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, "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, "vm_page_queue_init"); 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 * Reserve a large amount of low memory for potential 32-bit DMA 347 * space allocations. Once device initialization is complete we 348 * release most of it, but keep (vm_dma_reserved) memory reserved 349 * for later use. Typically for X / graphics. Through trial and 350 * error we find that GPUs usually requires ~60-100MB or so. 351 * 352 * By default, 128M is left in reserve on machines with 2G+ of ram. 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 = 128 * 1024 * 1024; /* 128MB */ 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(). If the page is on the HOLD queue 888 * it was freed while held and must be moved back to the FREE queue. 889 */ 890 void 891 vm_page_unhold(vm_page_t m) 892 { 893 KASSERT(m->hold_count > 0 && m->queue - m->pc != PQ_FREE, 894 ("vm_page_unhold: pg %p illegal hold_count (%d) or on FREE queue (%d)", 895 m, m->hold_count, m->queue - m->pc)); 896 vm_page_spin_lock(m); 897 atomic_add_int(&m->hold_count, -1); 898 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) { 899 _vm_page_queue_spin_lock(m); 900 _vm_page_rem_queue_spinlocked(m); 901 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); 902 _vm_page_queue_spin_unlock(m); 903 } 904 vm_page_spin_unlock(m); 905 } 906 907 /* 908 * vm_page_getfake: 909 * 910 * Create a fictitious page with the specified physical address and 911 * memory attribute. The memory attribute is the only the machine- 912 * dependent aspect of a fictitious page that must be initialized. 913 */ 914 915 void 916 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 917 { 918 919 if ((m->flags & PG_FICTITIOUS) != 0) { 920 /* 921 * The page's memattr might have changed since the 922 * previous initialization. Update the pmap to the 923 * new memattr. 924 */ 925 goto memattr; 926 } 927 m->phys_addr = paddr; 928 m->queue = PQ_NONE; 929 /* Fictitious pages don't use "segind". */ 930 /* Fictitious pages don't use "order" or "pool". */ 931 m->flags = PG_FICTITIOUS | PG_UNMANAGED | PG_BUSY; 932 m->wire_count = 1; 933 pmap_page_init(m); 934 memattr: 935 pmap_page_set_memattr(m, memattr); 936 } 937 938 /* 939 * Inserts the given vm_page into the object and object list. 940 * 941 * The pagetables are not updated but will presumably fault the page 942 * in if necessary, or if a kernel page the caller will at some point 943 * enter the page into the kernel's pmap. We are not allowed to block 944 * here so we *can't* do this anyway. 945 * 946 * This routine may not block. 947 * This routine must be called with the vm_object held. 948 * This routine must be called with a critical section held. 949 * 950 * This routine returns TRUE if the page was inserted into the object 951 * successfully, and FALSE if the page already exists in the object. 952 */ 953 int 954 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 955 { 956 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object)); 957 if (m->object != NULL) 958 panic("vm_page_insert: already inserted"); 959 960 object->generation++; 961 962 /* 963 * Record the object/offset pair in this page and add the 964 * pv_list_count of the page to the object. 965 * 966 * The vm_page spin lock is required for interactions with the pmap. 967 */ 968 vm_page_spin_lock(m); 969 m->object = object; 970 m->pindex = pindex; 971 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) { 972 m->object = NULL; 973 m->pindex = 0; 974 vm_page_spin_unlock(m); 975 return FALSE; 976 } 977 ++object->resident_page_count; 978 ++mycpu->gd_vmtotal.t_rm; 979 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */ 980 vm_page_spin_unlock(m); 981 982 /* 983 * Since we are inserting a new and possibly dirty page, 984 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 985 */ 986 if ((m->valid & m->dirty) || 987 (m->flags & (PG_WRITEABLE | PG_NEED_COMMIT))) 988 vm_object_set_writeable_dirty(object); 989 990 /* 991 * Checks for a swap assignment and sets PG_SWAPPED if appropriate. 992 */ 993 swap_pager_page_inserted(m); 994 return TRUE; 995 } 996 997 /* 998 * Removes the given vm_page_t from the (object,index) table 999 * 1000 * The underlying pmap entry (if any) is NOT removed here. 1001 * This routine may not block. 1002 * 1003 * The page must be BUSY and will remain BUSY on return. 1004 * No other requirements. 1005 * 1006 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave 1007 * it busy. 1008 */ 1009 void 1010 vm_page_remove(vm_page_t m) 1011 { 1012 vm_object_t object; 1013 1014 if (m->object == NULL) { 1015 return; 1016 } 1017 1018 if ((m->flags & PG_BUSY) == 0) 1019 panic("vm_page_remove: page not busy"); 1020 1021 object = m->object; 1022 1023 vm_object_hold(object); 1024 1025 /* 1026 * Remove the page from the object and update the object. 1027 * 1028 * The vm_page spin lock is required for interactions with the pmap. 1029 */ 1030 vm_page_spin_lock(m); 1031 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); 1032 --object->resident_page_count; 1033 --mycpu->gd_vmtotal.t_rm; 1034 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */ 1035 m->object = NULL; 1036 vm_page_spin_unlock(m); 1037 1038 object->generation++; 1039 1040 vm_object_drop(object); 1041 } 1042 1043 /* 1044 * Locate and return the page at (object, pindex), or NULL if the 1045 * page could not be found. 1046 * 1047 * The caller must hold the vm_object token. 1048 */ 1049 vm_page_t 1050 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 1051 { 1052 vm_page_t m; 1053 1054 /* 1055 * Search the hash table for this object/offset pair 1056 */ 1057 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1058 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1059 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex)); 1060 return(m); 1061 } 1062 1063 vm_page_t 1064 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object, 1065 vm_pindex_t pindex, 1066 int also_m_busy, const char *msg 1067 VM_PAGE_DEBUG_ARGS) 1068 { 1069 u_int32_t flags; 1070 vm_page_t m; 1071 1072 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1073 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1074 while (m) { 1075 KKASSERT(m->object == object && m->pindex == pindex); 1076 flags = m->flags; 1077 cpu_ccfence(); 1078 if (flags & PG_BUSY) { 1079 tsleep_interlock(m, 0); 1080 if (atomic_cmpset_int(&m->flags, flags, 1081 flags | PG_WANTED | PG_REFERENCED)) { 1082 tsleep(m, PINTERLOCKED, msg, 0); 1083 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1084 pindex); 1085 } 1086 } else if (also_m_busy && (flags & PG_SBUSY)) { 1087 tsleep_interlock(m, 0); 1088 if (atomic_cmpset_int(&m->flags, flags, 1089 flags | PG_WANTED | PG_REFERENCED)) { 1090 tsleep(m, PINTERLOCKED, msg, 0); 1091 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1092 pindex); 1093 } 1094 } else if (atomic_cmpset_int(&m->flags, flags, 1095 flags | PG_BUSY)) { 1096 #ifdef VM_PAGE_DEBUG 1097 m->busy_func = func; 1098 m->busy_line = lineno; 1099 #endif 1100 break; 1101 } 1102 } 1103 return m; 1104 } 1105 1106 /* 1107 * Attempt to lookup and busy a page. 1108 * 1109 * Returns NULL if the page could not be found 1110 * 1111 * Returns a vm_page and error == TRUE if the page exists but could not 1112 * be busied. 1113 * 1114 * Returns a vm_page and error == FALSE on success. 1115 */ 1116 vm_page_t 1117 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object, 1118 vm_pindex_t pindex, 1119 int also_m_busy, int *errorp 1120 VM_PAGE_DEBUG_ARGS) 1121 { 1122 u_int32_t flags; 1123 vm_page_t m; 1124 1125 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1126 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1127 *errorp = FALSE; 1128 while (m) { 1129 KKASSERT(m->object == object && m->pindex == pindex); 1130 flags = m->flags; 1131 cpu_ccfence(); 1132 if (flags & PG_BUSY) { 1133 *errorp = TRUE; 1134 break; 1135 } 1136 if (also_m_busy && (flags & PG_SBUSY)) { 1137 *errorp = TRUE; 1138 break; 1139 } 1140 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { 1141 #ifdef VM_PAGE_DEBUG 1142 m->busy_func = func; 1143 m->busy_line = lineno; 1144 #endif 1145 break; 1146 } 1147 } 1148 return m; 1149 } 1150 1151 /* 1152 * Caller must hold the related vm_object 1153 */ 1154 vm_page_t 1155 vm_page_next(vm_page_t m) 1156 { 1157 vm_page_t next; 1158 1159 next = vm_page_rb_tree_RB_NEXT(m); 1160 if (next && next->pindex != m->pindex + 1) 1161 next = NULL; 1162 return (next); 1163 } 1164 1165 /* 1166 * vm_page_rename() 1167 * 1168 * Move the given vm_page from its current object to the specified 1169 * target object/offset. The page must be busy and will remain so 1170 * on return. 1171 * 1172 * new_object must be held. 1173 * This routine might block. XXX ? 1174 * 1175 * NOTE: Swap associated with the page must be invalidated by the move. We 1176 * have to do this for several reasons: (1) we aren't freeing the 1177 * page, (2) we are dirtying the page, (3) the VM system is probably 1178 * moving the page from object A to B, and will then later move 1179 * the backing store from A to B and we can't have a conflict. 1180 * 1181 * NOTE: We *always* dirty the page. It is necessary both for the 1182 * fact that we moved it, and because we may be invalidating 1183 * swap. If the page is on the cache, we have to deactivate it 1184 * or vm_page_dirty() will panic. Dirty pages are not allowed 1185 * on the cache. 1186 */ 1187 void 1188 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1189 { 1190 KKASSERT(m->flags & PG_BUSY); 1191 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object)); 1192 if (m->object) { 1193 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m->object)); 1194 vm_page_remove(m); 1195 } 1196 if (vm_page_insert(m, new_object, new_pindex) == FALSE) { 1197 panic("vm_page_rename: target exists (%p,%"PRIu64")", 1198 new_object, new_pindex); 1199 } 1200 if (m->queue - m->pc == PQ_CACHE) 1201 vm_page_deactivate(m); 1202 vm_page_dirty(m); 1203 } 1204 1205 /* 1206 * vm_page_unqueue() without any wakeup. This routine is used when a page 1207 * is to remain BUSYied by the 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 KASSERT(m->hold_count == 0, ("m->hold_count is not zero " 1450 "pg %p q=%d flags=%08x hold=%d wire=%d", 1451 m, m->queue, m->flags, m->hold_count, m->wire_count)); 1452 KKASSERT(m->wire_count == 0); 1453 vm_page_spin_unlock(m); 1454 pagedaemon_wakeup(); 1455 1456 /* return busied and removed page */ 1457 return(m); 1458 } 1459 } 1460 return(m); 1461 } 1462 1463 /* 1464 * This implements a per-cpu cache of free, zero'd, ready-to-go pages. 1465 * The idea is to populate this cache prior to acquiring any locks so 1466 * we don't wind up potentially zeroing VM pages (under heavy loads) while 1467 * holding potentialy contending locks. 1468 * 1469 * Note that we allocate the page uninserted into anything and use a pindex 1470 * of 0, the vm_page_alloc() will effectively add gd_cpuid so these 1471 * allocations should wind up being uncontended. However, we still want 1472 * to rove across PQ_L2_SIZE. 1473 */ 1474 void 1475 vm_page_pcpu_cache(void) 1476 { 1477 #if 0 1478 globaldata_t gd = mycpu; 1479 vm_page_t m; 1480 1481 if (gd->gd_vmpg_count < GD_MINVMPG) { 1482 crit_enter_gd(gd); 1483 while (gd->gd_vmpg_count < GD_MAXVMPG) { 1484 m = vm_page_alloc(NULL, ticks & ~ncpus2_mask, 1485 VM_ALLOC_NULL_OK | VM_ALLOC_NORMAL | 1486 VM_ALLOC_NULL_OK | VM_ALLOC_ZERO); 1487 if (gd->gd_vmpg_count < GD_MAXVMPG) { 1488 if ((m->flags & PG_ZERO) == 0) { 1489 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 1490 vm_page_flag_set(m, PG_ZERO); 1491 } 1492 gd->gd_vmpg_array[gd->gd_vmpg_count++] = m; 1493 } else { 1494 vm_page_free(m); 1495 } 1496 } 1497 crit_exit_gd(gd); 1498 } 1499 #endif 1500 } 1501 1502 /* 1503 * vm_page_alloc() 1504 * 1505 * Allocate and return a memory cell associated with this VM object/offset 1506 * pair. If object is NULL an unassociated page will be allocated. 1507 * 1508 * The returned page will be busied and removed from its queues. This 1509 * routine can block and may return NULL if a race occurs and the page 1510 * is found to already exist at the specified (object, pindex). 1511 * 1512 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain 1513 * VM_ALLOC_QUICK like normal but cannot use cache 1514 * VM_ALLOC_SYSTEM greater free drain 1515 * VM_ALLOC_INTERRUPT allow free list to be completely drained 1516 * VM_ALLOC_ZERO advisory request for pre-zero'd page only 1517 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only 1518 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision 1519 * (see vm_page_grab()) 1520 * VM_ALLOC_USE_GD ok to use per-gd cache 1521 * 1522 * The object must be held if not NULL 1523 * This routine may not block 1524 * 1525 * Additional special handling is required when called from an interrupt 1526 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache 1527 * in this case. 1528 */ 1529 vm_page_t 1530 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req) 1531 { 1532 globaldata_t gd = mycpu; 1533 vm_object_t obj; 1534 vm_page_t m; 1535 u_short pg_color; 1536 1537 #if 0 1538 /* 1539 * Special per-cpu free VM page cache. The pages are pre-busied 1540 * and pre-zerod for us. 1541 */ 1542 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) { 1543 crit_enter_gd(gd); 1544 if (gd->gd_vmpg_count) { 1545 m = gd->gd_vmpg_array[--gd->gd_vmpg_count]; 1546 crit_exit_gd(gd); 1547 goto done; 1548 } 1549 crit_exit_gd(gd); 1550 } 1551 #endif 1552 m = NULL; 1553 1554 /* 1555 * Cpu twist - cpu localization algorithm 1556 */ 1557 if (object) { 1558 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask) + 1559 (object->pg_color & ~ncpus_fit_mask); 1560 } else { 1561 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask); 1562 } 1563 KKASSERT(page_req & 1564 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK| 1565 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 1566 1567 /* 1568 * Certain system threads (pageout daemon, buf_daemon's) are 1569 * allowed to eat deeper into the free page list. 1570 */ 1571 if (curthread->td_flags & TDF_SYSTHREAD) 1572 page_req |= VM_ALLOC_SYSTEM; 1573 1574 /* 1575 * Impose various limitations. Note that the v_free_reserved test 1576 * must match the opposite of vm_page_count_target() to avoid 1577 * livelocks, be careful. 1578 */ 1579 loop: 1580 if (vmstats.v_free_count >= vmstats.v_free_reserved || 1581 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) || 1582 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 && 1583 vmstats.v_free_count > vmstats.v_interrupt_free_min) 1584 ) { 1585 /* 1586 * The free queue has sufficient free pages to take one out. 1587 */ 1588 if (page_req & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) 1589 m = vm_page_select_free(pg_color, TRUE); 1590 else 1591 m = vm_page_select_free(pg_color, FALSE); 1592 } else if (page_req & VM_ALLOC_NORMAL) { 1593 /* 1594 * Allocatable from the cache (non-interrupt only). On 1595 * success, we must free the page and try again, thus 1596 * ensuring that vmstats.v_*_free_min counters are replenished. 1597 */ 1598 #ifdef INVARIANTS 1599 if (curthread->td_preempted) { 1600 kprintf("vm_page_alloc(): warning, attempt to allocate" 1601 " cache page from preempting interrupt\n"); 1602 m = NULL; 1603 } else { 1604 m = vm_page_select_cache(pg_color); 1605 } 1606 #else 1607 m = vm_page_select_cache(pg_color); 1608 #endif 1609 /* 1610 * On success move the page into the free queue and loop. 1611 * 1612 * Only do this if we can safely acquire the vm_object lock, 1613 * because this is effectively a random page and the caller 1614 * might be holding the lock shared, we don't want to 1615 * deadlock. 1616 */ 1617 if (m != NULL) { 1618 KASSERT(m->dirty == 0, 1619 ("Found dirty cache page %p", m)); 1620 if ((obj = m->object) != NULL) { 1621 if (vm_object_hold_try(obj)) { 1622 vm_page_protect(m, VM_PROT_NONE); 1623 vm_page_free(m); 1624 /* m->object NULL here */ 1625 vm_object_drop(obj); 1626 } else { 1627 vm_page_deactivate(m); 1628 vm_page_wakeup(m); 1629 } 1630 } else { 1631 vm_page_protect(m, VM_PROT_NONE); 1632 vm_page_free(m); 1633 } 1634 goto loop; 1635 } 1636 1637 /* 1638 * On failure return NULL 1639 */ 1640 #if defined(DIAGNOSTIC) 1641 if (vmstats.v_cache_count > 0) 1642 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count); 1643 #endif 1644 vm_pageout_deficit++; 1645 pagedaemon_wakeup(); 1646 return (NULL); 1647 } else { 1648 /* 1649 * No pages available, wakeup the pageout daemon and give up. 1650 */ 1651 vm_pageout_deficit++; 1652 pagedaemon_wakeup(); 1653 return (NULL); 1654 } 1655 1656 /* 1657 * v_free_count can race so loop if we don't find the expected 1658 * page. 1659 */ 1660 if (m == NULL) 1661 goto loop; 1662 1663 /* 1664 * Good page found. The page has already been busied for us and 1665 * removed from its queues. 1666 */ 1667 KASSERT(m->dirty == 0, 1668 ("vm_page_alloc: free/cache page %p was dirty", m)); 1669 KKASSERT(m->queue == PQ_NONE); 1670 1671 #if 0 1672 done: 1673 #endif 1674 /* 1675 * Initialize the structure, inheriting some flags but clearing 1676 * all the rest. The page has already been busied for us. 1677 */ 1678 vm_page_flag_clear(m, ~(PG_ZERO | PG_BUSY | PG_SBUSY)); 1679 KKASSERT(m->wire_count == 0); 1680 KKASSERT(m->busy == 0); 1681 m->act_count = 0; 1682 m->valid = 0; 1683 1684 /* 1685 * Caller must be holding the object lock (asserted by 1686 * vm_page_insert()). 1687 * 1688 * NOTE: Inserting a page here does not insert it into any pmaps 1689 * (which could cause us to block allocating memory). 1690 * 1691 * NOTE: If no object an unassociated page is allocated, m->pindex 1692 * can be used by the caller for any purpose. 1693 */ 1694 if (object) { 1695 if (vm_page_insert(m, object, pindex) == FALSE) { 1696 vm_page_free(m); 1697 if ((page_req & VM_ALLOC_NULL_OK) == 0) 1698 panic("PAGE RACE %p[%ld]/%p", 1699 object, (long)pindex, m); 1700 m = NULL; 1701 } 1702 } else { 1703 m->pindex = pindex; 1704 } 1705 1706 /* 1707 * Don't wakeup too often - wakeup the pageout daemon when 1708 * we would be nearly out of memory. 1709 */ 1710 pagedaemon_wakeup(); 1711 1712 /* 1713 * A PG_BUSY page is returned. 1714 */ 1715 return (m); 1716 } 1717 1718 /* 1719 * Returns number of pages available in our DMA memory reserve 1720 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf) 1721 */ 1722 vm_size_t 1723 vm_contig_avail_pages(void) 1724 { 1725 alist_blk_t blk; 1726 alist_blk_t count; 1727 alist_blk_t bfree; 1728 spin_lock(&vm_contig_spin); 1729 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 1730 spin_unlock(&vm_contig_spin); 1731 1732 return bfree; 1733 } 1734 1735 /* 1736 * Attempt to allocate contiguous physical memory with the specified 1737 * requirements. 1738 */ 1739 vm_page_t 1740 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high, 1741 unsigned long alignment, unsigned long boundary, 1742 unsigned long size, vm_memattr_t memattr) 1743 { 1744 alist_blk_t blk; 1745 vm_page_t m; 1746 int i; 1747 1748 alignment >>= PAGE_SHIFT; 1749 if (alignment == 0) 1750 alignment = 1; 1751 boundary >>= PAGE_SHIFT; 1752 if (boundary == 0) 1753 boundary = 1; 1754 size = (size + PAGE_MASK) >> PAGE_SHIFT; 1755 1756 spin_lock(&vm_contig_spin); 1757 blk = alist_alloc(&vm_contig_alist, 0, size); 1758 if (blk == ALIST_BLOCK_NONE) { 1759 spin_unlock(&vm_contig_spin); 1760 if (bootverbose) { 1761 kprintf("vm_page_alloc_contig: %ldk nospace\n", 1762 (size + PAGE_MASK) * (PAGE_SIZE / 1024)); 1763 } 1764 return(NULL); 1765 } 1766 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) { 1767 alist_free(&vm_contig_alist, blk, size); 1768 spin_unlock(&vm_contig_spin); 1769 if (bootverbose) { 1770 kprintf("vm_page_alloc_contig: %ldk high " 1771 "%016jx failed\n", 1772 (size + PAGE_MASK) * (PAGE_SIZE / 1024), 1773 (intmax_t)high); 1774 } 1775 return(NULL); 1776 } 1777 spin_unlock(&vm_contig_spin); 1778 if (vm_contig_verbose) { 1779 kprintf("vm_page_alloc_contig: %016jx/%ldk\n", 1780 (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT, 1781 (size + PAGE_MASK) * (PAGE_SIZE / 1024)); 1782 } 1783 1784 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 1785 if (memattr != VM_MEMATTR_DEFAULT) 1786 for (i = 0;i < size;i++) 1787 pmap_page_set_memattr(&m[i], memattr); 1788 return m; 1789 } 1790 1791 /* 1792 * Free contiguously allocated pages. The pages will be wired but not busy. 1793 * When freeing to the alist we leave them wired and not busy. 1794 */ 1795 void 1796 vm_page_free_contig(vm_page_t m, unsigned long size) 1797 { 1798 vm_paddr_t pa = VM_PAGE_TO_PHYS(m); 1799 vm_pindex_t start = pa >> PAGE_SHIFT; 1800 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT; 1801 1802 if (vm_contig_verbose) { 1803 kprintf("vm_page_free_contig: %016jx/%ldk\n", 1804 (intmax_t)pa, size / 1024); 1805 } 1806 if (pa < vm_low_phys_reserved) { 1807 KKASSERT(pa + size <= vm_low_phys_reserved); 1808 spin_lock(&vm_contig_spin); 1809 alist_free(&vm_contig_alist, start, pages); 1810 spin_unlock(&vm_contig_spin); 1811 } else { 1812 while (pages) { 1813 vm_page_busy_wait(m, FALSE, "cpgfr"); 1814 vm_page_unwire(m, 0); 1815 vm_page_free(m); 1816 --pages; 1817 ++m; 1818 } 1819 1820 } 1821 } 1822 1823 1824 /* 1825 * Wait for sufficient free memory for nominal heavy memory use kernel 1826 * operations. 1827 * 1828 * WARNING! Be sure never to call this in any vm_pageout code path, which 1829 * will trivially deadlock the system. 1830 */ 1831 void 1832 vm_wait_nominal(void) 1833 { 1834 while (vm_page_count_min(0)) 1835 vm_wait(0); 1836 } 1837 1838 /* 1839 * Test if vm_wait_nominal() would block. 1840 */ 1841 int 1842 vm_test_nominal(void) 1843 { 1844 if (vm_page_count_min(0)) 1845 return(1); 1846 return(0); 1847 } 1848 1849 /* 1850 * Block until free pages are available for allocation, called in various 1851 * places before memory allocations. 1852 * 1853 * The caller may loop if vm_page_count_min() == FALSE so we cannot be 1854 * more generous then that. 1855 */ 1856 void 1857 vm_wait(int timo) 1858 { 1859 /* 1860 * never wait forever 1861 */ 1862 if (timo == 0) 1863 timo = hz; 1864 lwkt_gettoken(&vm_token); 1865 1866 if (curthread == pagethread) { 1867 /* 1868 * The pageout daemon itself needs pages, this is bad. 1869 */ 1870 if (vm_page_count_min(0)) { 1871 vm_pageout_pages_needed = 1; 1872 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo); 1873 } 1874 } else { 1875 /* 1876 * Wakeup the pageout daemon if necessary and wait. 1877 * 1878 * Do not wait indefinitely for the target to be reached, 1879 * as load might prevent it from being reached any time soon. 1880 * But wait a little to try to slow down page allocations 1881 * and to give more important threads (the pagedaemon) 1882 * allocation priority. 1883 */ 1884 if (vm_page_count_target()) { 1885 if (vm_pages_needed == 0) { 1886 vm_pages_needed = 1; 1887 wakeup(&vm_pages_needed); 1888 } 1889 ++vm_pages_waiting; /* SMP race ok */ 1890 tsleep(&vmstats.v_free_count, 0, "vmwait", timo); 1891 } 1892 } 1893 lwkt_reltoken(&vm_token); 1894 } 1895 1896 /* 1897 * Block until free pages are available for allocation 1898 * 1899 * Called only from vm_fault so that processes page faulting can be 1900 * easily tracked. 1901 */ 1902 void 1903 vm_wait_pfault(void) 1904 { 1905 /* 1906 * Wakeup the pageout daemon if necessary and wait. 1907 * 1908 * Do not wait indefinitely for the target to be reached, 1909 * as load might prevent it from being reached any time soon. 1910 * But wait a little to try to slow down page allocations 1911 * and to give more important threads (the pagedaemon) 1912 * allocation priority. 1913 */ 1914 if (vm_page_count_min(0)) { 1915 lwkt_gettoken(&vm_token); 1916 while (vm_page_count_severe()) { 1917 if (vm_page_count_target()) { 1918 if (vm_pages_needed == 0) { 1919 vm_pages_needed = 1; 1920 wakeup(&vm_pages_needed); 1921 } 1922 ++vm_pages_waiting; /* SMP race ok */ 1923 tsleep(&vmstats.v_free_count, 0, "pfault", hz); 1924 } 1925 } 1926 lwkt_reltoken(&vm_token); 1927 } 1928 } 1929 1930 /* 1931 * Put the specified page on the active list (if appropriate). Ensure 1932 * that act_count is at least ACT_INIT but do not otherwise mess with it. 1933 * 1934 * The caller should be holding the page busied ? XXX 1935 * This routine may not block. 1936 */ 1937 void 1938 vm_page_activate(vm_page_t m) 1939 { 1940 u_short oqueue; 1941 1942 vm_page_spin_lock(m); 1943 if (m->queue - m->pc != PQ_ACTIVE) { 1944 _vm_page_queue_spin_lock(m); 1945 oqueue = _vm_page_rem_queue_spinlocked(m); 1946 /* page is left spinlocked, queue is unlocked */ 1947 1948 if (oqueue == PQ_CACHE) 1949 mycpu->gd_cnt.v_reactivated++; 1950 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 1951 if (m->act_count < ACT_INIT) 1952 m->act_count = ACT_INIT; 1953 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); 1954 } 1955 _vm_page_and_queue_spin_unlock(m); 1956 if (oqueue == PQ_CACHE || oqueue == PQ_FREE) 1957 pagedaemon_wakeup(); 1958 } else { 1959 if (m->act_count < ACT_INIT) 1960 m->act_count = ACT_INIT; 1961 vm_page_spin_unlock(m); 1962 } 1963 } 1964 1965 /* 1966 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 1967 * routine is called when a page has been added to the cache or free 1968 * queues. 1969 * 1970 * This routine may not block. 1971 */ 1972 static __inline void 1973 vm_page_free_wakeup(void) 1974 { 1975 /* 1976 * If the pageout daemon itself needs pages, then tell it that 1977 * there are some free. 1978 */ 1979 if (vm_pageout_pages_needed && 1980 vmstats.v_cache_count + vmstats.v_free_count >= 1981 vmstats.v_pageout_free_min 1982 ) { 1983 vm_pageout_pages_needed = 0; 1984 wakeup(&vm_pageout_pages_needed); 1985 } 1986 1987 /* 1988 * Wakeup processes that are waiting on memory. 1989 * 1990 * Generally speaking we want to wakeup stuck processes as soon as 1991 * possible. !vm_page_count_min(0) is the absolute minimum point 1992 * where we can do this. Wait a bit longer to reduce degenerate 1993 * re-blocking (vm_page_free_hysteresis). The target check is just 1994 * to make sure the min-check w/hysteresis does not exceed the 1995 * normal target. 1996 */ 1997 if (vm_pages_waiting) { 1998 if (!vm_page_count_min(vm_page_free_hysteresis) || 1999 !vm_page_count_target()) { 2000 vm_pages_waiting = 0; 2001 wakeup(&vmstats.v_free_count); 2002 ++mycpu->gd_cnt.v_ppwakeups; 2003 } 2004 #if 0 2005 if (!vm_page_count_target()) { 2006 /* 2007 * Plenty of pages are free, wakeup everyone. 2008 */ 2009 vm_pages_waiting = 0; 2010 wakeup(&vmstats.v_free_count); 2011 ++mycpu->gd_cnt.v_ppwakeups; 2012 } else if (!vm_page_count_min(0)) { 2013 /* 2014 * Some pages are free, wakeup someone. 2015 */ 2016 int wcount = vm_pages_waiting; 2017 if (wcount > 0) 2018 --wcount; 2019 vm_pages_waiting = wcount; 2020 wakeup_one(&vmstats.v_free_count); 2021 ++mycpu->gd_cnt.v_ppwakeups; 2022 } 2023 #endif 2024 } 2025 } 2026 2027 /* 2028 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates 2029 * it from its VM object. 2030 * 2031 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on 2032 * return (the page will have been freed). 2033 */ 2034 void 2035 vm_page_free_toq(vm_page_t m) 2036 { 2037 mycpu->gd_cnt.v_tfree++; 2038 KKASSERT((m->flags & PG_MAPPED) == 0); 2039 KKASSERT(m->flags & PG_BUSY); 2040 2041 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { 2042 kprintf("vm_page_free: pindex(%lu), busy(%d), " 2043 "PG_BUSY(%d), hold(%d)\n", 2044 (u_long)m->pindex, m->busy, 2045 ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count); 2046 if ((m->queue - m->pc) == PQ_FREE) 2047 panic("vm_page_free: freeing free page"); 2048 else 2049 panic("vm_page_free: freeing busy page"); 2050 } 2051 2052 /* 2053 * Remove from object, spinlock the page and its queues and 2054 * remove from any queue. No queue spinlock will be held 2055 * after this section (because the page was removed from any 2056 * queue). 2057 */ 2058 vm_page_remove(m); 2059 vm_page_and_queue_spin_lock(m); 2060 _vm_page_rem_queue_spinlocked(m); 2061 2062 /* 2063 * No further management of fictitious pages occurs beyond object 2064 * and queue removal. 2065 */ 2066 if ((m->flags & PG_FICTITIOUS) != 0) { 2067 vm_page_spin_unlock(m); 2068 vm_page_wakeup(m); 2069 return; 2070 } 2071 2072 m->valid = 0; 2073 vm_page_undirty(m); 2074 2075 if (m->wire_count != 0) { 2076 if (m->wire_count > 1) { 2077 panic( 2078 "vm_page_free: invalid wire count (%d), pindex: 0x%lx", 2079 m->wire_count, (long)m->pindex); 2080 } 2081 panic("vm_page_free: freeing wired page"); 2082 } 2083 2084 /* 2085 * Clear the UNMANAGED flag when freeing an unmanaged page. 2086 * Clear the NEED_COMMIT flag 2087 */ 2088 if (m->flags & PG_UNMANAGED) 2089 vm_page_flag_clear(m, PG_UNMANAGED); 2090 if (m->flags & PG_NEED_COMMIT) 2091 vm_page_flag_clear(m, PG_NEED_COMMIT); 2092 2093 if (m->hold_count != 0) { 2094 vm_page_flag_clear(m, PG_ZERO); 2095 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); 2096 } else { 2097 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); 2098 } 2099 2100 /* 2101 * This sequence allows us to clear PG_BUSY while still holding 2102 * its spin lock, which reduces contention vs allocators. We 2103 * must not leave the queue locked or _vm_page_wakeup() may 2104 * deadlock. 2105 */ 2106 _vm_page_queue_spin_unlock(m); 2107 if (_vm_page_wakeup(m)) { 2108 vm_page_spin_unlock(m); 2109 wakeup(m); 2110 } else { 2111 vm_page_spin_unlock(m); 2112 } 2113 vm_page_free_wakeup(); 2114 } 2115 2116 /* 2117 * vm_page_free_fromq_fast() 2118 * 2119 * Remove a non-zero page from one of the free queues; the page is removed for 2120 * zeroing, so do not issue a wakeup. 2121 */ 2122 vm_page_t 2123 vm_page_free_fromq_fast(void) 2124 { 2125 static int qi; 2126 vm_page_t m; 2127 int i; 2128 2129 for (i = 0; i < PQ_L2_SIZE; ++i) { 2130 m = vm_page_list_find(PQ_FREE, qi, FALSE); 2131 /* page is returned spinlocked and removed from its queue */ 2132 if (m) { 2133 if (vm_page_busy_try(m, TRUE)) { 2134 /* 2135 * We were unable to busy the page, deactivate 2136 * it and loop. 2137 */ 2138 _vm_page_deactivate_locked(m, 0); 2139 vm_page_spin_unlock(m); 2140 } else if (m->flags & PG_ZERO) { 2141 /* 2142 * The page is already PG_ZERO, requeue it and loop 2143 */ 2144 _vm_page_add_queue_spinlocked(m, 2145 PQ_FREE + m->pc, 2146 0); 2147 vm_page_queue_spin_unlock(m); 2148 if (_vm_page_wakeup(m)) { 2149 vm_page_spin_unlock(m); 2150 wakeup(m); 2151 } else { 2152 vm_page_spin_unlock(m); 2153 } 2154 } else { 2155 /* 2156 * The page is not PG_ZERO'd so return it. 2157 */ 2158 KKASSERT((m->flags & (PG_UNMANAGED | 2159 PG_NEED_COMMIT)) == 0); 2160 KKASSERT(m->hold_count == 0); 2161 KKASSERT(m->wire_count == 0); 2162 vm_page_spin_unlock(m); 2163 break; 2164 } 2165 m = NULL; 2166 } 2167 qi = (qi + PQ_PRIME2) & PQ_L2_MASK; 2168 } 2169 return (m); 2170 } 2171 2172 /* 2173 * vm_page_unmanage() 2174 * 2175 * Prevent PV management from being done on the page. The page is 2176 * removed from the paging queues as if it were wired, and as a 2177 * consequence of no longer being managed the pageout daemon will not 2178 * touch it (since there is no way to locate the pte mappings for the 2179 * page). madvise() calls that mess with the pmap will also no longer 2180 * operate on the page. 2181 * 2182 * Beyond that the page is still reasonably 'normal'. Freeing the page 2183 * will clear the flag. 2184 * 2185 * This routine is used by OBJT_PHYS objects - objects using unswappable 2186 * physical memory as backing store rather then swap-backed memory and 2187 * will eventually be extended to support 4MB unmanaged physical 2188 * mappings. 2189 * 2190 * Caller must be holding the page busy. 2191 */ 2192 void 2193 vm_page_unmanage(vm_page_t m) 2194 { 2195 KKASSERT(m->flags & PG_BUSY); 2196 if ((m->flags & PG_UNMANAGED) == 0) { 2197 if (m->wire_count == 0) 2198 vm_page_unqueue(m); 2199 } 2200 vm_page_flag_set(m, PG_UNMANAGED); 2201 } 2202 2203 /* 2204 * Mark this page as wired down by yet another map, removing it from 2205 * paging queues as necessary. 2206 * 2207 * Caller must be holding the page busy. 2208 */ 2209 void 2210 vm_page_wire(vm_page_t m) 2211 { 2212 /* 2213 * Only bump the wire statistics if the page is not already wired, 2214 * and only unqueue the page if it is on some queue (if it is unmanaged 2215 * it is already off the queues). Don't do anything with fictitious 2216 * pages because they are always wired. 2217 */ 2218 KKASSERT(m->flags & PG_BUSY); 2219 if ((m->flags & PG_FICTITIOUS) == 0) { 2220 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) { 2221 if ((m->flags & PG_UNMANAGED) == 0) 2222 vm_page_unqueue(m); 2223 atomic_add_int(&vmstats.v_wire_count, 1); 2224 } 2225 KASSERT(m->wire_count != 0, 2226 ("vm_page_wire: wire_count overflow m=%p", m)); 2227 } 2228 } 2229 2230 /* 2231 * Release one wiring of this page, potentially enabling it to be paged again. 2232 * 2233 * Many pages placed on the inactive queue should actually go 2234 * into the cache, but it is difficult to figure out which. What 2235 * we do instead, if the inactive target is well met, is to put 2236 * clean pages at the head of the inactive queue instead of the tail. 2237 * This will cause them to be moved to the cache more quickly and 2238 * if not actively re-referenced, freed more quickly. If we just 2239 * stick these pages at the end of the inactive queue, heavy filesystem 2240 * meta-data accesses can cause an unnecessary paging load on memory bound 2241 * processes. This optimization causes one-time-use metadata to be 2242 * reused more quickly. 2243 * 2244 * Pages marked PG_NEED_COMMIT are always activated and never placed on 2245 * the inactive queue. This helps the pageout daemon determine memory 2246 * pressure and act on out-of-memory situations more quickly. 2247 * 2248 * BUT, if we are in a low-memory situation we have no choice but to 2249 * put clean pages on the cache queue. 2250 * 2251 * A number of routines use vm_page_unwire() to guarantee that the page 2252 * will go into either the inactive or active queues, and will NEVER 2253 * be placed in the cache - for example, just after dirtying a page. 2254 * dirty pages in the cache are not allowed. 2255 * 2256 * This routine may not block. 2257 */ 2258 void 2259 vm_page_unwire(vm_page_t m, int activate) 2260 { 2261 KKASSERT(m->flags & PG_BUSY); 2262 if (m->flags & PG_FICTITIOUS) { 2263 /* do nothing */ 2264 } else if (m->wire_count <= 0) { 2265 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 2266 } else { 2267 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) { 2268 atomic_add_int(&vmstats.v_wire_count, -1); 2269 if (m->flags & PG_UNMANAGED) { 2270 ; 2271 } else if (activate || (m->flags & PG_NEED_COMMIT)) { 2272 vm_page_spin_lock(m); 2273 _vm_page_add_queue_spinlocked(m, 2274 PQ_ACTIVE + m->pc, 0); 2275 _vm_page_and_queue_spin_unlock(m); 2276 } else { 2277 vm_page_spin_lock(m); 2278 vm_page_flag_clear(m, PG_WINATCFLS); 2279 _vm_page_add_queue_spinlocked(m, 2280 PQ_INACTIVE + m->pc, 0); 2281 ++vm_swapcache_inactive_heuristic; 2282 _vm_page_and_queue_spin_unlock(m); 2283 } 2284 } 2285 } 2286 } 2287 2288 /* 2289 * Move the specified page to the inactive queue. If the page has 2290 * any associated swap, the swap is deallocated. 2291 * 2292 * Normally athead is 0 resulting in LRU operation. athead is set 2293 * to 1 if we want this page to be 'as if it were placed in the cache', 2294 * except without unmapping it from the process address space. 2295 * 2296 * vm_page's spinlock must be held on entry and will remain held on return. 2297 * This routine may not block. 2298 */ 2299 static void 2300 _vm_page_deactivate_locked(vm_page_t m, int athead) 2301 { 2302 u_short oqueue; 2303 2304 /* 2305 * Ignore if already inactive. 2306 */ 2307 if (m->queue - m->pc == PQ_INACTIVE) 2308 return; 2309 _vm_page_queue_spin_lock(m); 2310 oqueue = _vm_page_rem_queue_spinlocked(m); 2311 2312 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 2313 if (oqueue == PQ_CACHE) 2314 mycpu->gd_cnt.v_reactivated++; 2315 vm_page_flag_clear(m, PG_WINATCFLS); 2316 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead); 2317 if (athead == 0) 2318 ++vm_swapcache_inactive_heuristic; 2319 } 2320 /* NOTE: PQ_NONE if condition not taken */ 2321 _vm_page_queue_spin_unlock(m); 2322 /* leaves vm_page spinlocked */ 2323 } 2324 2325 /* 2326 * Attempt to deactivate a page. 2327 * 2328 * No requirements. 2329 */ 2330 void 2331 vm_page_deactivate(vm_page_t m) 2332 { 2333 vm_page_spin_lock(m); 2334 _vm_page_deactivate_locked(m, 0); 2335 vm_page_spin_unlock(m); 2336 } 2337 2338 void 2339 vm_page_deactivate_locked(vm_page_t m) 2340 { 2341 _vm_page_deactivate_locked(m, 0); 2342 } 2343 2344 /* 2345 * Attempt to move a page to PQ_CACHE. 2346 * 2347 * Returns 0 on failure, 1 on success 2348 * 2349 * The page should NOT be busied by the caller. This function will validate 2350 * whether the page can be safely moved to the cache. 2351 */ 2352 int 2353 vm_page_try_to_cache(vm_page_t m) 2354 { 2355 vm_page_spin_lock(m); 2356 if (vm_page_busy_try(m, TRUE)) { 2357 vm_page_spin_unlock(m); 2358 return(0); 2359 } 2360 if (m->dirty || m->hold_count || m->wire_count || 2361 (m->flags & (PG_UNMANAGED | PG_NEED_COMMIT))) { 2362 if (_vm_page_wakeup(m)) { 2363 vm_page_spin_unlock(m); 2364 wakeup(m); 2365 } else { 2366 vm_page_spin_unlock(m); 2367 } 2368 return(0); 2369 } 2370 vm_page_spin_unlock(m); 2371 2372 /* 2373 * Page busied by us and no longer spinlocked. Dirty pages cannot 2374 * be moved to the cache. 2375 */ 2376 vm_page_test_dirty(m); 2377 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2378 vm_page_wakeup(m); 2379 return(0); 2380 } 2381 vm_page_cache(m); 2382 return(1); 2383 } 2384 2385 /* 2386 * Attempt to free the page. If we cannot free it, we do nothing. 2387 * 1 is returned on success, 0 on failure. 2388 * 2389 * No requirements. 2390 */ 2391 int 2392 vm_page_try_to_free(vm_page_t m) 2393 { 2394 vm_page_spin_lock(m); 2395 if (vm_page_busy_try(m, TRUE)) { 2396 vm_page_spin_unlock(m); 2397 return(0); 2398 } 2399 2400 /* 2401 * The page can be in any state, including already being on the free 2402 * queue. Check to see if it really can be freed. 2403 */ 2404 if (m->dirty || /* can't free if it is dirty */ 2405 m->hold_count || /* or held (XXX may be wrong) */ 2406 m->wire_count || /* or wired */ 2407 (m->flags & (PG_UNMANAGED | /* or unmanaged */ 2408 PG_NEED_COMMIT)) || /* or needs a commit */ 2409 m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */ 2410 m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */ 2411 if (_vm_page_wakeup(m)) { 2412 vm_page_spin_unlock(m); 2413 wakeup(m); 2414 } else { 2415 vm_page_spin_unlock(m); 2416 } 2417 return(0); 2418 } 2419 vm_page_spin_unlock(m); 2420 2421 /* 2422 * We can probably free the page. 2423 * 2424 * Page busied by us and no longer spinlocked. Dirty pages will 2425 * not be freed by this function. We have to re-test the 2426 * dirty bit after cleaning out the pmaps. 2427 */ 2428 vm_page_test_dirty(m); 2429 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2430 vm_page_wakeup(m); 2431 return(0); 2432 } 2433 vm_page_protect(m, VM_PROT_NONE); 2434 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2435 vm_page_wakeup(m); 2436 return(0); 2437 } 2438 vm_page_free(m); 2439 return(1); 2440 } 2441 2442 /* 2443 * vm_page_cache 2444 * 2445 * Put the specified page onto the page cache queue (if appropriate). 2446 * 2447 * The page must be busy, and this routine will release the busy and 2448 * possibly even free the page. 2449 */ 2450 void 2451 vm_page_cache(vm_page_t m) 2452 { 2453 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) || 2454 m->busy || m->wire_count || m->hold_count) { 2455 kprintf("vm_page_cache: attempting to cache busy/held page\n"); 2456 vm_page_wakeup(m); 2457 return; 2458 } 2459 2460 /* 2461 * Already in the cache (and thus not mapped) 2462 */ 2463 if ((m->queue - m->pc) == PQ_CACHE) { 2464 KKASSERT((m->flags & PG_MAPPED) == 0); 2465 vm_page_wakeup(m); 2466 return; 2467 } 2468 2469 /* 2470 * Caller is required to test m->dirty, but note that the act of 2471 * removing the page from its maps can cause it to become dirty 2472 * on an SMP system due to another cpu running in usermode. 2473 */ 2474 if (m->dirty) { 2475 panic("vm_page_cache: caching a dirty page, pindex: %ld", 2476 (long)m->pindex); 2477 } 2478 2479 /* 2480 * Remove all pmaps and indicate that the page is not 2481 * writeable or mapped. Our vm_page_protect() call may 2482 * have blocked (especially w/ VM_PROT_NONE), so recheck 2483 * everything. 2484 */ 2485 vm_page_protect(m, VM_PROT_NONE); 2486 if ((m->flags & (PG_UNMANAGED | PG_MAPPED)) || 2487 m->busy || m->wire_count || m->hold_count) { 2488 vm_page_wakeup(m); 2489 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2490 vm_page_deactivate(m); 2491 vm_page_wakeup(m); 2492 } else { 2493 _vm_page_and_queue_spin_lock(m); 2494 _vm_page_rem_queue_spinlocked(m); 2495 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0); 2496 _vm_page_queue_spin_unlock(m); 2497 if (_vm_page_wakeup(m)) { 2498 vm_page_spin_unlock(m); 2499 wakeup(m); 2500 } else { 2501 vm_page_spin_unlock(m); 2502 } 2503 vm_page_free_wakeup(); 2504 } 2505 } 2506 2507 /* 2508 * vm_page_dontneed() 2509 * 2510 * Cache, deactivate, or do nothing as appropriate. This routine 2511 * is typically used by madvise() MADV_DONTNEED. 2512 * 2513 * Generally speaking we want to move the page into the cache so 2514 * it gets reused quickly. However, this can result in a silly syndrome 2515 * due to the page recycling too quickly. Small objects will not be 2516 * fully cached. On the otherhand, if we move the page to the inactive 2517 * queue we wind up with a problem whereby very large objects 2518 * unnecessarily blow away our inactive and cache queues. 2519 * 2520 * The solution is to move the pages based on a fixed weighting. We 2521 * either leave them alone, deactivate them, or move them to the cache, 2522 * where moving them to the cache has the highest weighting. 2523 * By forcing some pages into other queues we eventually force the 2524 * system to balance the queues, potentially recovering other unrelated 2525 * space from active. The idea is to not force this to happen too 2526 * often. 2527 * 2528 * The page must be busied. 2529 */ 2530 void 2531 vm_page_dontneed(vm_page_t m) 2532 { 2533 static int dnweight; 2534 int dnw; 2535 int head; 2536 2537 dnw = ++dnweight; 2538 2539 /* 2540 * occassionally leave the page alone 2541 */ 2542 if ((dnw & 0x01F0) == 0 || 2543 m->queue - m->pc == PQ_INACTIVE || 2544 m->queue - m->pc == PQ_CACHE 2545 ) { 2546 if (m->act_count >= ACT_INIT) 2547 --m->act_count; 2548 return; 2549 } 2550 2551 /* 2552 * If vm_page_dontneed() is inactivating a page, it must clear 2553 * the referenced flag; otherwise the pagedaemon will see references 2554 * on the page in the inactive queue and reactivate it. Until the 2555 * page can move to the cache queue, madvise's job is not done. 2556 */ 2557 vm_page_flag_clear(m, PG_REFERENCED); 2558 pmap_clear_reference(m); 2559 2560 if (m->dirty == 0) 2561 vm_page_test_dirty(m); 2562 2563 if (m->dirty || (dnw & 0x0070) == 0) { 2564 /* 2565 * Deactivate the page 3 times out of 32. 2566 */ 2567 head = 0; 2568 } else { 2569 /* 2570 * Cache the page 28 times out of every 32. Note that 2571 * the page is deactivated instead of cached, but placed 2572 * at the head of the queue instead of the tail. 2573 */ 2574 head = 1; 2575 } 2576 vm_page_spin_lock(m); 2577 _vm_page_deactivate_locked(m, head); 2578 vm_page_spin_unlock(m); 2579 } 2580 2581 /* 2582 * These routines manipulate the 'soft busy' count for a page. A soft busy 2583 * is almost like PG_BUSY except that it allows certain compatible operations 2584 * to occur on the page while it is busy. For example, a page undergoing a 2585 * write can still be mapped read-only. 2586 * 2587 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only 2588 * adjusted while the vm_page is PG_BUSY so the flash will occur when the 2589 * busy bit is cleared. 2590 */ 2591 void 2592 vm_page_io_start(vm_page_t m) 2593 { 2594 KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!")); 2595 atomic_add_char(&m->busy, 1); 2596 vm_page_flag_set(m, PG_SBUSY); 2597 } 2598 2599 void 2600 vm_page_io_finish(vm_page_t m) 2601 { 2602 KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!")); 2603 atomic_subtract_char(&m->busy, 1); 2604 if (m->busy == 0) 2605 vm_page_flag_clear(m, PG_SBUSY); 2606 } 2607 2608 /* 2609 * Indicate that a clean VM page requires a filesystem commit and cannot 2610 * be reused. Used by tmpfs. 2611 */ 2612 void 2613 vm_page_need_commit(vm_page_t m) 2614 { 2615 vm_page_flag_set(m, PG_NEED_COMMIT); 2616 vm_object_set_writeable_dirty(m->object); 2617 } 2618 2619 void 2620 vm_page_clear_commit(vm_page_t m) 2621 { 2622 vm_page_flag_clear(m, PG_NEED_COMMIT); 2623 } 2624 2625 /* 2626 * Grab a page, blocking if it is busy and allocating a page if necessary. 2627 * A busy page is returned or NULL. The page may or may not be valid and 2628 * might not be on a queue (the caller is responsible for the disposition of 2629 * the page). 2630 * 2631 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the 2632 * page will be zero'd and marked valid. 2633 * 2634 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked 2635 * valid even if it already exists. 2636 * 2637 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also 2638 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified. 2639 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified. 2640 * 2641 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is 2642 * always returned if we had blocked. 2643 * 2644 * This routine may not be called from an interrupt. 2645 * 2646 * PG_ZERO is *ALWAYS* cleared by this routine. 2647 * 2648 * No other requirements. 2649 */ 2650 vm_page_t 2651 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 2652 { 2653 vm_page_t m; 2654 int error; 2655 int shared = 1; 2656 2657 KKASSERT(allocflags & 2658 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 2659 vm_object_hold_shared(object); 2660 for (;;) { 2661 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error); 2662 if (error) { 2663 vm_page_sleep_busy(m, TRUE, "pgrbwt"); 2664 if ((allocflags & VM_ALLOC_RETRY) == 0) { 2665 m = NULL; 2666 break; 2667 } 2668 /* retry */ 2669 } else if (m == NULL) { 2670 if (shared) { 2671 vm_object_upgrade(object); 2672 shared = 0; 2673 } 2674 if (allocflags & VM_ALLOC_RETRY) 2675 allocflags |= VM_ALLOC_NULL_OK; 2676 m = vm_page_alloc(object, pindex, 2677 allocflags & ~VM_ALLOC_RETRY); 2678 if (m) 2679 break; 2680 vm_wait(0); 2681 if ((allocflags & VM_ALLOC_RETRY) == 0) 2682 goto failed; 2683 } else { 2684 /* m found */ 2685 break; 2686 } 2687 } 2688 2689 /* 2690 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid. 2691 * 2692 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set 2693 * valid even if already valid. 2694 */ 2695 if (m->valid == 0) { 2696 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) { 2697 if ((m->flags & PG_ZERO) == 0) 2698 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 2699 m->valid = VM_PAGE_BITS_ALL; 2700 } 2701 } else if (allocflags & VM_ALLOC_FORCE_ZERO) { 2702 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 2703 m->valid = VM_PAGE_BITS_ALL; 2704 } 2705 vm_page_flag_clear(m, PG_ZERO); 2706 failed: 2707 vm_object_drop(object); 2708 return(m); 2709 } 2710 2711 /* 2712 * Mapping function for valid bits or for dirty bits in 2713 * a page. May not block. 2714 * 2715 * Inputs are required to range within a page. 2716 * 2717 * No requirements. 2718 * Non blocking. 2719 */ 2720 int 2721 vm_page_bits(int base, int size) 2722 { 2723 int first_bit; 2724 int last_bit; 2725 2726 KASSERT( 2727 base + size <= PAGE_SIZE, 2728 ("vm_page_bits: illegal base/size %d/%d", base, size) 2729 ); 2730 2731 if (size == 0) /* handle degenerate case */ 2732 return(0); 2733 2734 first_bit = base >> DEV_BSHIFT; 2735 last_bit = (base + size - 1) >> DEV_BSHIFT; 2736 2737 return ((2 << last_bit) - (1 << first_bit)); 2738 } 2739 2740 /* 2741 * Sets portions of a page valid and clean. The arguments are expected 2742 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2743 * of any partial chunks touched by the range. The invalid portion of 2744 * such chunks will be zero'd. 2745 * 2746 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically 2747 * align base to DEV_BSIZE so as not to mark clean a partially 2748 * truncated device block. Otherwise the dirty page status might be 2749 * lost. 2750 * 2751 * This routine may not block. 2752 * 2753 * (base + size) must be less then or equal to PAGE_SIZE. 2754 */ 2755 static void 2756 _vm_page_zero_valid(vm_page_t m, int base, int size) 2757 { 2758 int frag; 2759 int endoff; 2760 2761 if (size == 0) /* handle degenerate case */ 2762 return; 2763 2764 /* 2765 * If the base is not DEV_BSIZE aligned and the valid 2766 * bit is clear, we have to zero out a portion of the 2767 * first block. 2768 */ 2769 2770 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2771 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 2772 ) { 2773 pmap_zero_page_area( 2774 VM_PAGE_TO_PHYS(m), 2775 frag, 2776 base - frag 2777 ); 2778 } 2779 2780 /* 2781 * If the ending offset is not DEV_BSIZE aligned and the 2782 * valid bit is clear, we have to zero out a portion of 2783 * the last block. 2784 */ 2785 2786 endoff = base + size; 2787 2788 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2789 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 2790 ) { 2791 pmap_zero_page_area( 2792 VM_PAGE_TO_PHYS(m), 2793 endoff, 2794 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 2795 ); 2796 } 2797 } 2798 2799 /* 2800 * Set valid, clear dirty bits. If validating the entire 2801 * page we can safely clear the pmap modify bit. We also 2802 * use this opportunity to clear the PG_NOSYNC flag. If a process 2803 * takes a write fault on a MAP_NOSYNC memory area the flag will 2804 * be set again. 2805 * 2806 * We set valid bits inclusive of any overlap, but we can only 2807 * clear dirty bits for DEV_BSIZE chunks that are fully within 2808 * the range. 2809 * 2810 * Page must be busied? 2811 * No other requirements. 2812 */ 2813 void 2814 vm_page_set_valid(vm_page_t m, int base, int size) 2815 { 2816 _vm_page_zero_valid(m, base, size); 2817 m->valid |= vm_page_bits(base, size); 2818 } 2819 2820 2821 /* 2822 * Set valid bits and clear dirty bits. 2823 * 2824 * NOTE: This function does not clear the pmap modified bit. 2825 * Also note that e.g. NFS may use a byte-granular base 2826 * and size. 2827 * 2828 * WARNING: Page must be busied? But vfs_clean_one_page() will call 2829 * this without necessarily busying the page (via bdwrite()). 2830 * So for now vm_token must also be held. 2831 * 2832 * No other requirements. 2833 */ 2834 void 2835 vm_page_set_validclean(vm_page_t m, int base, int size) 2836 { 2837 int pagebits; 2838 2839 _vm_page_zero_valid(m, base, size); 2840 pagebits = vm_page_bits(base, size); 2841 m->valid |= pagebits; 2842 m->dirty &= ~pagebits; 2843 if (base == 0 && size == PAGE_SIZE) { 2844 /*pmap_clear_modify(m);*/ 2845 vm_page_flag_clear(m, PG_NOSYNC); 2846 } 2847 } 2848 2849 /* 2850 * Set valid & dirty. Used by buwrite() 2851 * 2852 * WARNING: Page must be busied? But vfs_dirty_one_page() will 2853 * call this function in buwrite() so for now vm_token must 2854 * be held. 2855 * 2856 * No other requirements. 2857 */ 2858 void 2859 vm_page_set_validdirty(vm_page_t m, int base, int size) 2860 { 2861 int pagebits; 2862 2863 pagebits = vm_page_bits(base, size); 2864 m->valid |= pagebits; 2865 m->dirty |= pagebits; 2866 if (m->object) 2867 vm_object_set_writeable_dirty(m->object); 2868 } 2869 2870 /* 2871 * Clear dirty bits. 2872 * 2873 * NOTE: This function does not clear the pmap modified bit. 2874 * Also note that e.g. NFS may use a byte-granular base 2875 * and size. 2876 * 2877 * Page must be busied? 2878 * No other requirements. 2879 */ 2880 void 2881 vm_page_clear_dirty(vm_page_t m, int base, int size) 2882 { 2883 m->dirty &= ~vm_page_bits(base, size); 2884 if (base == 0 && size == PAGE_SIZE) { 2885 /*pmap_clear_modify(m);*/ 2886 vm_page_flag_clear(m, PG_NOSYNC); 2887 } 2888 } 2889 2890 /* 2891 * Make the page all-dirty. 2892 * 2893 * Also make sure the related object and vnode reflect the fact that the 2894 * object may now contain a dirty page. 2895 * 2896 * Page must be busied? 2897 * No other requirements. 2898 */ 2899 void 2900 vm_page_dirty(vm_page_t m) 2901 { 2902 #ifdef INVARIANTS 2903 int pqtype = m->queue - m->pc; 2904 #endif 2905 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE, 2906 ("vm_page_dirty: page in free/cache queue!")); 2907 if (m->dirty != VM_PAGE_BITS_ALL) { 2908 m->dirty = VM_PAGE_BITS_ALL; 2909 if (m->object) 2910 vm_object_set_writeable_dirty(m->object); 2911 } 2912 } 2913 2914 /* 2915 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2916 * valid and dirty bits for the effected areas are cleared. 2917 * 2918 * Page must be busied? 2919 * Does not block. 2920 * No other requirements. 2921 */ 2922 void 2923 vm_page_set_invalid(vm_page_t m, int base, int size) 2924 { 2925 int bits; 2926 2927 bits = vm_page_bits(base, size); 2928 m->valid &= ~bits; 2929 m->dirty &= ~bits; 2930 m->object->generation++; 2931 } 2932 2933 /* 2934 * The kernel assumes that the invalid portions of a page contain 2935 * garbage, but such pages can be mapped into memory by user code. 2936 * When this occurs, we must zero out the non-valid portions of the 2937 * page so user code sees what it expects. 2938 * 2939 * Pages are most often semi-valid when the end of a file is mapped 2940 * into memory and the file's size is not page aligned. 2941 * 2942 * Page must be busied? 2943 * No other requirements. 2944 */ 2945 void 2946 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2947 { 2948 int b; 2949 int i; 2950 2951 /* 2952 * Scan the valid bits looking for invalid sections that 2953 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2954 * valid bit may be set ) have already been zerod by 2955 * vm_page_set_validclean(). 2956 */ 2957 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2958 if (i == (PAGE_SIZE / DEV_BSIZE) || 2959 (m->valid & (1 << i)) 2960 ) { 2961 if (i > b) { 2962 pmap_zero_page_area( 2963 VM_PAGE_TO_PHYS(m), 2964 b << DEV_BSHIFT, 2965 (i - b) << DEV_BSHIFT 2966 ); 2967 } 2968 b = i + 1; 2969 } 2970 } 2971 2972 /* 2973 * setvalid is TRUE when we can safely set the zero'd areas 2974 * as being valid. We can do this if there are no cache consistency 2975 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 2976 */ 2977 if (setvalid) 2978 m->valid = VM_PAGE_BITS_ALL; 2979 } 2980 2981 /* 2982 * Is a (partial) page valid? Note that the case where size == 0 2983 * will return FALSE in the degenerate case where the page is entirely 2984 * invalid, and TRUE otherwise. 2985 * 2986 * Does not block. 2987 * No other requirements. 2988 */ 2989 int 2990 vm_page_is_valid(vm_page_t m, int base, int size) 2991 { 2992 int bits = vm_page_bits(base, size); 2993 2994 if (m->valid && ((m->valid & bits) == bits)) 2995 return 1; 2996 else 2997 return 0; 2998 } 2999 3000 /* 3001 * update dirty bits from pmap/mmu. May not block. 3002 * 3003 * Caller must hold the page busy 3004 */ 3005 void 3006 vm_page_test_dirty(vm_page_t m) 3007 { 3008 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 3009 vm_page_dirty(m); 3010 } 3011 } 3012 3013 /* 3014 * Register an action, associating it with its vm_page 3015 */ 3016 void 3017 vm_page_register_action(vm_page_action_t action, vm_page_event_t event) 3018 { 3019 struct vm_page_action_list *list; 3020 int hv; 3021 3022 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; 3023 list = &action_list[hv]; 3024 3025 lwkt_gettoken(&vm_token); 3026 vm_page_flag_set(action->m, PG_ACTIONLIST); 3027 action->event = event; 3028 LIST_INSERT_HEAD(list, action, entry); 3029 lwkt_reltoken(&vm_token); 3030 } 3031 3032 /* 3033 * Unregister an action, disassociating it from its related vm_page 3034 */ 3035 void 3036 vm_page_unregister_action(vm_page_action_t action) 3037 { 3038 struct vm_page_action_list *list; 3039 int hv; 3040 3041 lwkt_gettoken(&vm_token); 3042 if (action->event != VMEVENT_NONE) { 3043 action->event = VMEVENT_NONE; 3044 LIST_REMOVE(action, entry); 3045 3046 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; 3047 list = &action_list[hv]; 3048 if (LIST_EMPTY(list)) 3049 vm_page_flag_clear(action->m, PG_ACTIONLIST); 3050 } 3051 lwkt_reltoken(&vm_token); 3052 } 3053 3054 /* 3055 * Issue an event on a VM page. Corresponding action structures are 3056 * removed from the page's list and called. 3057 * 3058 * If the vm_page has no more pending action events we clear its 3059 * PG_ACTIONLIST flag. 3060 */ 3061 void 3062 vm_page_event_internal(vm_page_t m, vm_page_event_t event) 3063 { 3064 struct vm_page_action_list *list; 3065 struct vm_page_action *scan; 3066 struct vm_page_action *next; 3067 int hv; 3068 int all; 3069 3070 hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK; 3071 list = &action_list[hv]; 3072 all = 1; 3073 3074 lwkt_gettoken(&vm_token); 3075 LIST_FOREACH_MUTABLE(scan, list, entry, next) { 3076 if (scan->m == m) { 3077 if (scan->event == event) { 3078 scan->event = VMEVENT_NONE; 3079 LIST_REMOVE(scan, entry); 3080 scan->func(m, scan); 3081 /* XXX */ 3082 } else { 3083 all = 0; 3084 } 3085 } 3086 } 3087 if (all) 3088 vm_page_flag_clear(m, PG_ACTIONLIST); 3089 lwkt_reltoken(&vm_token); 3090 } 3091 3092 #include "opt_ddb.h" 3093 #ifdef DDB 3094 #include <sys/kernel.h> 3095 3096 #include <ddb/ddb.h> 3097 3098 DB_SHOW_COMMAND(page, vm_page_print_page_info) 3099 { 3100 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count); 3101 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count); 3102 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count); 3103 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count); 3104 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count); 3105 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved); 3106 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min); 3107 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target); 3108 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min); 3109 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target); 3110 } 3111 3112 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 3113 { 3114 int i; 3115 db_printf("PQ_FREE:"); 3116 for(i=0;i<PQ_L2_SIZE;i++) { 3117 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 3118 } 3119 db_printf("\n"); 3120 3121 db_printf("PQ_CACHE:"); 3122 for(i=0;i<PQ_L2_SIZE;i++) { 3123 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 3124 } 3125 db_printf("\n"); 3126 3127 db_printf("PQ_ACTIVE:"); 3128 for(i=0;i<PQ_L2_SIZE;i++) { 3129 db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt); 3130 } 3131 db_printf("\n"); 3132 3133 db_printf("PQ_INACTIVE:"); 3134 for(i=0;i<PQ_L2_SIZE;i++) { 3135 db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt); 3136 } 3137 db_printf("\n"); 3138 } 3139 #endif /* DDB */ 3140