 __status & -1UL; \ 162 }) 163 164 #ifdef CONFIG_DEBUG_FS 165 struct vmballoon_stats { 166 unsigned int timer; 167 168 /* allocation statistics */ 169 unsigned int alloc; 170 unsigned int alloc_fail; 171 unsigned int sleep_alloc; 172 unsigned int sleep_alloc_fail; 173 unsigned int refused_alloc; 174 unsigned int refused_free; 175 unsigned int free; 176 177 /* monitor operations */ 178 unsigned int lock; 179 unsigned int lock_fail; 180 unsigned int unlock; 181 unsigned int unlock_fail; 182 unsigned int target; 183 unsigned int target_fail; 184 unsigned int start; 185 unsigned int start_fail; 186 unsigned int guest_type; 187 unsigned int guest_type_fail; 188 }; 189 190 #define STATS_INC(stat) (stat)++ 191 #else 192 #define STATS_INC(stat) 193 #endif 194 195 struct vmballoon { 196 197 /* list of reserved physical pages */ 198 struct list_head pages; 199 200 /* transient list of non-balloonable pages */ 201 struct list_head refused_pages; 202 unsigned int n_refused_pages; 203 204 /* balloon size in pages */ 205 unsigned int size; 206 unsigned int target; 207 208 /* reset flag */ 209 bool reset_required; 210 211 /* adjustment rates (pages per second) */ 212 unsigned int rate_alloc; 213 unsigned int rate_free; 214 215 /* slowdown page allocations for next few cycles */ 216 unsigned int slow_allocation_cycles; 217 218 #ifdef CONFIG_DEBUG_FS 219 /* statistics */ 220 struct vmballoon_stats stats; 221 222 /* debugfs file exporting statistics */ 223 struct dentry *dbg_entry; 224 #endif 225 226 struct sysinfo sysinfo; 227 228 struct delayed_work dwork; 229 }; 230 231 static struct vmballoon balloon; 232 233 /* 234 * Send "start" command to the host, communicating supported version 235 * of the protocol. 236 */ 237 static bool vmballoon_send_start(struct vmballoon *b) 238 { 239 unsigned long status, capabilities; 240 241 STATS_INC(b->stats.start); 242 243 status = VMWARE_BALLOON_CMD(START, VMW_BALLOON_CAPABILITIES, 244 capabilities); 245 if (status == VMW_BALLOON_SUCCESS) 246 return true; 247 248 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 249 STATS_INC(b->stats.start_fail); 250 return false; 251 } 252 253 static bool vmballoon_check_status(struct vmballoon *b, unsigned long status) 254 { 255 switch (status) { 256 case VMW_BALLOON_SUCCESS: 257 return true; 258 259 case VMW_BALLOON_ERROR_RESET: 260 b->reset_required = true; 261 /* fall through */ 262 263 default: 264 return false; 265 } 266 } 267 268 /* 269 * Communicate guest type to the host so that it can adjust ballooning 270 * algorithm to the one most appropriate for the guest. This command 271 * is normally issued after sending "start" command and is part of 272 * standard reset sequence. 273 */ 274 static bool vmballoon_send_guest_id(struct vmballoon *b) 275 { 276 unsigned long status, dummy; 277 278 status = VMWARE_BALLOON_CMD(GUEST_ID, VMW_BALLOON_GUEST_ID, dummy); 279 280 STATS_INC(b->stats.guest_type); 281 282 if (vmballoon_check_status(b, status)) 283 return true; 284 285 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 286 STATS_INC(b->stats.guest_type_fail); 287 return false; 288 } 289 290 /* 291 * Retrieve desired balloon size from the host. 292 */ 293 static bool vmballoon_send_get_target(struct vmballoon *b, u32 *new_target) 294 { 295 unsigned long status; 296 unsigned long target; 297 unsigned long limit; 298 u32 limit32; 299 300 /* 301 * si_meminfo() is cheap. Moreover, we want to provide dynamic 302 * max balloon size later. So let us call si_meminfo() every 303 * iteration. 304 */ 305 si_meminfo(&b->sysinfo); 306 limit = b->sysinfo.totalram; 307 308 /* Ensure limit fits in 32-bits */ 309 limit32 = (u32)limit; 310 if (limit != limit32) 311 return false; 312 313 /* update stats */ 314 STATS_INC(b->stats.target); 315 316 status = VMWARE_BALLOON_CMD(GET_TARGET, limit, target); 317 if (vmballoon_check_status(b, status)) { 318 *new_target = target; 319 return true; 320 } 321 322 pr_debug("%s - failed, hv returns %ld\n", __func__, status); 323 STATS_INC(b->stats.target_fail); 324 return false; 325 } 326 327 /* 328 * Notify the host about allocated page so that host can use it without 329 * fear that guest will need it. Host may reject some pages, we need to 330 * check the return value and maybe submit a different page. 331 */ 332 static int vmballoon_send_lock_page(struct vmballoon *b, unsigned long pfn, 333 unsigned int *hv_status) 334 { 335 unsigned long status, dummy; 336 u32 pfn32; 337 338 pfn32 = (u32)pfn; 339 if (pfn32 != pfn) 340 return -1; 341 342 STATS_INC(b->stats.lock); 343 344 *hv_status = status = VMWARE_BALLOON_CMD(LOCK, pfn, dummy); 345 if (vmballoon_check_status(b, status)) 346 return 0; 347 348 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 349 STATS_INC(b->stats.lock_fail); 350 return 1; 351 } 352 353 /* 354 * Notify the host that guest intends to release given page back into 355 * the pool of available (to the guest) pages. 356 */ 357 static bool vmballoon_send_unlock_page(struct vmballoon *b, unsigned long pfn) 358 { 359 unsigned long status, dummy; 360 u32 pfn32; 361 362 pfn32 = (u32)pfn; 363 if (pfn32 != pfn) 364 return false; 365 366 STATS_INC(b->stats.unlock); 367 368 status = VMWARE_BALLOON_CMD(UNLOCK, pfn, dummy); 369 if (vmballoon_check_status(b, status)) 370 return true; 371 372 pr_debug("%s - ppn %lx, hv returns %ld\n", __func__, pfn, status); 373 STATS_INC(b->stats.unlock_fail); 374 return false; 375 } 376 377 /* 378 * Quickly release all pages allocated for the balloon. This function is 379 * called when host decides to "reset" balloon for one reason or another. 380 * Unlike normal "deflate" we do not (shall not) notify host of the pages 381 * being released. 382 */ 383 static void vmballoon_pop(struct vmballoon *b) 384 { 385 struct page *page, *next; 386 unsigned int count = 0; 387 388 list_for_each_entry_safe(page, next, &b->pages, lru) { 389 list_del(&page->lru); 390 __free_page(page); 391 STATS_INC(b->stats.free); 392 b->size--; 393 394 if (++count >= b->rate_free) { 395 count = 0; 396 cond_resched(); 397 } 398 } 399 } 400 401 /* 402 * Perform standard reset sequence by popping the balloon (in case it 403 * is not empty) and then restarting protocol. This operation normally 404 * happens when host responds with VMW_BALLOON_ERROR_RESET to a command. 405 */ 406 static void vmballoon_reset(struct vmballoon *b) 407 { 408 /* free all pages, skipping monitor unlock */ 409 vmballoon_pop(b); 410 411 if (vmballoon_send_start(b)) { 412 b->reset_required = false; 413 if (!vmballoon_send_guest_id(b)) 414 pr_err("failed to send guest ID to the host\n"); 415 } 416 } 417 418 /* 419 * Notify the host of a ballooned page. If host rejects the page put it on the 420 * refuse list, those refused page are then released at the end of the 421 * inflation cycle. 422 */ 423 static int vmballoon_lock_page(struct vmballoon *b, struct page *page) 424 { 425 int locked, hv_status; 426 427 locked = vmballoon_send_lock_page(b, page_to_pfn(page), &hv_status); 428 if (locked > 0) { 429 STATS_INC(b->stats.refused_alloc); 430 431 if (hv_status == VMW_BALLOON_ERROR_RESET || 432 hv_status == VMW_BALLOON_ERROR_PPN_NOTNEEDED) { 433 __free_page(page); 434 return -EIO; 435 } 436 437 /* 438 * Place page on the list of non-balloonable pages 439 * and retry allocation, unless we already accumulated 440 * too many of them, in which case take a breather. 441 */ 442 if (b->n_refused_pages < VMW_BALLOON_MAX_REFUSED) { 443 b->n_refused_pages++; 444 list_add(&page->lru, &b->refused_pages); 445 } else { 446 __free_page(page); 447 } 448 return -EIO; 449 } 450 451 /* track allocated page */ 452 list_add(&page->lru, &b->pages); 453 454 /* update balloon size */ 455 b->size++; 456 457 return 0; 458 } 459 460 /* 461 * Release the page allocated for the balloon. Note that we first notify 462 * the host so it can make sure the page will be available for the guest 463 * to use, if needed. 464 */ 465 static int vmballoon_release_page(struct vmballoon *b, struct page *page) 466 { 467 if (!vmballoon_send_unlock_page(b, page_to_pfn(page))) 468 return -EIO; 469 470 list_del(&page->lru); 471 472 /* deallocate page */ 473 __free_page(page); 474 STATS_INC(b->stats.free); 475 476 /* update balloon size */ 477 b->size--; 478 479 return 0; 480 } 481 482 /* 483 * Release pages that were allocated while attempting to inflate the 484 * balloon but were refused by the host for one reason or another. 485 */ 486 static void vmballoon_release_refused_pages(struct vmballoon *b) 487 { 488 struct page *page, *next; 489 490 list_for_each_entry_safe(page, next, &b->refused_pages, lru) { 491 list_del(&page->lru); 492 __free_page(page); 493 STATS_INC(b->stats.refused_free); 494 } 495 496 b->n_refused_pages = 0; 497 } 498 499 /* 500 * Inflate the balloon towards its target size. Note that we try to limit 501 * the rate of allocation to make sure we are not choking the rest of the 502 * system. 503 */ 504 static void vmballoon_inflate(struct vmballoon *b) 505 { 506 unsigned int goal; 507 unsigned int rate; 508 unsigned int i; 509 unsigned int allocations = 0; 510 int error = 0; 511 gfp_t flags = VMW_PAGE_ALLOC_NOSLEEP; 512 513 pr_debug("%s - size: %d, target %d\n", __func__, b->size, b->target); 514 515 /* 516 * First try NOSLEEP page allocations to inflate balloon. 517 * 518 * If we do not throttle nosleep allocations, we can drain all 519 * free pages in the guest quickly (if the balloon target is high). 520 * As a side-effect, draining free pages helps to inform (force) 521 * the guest to start swapping if balloon target is not met yet, 522 * which is a desired behavior. However, balloon driver can consume 523 * all available CPU cycles if too many pages are allocated in a 524 * second. Therefore, we throttle nosleep allocations even when 525 * the guest is not under memory pressure. OTOH, if we have already 526 * predicted that the guest is under memory pressure, then we 527 * slowdown page allocations considerably. 528 */ 529 530 goal = b->target - b->size; 531 /* 532 * Start with no sleep allocation rate which may be higher 533 * than sleeping allocation rate. 534 */ 535 rate = b->slow_allocation_cycles ? 536 b->rate_alloc : VMW_BALLOON_NOSLEEP_ALLOC_MAX; 537 538 pr_debug("%s - goal: %d, no-sleep rate: %d, sleep rate: %d\n", 539 __func__, goal, rate, b->rate_alloc); 540 541 for (i = 0; i < goal; i++) { 542 struct page *page; 543 544 if (flags == VMW_PAGE_ALLOC_NOSLEEP) 545 STATS_INC(b->stats.alloc); 546 else 547 STATS_INC(b->stats.sleep_alloc); 548 549 page = alloc_page(flags); 550 if (!page) { 551 if (flags == VMW_PAGE_ALLOC_CANSLEEP) { 552 /* 553 * CANSLEEP page allocation failed, so guest 554 * is under severe memory pressure. Quickly 555 * decrease allocation rate. 556 */ 557 b->rate_alloc = max(b->rate_alloc / 2, 558 VMW_BALLOON_RATE_ALLOC_MIN); 559 STATS_INC(b->stats.sleep_alloc_fail); 560 break; 561 } 562 STATS_INC(b->stats.alloc_fail); 563 564 /* 565 * NOSLEEP page allocation failed, so the guest is 566 * under memory pressure. Let us slow down page 567 * allocations for next few cycles so that the guest 568 * gets out of memory pressure. Also, if we already 569 * allocated b->rate_alloc pages, let's pause, 570 * otherwise switch to sleeping allocations. 571 */ 572 b->slow_allocation_cycles = VMW_BALLOON_SLOW_CYCLES; 573 574 if (i >= b->rate_alloc) 575 break; 576 577 flags = VMW_PAGE_ALLOC_CANSLEEP; 578 /* Lower rate for sleeping allocations. */ 579 rate = b->rate_alloc; 580 continue; 581 } 582 583 error = vmballoon_lock_page(b, page); 584 if (error) 585 break; 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