1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1991 Regents of the University of California. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 35 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $ 36 */ 37 38 /* 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 */ 64 /* 65 * Resident memory management module. The module manipulates 'VM pages'. 66 * A VM page is the core building block for memory management. 67 */ 68 69 #include <sys/param.h> 70 #include <sys/systm.h> 71 #include <sys/malloc.h> 72 #include <sys/proc.h> 73 #include <sys/vmmeter.h> 74 #include <sys/vnode.h> 75 #include <sys/kernel.h> 76 #include <sys/alist.h> 77 #include <sys/sysctl.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <sys/lock.h> 82 #include <vm/vm_kern.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_object.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_pageout.h> 88 #include <vm/vm_pager.h> 89 #include <vm/vm_extern.h> 90 #include <vm/swap_pager.h> 91 92 #include <machine/inttypes.h> 93 #include <machine/md_var.h> 94 #include <machine/specialreg.h> 95 96 #include <vm/vm_page2.h> 97 #include <sys/spinlock2.h> 98 99 #define VMACTION_HSIZE 256 100 #define VMACTION_HMASK (VMACTION_HSIZE - 1) 101 102 static void vm_page_queue_init(void); 103 static void vm_page_free_wakeup(void); 104 static vm_page_t vm_page_select_cache(u_short pg_color); 105 static vm_page_t _vm_page_list_find2(int basequeue, int index); 106 static void _vm_page_deactivate_locked(vm_page_t m, int athead); 107 108 /* 109 * Array of tailq lists 110 */ 111 __cachealign struct vpgqueues vm_page_queues[PQ_COUNT]; 112 113 LIST_HEAD(vm_page_action_list, vm_page_action); 114 struct vm_page_action_list action_list[VMACTION_HSIZE]; 115 static volatile int vm_pages_waiting; 116 117 static struct alist vm_contig_alist; 118 static struct almeta vm_contig_ameta[ALIST_RECORDS_65536]; 119 static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin); 120 121 static u_long vm_dma_reserved = 0; 122 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved); 123 SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0, 124 "Memory reserved for DMA"); 125 SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD, 126 &vm_contig_alist.bl_free, 0, "Memory reserved for DMA"); 127 128 static int vm_contig_verbose = 0; 129 TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose); 130 131 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, 132 vm_pindex_t, pindex); 133 134 static void 135 vm_page_queue_init(void) 136 { 137 int i; 138 139 for (i = 0; i < PQ_L2_SIZE; i++) 140 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count; 141 for (i = 0; i < PQ_L2_SIZE; i++) 142 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count; 143 for (i = 0; i < PQ_L2_SIZE; i++) 144 vm_page_queues[PQ_INACTIVE+i].cnt = &vmstats.v_inactive_count; 145 for (i = 0; i < PQ_L2_SIZE; i++) 146 vm_page_queues[PQ_ACTIVE+i].cnt = &vmstats.v_active_count; 147 for (i = 0; i < PQ_L2_SIZE; i++) 148 vm_page_queues[PQ_HOLD+i].cnt = &vmstats.v_active_count; 149 /* PQ_NONE has no queue */ 150 151 for (i = 0; i < PQ_COUNT; i++) { 152 TAILQ_INIT(&vm_page_queues[i].pl); 153 spin_init(&vm_page_queues[i].spin); 154 } 155 156 for (i = 0; i < VMACTION_HSIZE; i++) 157 LIST_INIT(&action_list[i]); 158 } 159 160 /* 161 * note: place in initialized data section? Is this necessary? 162 */ 163 long first_page = 0; 164 int vm_page_array_size = 0; 165 int vm_page_zero_count = 0; 166 vm_page_t vm_page_array = NULL; 167 vm_paddr_t vm_low_phys_reserved; 168 169 /* 170 * (low level boot) 171 * 172 * Sets the page size, perhaps based upon the memory size. 173 * Must be called before any use of page-size dependent functions. 174 */ 175 void 176 vm_set_page_size(void) 177 { 178 if (vmstats.v_page_size == 0) 179 vmstats.v_page_size = PAGE_SIZE; 180 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0) 181 panic("vm_set_page_size: page size not a power of two"); 182 } 183 184 /* 185 * (low level boot) 186 * 187 * Add a new page to the freelist for use by the system. New pages 188 * are added to both the head and tail of the associated free page 189 * queue in a bottom-up fashion, so both zero'd and non-zero'd page 190 * requests pull 'recent' adds (higher physical addresses) first. 191 * 192 * Beware that the page zeroing daemon will also be running soon after 193 * boot, moving pages from the head to the tail of the PQ_FREE queues. 194 * 195 * Must be called in a critical section. 196 */ 197 static void 198 vm_add_new_page(vm_paddr_t pa) 199 { 200 struct vpgqueues *vpq; 201 vm_page_t m; 202 203 m = PHYS_TO_VM_PAGE(pa); 204 m->phys_addr = pa; 205 m->flags = 0; 206 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; 207 m->pat_mode = PAT_WRITE_BACK; 208 /* 209 * Twist for cpu localization in addition to page coloring, so 210 * different cpus selecting by m->queue get different page colors. 211 */ 212 m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE) & PQ_L2_MASK; 213 m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)) & PQ_L2_MASK; 214 /* 215 * Reserve a certain number of contiguous low memory pages for 216 * contigmalloc() to use. 217 */ 218 if (pa < vm_low_phys_reserved) { 219 atomic_add_int(&vmstats.v_page_count, 1); 220 atomic_add_int(&vmstats.v_dma_pages, 1); 221 m->queue = PQ_NONE; 222 m->wire_count = 1; 223 atomic_add_int(&vmstats.v_wire_count, 1); 224 alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1); 225 return; 226 } 227 228 /* 229 * General page 230 */ 231 m->queue = m->pc + PQ_FREE; 232 KKASSERT(m->dirty == 0); 233 234 atomic_add_int(&vmstats.v_page_count, 1); 235 atomic_add_int(&vmstats.v_free_count, 1); 236 vpq = &vm_page_queues[m->queue]; 237 if ((vpq->flipflop & 15) == 0) { 238 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 239 m->flags |= PG_ZERO; 240 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); 241 atomic_add_int(&vm_page_zero_count, 1); 242 } else { 243 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); 244 } 245 ++vpq->flipflop; 246 ++vpq->lcnt; 247 } 248 249 /* 250 * (low level boot) 251 * 252 * Initializes the resident memory module. 253 * 254 * Preallocates memory for critical VM structures and arrays prior to 255 * kernel_map becoming available. 256 * 257 * Memory is allocated from (virtual2_start, virtual2_end) if available, 258 * otherwise memory is allocated from (virtual_start, virtual_end). 259 * 260 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be 261 * large enough to hold vm_page_array & other structures for machines with 262 * large amounts of ram, so we want to use virtual2* when available. 263 */ 264 void 265 vm_page_startup(void) 266 { 267 vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start; 268 vm_offset_t mapped; 269 vm_size_t npages; 270 vm_paddr_t page_range; 271 vm_paddr_t new_end; 272 int i; 273 vm_paddr_t pa; 274 int nblocks; 275 vm_paddr_t last_pa; 276 vm_paddr_t end; 277 vm_paddr_t biggestone, biggestsize; 278 vm_paddr_t total; 279 280 total = 0; 281 biggestsize = 0; 282 biggestone = 0; 283 nblocks = 0; 284 vaddr = round_page(vaddr); 285 286 for (i = 0; phys_avail[i + 1]; i += 2) { 287 phys_avail[i] = round_page64(phys_avail[i]); 288 phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]); 289 } 290 291 for (i = 0; phys_avail[i + 1]; i += 2) { 292 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; 293 294 if (size > biggestsize) { 295 biggestone = i; 296 biggestsize = size; 297 } 298 ++nblocks; 299 total += size; 300 } 301 302 end = phys_avail[biggestone+1]; 303 end = trunc_page(end); 304 305 /* 306 * Initialize the queue headers for the free queue, the active queue 307 * and the inactive queue. 308 */ 309 vm_page_queue_init(); 310 311 #if !defined(_KERNEL_VIRTUAL) 312 /* 313 * VKERNELs don't support minidumps and as such don't need 314 * vm_page_dump 315 * 316 * Allocate a bitmap to indicate that a random physical page 317 * needs to be included in a minidump. 318 * 319 * The amd64 port needs this to indicate which direct map pages 320 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 321 * 322 * However, i386 still needs this workspace internally within the 323 * minidump code. In theory, they are not needed on i386, but are 324 * included should the sf_buf code decide to use them. 325 */ 326 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; 327 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 328 end -= vm_page_dump_size; 329 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size, 330 VM_PROT_READ | VM_PROT_WRITE); 331 bzero((void *)vm_page_dump, vm_page_dump_size); 332 #endif 333 /* 334 * Compute the number of pages of memory that will be available for 335 * use (taking into account the overhead of a page structure per 336 * page). 337 */ 338 first_page = phys_avail[0] / PAGE_SIZE; 339 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 340 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE; 341 342 #ifndef _KERNEL_VIRTUAL 343 /* 344 * (only applies to real kernels) 345 * 346 * Initialize the contiguous reserve map. We initially reserve up 347 * to 1/4 available physical memory or 65536 pages (~256MB), whichever 348 * is lower. 349 * 350 * Once device initialization is complete we return most of the 351 * reserved memory back to the normal page queues but leave some 352 * in reserve for things like usb attachments. 353 */ 354 vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT; 355 if (vm_low_phys_reserved > total / 4) 356 vm_low_phys_reserved = total / 4; 357 if (vm_dma_reserved == 0) { 358 vm_dma_reserved = 16 * 1024 * 1024; /* 16MB */ 359 if (vm_dma_reserved > total / 16) 360 vm_dma_reserved = total / 16; 361 } 362 #endif 363 alist_init(&vm_contig_alist, 65536, vm_contig_ameta, 364 ALIST_RECORDS_65536); 365 366 /* 367 * Initialize the mem entry structures now, and put them in the free 368 * queue. 369 */ 370 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 371 mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE); 372 vm_page_array = (vm_page_t)mapped; 373 374 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL) 375 /* 376 * since pmap_map on amd64 returns stuff out of a direct-map region, 377 * we have to manually add these pages to the minidump tracking so 378 * that they can be dumped, including the vm_page_array. 379 */ 380 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 381 dump_add_page(pa); 382 #endif 383 384 /* 385 * Clear all of the page structures 386 */ 387 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 388 vm_page_array_size = page_range; 389 390 /* 391 * Construct the free queue(s) in ascending order (by physical 392 * address) so that the first 16MB of physical memory is allocated 393 * last rather than first. On large-memory machines, this avoids 394 * the exhaustion of low physical memory before isa_dmainit has run. 395 */ 396 vmstats.v_page_count = 0; 397 vmstats.v_free_count = 0; 398 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 399 pa = phys_avail[i]; 400 if (i == biggestone) 401 last_pa = new_end; 402 else 403 last_pa = phys_avail[i + 1]; 404 while (pa < last_pa && npages-- > 0) { 405 vm_add_new_page(pa); 406 pa += PAGE_SIZE; 407 } 408 } 409 if (virtual2_start) 410 virtual2_start = vaddr; 411 else 412 virtual_start = vaddr; 413 } 414 415 /* 416 * We tended to reserve a ton of memory for contigmalloc(). Now that most 417 * drivers have initialized we want to return most the remaining free 418 * reserve back to the VM page queues so they can be used for normal 419 * allocations. 420 * 421 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool. 422 */ 423 static void 424 vm_page_startup_finish(void *dummy __unused) 425 { 426 alist_blk_t blk; 427 alist_blk_t rblk; 428 alist_blk_t count; 429 alist_blk_t xcount; 430 alist_blk_t bfree; 431 vm_page_t m; 432 433 spin_lock(&vm_contig_spin); 434 for (;;) { 435 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 436 if (bfree <= vm_dma_reserved / PAGE_SIZE) 437 break; 438 if (count == 0) 439 break; 440 441 /* 442 * Figure out how much of the initial reserve we have to 443 * free in order to reach our target. 444 */ 445 bfree -= vm_dma_reserved / PAGE_SIZE; 446 if (count > bfree) { 447 blk += count - bfree; 448 count = bfree; 449 } 450 451 /* 452 * Calculate the nearest power of 2 <= count. 453 */ 454 for (xcount = 1; xcount <= count; xcount <<= 1) 455 ; 456 xcount >>= 1; 457 blk += count - xcount; 458 count = xcount; 459 460 /* 461 * Allocate the pages from the alist, then free them to 462 * the normal VM page queues. 463 * 464 * Pages allocated from the alist are wired. We have to 465 * busy, unwire, and free them. We must also adjust 466 * vm_low_phys_reserved before freeing any pages to prevent 467 * confusion. 468 */ 469 rblk = alist_alloc(&vm_contig_alist, blk, count); 470 if (rblk != blk) { 471 kprintf("vm_page_startup_finish: Unable to return " 472 "dma space @0x%08x/%d -> 0x%08x\n", 473 blk, count, rblk); 474 break; 475 } 476 atomic_add_int(&vmstats.v_dma_pages, -count); 477 spin_unlock(&vm_contig_spin); 478 479 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 480 vm_low_phys_reserved = VM_PAGE_TO_PHYS(m); 481 while (count) { 482 vm_page_busy_wait(m, FALSE, "cpgfr"); 483 vm_page_unwire(m, 0); 484 vm_page_free(m); 485 --count; 486 ++m; 487 } 488 spin_lock(&vm_contig_spin); 489 } 490 spin_unlock(&vm_contig_spin); 491 492 /* 493 * Print out how much DMA space drivers have already allocated and 494 * how much is left over. 495 */ 496 kprintf("DMA space used: %jdk, remaining available: %jdk\n", 497 (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) * 498 (PAGE_SIZE / 1024), 499 (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024)); 500 } 501 SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY, 502 vm_page_startup_finish, NULL) 503 504 505 /* 506 * Scan comparison function for Red-Black tree scans. An inclusive 507 * (start,end) is expected. Other fields are not used. 508 */ 509 int 510 rb_vm_page_scancmp(struct vm_page *p, void *data) 511 { 512 struct rb_vm_page_scan_info *info = data; 513 514 if (p->pindex < info->start_pindex) 515 return(-1); 516 if (p->pindex > info->end_pindex) 517 return(1); 518 return(0); 519 } 520 521 int 522 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2) 523 { 524 if (p1->pindex < p2->pindex) 525 return(-1); 526 if (p1->pindex > p2->pindex) 527 return(1); 528 return(0); 529 } 530 531 void 532 vm_page_init(vm_page_t m) 533 { 534 /* do nothing for now. Called from pmap_page_init() */ 535 } 536 537 /* 538 * Each page queue has its own spin lock, which is fairly optimal for 539 * allocating and freeing pages at least. 540 * 541 * The caller must hold the vm_page_spin_lock() before locking a vm_page's 542 * queue spinlock via this function. Also note that m->queue cannot change 543 * unless both the page and queue are locked. 544 */ 545 static __inline 546 void 547 _vm_page_queue_spin_lock(vm_page_t m) 548 { 549 u_short queue; 550 551 queue = m->queue; 552 if (queue != PQ_NONE) { 553 spin_lock(&vm_page_queues[queue].spin); 554 KKASSERT(queue == m->queue); 555 } 556 } 557 558 static __inline 559 void 560 _vm_page_queue_spin_unlock(vm_page_t m) 561 { 562 u_short queue; 563 564 queue = m->queue; 565 cpu_ccfence(); 566 if (queue != PQ_NONE) 567 spin_unlock(&vm_page_queues[queue].spin); 568 } 569 570 static __inline 571 void 572 _vm_page_queues_spin_lock(u_short queue) 573 { 574 cpu_ccfence(); 575 if (queue != PQ_NONE) 576 spin_lock(&vm_page_queues[queue].spin); 577 } 578 579 580 static __inline 581 void 582 _vm_page_queues_spin_unlock(u_short queue) 583 { 584 cpu_ccfence(); 585 if (queue != PQ_NONE) 586 spin_unlock(&vm_page_queues[queue].spin); 587 } 588 589 void 590 vm_page_queue_spin_lock(vm_page_t m) 591 { 592 _vm_page_queue_spin_lock(m); 593 } 594 595 void 596 vm_page_queues_spin_lock(u_short queue) 597 { 598 _vm_page_queues_spin_lock(queue); 599 } 600 601 void 602 vm_page_queue_spin_unlock(vm_page_t m) 603 { 604 _vm_page_queue_spin_unlock(m); 605 } 606 607 void 608 vm_page_queues_spin_unlock(u_short queue) 609 { 610 _vm_page_queues_spin_unlock(queue); 611 } 612 613 /* 614 * This locks the specified vm_page and its queue in the proper order 615 * (page first, then queue). The queue may change so the caller must 616 * recheck on return. 617 */ 618 static __inline 619 void 620 _vm_page_and_queue_spin_lock(vm_page_t m) 621 { 622 vm_page_spin_lock(m); 623 _vm_page_queue_spin_lock(m); 624 } 625 626 static __inline 627 void 628 _vm_page_and_queue_spin_unlock(vm_page_t m) 629 { 630 _vm_page_queues_spin_unlock(m->queue); 631 vm_page_spin_unlock(m); 632 } 633 634 void 635 vm_page_and_queue_spin_unlock(vm_page_t m) 636 { 637 _vm_page_and_queue_spin_unlock(m); 638 } 639 640 void 641 vm_page_and_queue_spin_lock(vm_page_t m) 642 { 643 _vm_page_and_queue_spin_lock(m); 644 } 645 646 /* 647 * Helper function removes vm_page from its current queue. 648 * Returns the base queue the page used to be on. 649 * 650 * The vm_page and the queue must be spinlocked. 651 * This function will unlock the queue but leave the page spinlocked. 652 */ 653 static __inline u_short 654 _vm_page_rem_queue_spinlocked(vm_page_t m) 655 { 656 struct vpgqueues *pq; 657 u_short queue; 658 659 queue = m->queue; 660 if (queue != PQ_NONE) { 661 pq = &vm_page_queues[queue]; 662 TAILQ_REMOVE(&pq->pl, m, pageq); 663 atomic_add_int(pq->cnt, -1); 664 pq->lcnt--; 665 m->queue = PQ_NONE; 666 vm_page_queues_spin_unlock(queue); 667 if ((queue - m->pc) == PQ_FREE && (m->flags & PG_ZERO)) 668 atomic_subtract_int(&vm_page_zero_count, 1); 669 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE) 670 return (queue - m->pc); 671 } 672 return queue; 673 } 674 675 /* 676 * Helper function places the vm_page on the specified queue. 677 * 678 * The vm_page must be spinlocked. 679 * This function will return with both the page and the queue locked. 680 */ 681 static __inline void 682 _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead) 683 { 684 struct vpgqueues *pq; 685 686 KKASSERT(m->queue == PQ_NONE); 687 688 if (queue != PQ_NONE) { 689 vm_page_queues_spin_lock(queue); 690 pq = &vm_page_queues[queue]; 691 ++pq->lcnt; 692 atomic_add_int(pq->cnt, 1); 693 m->queue = queue; 694 695 /* 696 * Put zero'd pages on the end ( where we look for zero'd pages 697 * first ) and non-zerod pages at the head. 698 */ 699 if (queue - m->pc == PQ_FREE) { 700 if (m->flags & PG_ZERO) { 701 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 702 atomic_add_int(&vm_page_zero_count, 1); 703 } else { 704 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 705 } 706 } else if (athead) { 707 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 708 } else { 709 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 710 } 711 /* leave the queue spinlocked */ 712 } 713 } 714 715 /* 716 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) 717 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we 718 * did not. Only one sleep call will be made before returning. 719 * 720 * This function does NOT busy the page and on return the page is not 721 * guaranteed to be available. 722 */ 723 void 724 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 725 { 726 u_int32_t flags; 727 728 for (;;) { 729 flags = m->flags; 730 cpu_ccfence(); 731 732 if ((flags & PG_BUSY) == 0 && 733 (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) { 734 break; 735 } 736 tsleep_interlock(m, 0); 737 if (atomic_cmpset_int(&m->flags, flags, 738 flags | PG_WANTED | PG_REFERENCED)) { 739 tsleep(m, PINTERLOCKED, msg, 0); 740 break; 741 } 742 } 743 } 744 745 /* 746 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we 747 * also wait for m->busy to become 0 before setting PG_BUSY. 748 */ 749 void 750 VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m, 751 int also_m_busy, const char *msg 752 VM_PAGE_DEBUG_ARGS) 753 { 754 u_int32_t flags; 755 756 for (;;) { 757 flags = m->flags; 758 cpu_ccfence(); 759 if (flags & PG_BUSY) { 760 tsleep_interlock(m, 0); 761 if (atomic_cmpset_int(&m->flags, flags, 762 flags | PG_WANTED | PG_REFERENCED)) { 763 tsleep(m, PINTERLOCKED, msg, 0); 764 } 765 } else if (also_m_busy && (flags & PG_SBUSY)) { 766 tsleep_interlock(m, 0); 767 if (atomic_cmpset_int(&m->flags, flags, 768 flags | PG_WANTED | PG_REFERENCED)) { 769 tsleep(m, PINTERLOCKED, msg, 0); 770 } 771 } else { 772 if (atomic_cmpset_int(&m->flags, flags, 773 flags | PG_BUSY)) { 774 #ifdef VM_PAGE_DEBUG 775 m->busy_func = func; 776 m->busy_line = lineno; 777 #endif 778 break; 779 } 780 } 781 } 782 } 783 784 /* 785 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy 786 * is also 0. 787 * 788 * Returns non-zero on failure. 789 */ 790 int 791 VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy 792 VM_PAGE_DEBUG_ARGS) 793 { 794 u_int32_t flags; 795 796 for (;;) { 797 flags = m->flags; 798 cpu_ccfence(); 799 if (flags & PG_BUSY) 800 return TRUE; 801 if (also_m_busy && (flags & PG_SBUSY)) 802 return TRUE; 803 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { 804 #ifdef VM_PAGE_DEBUG 805 m->busy_func = func; 806 m->busy_line = lineno; 807 #endif 808 return FALSE; 809 } 810 } 811 } 812 813 /* 814 * Clear the PG_BUSY flag and return non-zero to indicate to the caller 815 * that a wakeup() should be performed. 816 * 817 * The vm_page must be spinlocked and will remain spinlocked on return. 818 * The related queue must NOT be spinlocked (which could deadlock us). 819 * 820 * (inline version) 821 */ 822 static __inline 823 int 824 _vm_page_wakeup(vm_page_t m) 825 { 826 u_int32_t flags; 827 828 for (;;) { 829 flags = m->flags; 830 cpu_ccfence(); 831 if (atomic_cmpset_int(&m->flags, flags, 832 flags & ~(PG_BUSY | PG_WANTED))) { 833 break; 834 } 835 } 836 return(flags & PG_WANTED); 837 } 838 839 /* 840 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This 841 * is typically the last call you make on a page before moving onto 842 * other things. 843 */ 844 void 845 vm_page_wakeup(vm_page_t m) 846 { 847 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 848 vm_page_spin_lock(m); 849 if (_vm_page_wakeup(m)) { 850 vm_page_spin_unlock(m); 851 wakeup(m); 852 } else { 853 vm_page_spin_unlock(m); 854 } 855 } 856 857 /* 858 * Holding a page keeps it from being reused. Other parts of the system 859 * can still disassociate the page from its current object and free it, or 860 * perform read or write I/O on it and/or otherwise manipulate the page, 861 * but if the page is held the VM system will leave the page and its data 862 * intact and not reuse the page for other purposes until the last hold 863 * reference is released. (see vm_page_wire() if you want to prevent the 864 * page from being disassociated from its object too). 865 * 866 * The caller must still validate the contents of the page and, if necessary, 867 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete 868 * before manipulating the page. 869 * 870 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary 871 */ 872 void 873 vm_page_hold(vm_page_t m) 874 { 875 vm_page_spin_lock(m); 876 atomic_add_int(&m->hold_count, 1); 877 if (m->queue - m->pc == PQ_FREE) { 878 _vm_page_queue_spin_lock(m); 879 _vm_page_rem_queue_spinlocked(m); 880 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); 881 _vm_page_queue_spin_unlock(m); 882 } 883 vm_page_spin_unlock(m); 884 } 885 886 /* 887 * The opposite of vm_page_hold(). A page can be freed while being held, 888 * which places it on the PQ_HOLD queue. If we are able to busy the page 889 * after the hold count drops to zero we will move the page to the 890 * appropriate PQ_FREE queue by calling vm_page_free_toq(). 891 */ 892 void 893 vm_page_unhold(vm_page_t m) 894 { 895 vm_page_spin_lock(m); 896 atomic_add_int(&m->hold_count, -1); 897 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) { 898 _vm_page_queue_spin_lock(m); 899 _vm_page_rem_queue_spinlocked(m); 900 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); 901 _vm_page_queue_spin_unlock(m); 902 } 903 vm_page_spin_unlock(m); 904 } 905 906 /* 907 * vm_page_getfake: 908 * 909 * Create a fictitious page with the specified physical address and 910 * memory attribute. The memory attribute is the only the machine- 911 * dependent aspect of a fictitious page that must be initialized. 912 */ 913 914 void 915 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 916 { 917 918 if ((m->flags & PG_FICTITIOUS) != 0) { 919 /* 920 * The page's memattr might have changed since the 921 * previous initialization. Update the pmap to the 922 * new memattr. 923 */ 924 goto memattr; 925 } 926 m->phys_addr = paddr; 927 m->queue = PQ_NONE; 928 /* Fictitious pages don't use "segind". */ 929 /* Fictitious pages don't use "order" or "pool". */ 930 m->flags = PG_FICTITIOUS | PG_UNMANAGED | PG_BUSY; 931 m->wire_count = 1; 932 pmap_page_init(m); 933 memattr: 934 pmap_page_set_memattr(m, memattr); 935 } 936 937 /* 938 * Inserts the given vm_page into the object and object list. 939 * 940 * The pagetables are not updated but will presumably fault the page 941 * in if necessary, or if a kernel page the caller will at some point 942 * enter the page into the kernel's pmap. We are not allowed to block 943 * here so we *can't* do this anyway. 944 * 945 * This routine may not block. 946 * This routine must be called with the vm_object held. 947 * This routine must be called with a critical section held. 948 * 949 * This routine returns TRUE if the page was inserted into the object 950 * successfully, and FALSE if the page already exists in the object. 951 */ 952 int 953 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 954 { 955 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object)); 956 if (m->object != NULL) 957 panic("vm_page_insert: already inserted"); 958 959 object->generation++; 960 961 /* 962 * Record the object/offset pair in this page and add the 963 * pv_list_count of the page to the object. 964 * 965 * The vm_page spin lock is required for interactions with the pmap. 966 */ 967 vm_page_spin_lock(m); 968 m->object = object; 969 m->pindex = pindex; 970 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) { 971 m->object = NULL; 972 m->pindex = 0; 973 vm_page_spin_unlock(m); 974 return FALSE; 975 } 976 ++object->resident_page_count; 977 ++mycpu->gd_vmtotal.t_rm; 978 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */ 979 vm_page_spin_unlock(m); 980 981 /* 982 * Since we are inserting a new and possibly dirty page, 983 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 984 */ 985 if ((m->valid & m->dirty) || 986 (m->flags & (PG_WRITEABLE | PG_NEED_COMMIT))) 987 vm_object_set_writeable_dirty(object); 988 989 /* 990 * Checks for a swap assignment and sets PG_SWAPPED if appropriate. 991 */ 992 swap_pager_page_inserted(m); 993 return TRUE; 994 } 995 996 /* 997 * Removes the given vm_page_t from the (object,index) table 998 * 999 * The underlying pmap entry (if any) is NOT removed here. 1000 * This routine may not block. 1001 * 1002 * The page must be BUSY and will remain BUSY on return. 1003 * No other requirements. 1004 * 1005 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave 1006 * it busy. 1007 */ 1008 void 1009 vm_page_remove(vm_page_t m) 1010 { 1011 vm_object_t object; 1012 1013 if (m->object == NULL) { 1014 return; 1015 } 1016 1017 if ((m->flags & PG_BUSY) == 0) 1018 panic("vm_page_remove: page not busy"); 1019 1020 object = m->object; 1021 1022 vm_object_hold(object); 1023 1024 /* 1025 * Remove the page from the object and update the object. 1026 * 1027 * The vm_page spin lock is required for interactions with the pmap. 1028 */ 1029 vm_page_spin_lock(m); 1030 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); 1031 --object->resident_page_count; 1032 --mycpu->gd_vmtotal.t_rm; 1033 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */ 1034 m->object = NULL; 1035 vm_page_spin_unlock(m); 1036 1037 object->generation++; 1038 1039 vm_object_drop(object); 1040 } 1041 1042 /* 1043 * Locate and return the page at (object, pindex), or NULL if the 1044 * page could not be found. 1045 * 1046 * The caller must hold the vm_object token. 1047 */ 1048 vm_page_t 1049 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 1050 { 1051 vm_page_t m; 1052 1053 /* 1054 * Search the hash table for this object/offset pair 1055 */ 1056 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1057 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1058 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex)); 1059 return(m); 1060 } 1061 1062 vm_page_t 1063 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object, 1064 vm_pindex_t pindex, 1065 int also_m_busy, const char *msg 1066 VM_PAGE_DEBUG_ARGS) 1067 { 1068 u_int32_t flags; 1069 vm_page_t m; 1070 1071 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1072 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1073 while (m) { 1074 KKASSERT(m->object == object && m->pindex == pindex); 1075 flags = m->flags; 1076 cpu_ccfence(); 1077 if (flags & PG_BUSY) { 1078 tsleep_interlock(m, 0); 1079 if (atomic_cmpset_int(&m->flags, flags, 1080 flags | PG_WANTED | PG_REFERENCED)) { 1081 tsleep(m, PINTERLOCKED, msg, 0); 1082 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1083 pindex); 1084 } 1085 } else if (also_m_busy && (flags & PG_SBUSY)) { 1086 tsleep_interlock(m, 0); 1087 if (atomic_cmpset_int(&m->flags, flags, 1088 flags | PG_WANTED | PG_REFERENCED)) { 1089 tsleep(m, PINTERLOCKED, msg, 0); 1090 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1091 pindex); 1092 } 1093 } else if (atomic_cmpset_int(&m->flags, flags, 1094 flags | PG_BUSY)) { 1095 #ifdef VM_PAGE_DEBUG 1096 m->busy_func = func; 1097 m->busy_line = lineno; 1098 #endif 1099 break; 1100 } 1101 } 1102 return m; 1103 } 1104 1105 /* 1106 * Attempt to lookup and busy a page. 1107 * 1108 * Returns NULL if the page could not be found 1109 * 1110 * Returns a vm_page and error == TRUE if the page exists but could not 1111 * be busied. 1112 * 1113 * Returns a vm_page and error == FALSE on success. 1114 */ 1115 vm_page_t 1116 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object, 1117 vm_pindex_t pindex, 1118 int also_m_busy, int *errorp 1119 VM_PAGE_DEBUG_ARGS) 1120 { 1121 u_int32_t flags; 1122 vm_page_t m; 1123 1124 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1125 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1126 *errorp = FALSE; 1127 while (m) { 1128 KKASSERT(m->object == object && m->pindex == pindex); 1129 flags = m->flags; 1130 cpu_ccfence(); 1131 if (flags & PG_BUSY) { 1132 *errorp = TRUE; 1133 break; 1134 } 1135 if (also_m_busy && (flags & PG_SBUSY)) { 1136 *errorp = TRUE; 1137 break; 1138 } 1139 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { 1140 #ifdef VM_PAGE_DEBUG 1141 m->busy_func = func; 1142 m->busy_line = lineno; 1143 #endif 1144 break; 1145 } 1146 } 1147 return m; 1148 } 1149 1150 /* 1151 * Caller must hold the related vm_object 1152 */ 1153 vm_page_t 1154 vm_page_next(vm_page_t m) 1155 { 1156 vm_page_t next; 1157 1158 next = vm_page_rb_tree_RB_NEXT(m); 1159 if (next && next->pindex != m->pindex + 1) 1160 next = NULL; 1161 return (next); 1162 } 1163 1164 /* 1165 * vm_page_rename() 1166 * 1167 * Move the given vm_page from its current object to the specified 1168 * target object/offset. The page must be busy and will remain so 1169 * on return. 1170 * 1171 * new_object must be held. 1172 * This routine might block. XXX ? 1173 * 1174 * NOTE: Swap associated with the page must be invalidated by the move. We 1175 * have to do this for several reasons: (1) we aren't freeing the 1176 * page, (2) we are dirtying the page, (3) the VM system is probably 1177 * moving the page from object A to B, and will then later move 1178 * the backing store from A to B and we can't have a conflict. 1179 * 1180 * NOTE: We *always* dirty the page. It is necessary both for the 1181 * fact that we moved it, and because we may be invalidating 1182 * swap. If the page is on the cache, we have to deactivate it 1183 * or vm_page_dirty() will panic. Dirty pages are not allowed 1184 * on the cache. 1185 */ 1186 void 1187 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1188 { 1189 KKASSERT(m->flags & PG_BUSY); 1190 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object)); 1191 if (m->object) { 1192 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m->object)); 1193 vm_page_remove(m); 1194 } 1195 if (vm_page_insert(m, new_object, new_pindex) == FALSE) { 1196 panic("vm_page_rename: target exists (%p,%"PRIu64")", 1197 new_object, new_pindex); 1198 } 1199 if (m->queue - m->pc == PQ_CACHE) 1200 vm_page_deactivate(m); 1201 vm_page_dirty(m); 1202 } 1203 1204 /* 1205 * vm_page_unqueue() without any wakeup. This routine is used when a page 1206 * is being moved between queues or otherwise is to remain BUSYied by the 1207 * caller. 1208 * 1209 * This routine may not block. 1210 */ 1211 void 1212 vm_page_unqueue_nowakeup(vm_page_t m) 1213 { 1214 vm_page_and_queue_spin_lock(m); 1215 (void)_vm_page_rem_queue_spinlocked(m); 1216 vm_page_spin_unlock(m); 1217 } 1218 1219 /* 1220 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon 1221 * if necessary. 1222 * 1223 * This routine may not block. 1224 */ 1225 void 1226 vm_page_unqueue(vm_page_t m) 1227 { 1228 u_short queue; 1229 1230 vm_page_and_queue_spin_lock(m); 1231 queue = _vm_page_rem_queue_spinlocked(m); 1232 if (queue == PQ_FREE || queue == PQ_CACHE) { 1233 vm_page_spin_unlock(m); 1234 pagedaemon_wakeup(); 1235 } else { 1236 vm_page_spin_unlock(m); 1237 } 1238 } 1239 1240 /* 1241 * vm_page_list_find() 1242 * 1243 * Find a page on the specified queue with color optimization. 1244 * 1245 * The page coloring optimization attempts to locate a page that does 1246 * not overload other nearby pages in the object in the cpu's L1 or L2 1247 * caches. We need this optimization because cpu caches tend to be 1248 * physical caches, while object spaces tend to be virtual. 1249 * 1250 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock 1251 * and the algorithm is adjusted to localize allocations on a per-core basis. 1252 * This is done by 'twisting' the colors. 1253 * 1254 * The page is returned spinlocked and removed from its queue (it will 1255 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller 1256 * is responsible for dealing with the busy-page case (usually by 1257 * deactivating the page and looping). 1258 * 1259 * NOTE: This routine is carefully inlined. A non-inlined version 1260 * is available for outside callers but the only critical path is 1261 * from within this source file. 1262 * 1263 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE 1264 * represent stable storage, allowing us to order our locks vm_page 1265 * first, then queue. 1266 */ 1267 static __inline 1268 vm_page_t 1269 _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) 1270 { 1271 vm_page_t m; 1272 1273 for (;;) { 1274 if (prefer_zero) 1275 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist); 1276 else 1277 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl); 1278 if (m == NULL) { 1279 m = _vm_page_list_find2(basequeue, index); 1280 return(m); 1281 } 1282 vm_page_and_queue_spin_lock(m); 1283 if (m->queue == basequeue + index) { 1284 _vm_page_rem_queue_spinlocked(m); 1285 /* vm_page_t spin held, no queue spin */ 1286 break; 1287 } 1288 vm_page_and_queue_spin_unlock(m); 1289 } 1290 return(m); 1291 } 1292 1293 static vm_page_t 1294 _vm_page_list_find2(int basequeue, int index) 1295 { 1296 int i; 1297 vm_page_t m = NULL; 1298 struct vpgqueues *pq; 1299 1300 pq = &vm_page_queues[basequeue]; 1301 1302 /* 1303 * Note that for the first loop, index+i and index-i wind up at the 1304 * same place. Even though this is not totally optimal, we've already 1305 * blown it by missing the cache case so we do not care. 1306 */ 1307 for (i = PQ_L2_SIZE / 2; i > 0; --i) { 1308 for (;;) { 1309 m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl); 1310 if (m) { 1311 _vm_page_and_queue_spin_lock(m); 1312 if (m->queue == 1313 basequeue + ((index + i) & PQ_L2_MASK)) { 1314 _vm_page_rem_queue_spinlocked(m); 1315 return(m); 1316 } 1317 _vm_page_and_queue_spin_unlock(m); 1318 continue; 1319 } 1320 m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl); 1321 if (m) { 1322 _vm_page_and_queue_spin_lock(m); 1323 if (m->queue == 1324 basequeue + ((index - i) & PQ_L2_MASK)) { 1325 _vm_page_rem_queue_spinlocked(m); 1326 return(m); 1327 } 1328 _vm_page_and_queue_spin_unlock(m); 1329 continue; 1330 } 1331 break; /* next i */ 1332 } 1333 } 1334 return(m); 1335 } 1336 1337 /* 1338 * Returns a vm_page candidate for allocation. The page is not busied so 1339 * it can move around. The caller must busy the page (and typically 1340 * deactivate it if it cannot be busied!) 1341 * 1342 * Returns a spinlocked vm_page that has been removed from its queue. 1343 */ 1344 vm_page_t 1345 vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) 1346 { 1347 return(_vm_page_list_find(basequeue, index, prefer_zero)); 1348 } 1349 1350 /* 1351 * Find a page on the cache queue with color optimization, remove it 1352 * from the queue, and busy it. The returned page will not be spinlocked. 1353 * 1354 * A candidate failure will be deactivated. Candidates can fail due to 1355 * being busied by someone else, in which case they will be deactivated. 1356 * 1357 * This routine may not block. 1358 * 1359 */ 1360 static vm_page_t 1361 vm_page_select_cache(u_short pg_color) 1362 { 1363 vm_page_t m; 1364 1365 for (;;) { 1366 m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK, FALSE); 1367 if (m == NULL) 1368 break; 1369 /* 1370 * (m) has been removed from its queue and spinlocked 1371 */ 1372 if (vm_page_busy_try(m, TRUE)) { 1373 _vm_page_deactivate_locked(m, 0); 1374 vm_page_spin_unlock(m); 1375 } else { 1376 /* 1377 * We successfully busied the page 1378 */ 1379 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) == 0 && 1380 m->hold_count == 0 && 1381 m->wire_count == 0 && 1382 (m->dirty & m->valid) == 0) { 1383 vm_page_spin_unlock(m); 1384 pagedaemon_wakeup(); 1385 return(m); 1386 } 1387 1388 /* 1389 * The page cannot be recycled, deactivate it. 1390 */ 1391 _vm_page_deactivate_locked(m, 0); 1392 if (_vm_page_wakeup(m)) { 1393 vm_page_spin_unlock(m); 1394 wakeup(m); 1395 } else { 1396 vm_page_spin_unlock(m); 1397 } 1398 } 1399 } 1400 return (m); 1401 } 1402 1403 /* 1404 * Find a free or zero page, with specified preference. We attempt to 1405 * inline the nominal case and fall back to _vm_page_select_free() 1406 * otherwise. A busied page is removed from the queue and returned. 1407 * 1408 * This routine may not block. 1409 */ 1410 static __inline vm_page_t 1411 vm_page_select_free(u_short pg_color, boolean_t prefer_zero) 1412 { 1413 vm_page_t m; 1414 1415 for (;;) { 1416 m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK, 1417 prefer_zero); 1418 if (m == NULL) 1419 break; 1420 if (vm_page_busy_try(m, TRUE)) { 1421 /* 1422 * Various mechanisms such as a pmap_collect can 1423 * result in a busy page on the free queue. We 1424 * have to move the page out of the way so we can 1425 * retry the allocation. If the other thread is not 1426 * allocating the page then m->valid will remain 0 and 1427 * the pageout daemon will free the page later on. 1428 * 1429 * Since we could not busy the page, however, we 1430 * cannot make assumptions as to whether the page 1431 * will be allocated by the other thread or not, 1432 * so all we can do is deactivate it to move it out 1433 * of the way. In particular, if the other thread 1434 * wires the page it may wind up on the inactive 1435 * queue and the pageout daemon will have to deal 1436 * with that case too. 1437 */ 1438 _vm_page_deactivate_locked(m, 0); 1439 vm_page_spin_unlock(m); 1440 } else { 1441 /* 1442 * Theoretically if we are able to busy the page 1443 * atomic with the queue removal (using the vm_page 1444 * lock) nobody else should be able to mess with the 1445 * page before us. 1446 */ 1447 KKASSERT((m->flags & (PG_UNMANAGED | 1448 PG_NEED_COMMIT)) == 0); 1449 KKASSERT(m->hold_count == 0); 1450 KKASSERT(m->wire_count == 0); 1451 vm_page_spin_unlock(m); 1452 pagedaemon_wakeup(); 1453 1454 /* return busied and removed page */ 1455 return(m); 1456 } 1457 } 1458 return(m); 1459 } 1460 1461 /* 1462 * This implements a per-cpu cache of free, zero'd, ready-to-go pages. 1463 * The idea is to populate this cache prior to acquiring any locks so 1464 * we don't wind up potentially zeroing VM pages (under heavy loads) while 1465 * holding potentialy contending locks. 1466 * 1467 * Note that we allocate the page uninserted into anything and use a pindex 1468 * of 0, the vm_page_alloc() will effectively add gd_cpuid so these 1469 * allocations should wind up being uncontended. However, we still want 1470 * to rove across PQ_L2_SIZE. 1471 */ 1472 void 1473 vm_page_pcpu_cache(void) 1474 { 1475 #if 0 1476 globaldata_t gd = mycpu; 1477 vm_page_t m; 1478 1479 if (gd->gd_vmpg_count < GD_MINVMPG) { 1480 crit_enter_gd(gd); 1481 while (gd->gd_vmpg_count < GD_MAXVMPG) { 1482 m = vm_page_alloc(NULL, ticks & ~ncpus2_mask, 1483 VM_ALLOC_NULL_OK | VM_ALLOC_NORMAL | 1484 VM_ALLOC_NULL_OK | VM_ALLOC_ZERO); 1485 if (gd->gd_vmpg_count < GD_MAXVMPG) { 1486 if ((m->flags & PG_ZERO) == 0) { 1487 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 1488 vm_page_flag_set(m, PG_ZERO); 1489 } 1490 gd->gd_vmpg_array[gd->gd_vmpg_count++] = m; 1491 } else { 1492 vm_page_free(m); 1493 } 1494 } 1495 crit_exit_gd(gd); 1496 } 1497 #endif 1498 } 1499 1500 /* 1501 * vm_page_alloc() 1502 * 1503 * Allocate and return a memory cell associated with this VM object/offset 1504 * pair. If object is NULL an unassociated page will be allocated. 1505 * 1506 * The returned page will be busied and removed from its queues. This 1507 * routine can block and may return NULL if a race occurs and the page 1508 * is found to already exist at the specified (object, pindex). 1509 * 1510 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain 1511 * VM_ALLOC_QUICK like normal but cannot use cache 1512 * VM_ALLOC_SYSTEM greater free drain 1513 * VM_ALLOC_INTERRUPT allow free list to be completely drained 1514 * VM_ALLOC_ZERO advisory request for pre-zero'd page only 1515 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only 1516 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision 1517 * (see vm_page_grab()) 1518 * VM_ALLOC_USE_GD ok to use per-gd cache 1519 * 1520 * The object must be held if not NULL 1521 * This routine may not block 1522 * 1523 * Additional special handling is required when called from an interrupt 1524 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache 1525 * in this case. 1526 */ 1527 vm_page_t 1528 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req) 1529 { 1530 globaldata_t gd = mycpu; 1531 vm_object_t obj; 1532 vm_page_t m; 1533 u_short pg_color; 1534 1535 #if 0 1536 /* 1537 * Special per-cpu free VM page cache. The pages are pre-busied 1538 * and pre-zerod for us. 1539 */ 1540 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) { 1541 crit_enter_gd(gd); 1542 if (gd->gd_vmpg_count) { 1543 m = gd->gd_vmpg_array[--gd->gd_vmpg_count]; 1544 crit_exit_gd(gd); 1545 goto done; 1546 } 1547 crit_exit_gd(gd); 1548 } 1549 #endif 1550 m = NULL; 1551 1552 /* 1553 * Cpu twist - cpu localization algorithm 1554 */ 1555 if (object) { 1556 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask) + 1557 (object->pg_color & ~ncpus_fit_mask); 1558 } else { 1559 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask); 1560 } 1561 KKASSERT(page_req & 1562 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK| 1563 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 1564 1565 /* 1566 * Certain system threads (pageout daemon, buf_daemon's) are 1567 * allowed to eat deeper into the free page list. 1568 */ 1569 if (curthread->td_flags & TDF_SYSTHREAD) 1570 page_req |= VM_ALLOC_SYSTEM; 1571 1572 loop: 1573 if (vmstats.v_free_count > vmstats.v_free_reserved || 1574 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) || 1575 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 && 1576 vmstats.v_free_count > vmstats.v_interrupt_free_min) 1577 ) { 1578 /* 1579 * The free queue has sufficient free pages to take one out. 1580 */ 1581 if (page_req & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) 1582 m = vm_page_select_free(pg_color, TRUE); 1583 else 1584 m = vm_page_select_free(pg_color, FALSE); 1585 } else if (page_req & VM_ALLOC_NORMAL) { 1586 /* 1587 * Allocatable from the cache (non-interrupt only). On 1588 * success, we must free the page and try again, thus 1589 * ensuring that vmstats.v_*_free_min counters are replenished. 1590 */ 1591 #ifdef INVARIANTS 1592 if (curthread->td_preempted) { 1593 kprintf("vm_page_alloc(): warning, attempt to allocate" 1594 " cache page from preempting interrupt\n"); 1595 m = NULL; 1596 } else { 1597 m = vm_page_select_cache(pg_color); 1598 } 1599 #else 1600 m = vm_page_select_cache(pg_color); 1601 #endif 1602 /* 1603 * On success move the page into the free queue and loop. 1604 * 1605 * Only do this if we can safely acquire the vm_object lock, 1606 * because this is effectively a random page and the caller 1607 * might be holding the lock shared, we don't want to 1608 * deadlock. 1609 */ 1610 if (m != NULL) { 1611 KASSERT(m->dirty == 0, 1612 ("Found dirty cache page %p", m)); 1613 if ((obj = m->object) != NULL) { 1614 if (vm_object_hold_try(obj)) { 1615 vm_page_protect(m, VM_PROT_NONE); 1616 vm_page_free(m); 1617 /* m->object NULL here */ 1618 vm_object_drop(obj); 1619 } else { 1620 vm_page_deactivate(m); 1621 vm_page_wakeup(m); 1622 } 1623 } else { 1624 vm_page_protect(m, VM_PROT_NONE); 1625 vm_page_free(m); 1626 } 1627 goto loop; 1628 } 1629 1630 /* 1631 * On failure return NULL 1632 */ 1633 #if defined(DIAGNOSTIC) 1634 if (vmstats.v_cache_count > 0) 1635 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count); 1636 #endif 1637 vm_pageout_deficit++; 1638 pagedaemon_wakeup(); 1639 return (NULL); 1640 } else { 1641 /* 1642 * No pages available, wakeup the pageout daemon and give up. 1643 */ 1644 vm_pageout_deficit++; 1645 pagedaemon_wakeup(); 1646 return (NULL); 1647 } 1648 1649 /* 1650 * v_free_count can race so loop if we don't find the expected 1651 * page. 1652 */ 1653 if (m == NULL) 1654 goto loop; 1655 1656 /* 1657 * Good page found. The page has already been busied for us and 1658 * removed from its queues. 1659 */ 1660 KASSERT(m->dirty == 0, 1661 ("vm_page_alloc: free/cache page %p was dirty", m)); 1662 KKASSERT(m->queue == PQ_NONE); 1663 1664 #if 0 1665 done: 1666 #endif 1667 /* 1668 * Initialize the structure, inheriting some flags but clearing 1669 * all the rest. The page has already been busied for us. 1670 */ 1671 vm_page_flag_clear(m, ~(PG_ZERO | PG_BUSY | PG_SBUSY)); 1672 KKASSERT(m->wire_count == 0); 1673 KKASSERT(m->busy == 0); 1674 m->act_count = 0; 1675 m->valid = 0; 1676 1677 /* 1678 * Caller must be holding the object lock (asserted by 1679 * vm_page_insert()). 1680 * 1681 * NOTE: Inserting a page here does not insert it into any pmaps 1682 * (which could cause us to block allocating memory). 1683 * 1684 * NOTE: If no object an unassociated page is allocated, m->pindex 1685 * can be used by the caller for any purpose. 1686 */ 1687 if (object) { 1688 if (vm_page_insert(m, object, pindex) == FALSE) { 1689 vm_page_free(m); 1690 if ((page_req & VM_ALLOC_NULL_OK) == 0) 1691 panic("PAGE RACE %p[%ld]/%p", 1692 object, (long)pindex, m); 1693 m = NULL; 1694 } 1695 } else { 1696 m->pindex = pindex; 1697 } 1698 1699 /* 1700 * Don't wakeup too often - wakeup the pageout daemon when 1701 * we would be nearly out of memory. 1702 */ 1703 pagedaemon_wakeup(); 1704 1705 /* 1706 * A PG_BUSY page is returned. 1707 */ 1708 return (m); 1709 } 1710 1711 /* 1712 * Returns number of pages available in our DMA memory reserve 1713 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf) 1714 */ 1715 vm_size_t 1716 vm_contig_avail_pages(void) 1717 { 1718 alist_blk_t blk; 1719 alist_blk_t count; 1720 alist_blk_t bfree; 1721 spin_lock(&vm_contig_spin); 1722 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 1723 spin_unlock(&vm_contig_spin); 1724 1725 return bfree; 1726 } 1727 1728 /* 1729 * Attempt to allocate contiguous physical memory with the specified 1730 * requirements. 1731 */ 1732 vm_page_t 1733 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high, 1734 unsigned long alignment, unsigned long boundary, 1735 unsigned long size, vm_memattr_t memattr) 1736 { 1737 alist_blk_t blk; 1738 vm_page_t m; 1739 int i; 1740 1741 alignment >>= PAGE_SHIFT; 1742 if (alignment == 0) 1743 alignment = 1; 1744 boundary >>= PAGE_SHIFT; 1745 if (boundary == 0) 1746 boundary = 1; 1747 size = (size + PAGE_MASK) >> PAGE_SHIFT; 1748 1749 spin_lock(&vm_contig_spin); 1750 blk = alist_alloc(&vm_contig_alist, 0, size); 1751 if (blk == ALIST_BLOCK_NONE) { 1752 spin_unlock(&vm_contig_spin); 1753 if (bootverbose) { 1754 kprintf("vm_page_alloc_contig: %ldk nospace\n", 1755 (size + PAGE_MASK) * (PAGE_SIZE / 1024)); 1756 } 1757 return(NULL); 1758 } 1759 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) { 1760 alist_free(&vm_contig_alist, blk, size); 1761 spin_unlock(&vm_contig_spin); 1762 if (bootverbose) { 1763 kprintf("vm_page_alloc_contig: %ldk high " 1764 "%016jx failed\n", 1765 (size + PAGE_MASK) * (PAGE_SIZE / 1024), 1766 (intmax_t)high); 1767 } 1768 return(NULL); 1769 } 1770 spin_unlock(&vm_contig_spin); 1771 if (vm_contig_verbose) { 1772 kprintf("vm_page_alloc_contig: %016jx/%ldk\n", 1773 (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT, 1774 (size + PAGE_MASK) * (PAGE_SIZE / 1024)); 1775 } 1776 1777 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 1778 if (memattr != VM_MEMATTR_DEFAULT) 1779 for (i = 0;i < size;i++) 1780 pmap_page_set_memattr(&m[i], memattr); 1781 return m; 1782 } 1783 1784 /* 1785 * Free contiguously allocated pages. The pages will be wired but not busy. 1786 * When freeing to the alist we leave them wired and not busy. 1787 */ 1788 void 1789 vm_page_free_contig(vm_page_t m, unsigned long size) 1790 { 1791 vm_paddr_t pa = VM_PAGE_TO_PHYS(m); 1792 vm_pindex_t start = pa >> PAGE_SHIFT; 1793 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT; 1794 1795 if (vm_contig_verbose) { 1796 kprintf("vm_page_free_contig: %016jx/%ldk\n", 1797 (intmax_t)pa, size / 1024); 1798 } 1799 if (pa < vm_low_phys_reserved) { 1800 KKASSERT(pa + size <= vm_low_phys_reserved); 1801 spin_lock(&vm_contig_spin); 1802 alist_free(&vm_contig_alist, start, pages); 1803 spin_unlock(&vm_contig_spin); 1804 } else { 1805 while (pages) { 1806 vm_page_busy_wait(m, FALSE, "cpgfr"); 1807 vm_page_unwire(m, 0); 1808 vm_page_free(m); 1809 --pages; 1810 ++m; 1811 } 1812 1813 } 1814 } 1815 1816 1817 /* 1818 * Wait for sufficient free memory for nominal heavy memory use kernel 1819 * operations. 1820 * 1821 * WARNING! Be sure never to call this in any vm_pageout code path, which 1822 * will trivially deadlock the system. 1823 */ 1824 void 1825 vm_wait_nominal(void) 1826 { 1827 while (vm_page_count_min(0)) 1828 vm_wait(0); 1829 } 1830 1831 /* 1832 * Test if vm_wait_nominal() would block. 1833 */ 1834 int 1835 vm_test_nominal(void) 1836 { 1837 if (vm_page_count_min(0)) 1838 return(1); 1839 return(0); 1840 } 1841 1842 /* 1843 * Block until free pages are available for allocation, called in various 1844 * places before memory allocations. 1845 * 1846 * The caller may loop if vm_page_count_min() == FALSE so we cannot be 1847 * more generous then that. 1848 */ 1849 void 1850 vm_wait(int timo) 1851 { 1852 /* 1853 * never wait forever 1854 */ 1855 if (timo == 0) 1856 timo = hz; 1857 lwkt_gettoken(&vm_token); 1858 1859 if (curthread == pagethread) { 1860 /* 1861 * The pageout daemon itself needs pages, this is bad. 1862 */ 1863 if (vm_page_count_min(0)) { 1864 vm_pageout_pages_needed = 1; 1865 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo); 1866 } 1867 } else { 1868 /* 1869 * Wakeup the pageout daemon if necessary and wait. 1870 * 1871 * Do not wait indefinitely for the target to be reached, 1872 * as load might prevent it from being reached any time soon. 1873 * But wait a little to try to slow down page allocations 1874 * and to give more important threads (the pagedaemon) 1875 * allocation priority. 1876 */ 1877 if (vm_page_count_target()) { 1878 if (vm_pages_needed == 0) { 1879 vm_pages_needed = 1; 1880 wakeup(&vm_pages_needed); 1881 } 1882 ++vm_pages_waiting; /* SMP race ok */ 1883 tsleep(&vmstats.v_free_count, 0, "vmwait", timo); 1884 } 1885 } 1886 lwkt_reltoken(&vm_token); 1887 } 1888 1889 /* 1890 * Block until free pages are available for allocation 1891 * 1892 * Called only from vm_fault so that processes page faulting can be 1893 * easily tracked. 1894 */ 1895 void 1896 vm_wait_pfault(void) 1897 { 1898 /* 1899 * Wakeup the pageout daemon if necessary and wait. 1900 * 1901 * Do not wait indefinitely for the target to be reached, 1902 * as load might prevent it from being reached any time soon. 1903 * But wait a little to try to slow down page allocations 1904 * and to give more important threads (the pagedaemon) 1905 * allocation priority. 1906 */ 1907 if (vm_page_count_min(0)) { 1908 lwkt_gettoken(&vm_token); 1909 while (vm_page_count_severe()) { 1910 if (vm_page_count_target()) { 1911 if (vm_pages_needed == 0) { 1912 vm_pages_needed = 1; 1913 wakeup(&vm_pages_needed); 1914 } 1915 ++vm_pages_waiting; /* SMP race ok */ 1916 tsleep(&vmstats.v_free_count, 0, "pfault", hz); 1917 } 1918 } 1919 lwkt_reltoken(&vm_token); 1920 } 1921 } 1922 1923 /* 1924 * Put the specified page on the active list (if appropriate). Ensure 1925 * that act_count is at least ACT_INIT but do not otherwise mess with it. 1926 * 1927 * The caller should be holding the page busied ? XXX 1928 * This routine may not block. 1929 */ 1930 void 1931 vm_page_activate(vm_page_t m) 1932 { 1933 u_short oqueue; 1934 1935 vm_page_spin_lock(m); 1936 if (m->queue - m->pc != PQ_ACTIVE) { 1937 _vm_page_queue_spin_lock(m); 1938 oqueue = _vm_page_rem_queue_spinlocked(m); 1939 /* page is left spinlocked, queue is unlocked */ 1940 1941 if (oqueue == PQ_CACHE) 1942 mycpu->gd_cnt.v_reactivated++; 1943 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1944 if (m->act_count < ACT_INIT) 1945 m->act_count = ACT_INIT; 1946 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); 1947 } 1948 _vm_page_and_queue_spin_unlock(m); 1949 if (oqueue == PQ_CACHE || oqueue == PQ_FREE) 1950 pagedaemon_wakeup(); 1951 } else { 1952 if (m->act_count < ACT_INIT) 1953 m->act_count = ACT_INIT; 1954 vm_page_spin_unlock(m); 1955 } 1956 } 1957 1958 /* 1959 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1960 * routine is called when a page has been added to the cache or free 1961 * queues. 1962 * 1963 * This routine may not block. 1964 */ 1965 static __inline void 1966 vm_page_free_wakeup(void) 1967 { 1968 /* 1969 * If the pageout daemon itself needs pages, then tell it that 1970 * there are some free. 1971 */ 1972 if (vm_pageout_pages_needed && 1973 vmstats.v_cache_count + vmstats.v_free_count >= 1974 vmstats.v_pageout_free_min 1975 ) { 1976 vm_pageout_pages_needed = 0; 1977 wakeup(&vm_pageout_pages_needed); 1978 } 1979 1980 /* 1981 * Wakeup processes that are waiting on memory. 1982 * 1983 * Generally speaking we want to wakeup stuck processes as soon as 1984 * possible. !vm_page_count_min(0) is the absolute minimum point 1985 * where we can do this. Wait a bit longer to reduce degenerate 1986 * re-blocking (vm_page_free_hysteresis). The target check is just 1987 * to make sure the min-check w/hysteresis does not exceed the 1988 * normal target. 1989 */ 1990 if (vm_pages_waiting) { 1991 if (!vm_page_count_min(vm_page_free_hysteresis) || 1992 !vm_page_count_target()) { 1993 vm_pages_waiting = 0; 1994 wakeup(&vmstats.v_free_count); 1995 ++mycpu->gd_cnt.v_ppwakeups; 1996 } 1997 #if 0 1998 if (!vm_page_count_target()) { 1999 /* 2000 * Plenty of pages are free, wakeup everyone. 2001 */ 2002 vm_pages_waiting = 0; 2003 wakeup(&vmstats.v_free_count); 2004 ++mycpu->gd_cnt.v_ppwakeups; 2005 } else if (!vm_page_count_min(0)) { 2006 /* 2007 * Some pages are free, wakeup someone. 2008 */ 2009 int wcount = vm_pages_waiting; 2010 if (wcount > 0) 2011 --wcount; 2012 vm_pages_waiting = wcount; 2013 wakeup_one(&vmstats.v_free_count); 2014 ++mycpu->gd_cnt.v_ppwakeups; 2015 } 2016 #endif 2017 } 2018 } 2019 2020 /* 2021 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates 2022 * it from its VM object. 2023 * 2024 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on 2025 * return (the page will have been freed). 2026 */ 2027 void 2028 vm_page_free_toq(vm_page_t m) 2029 { 2030 mycpu->gd_cnt.v_tfree++; 2031 KKASSERT((m->flags & PG_MAPPED) == 0); 2032 KKASSERT(m->flags & PG_BUSY); 2033 2034 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { 2035 kprintf("vm_page_free: pindex(%lu), busy(%d), " 2036 "PG_BUSY(%d), hold(%d)\n", 2037 (u_long)m->pindex, m->busy, 2038 ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count); 2039 if ((m->queue - m->pc) == PQ_FREE) 2040 panic("vm_page_free: freeing free page"); 2041 else 2042 panic("vm_page_free: freeing busy page"); 2043 } 2044 2045 /* 2046 * Remove from object, spinlock the page and its queues and 2047 * remove from any queue. No queue spinlock will be held 2048 * after this section (because the page was removed from any 2049 * queue). 2050 */ 2051 vm_page_remove(m); 2052 vm_page_and_queue_spin_lock(m); 2053 _vm_page_rem_queue_spinlocked(m); 2054 2055 /* 2056 * No further management of fictitious pages occurs beyond object 2057 * and queue removal. 2058 */ 2059 if ((m->flags & PG_FICTITIOUS) != 0) { 2060 vm_page_spin_unlock(m); 2061 vm_page_wakeup(m); 2062 return; 2063 } 2064 2065 m->valid = 0; 2066 vm_page_undirty(m); 2067 2068 if (m->wire_count != 0) { 2069 if (m->wire_count > 1) { 2070 panic( 2071 "vm_page_free: invalid wire count (%d), pindex: 0x%lx", 2072 m->wire_count, (long)m->pindex); 2073 } 2074 panic("vm_page_free: freeing wired page"); 2075 } 2076 2077 /* 2078 * Clear the UNMANAGED flag when freeing an unmanaged page. 2079 * Clear the NEED_COMMIT flag 2080 */ 2081 if (m->flags & PG_UNMANAGED) 2082 vm_page_flag_clear(m, PG_UNMANAGED); 2083 if (m->flags & PG_NEED_COMMIT) 2084 vm_page_flag_clear(m, PG_NEED_COMMIT); 2085 2086 if (m->hold_count != 0) { 2087 vm_page_flag_clear(m, PG_ZERO); 2088 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); 2089 } else { 2090 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); 2091 } 2092 2093 /* 2094 * This sequence allows us to clear PG_BUSY while still holding 2095 * its spin lock, which reduces contention vs allocators. We 2096 * must not leave the queue locked or _vm_page_wakeup() may 2097 * deadlock. 2098 */ 2099 _vm_page_queue_spin_unlock(m); 2100 if (_vm_page_wakeup(m)) { 2101 vm_page_spin_unlock(m); 2102 wakeup(m); 2103 } else { 2104 vm_page_spin_unlock(m); 2105 } 2106 vm_page_free_wakeup(); 2107 } 2108 2109 /* 2110 * vm_page_free_fromq_fast() 2111 * 2112 * Remove a non-zero page from one of the free queues; the page is removed for 2113 * zeroing, so do not issue a wakeup. 2114 */ 2115 vm_page_t 2116 vm_page_free_fromq_fast(void) 2117 { 2118 static int qi; 2119 vm_page_t m; 2120 int i; 2121 2122 for (i = 0; i < PQ_L2_SIZE; ++i) { 2123 m = vm_page_list_find(PQ_FREE, qi, FALSE); 2124 /* page is returned spinlocked and removed from its queue */ 2125 if (m) { 2126 if (vm_page_busy_try(m, TRUE)) { 2127 /* 2128 * We were unable to busy the page, deactivate 2129 * it and loop. 2130 */ 2131 _vm_page_deactivate_locked(m, 0); 2132 vm_page_spin_unlock(m); 2133 } else if (m->flags & PG_ZERO) { 2134 /* 2135 * The page is PG_ZERO, requeue it and loop 2136 */ 2137 _vm_page_add_queue_spinlocked(m, 2138 PQ_FREE + m->pc, 2139 0); 2140 vm_page_queue_spin_unlock(m); 2141 if (_vm_page_wakeup(m)) { 2142 vm_page_spin_unlock(m); 2143 wakeup(m); 2144 } else { 2145 vm_page_spin_unlock(m); 2146 } 2147 } else { 2148 /* 2149 * The page is not PG_ZERO'd so return it. 2150 */ 2151 vm_page_spin_unlock(m); 2152 KKASSERT((m->flags & (PG_UNMANAGED | 2153 PG_NEED_COMMIT)) == 0); 2154 KKASSERT(m->hold_count == 0); 2155 KKASSERT(m->wire_count == 0); 2156 break; 2157 } 2158 m = NULL; 2159 } 2160 qi = (qi + PQ_PRIME2) & PQ_L2_MASK; 2161 } 2162 return (m); 2163 } 2164 2165 /* 2166 * vm_page_unmanage() 2167 * 2168 * Prevent PV management from being done on the page. The page is 2169 * removed from the paging queues as if it were wired, and as a 2170 * consequence of no longer being managed the pageout daemon will not 2171 * touch it (since there is no way to locate the pte mappings for the 2172 * page). madvise() calls that mess with the pmap will also no longer 2173 * operate on the page. 2174 * 2175 * Beyond that the page is still reasonably 'normal'. Freeing the page 2176 * will clear the flag. 2177 * 2178 * This routine is used by OBJT_PHYS objects - objects using unswappable 2179 * physical memory as backing store rather then swap-backed memory and 2180 * will eventually be extended to support 4MB unmanaged physical 2181 * mappings. 2182 * 2183 * Caller must be holding the page busy. 2184 */ 2185 void 2186 vm_page_unmanage(vm_page_t m) 2187 { 2188 KKASSERT(m->flags & PG_BUSY); 2189 if ((m->flags & PG_UNMANAGED) == 0) { 2190 if (m->wire_count == 0) 2191 vm_page_unqueue(m); 2192 } 2193 vm_page_flag_set(m, PG_UNMANAGED); 2194 } 2195 2196 /* 2197 * Mark this page as wired down by yet another map, removing it from 2198 * paging queues as necessary. 2199 * 2200 * Caller must be holding the page busy. 2201 */ 2202 void 2203 vm_page_wire(vm_page_t m) 2204 { 2205 /* 2206 * Only bump the wire statistics if the page is not already wired, 2207 * and only unqueue the page if it is on some queue (if it is unmanaged 2208 * it is already off the queues). Don't do anything with fictitious 2209 * pages because they are always wired. 2210 */ 2211 KKASSERT(m->flags & PG_BUSY); 2212 if ((m->flags & PG_FICTITIOUS) == 0) { 2213 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) { 2214 if ((m->flags & PG_UNMANAGED) == 0) 2215 vm_page_unqueue(m); 2216 atomic_add_int(&vmstats.v_wire_count, 1); 2217 } 2218 KASSERT(m->wire_count != 0, 2219 ("vm_page_wire: wire_count overflow m=%p", m)); 2220 } 2221 } 2222 2223 /* 2224 * Release one wiring of this page, potentially enabling it to be paged again. 2225 * 2226 * Many pages placed on the inactive queue should actually go 2227 * into the cache, but it is difficult to figure out which. What 2228 * we do instead, if the inactive target is well met, is to put 2229 * clean pages at the head of the inactive queue instead of the tail. 2230 * This will cause them to be moved to the cache more quickly and 2231 * if not actively re-referenced, freed more quickly. If we just 2232 * stick these pages at the end of the inactive queue, heavy filesystem 2233 * meta-data accesses can cause an unnecessary paging load on memory bound 2234 * processes. This optimization causes one-time-use metadata to be 2235 * reused more quickly. 2236 * 2237 * Pages marked PG_NEED_COMMIT are always activated and never placed on 2238 * the inactive queue. This helps the pageout daemon determine memory 2239 * pressure and act on out-of-memory situations more quickly. 2240 * 2241 * BUT, if we are in a low-memory situation we have no choice but to 2242 * put clean pages on the cache queue. 2243 * 2244 * A number of routines use vm_page_unwire() to guarantee that the page 2245 * will go into either the inactive or active queues, and will NEVER 2246 * be placed in the cache - for example, just after dirtying a page. 2247 * dirty pages in the cache are not allowed. 2248 * 2249 * This routine may not block. 2250 */ 2251 void 2252 vm_page_unwire(vm_page_t m, int activate) 2253 { 2254 KKASSERT(m->flags & PG_BUSY); 2255 if (m->flags & PG_FICTITIOUS) { 2256 /* do nothing */ 2257 } else if (m->wire_count <= 0) { 2258 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 2259 } else { 2260 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) { 2261 atomic_add_int(&vmstats.v_wire_count, -1); 2262 if (m->flags & PG_UNMANAGED) { 2263 ; 2264 } else if (activate || (m->flags & PG_NEED_COMMIT)) { 2265 vm_page_spin_lock(m); 2266 _vm_page_add_queue_spinlocked(m, 2267 PQ_ACTIVE + m->pc, 0); 2268 _vm_page_and_queue_spin_unlock(m); 2269 } else { 2270 vm_page_spin_lock(m); 2271 vm_page_flag_clear(m, PG_WINATCFLS); 2272 _vm_page_add_queue_spinlocked(m, 2273 PQ_INACTIVE + m->pc, 0); 2274 ++vm_swapcache_inactive_heuristic; 2275 _vm_page_and_queue_spin_unlock(m); 2276 } 2277 } 2278 } 2279 } 2280 2281 /* 2282 * Move the specified page to the inactive queue. If the page has 2283 * any associated swap, the swap is deallocated. 2284 * 2285 * Normally athead is 0 resulting in LRU operation. athead is set 2286 * to 1 if we want this page to be 'as if it were placed in the cache', 2287 * except without unmapping it from the process address space. 2288 * 2289 * vm_page's spinlock must be held on entry and will remain held on return. 2290 * This routine may not block. 2291 */ 2292 static void 2293 _vm_page_deactivate_locked(vm_page_t m, int athead) 2294 { 2295 u_short oqueue; 2296 2297 /* 2298 * Ignore if already inactive. 2299 */ 2300 if (m->queue - m->pc == PQ_INACTIVE) 2301 return; 2302 _vm_page_queue_spin_lock(m); 2303 oqueue = _vm_page_rem_queue_spinlocked(m); 2304 2305 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 2306 if (oqueue == PQ_CACHE) 2307 mycpu->gd_cnt.v_reactivated++; 2308 vm_page_flag_clear(m, PG_WINATCFLS); 2309 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead); 2310 if (athead == 0) 2311 ++vm_swapcache_inactive_heuristic; 2312 } 2313 /* NOTE: PQ_NONE if condition not taken */ 2314 _vm_page_queue_spin_unlock(m); 2315 /* leaves vm_page spinlocked */ 2316 } 2317 2318 /* 2319 * Attempt to deactivate a page. 2320 * 2321 * No requirements. 2322 */ 2323 void 2324 vm_page_deactivate(vm_page_t m) 2325 { 2326 vm_page_spin_lock(m); 2327 _vm_page_deactivate_locked(m, 0); 2328 vm_page_spin_unlock(m); 2329 } 2330 2331 void 2332 vm_page_deactivate_locked(vm_page_t m) 2333 { 2334 _vm_page_deactivate_locked(m, 0); 2335 } 2336 2337 /* 2338 * Attempt to move a page to PQ_CACHE. 2339 * 2340 * Returns 0 on failure, 1 on success 2341 * 2342 * The page should NOT be busied by the caller. This function will validate 2343 * whether the page can be safely moved to the cache. 2344 */ 2345 int 2346 vm_page_try_to_cache(vm_page_t m) 2347 { 2348 vm_page_spin_lock(m); 2349 if (vm_page_busy_try(m, TRUE)) { 2350 vm_page_spin_unlock(m); 2351 return(0); 2352 } 2353 if (m->dirty || m->hold_count || m->wire_count || 2354 (m->flags & (PG_UNMANAGED | PG_NEED_COMMIT))) { 2355 if (_vm_page_wakeup(m)) { 2356 vm_page_spin_unlock(m); 2357 wakeup(m); 2358 } else { 2359 vm_page_spin_unlock(m); 2360 } 2361 return(0); 2362 } 2363 vm_page_spin_unlock(m); 2364 2365 /* 2366 * Page busied by us and no longer spinlocked. Dirty pages cannot 2367 * be moved to the cache. 2368 */ 2369 vm_page_test_dirty(m); 2370 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2371 vm_page_wakeup(m); 2372 return(0); 2373 } 2374 vm_page_cache(m); 2375 return(1); 2376 } 2377 2378 /* 2379 * Attempt to free the page. If we cannot free it, we do nothing. 2380 * 1 is returned on success, 0 on failure. 2381 * 2382 * No requirements. 2383 */ 2384 int 2385 vm_page_try_to_free(vm_page_t m) 2386 { 2387 vm_page_spin_lock(m); 2388 if (vm_page_busy_try(m, TRUE)) { 2389 vm_page_spin_unlock(m); 2390 return(0); 2391 } 2392 2393 /* 2394 * The page can be in any state, including already being on the free 2395 * queue. Check to see if it really can be freed. 2396 */ 2397 if (m->dirty || /* can't free if it is dirty */ 2398 m->hold_count || /* or held (XXX may be wrong) */ 2399 m->wire_count || /* or wired */ 2400 (m->flags & (PG_UNMANAGED | /* or unmanaged */ 2401 PG_NEED_COMMIT)) || /* or needs a commit */ 2402 m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */ 2403 m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */ 2404 if (_vm_page_wakeup(m)) { 2405 vm_page_spin_unlock(m); 2406 wakeup(m); 2407 } else { 2408 vm_page_spin_unlock(m); 2409 } 2410 return(0); 2411 } 2412 vm_page_spin_unlock(m); 2413 2414 /* 2415 * We can probably free the page. 2416 * 2417 * Page busied by us and no longer spinlocked. Dirty pages will 2418 * not be freed by this function. We have to re-test the 2419 * dirty bit after cleaning out the pmaps. 2420 */ 2421 vm_page_test_dirty(m); 2422 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2423 vm_page_wakeup(m); 2424 return(0); 2425 } 2426 vm_page_protect(m, VM_PROT_NONE); 2427 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2428 vm_page_wakeup(m); 2429 return(0); 2430 } 2431 vm_page_free(m); 2432 return(1); 2433 } 2434 2435 /* 2436 * vm_page_cache 2437 * 2438 * Put the specified page onto the page cache queue (if appropriate). 2439 * 2440 * The page must be busy, and this routine will release the busy and 2441 * possibly even free the page. 2442 */ 2443 void 2444 vm_page_cache(vm_page_t m) 2445 { 2446 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) || 2447 m->busy || m->wire_count || m->hold_count) { 2448 kprintf("vm_page_cache: attempting to cache busy/held page\n"); 2449 vm_page_wakeup(m); 2450 return; 2451 } 2452 2453 /* 2454 * Already in the cache (and thus not mapped) 2455 */ 2456 if ((m->queue - m->pc) == PQ_CACHE) { 2457 KKASSERT((m->flags & PG_MAPPED) == 0); 2458 vm_page_wakeup(m); 2459 return; 2460 } 2461 2462 /* 2463 * Caller is required to test m->dirty, but note that the act of 2464 * removing the page from its maps can cause it to become dirty 2465 * on an SMP system due to another cpu running in usermode. 2466 */ 2467 if (m->dirty) { 2468 panic("vm_page_cache: caching a dirty page, pindex: %ld", 2469 (long)m->pindex); 2470 } 2471 2472 /* 2473 * Remove all pmaps and indicate that the page is not 2474 * writeable or mapped. Our vm_page_protect() call may 2475 * have blocked (especially w/ VM_PROT_NONE), so recheck 2476 * everything. 2477 */ 2478 vm_page_protect(m, VM_PROT_NONE); 2479 if ((m->flags & (PG_UNMANAGED | PG_MAPPED)) || 2480 m->busy || m->wire_count || m->hold_count) { 2481 vm_page_wakeup(m); 2482 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2483 vm_page_deactivate(m); 2484 vm_page_wakeup(m); 2485 } else { 2486 _vm_page_and_queue_spin_lock(m); 2487 _vm_page_rem_queue_spinlocked(m); 2488 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0); 2489 _vm_page_queue_spin_unlock(m); 2490 if (_vm_page_wakeup(m)) { 2491 vm_page_spin_unlock(m); 2492 wakeup(m); 2493 } else { 2494 vm_page_spin_unlock(m); 2495 } 2496 vm_page_free_wakeup(); 2497 } 2498 } 2499 2500 /* 2501 * vm_page_dontneed() 2502 * 2503 * Cache, deactivate, or do nothing as appropriate. This routine 2504 * is typically used by madvise() MADV_DONTNEED. 2505 * 2506 * Generally speaking we want to move the page into the cache so 2507 * it gets reused quickly. However, this can result in a silly syndrome 2508 * due to the page recycling too quickly. Small objects will not be 2509 * fully cached. On the otherhand, if we move the page to the inactive 2510 * queue we wind up with a problem whereby very large objects 2511 * unnecessarily blow away our inactive and cache queues. 2512 * 2513 * The solution is to move the pages based on a fixed weighting. We 2514 * either leave them alone, deactivate them, or move them to the cache, 2515 * where moving them to the cache has the highest weighting. 2516 * By forcing some pages into other queues we eventually force the 2517 * system to balance the queues, potentially recovering other unrelated 2518 * space from active. The idea is to not force this to happen too 2519 * often. 2520 * 2521 * The page must be busied. 2522 */ 2523 void 2524 vm_page_dontneed(vm_page_t m) 2525 { 2526 static int dnweight; 2527 int dnw; 2528 int head; 2529 2530 dnw = ++dnweight; 2531 2532 /* 2533 * occassionally leave the page alone 2534 */ 2535 if ((dnw & 0x01F0) == 0 || 2536 m->queue - m->pc == PQ_INACTIVE || 2537 m->queue - m->pc == PQ_CACHE 2538 ) { 2539 if (m->act_count >= ACT_INIT) 2540 --m->act_count; 2541 return; 2542 } 2543 2544 /* 2545 * If vm_page_dontneed() is inactivating a page, it must clear 2546 * the referenced flag; otherwise the pagedaemon will see references 2547 * on the page in the inactive queue and reactivate it. Until the 2548 * page can move to the cache queue, madvise's job is not done. 2549 */ 2550 vm_page_flag_clear(m, PG_REFERENCED); 2551 pmap_clear_reference(m); 2552 2553 if (m->dirty == 0) 2554 vm_page_test_dirty(m); 2555 2556 if (m->dirty || (dnw & 0x0070) == 0) { 2557 /* 2558 * Deactivate the page 3 times out of 32. 2559 */ 2560 head = 0; 2561 } else { 2562 /* 2563 * Cache the page 28 times out of every 32. Note that 2564 * the page is deactivated instead of cached, but placed 2565 * at the head of the queue instead of the tail. 2566 */ 2567 head = 1; 2568 } 2569 vm_page_spin_lock(m); 2570 _vm_page_deactivate_locked(m, head); 2571 vm_page_spin_unlock(m); 2572 } 2573 2574 /* 2575 * These routines manipulate the 'soft busy' count for a page. A soft busy 2576 * is almost like PG_BUSY except that it allows certain compatible operations 2577 * to occur on the page while it is busy. For example, a page undergoing a 2578 * write can still be mapped read-only. 2579 * 2580 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only 2581 * adjusted while the vm_page is PG_BUSY so the flash will occur when the 2582 * busy bit is cleared. 2583 */ 2584 void 2585 vm_page_io_start(vm_page_t m) 2586 { 2587 KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!")); 2588 atomic_add_char(&m->busy, 1); 2589 vm_page_flag_set(m, PG_SBUSY); 2590 } 2591 2592 void 2593 vm_page_io_finish(vm_page_t m) 2594 { 2595 KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!")); 2596 atomic_subtract_char(&m->busy, 1); 2597 if (m->busy == 0) 2598 vm_page_flag_clear(m, PG_SBUSY); 2599 } 2600 2601 /* 2602 * Indicate that a clean VM page requires a filesystem commit and cannot 2603 * be reused. Used by tmpfs. 2604 */ 2605 void 2606 vm_page_need_commit(vm_page_t m) 2607 { 2608 vm_page_flag_set(m, PG_NEED_COMMIT); 2609 vm_object_set_writeable_dirty(m->object); 2610 } 2611 2612 void 2613 vm_page_clear_commit(vm_page_t m) 2614 { 2615 vm_page_flag_clear(m, PG_NEED_COMMIT); 2616 } 2617 2618 /* 2619 * Grab a page, blocking if it is busy and allocating a page if necessary. 2620 * A busy page is returned or NULL. The page may or may not be valid and 2621 * might not be on a queue (the caller is responsible for the disposition of 2622 * the page). 2623 * 2624 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the 2625 * page will be zero'd and marked valid. 2626 * 2627 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked 2628 * valid even if it already exists. 2629 * 2630 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also 2631 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified. 2632 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified. 2633 * 2634 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is 2635 * always returned if we had blocked. 2636 * 2637 * This routine may not be called from an interrupt. 2638 * 2639 * PG_ZERO is *ALWAYS* cleared by this routine. 2640 * 2641 * No other requirements. 2642 */ 2643 vm_page_t 2644 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 2645 { 2646 vm_page_t m; 2647 int error; 2648 int shared = 1; 2649 2650 KKASSERT(allocflags & 2651 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 2652 vm_object_hold_shared(object); 2653 for (;;) { 2654 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error); 2655 if (error) { 2656 vm_page_sleep_busy(m, TRUE, "pgrbwt"); 2657 if ((allocflags & VM_ALLOC_RETRY) == 0) { 2658 m = NULL; 2659 break; 2660 } 2661 /* retry */ 2662 } else if (m == NULL) { 2663 if (shared) { 2664 vm_object_upgrade(object); 2665 shared = 0; 2666 } 2667 if (allocflags & VM_ALLOC_RETRY) 2668 allocflags |= VM_ALLOC_NULL_OK; 2669 m = vm_page_alloc(object, pindex, 2670 allocflags & ~VM_ALLOC_RETRY); 2671 if (m) 2672 break; 2673 vm_wait(0); 2674 if ((allocflags & VM_ALLOC_RETRY) == 0) 2675 goto failed; 2676 } else { 2677 /* m found */ 2678 break; 2679 } 2680 } 2681 2682 /* 2683 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid. 2684 * 2685 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set 2686 * valid even if already valid. 2687 */ 2688 if (m->valid == 0) { 2689 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) { 2690 if ((m->flags & PG_ZERO) == 0) 2691 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 2692 m->valid = VM_PAGE_BITS_ALL; 2693 } 2694 } else if (allocflags & VM_ALLOC_FORCE_ZERO) { 2695 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 2696 m->valid = VM_PAGE_BITS_ALL; 2697 } 2698 vm_page_flag_clear(m, PG_ZERO); 2699 failed: 2700 vm_object_drop(object); 2701 return(m); 2702 } 2703 2704 /* 2705 * Mapping function for valid bits or for dirty bits in 2706 * a page. May not block. 2707 * 2708 * Inputs are required to range within a page. 2709 * 2710 * No requirements. 2711 * Non blocking. 2712 */ 2713 int 2714 vm_page_bits(int base, int size) 2715 { 2716 int first_bit; 2717 int last_bit; 2718 2719 KASSERT( 2720 base + size <= PAGE_SIZE, 2721 ("vm_page_bits: illegal base/size %d/%d", base, size) 2722 ); 2723 2724 if (size == 0) /* handle degenerate case */ 2725 return(0); 2726 2727 first_bit = base >> DEV_BSHIFT; 2728 last_bit = (base + size - 1) >> DEV_BSHIFT; 2729 2730 return ((2 << last_bit) - (1 << first_bit)); 2731 } 2732 2733 /* 2734 * Sets portions of a page valid and clean. The arguments are expected 2735 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2736 * of any partial chunks touched by the range. The invalid portion of 2737 * such chunks will be zero'd. 2738 * 2739 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically 2740 * align base to DEV_BSIZE so as not to mark clean a partially 2741 * truncated device block. Otherwise the dirty page status might be 2742 * lost. 2743 * 2744 * This routine may not block. 2745 * 2746 * (base + size) must be less then or equal to PAGE_SIZE. 2747 */ 2748 static void 2749 _vm_page_zero_valid(vm_page_t m, int base, int size) 2750 { 2751 int frag; 2752 int endoff; 2753 2754 if (size == 0) /* handle degenerate case */ 2755 return; 2756 2757 /* 2758 * If the base is not DEV_BSIZE aligned and the valid 2759 * bit is clear, we have to zero out a portion of the 2760 * first block. 2761 */ 2762 2763 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2764 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 2765 ) { 2766 pmap_zero_page_area( 2767 VM_PAGE_TO_PHYS(m), 2768 frag, 2769 base - frag 2770 ); 2771 } 2772 2773 /* 2774 * If the ending offset is not DEV_BSIZE aligned and the 2775 * valid bit is clear, we have to zero out a portion of 2776 * the last block. 2777 */ 2778 2779 endoff = base + size; 2780 2781 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2782 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 2783 ) { 2784 pmap_zero_page_area( 2785 VM_PAGE_TO_PHYS(m), 2786 endoff, 2787 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 2788 ); 2789 } 2790 } 2791 2792 /* 2793 * Set valid, clear dirty bits. If validating the entire 2794 * page we can safely clear the pmap modify bit. We also 2795 * use this opportunity to clear the PG_NOSYNC flag. If a process 2796 * takes a write fault on a MAP_NOSYNC memory area the flag will 2797 * be set again. 2798 * 2799 * We set valid bits inclusive of any overlap, but we can only 2800 * clear dirty bits for DEV_BSIZE chunks that are fully within 2801 * the range. 2802 * 2803 * Page must be busied? 2804 * No other requirements. 2805 */ 2806 void 2807 vm_page_set_valid(vm_page_t m, int base, int size) 2808 { 2809 _vm_page_zero_valid(m, base, size); 2810 m->valid |= vm_page_bits(base, size); 2811 } 2812 2813 2814 /* 2815 * Set valid bits and clear dirty bits. 2816 * 2817 * NOTE: This function does not clear the pmap modified bit. 2818 * Also note that e.g. NFS may use a byte-granular base 2819 * and size. 2820 * 2821 * WARNING: Page must be busied? But vfs_clean_one_page() will call 2822 * this without necessarily busying the page (via bdwrite()). 2823 * So for now vm_token must also be held. 2824 * 2825 * No other requirements. 2826 */ 2827 void 2828 vm_page_set_validclean(vm_page_t m, int base, int size) 2829 { 2830 int pagebits; 2831 2832 _vm_page_zero_valid(m, base, size); 2833 pagebits = vm_page_bits(base, size); 2834 m->valid |= pagebits; 2835 m->dirty &= ~pagebits; 2836 if (base == 0 && size == PAGE_SIZE) { 2837 /*pmap_clear_modify(m);*/ 2838 vm_page_flag_clear(m, PG_NOSYNC); 2839 } 2840 } 2841 2842 /* 2843 * Set valid & dirty. Used by buwrite() 2844 * 2845 * WARNING: Page must be busied? But vfs_dirty_one_page() will 2846 * call this function in buwrite() so for now vm_token must 2847 * be held. 2848 * 2849 * No other requirements. 2850 */ 2851 void 2852 vm_page_set_validdirty(vm_page_t m, int base, int size) 2853 { 2854 int pagebits; 2855 2856 pagebits = vm_page_bits(base, size); 2857 m->valid |= pagebits; 2858 m->dirty |= pagebits; 2859 if (m->object) 2860 vm_object_set_writeable_dirty(m->object); 2861 } 2862 2863 /* 2864 * Clear dirty bits. 2865 * 2866 * NOTE: This function does not clear the pmap modified bit. 2867 * Also note that e.g. NFS may use a byte-granular base 2868 * and size. 2869 * 2870 * Page must be busied? 2871 * No other requirements. 2872 */ 2873 void 2874 vm_page_clear_dirty(vm_page_t m, int base, int size) 2875 { 2876 m->dirty &= ~vm_page_bits(base, size); 2877 if (base == 0 && size == PAGE_SIZE) { 2878 /*pmap_clear_modify(m);*/ 2879 vm_page_flag_clear(m, PG_NOSYNC); 2880 } 2881 } 2882 2883 /* 2884 * Make the page all-dirty. 2885 * 2886 * Also make sure the related object and vnode reflect the fact that the 2887 * object may now contain a dirty page. 2888 * 2889 * Page must be busied? 2890 * No other requirements. 2891 */ 2892 void 2893 vm_page_dirty(vm_page_t m) 2894 { 2895 #ifdef INVARIANTS 2896 int pqtype = m->queue - m->pc; 2897 #endif 2898 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE, 2899 ("vm_page_dirty: page in free/cache queue!")); 2900 if (m->dirty != VM_PAGE_BITS_ALL) { 2901 m->dirty = VM_PAGE_BITS_ALL; 2902 if (m->object) 2903 vm_object_set_writeable_dirty(m->object); 2904 } 2905 } 2906 2907 /* 2908 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2909 * valid and dirty bits for the effected areas are cleared. 2910 * 2911 * Page must be busied? 2912 * Does not block. 2913 * No other requirements. 2914 */ 2915 void 2916 vm_page_set_invalid(vm_page_t m, int base, int size) 2917 { 2918 int bits; 2919 2920 bits = vm_page_bits(base, size); 2921 m->valid &= ~bits; 2922 m->dirty &= ~bits; 2923 m->object->generation++; 2924 } 2925 2926 /* 2927 * The kernel assumes that the invalid portions of a page contain 2928 * garbage, but such pages can be mapped into memory by user code. 2929 * When this occurs, we must zero out the non-valid portions of the 2930 * page so user code sees what it expects. 2931 * 2932 * Pages are most often semi-valid when the end of a file is mapped 2933 * into memory and the file's size is not page aligned. 2934 * 2935 * Page must be busied? 2936 * No other requirements. 2937 */ 2938 void 2939 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2940 { 2941 int b; 2942 int i; 2943 2944 /* 2945 * Scan the valid bits looking for invalid sections that 2946 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2947 * valid bit may be set ) have already been zerod by 2948 * vm_page_set_validclean(). 2949 */ 2950 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2951 if (i == (PAGE_SIZE / DEV_BSIZE) || 2952 (m->valid & (1 << i)) 2953 ) { 2954 if (i > b) { 2955 pmap_zero_page_area( 2956 VM_PAGE_TO_PHYS(m), 2957 b << DEV_BSHIFT, 2958 (i - b) << DEV_BSHIFT 2959 ); 2960 } 2961 b = i + 1; 2962 } 2963 } 2964 2965 /* 2966 * setvalid is TRUE when we can safely set the zero'd areas 2967 * as being valid. We can do this if there are no cache consistency 2968 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2969 */ 2970 if (setvalid) 2971 m->valid = VM_PAGE_BITS_ALL; 2972 } 2973 2974 /* 2975 * Is a (partial) page valid? Note that the case where size == 0 2976 * will return FALSE in the degenerate case where the page is entirely 2977 * invalid, and TRUE otherwise. 2978 * 2979 * Does not block. 2980 * No other requirements. 2981 */ 2982 int 2983 vm_page_is_valid(vm_page_t m, int base, int size) 2984 { 2985 int bits = vm_page_bits(base, size); 2986 2987 if (m->valid && ((m->valid & bits) == bits)) 2988 return 1; 2989 else 2990 return 0; 2991 } 2992 2993 /* 2994 * update dirty bits from pmap/mmu. May not block. 2995 * 2996 * Caller must hold the page busy 2997 */ 2998 void 2999 vm_page_test_dirty(vm_page_t m) 3000 { 3001 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 3002 vm_page_dirty(m); 3003 } 3004 } 3005 3006 /* 3007 * Register an action, associating it with its vm_page 3008 */ 3009 void 3010 vm_page_register_action(vm_page_action_t action, vm_page_event_t event) 3011 { 3012 struct vm_page_action_list *list; 3013 int hv; 3014 3015 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; 3016 list = &action_list[hv]; 3017 3018 lwkt_gettoken(&vm_token); 3019 vm_page_flag_set(action->m, PG_ACTIONLIST); 3020 action->event = event; 3021 LIST_INSERT_HEAD(list, action, entry); 3022 lwkt_reltoken(&vm_token); 3023 } 3024 3025 /* 3026 * Unregister an action, disassociating it from its related vm_page 3027 */ 3028 void 3029 vm_page_unregister_action(vm_page_action_t action) 3030 { 3031 struct vm_page_action_list *list; 3032 int hv; 3033 3034 lwkt_gettoken(&vm_token); 3035 if (action->event != VMEVENT_NONE) { 3036 action->event = VMEVENT_NONE; 3037 LIST_REMOVE(action, entry); 3038 3039 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; 3040 list = &action_list[hv]; 3041 if (LIST_EMPTY(list)) 3042 vm_page_flag_clear(action->m, PG_ACTIONLIST); 3043 } 3044 lwkt_reltoken(&vm_token); 3045 } 3046 3047 /* 3048 * Issue an event on a VM page. Corresponding action structures are 3049 * removed from the page's list and called. 3050 * 3051 * If the vm_page has no more pending action events we clear its 3052 * PG_ACTIONLIST flag. 3053 */ 3054 void 3055 vm_page_event_internal(vm_page_t m, vm_page_event_t event) 3056 { 3057 struct vm_page_action_list *list; 3058 struct vm_page_action *scan; 3059 struct vm_page_action *next; 3060 int hv; 3061 int all; 3062 3063 hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK; 3064 list = &action_list[hv]; 3065 all = 1; 3066 3067 lwkt_gettoken(&vm_token); 3068 LIST_FOREACH_MUTABLE(scan, list, entry, next) { 3069 if (scan->m == m) { 3070 if (scan->event == event) { 3071 scan->event = VMEVENT_NONE; 3072 LIST_REMOVE(scan, entry); 3073 scan->func(m, scan); 3074 /* XXX */ 3075 } else { 3076 all = 0; 3077 } 3078 } 3079 } 3080 if (all) 3081 vm_page_flag_clear(m, PG_ACTIONLIST); 3082 lwkt_reltoken(&vm_token); 3083 } 3084 3085 #include "opt_ddb.h" 3086 #ifdef DDB 3087 #include <sys/kernel.h> 3088 3089 #include <ddb/ddb.h> 3090 3091 DB_SHOW_COMMAND(page, vm_page_print_page_info) 3092 { 3093 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count); 3094 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count); 3095 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count); 3096 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count); 3097 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count); 3098 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved); 3099 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min); 3100 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target); 3101 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min); 3102 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target); 3103 } 3104 3105 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 3106 { 3107 int i; 3108 db_printf("PQ_FREE:"); 3109 for(i=0;i<PQ_L2_SIZE;i++) { 3110 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 3111 } 3112 db_printf("\n"); 3113 3114 db_printf("PQ_CACHE:"); 3115 for(i=0;i<PQ_L2_SIZE;i++) { 3116 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 3117 } 3118 db_printf("\n"); 3119 3120 db_printf("PQ_ACTIVE:"); 3121 for(i=0;i<PQ_L2_SIZE;i++) { 3122 db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt); 3123 } 3124 db_printf("\n"); 3125 3126 db_printf("PQ_INACTIVE:"); 3127 for(i=0;i<PQ_L2_SIZE;i++) { 3128 db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt); 3129 } 3130 db_printf("\n"); 3131 } 3132 #endif /* DDB */ 3133