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 #include <sys/cpu_topology.h> 79 80 #include <vm/vm.h> 81 #include <vm/vm_param.h> 82 #include <sys/lock.h> 83 #include <vm/vm_kern.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_object.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_pageout.h> 89 #include <vm/vm_pager.h> 90 #include <vm/vm_extern.h> 91 #include <vm/swap_pager.h> 92 93 #include <machine/inttypes.h> 94 #include <machine/md_var.h> 95 #include <machine/specialreg.h> 96 97 #include <vm/vm_page2.h> 98 #include <sys/spinlock2.h> 99 100 /* 101 * Action hash for user umtx support. 102 */ 103 #define VMACTION_HSIZE 256 104 #define VMACTION_HMASK (VMACTION_HSIZE - 1) 105 106 /* 107 * SET - Minimum required set associative size, must be a power of 2. We 108 * want this to match or exceed the set-associativeness of the cpu. 109 * 110 * GRP - A larger set that allows bleed-over into the domains of other 111 * nearby cpus. Also must be a power of 2. Used by the page zeroing 112 * code to smooth things out a bit. 113 */ 114 #define PQ_SET_ASSOC 16 115 #define PQ_SET_ASSOC_MASK (PQ_SET_ASSOC - 1) 116 117 #define PQ_GRP_ASSOC (PQ_SET_ASSOC * 2) 118 #define PQ_GRP_ASSOC_MASK (PQ_GRP_ASSOC - 1) 119 120 static void vm_page_queue_init(void); 121 static void vm_page_free_wakeup(void); 122 static vm_page_t vm_page_select_cache(u_short pg_color); 123 static vm_page_t _vm_page_list_find2(int basequeue, int index); 124 static void _vm_page_deactivate_locked(vm_page_t m, int athead); 125 126 /* 127 * Array of tailq lists 128 */ 129 __cachealign struct vpgqueues vm_page_queues[PQ_COUNT]; 130 131 LIST_HEAD(vm_page_action_list, vm_page_action); 132 struct vm_page_action_list action_list[VMACTION_HSIZE]; 133 static volatile int vm_pages_waiting; 134 135 static struct alist vm_contig_alist; 136 static struct almeta vm_contig_ameta[ALIST_RECORDS_65536]; 137 static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin, "vm_contig_spin"); 138 139 static u_long vm_dma_reserved = 0; 140 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved); 141 SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0, 142 "Memory reserved for DMA"); 143 SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD, 144 &vm_contig_alist.bl_free, 0, "Memory reserved for DMA"); 145 146 static int vm_contig_verbose = 0; 147 TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose); 148 149 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, 150 vm_pindex_t, pindex); 151 152 static void 153 vm_page_queue_init(void) 154 { 155 int i; 156 157 for (i = 0; i < PQ_L2_SIZE; i++) 158 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count; 159 for (i = 0; i < PQ_L2_SIZE; i++) 160 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count; 161 for (i = 0; i < PQ_L2_SIZE; i++) 162 vm_page_queues[PQ_INACTIVE+i].cnt = &vmstats.v_inactive_count; 163 for (i = 0; i < PQ_L2_SIZE; i++) 164 vm_page_queues[PQ_ACTIVE+i].cnt = &vmstats.v_active_count; 165 for (i = 0; i < PQ_L2_SIZE; i++) 166 vm_page_queues[PQ_HOLD+i].cnt = &vmstats.v_active_count; 167 /* PQ_NONE has no queue */ 168 169 for (i = 0; i < PQ_COUNT; i++) { 170 TAILQ_INIT(&vm_page_queues[i].pl); 171 spin_init(&vm_page_queues[i].spin, "vm_page_queue_init"); 172 } 173 174 for (i = 0; i < VMACTION_HSIZE; i++) 175 LIST_INIT(&action_list[i]); 176 } 177 178 /* 179 * note: place in initialized data section? Is this necessary? 180 */ 181 long first_page = 0; 182 int vm_page_array_size = 0; 183 vm_page_t vm_page_array = NULL; 184 vm_paddr_t vm_low_phys_reserved; 185 186 /* 187 * (low level boot) 188 * 189 * Sets the page size, perhaps based upon the memory size. 190 * Must be called before any use of page-size dependent functions. 191 */ 192 void 193 vm_set_page_size(void) 194 { 195 if (vmstats.v_page_size == 0) 196 vmstats.v_page_size = PAGE_SIZE; 197 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0) 198 panic("vm_set_page_size: page size not a power of two"); 199 } 200 201 /* 202 * (low level boot) 203 * 204 * Add a new page to the freelist for use by the system. New pages 205 * are added to both the head and tail of the associated free page 206 * queue in a bottom-up fashion, so both zero'd and non-zero'd page 207 * requests pull 'recent' adds (higher physical addresses) first. 208 * 209 * Beware that the page zeroing daemon will also be running soon after 210 * boot, moving pages from the head to the tail of the PQ_FREE queues. 211 * 212 * Must be called in a critical section. 213 */ 214 static void 215 vm_add_new_page(vm_paddr_t pa) 216 { 217 struct vpgqueues *vpq; 218 vm_page_t m; 219 220 m = PHYS_TO_VM_PAGE(pa); 221 m->phys_addr = pa; 222 m->flags = 0; 223 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; 224 m->pat_mode = PAT_WRITE_BACK; 225 /* 226 * Twist for cpu localization in addition to page coloring, so 227 * different cpus selecting by m->queue get different page colors. 228 */ 229 m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE) & PQ_L2_MASK; 230 m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)) & PQ_L2_MASK; 231 /* 232 * Reserve a certain number of contiguous low memory pages for 233 * contigmalloc() to use. 234 */ 235 if (pa < vm_low_phys_reserved) { 236 atomic_add_int(&vmstats.v_page_count, 1); 237 atomic_add_int(&vmstats.v_dma_pages, 1); 238 m->queue = PQ_NONE; 239 m->wire_count = 1; 240 atomic_add_int(&vmstats.v_wire_count, 1); 241 alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1); 242 return; 243 } 244 245 /* 246 * General page 247 */ 248 m->queue = m->pc + PQ_FREE; 249 KKASSERT(m->dirty == 0); 250 251 atomic_add_int(&vmstats.v_page_count, 1); 252 atomic_add_int(&vmstats.v_free_count, 1); 253 vpq = &vm_page_queues[m->queue]; 254 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); 255 ++vpq->lcnt; 256 } 257 258 /* 259 * (low level boot) 260 * 261 * Initializes the resident memory module. 262 * 263 * Preallocates memory for critical VM structures and arrays prior to 264 * kernel_map becoming available. 265 * 266 * Memory is allocated from (virtual2_start, virtual2_end) if available, 267 * otherwise memory is allocated from (virtual_start, virtual_end). 268 * 269 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be 270 * large enough to hold vm_page_array & other structures for machines with 271 * large amounts of ram, so we want to use virtual2* when available. 272 */ 273 void 274 vm_page_startup(void) 275 { 276 vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start; 277 vm_offset_t mapped; 278 vm_size_t npages; 279 vm_paddr_t page_range; 280 vm_paddr_t new_end; 281 int i; 282 vm_paddr_t pa; 283 int nblocks; 284 vm_paddr_t last_pa; 285 vm_paddr_t end; 286 vm_paddr_t biggestone, biggestsize; 287 vm_paddr_t total; 288 289 total = 0; 290 biggestsize = 0; 291 biggestone = 0; 292 nblocks = 0; 293 vaddr = round_page(vaddr); 294 295 for (i = 0; phys_avail[i + 1]; i += 2) { 296 phys_avail[i] = round_page64(phys_avail[i]); 297 phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]); 298 } 299 300 for (i = 0; phys_avail[i + 1]; i += 2) { 301 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; 302 303 if (size > biggestsize) { 304 biggestone = i; 305 biggestsize = size; 306 } 307 ++nblocks; 308 total += size; 309 } 310 311 end = phys_avail[biggestone+1]; 312 end = trunc_page(end); 313 314 /* 315 * Initialize the queue headers for the free queue, the active queue 316 * and the inactive queue. 317 */ 318 vm_page_queue_init(); 319 320 #if !defined(_KERNEL_VIRTUAL) 321 /* 322 * VKERNELs don't support minidumps and as such don't need 323 * vm_page_dump 324 * 325 * Allocate a bitmap to indicate that a random physical page 326 * needs to be included in a minidump. 327 * 328 * The amd64 port needs this to indicate which direct map pages 329 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 330 * 331 * However, i386 still needs this workspace internally within the 332 * minidump code. In theory, they are not needed on i386, but are 333 * included should the sf_buf code decide to use them. 334 */ 335 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; 336 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 337 end -= vm_page_dump_size; 338 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size, 339 VM_PROT_READ | VM_PROT_WRITE); 340 bzero((void *)vm_page_dump, vm_page_dump_size); 341 #endif 342 /* 343 * Compute the number of pages of memory that will be available for 344 * use (taking into account the overhead of a page structure per 345 * page). 346 */ 347 first_page = phys_avail[0] / PAGE_SIZE; 348 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; 349 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE; 350 351 #ifndef _KERNEL_VIRTUAL 352 /* 353 * (only applies to real kernels) 354 * 355 * Reserve a large amount of low memory for potential 32-bit DMA 356 * space allocations. Once device initialization is complete we 357 * release most of it, but keep (vm_dma_reserved) memory reserved 358 * for later use. Typically for X / graphics. Through trial and 359 * error we find that GPUs usually requires ~60-100MB or so. 360 * 361 * By default, 128M is left in reserve on machines with 2G+ of ram. 362 */ 363 vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT; 364 if (vm_low_phys_reserved > total / 4) 365 vm_low_phys_reserved = total / 4; 366 if (vm_dma_reserved == 0) { 367 vm_dma_reserved = 128 * 1024 * 1024; /* 128MB */ 368 if (vm_dma_reserved > total / 16) 369 vm_dma_reserved = total / 16; 370 } 371 #endif 372 alist_init(&vm_contig_alist, 65536, vm_contig_ameta, 373 ALIST_RECORDS_65536); 374 375 /* 376 * Initialize the mem entry structures now, and put them in the free 377 * queue. 378 */ 379 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 380 mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE); 381 vm_page_array = (vm_page_t)mapped; 382 383 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL) 384 /* 385 * since pmap_map on amd64 returns stuff out of a direct-map region, 386 * we have to manually add these pages to the minidump tracking so 387 * that they can be dumped, including the vm_page_array. 388 */ 389 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) 390 dump_add_page(pa); 391 #endif 392 393 /* 394 * Clear all of the page structures 395 */ 396 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 397 vm_page_array_size = page_range; 398 399 /* 400 * Construct the free queue(s) in ascending order (by physical 401 * address) so that the first 16MB of physical memory is allocated 402 * last rather than first. On large-memory machines, this avoids 403 * the exhaustion of low physical memory before isa_dmainit has run. 404 */ 405 vmstats.v_page_count = 0; 406 vmstats.v_free_count = 0; 407 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { 408 pa = phys_avail[i]; 409 if (i == biggestone) 410 last_pa = new_end; 411 else 412 last_pa = phys_avail[i + 1]; 413 while (pa < last_pa && npages-- > 0) { 414 vm_add_new_page(pa); 415 pa += PAGE_SIZE; 416 } 417 } 418 if (virtual2_start) 419 virtual2_start = vaddr; 420 else 421 virtual_start = vaddr; 422 } 423 424 /* 425 * We tended to reserve a ton of memory for contigmalloc(). Now that most 426 * drivers have initialized we want to return most the remaining free 427 * reserve back to the VM page queues so they can be used for normal 428 * allocations. 429 * 430 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool. 431 */ 432 static void 433 vm_page_startup_finish(void *dummy __unused) 434 { 435 alist_blk_t blk; 436 alist_blk_t rblk; 437 alist_blk_t count; 438 alist_blk_t xcount; 439 alist_blk_t bfree; 440 vm_page_t m; 441 442 spin_lock(&vm_contig_spin); 443 for (;;) { 444 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 445 if (bfree <= vm_dma_reserved / PAGE_SIZE) 446 break; 447 if (count == 0) 448 break; 449 450 /* 451 * Figure out how much of the initial reserve we have to 452 * free in order to reach our target. 453 */ 454 bfree -= vm_dma_reserved / PAGE_SIZE; 455 if (count > bfree) { 456 blk += count - bfree; 457 count = bfree; 458 } 459 460 /* 461 * Calculate the nearest power of 2 <= count. 462 */ 463 for (xcount = 1; xcount <= count; xcount <<= 1) 464 ; 465 xcount >>= 1; 466 blk += count - xcount; 467 count = xcount; 468 469 /* 470 * Allocate the pages from the alist, then free them to 471 * the normal VM page queues. 472 * 473 * Pages allocated from the alist are wired. We have to 474 * busy, unwire, and free them. We must also adjust 475 * vm_low_phys_reserved before freeing any pages to prevent 476 * confusion. 477 */ 478 rblk = alist_alloc(&vm_contig_alist, blk, count); 479 if (rblk != blk) { 480 kprintf("vm_page_startup_finish: Unable to return " 481 "dma space @0x%08x/%d -> 0x%08x\n", 482 blk, count, rblk); 483 break; 484 } 485 atomic_add_int(&vmstats.v_dma_pages, -count); 486 spin_unlock(&vm_contig_spin); 487 488 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 489 vm_low_phys_reserved = VM_PAGE_TO_PHYS(m); 490 while (count) { 491 vm_page_busy_wait(m, FALSE, "cpgfr"); 492 vm_page_unwire(m, 0); 493 vm_page_free(m); 494 --count; 495 ++m; 496 } 497 spin_lock(&vm_contig_spin); 498 } 499 spin_unlock(&vm_contig_spin); 500 501 /* 502 * Print out how much DMA space drivers have already allocated and 503 * how much is left over. 504 */ 505 kprintf("DMA space used: %jdk, remaining available: %jdk\n", 506 (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) * 507 (PAGE_SIZE / 1024), 508 (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024)); 509 } 510 SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY, 511 vm_page_startup_finish, NULL); 512 513 514 /* 515 * Scan comparison function for Red-Black tree scans. An inclusive 516 * (start,end) is expected. Other fields are not used. 517 */ 518 int 519 rb_vm_page_scancmp(struct vm_page *p, void *data) 520 { 521 struct rb_vm_page_scan_info *info = data; 522 523 if (p->pindex < info->start_pindex) 524 return(-1); 525 if (p->pindex > info->end_pindex) 526 return(1); 527 return(0); 528 } 529 530 int 531 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2) 532 { 533 if (p1->pindex < p2->pindex) 534 return(-1); 535 if (p1->pindex > p2->pindex) 536 return(1); 537 return(0); 538 } 539 540 void 541 vm_page_init(vm_page_t m) 542 { 543 /* do nothing for now. Called from pmap_page_init() */ 544 } 545 546 /* 547 * Each page queue has its own spin lock, which is fairly optimal for 548 * allocating and freeing pages at least. 549 * 550 * The caller must hold the vm_page_spin_lock() before locking a vm_page's 551 * queue spinlock via this function. Also note that m->queue cannot change 552 * unless both the page and queue are locked. 553 */ 554 static __inline 555 void 556 _vm_page_queue_spin_lock(vm_page_t m) 557 { 558 u_short queue; 559 560 queue = m->queue; 561 if (queue != PQ_NONE) { 562 spin_lock(&vm_page_queues[queue].spin); 563 KKASSERT(queue == m->queue); 564 } 565 } 566 567 static __inline 568 void 569 _vm_page_queue_spin_unlock(vm_page_t m) 570 { 571 u_short queue; 572 573 queue = m->queue; 574 cpu_ccfence(); 575 if (queue != PQ_NONE) 576 spin_unlock(&vm_page_queues[queue].spin); 577 } 578 579 static __inline 580 void 581 _vm_page_queues_spin_lock(u_short queue) 582 { 583 cpu_ccfence(); 584 if (queue != PQ_NONE) 585 spin_lock(&vm_page_queues[queue].spin); 586 } 587 588 589 static __inline 590 void 591 _vm_page_queues_spin_unlock(u_short queue) 592 { 593 cpu_ccfence(); 594 if (queue != PQ_NONE) 595 spin_unlock(&vm_page_queues[queue].spin); 596 } 597 598 void 599 vm_page_queue_spin_lock(vm_page_t m) 600 { 601 _vm_page_queue_spin_lock(m); 602 } 603 604 void 605 vm_page_queues_spin_lock(u_short queue) 606 { 607 _vm_page_queues_spin_lock(queue); 608 } 609 610 void 611 vm_page_queue_spin_unlock(vm_page_t m) 612 { 613 _vm_page_queue_spin_unlock(m); 614 } 615 616 void 617 vm_page_queues_spin_unlock(u_short queue) 618 { 619 _vm_page_queues_spin_unlock(queue); 620 } 621 622 /* 623 * This locks the specified vm_page and its queue in the proper order 624 * (page first, then queue). The queue may change so the caller must 625 * recheck on return. 626 */ 627 static __inline 628 void 629 _vm_page_and_queue_spin_lock(vm_page_t m) 630 { 631 vm_page_spin_lock(m); 632 _vm_page_queue_spin_lock(m); 633 } 634 635 static __inline 636 void 637 _vm_page_and_queue_spin_unlock(vm_page_t m) 638 { 639 _vm_page_queues_spin_unlock(m->queue); 640 vm_page_spin_unlock(m); 641 } 642 643 void 644 vm_page_and_queue_spin_unlock(vm_page_t m) 645 { 646 _vm_page_and_queue_spin_unlock(m); 647 } 648 649 void 650 vm_page_and_queue_spin_lock(vm_page_t m) 651 { 652 _vm_page_and_queue_spin_lock(m); 653 } 654 655 /* 656 * Helper function removes vm_page from its current queue. 657 * Returns the base queue the page used to be on. 658 * 659 * The vm_page and the queue must be spinlocked. 660 * This function will unlock the queue but leave the page spinlocked. 661 */ 662 static __inline u_short 663 _vm_page_rem_queue_spinlocked(vm_page_t m) 664 { 665 struct vpgqueues *pq; 666 u_short queue; 667 u_short oqueue; 668 669 queue = m->queue; 670 if (queue != PQ_NONE) { 671 pq = &vm_page_queues[queue]; 672 TAILQ_REMOVE(&pq->pl, m, pageq); 673 atomic_add_int(pq->cnt, -1); 674 pq->lcnt--; 675 m->queue = PQ_NONE; 676 oqueue = queue; 677 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE) 678 queue -= m->pc; 679 vm_page_queues_spin_unlock(oqueue); /* intended */ 680 } 681 return queue; 682 } 683 684 /* 685 * Helper function places the vm_page on the specified queue. 686 * 687 * The vm_page must be spinlocked. 688 * This function will return with both the page and the queue locked. 689 */ 690 static __inline void 691 _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead) 692 { 693 struct vpgqueues *pq; 694 695 KKASSERT(m->queue == PQ_NONE); 696 697 if (queue != PQ_NONE) { 698 vm_page_queues_spin_lock(queue); 699 pq = &vm_page_queues[queue]; 700 ++pq->lcnt; 701 atomic_add_int(pq->cnt, 1); 702 m->queue = queue; 703 704 /* 705 * PQ_FREE is always handled LIFO style to try to provide 706 * cache-hot pages to programs. 707 */ 708 if (queue - m->pc == PQ_FREE) { 709 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 710 } else if (athead) { 711 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 712 } else { 713 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 714 } 715 /* leave the queue spinlocked */ 716 } 717 } 718 719 /* 720 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) 721 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we 722 * did not. Only one sleep call will be made before returning. 723 * 724 * This function does NOT busy the page and on return the page is not 725 * guaranteed to be available. 726 */ 727 void 728 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 729 { 730 u_int32_t flags; 731 732 for (;;) { 733 flags = m->flags; 734 cpu_ccfence(); 735 736 if ((flags & PG_BUSY) == 0 && 737 (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) { 738 break; 739 } 740 tsleep_interlock(m, 0); 741 if (atomic_cmpset_int(&m->flags, flags, 742 flags | PG_WANTED | PG_REFERENCED)) { 743 tsleep(m, PINTERLOCKED, msg, 0); 744 break; 745 } 746 } 747 } 748 749 /* 750 * This calculates and returns a page color given an optional VM object and 751 * either a pindex or an iterator. We attempt to return a cpu-localized 752 * pg_color that is still roughly 16-way set-associative. The CPU topology 753 * is used if it was probed. 754 * 755 * The caller may use the returned value to index into e.g. PQ_FREE when 756 * allocating a page in order to nominally obtain pages that are hopefully 757 * already localized to the requesting cpu. This function is not able to 758 * provide any sort of guarantee of this, but does its best to improve 759 * hardware cache management performance. 760 * 761 * WARNING! The caller must mask the returned value with PQ_L2_MASK. 762 */ 763 u_short 764 vm_get_pg_color(globaldata_t gd, vm_object_t object, vm_pindex_t pindex) 765 { 766 u_short pg_color; 767 int phys_id; 768 int core_id; 769 int object_pg_color; 770 771 phys_id = get_cpu_phys_id(gd->gd_cpuid); 772 core_id = get_cpu_core_id(gd->gd_cpuid); 773 object_pg_color = object ? object->pg_color : 0; 774 775 if (cpu_topology_phys_ids && cpu_topology_core_ids) { 776 int grpsize = PQ_L2_SIZE / cpu_topology_phys_ids; 777 778 if (grpsize / cpu_topology_core_ids >= PQ_SET_ASSOC) { 779 /* 780 * Enough space for a full break-down. 781 */ 782 pg_color = phys_id * grpsize; 783 pg_color += core_id * grpsize / cpu_topology_core_ids; 784 pg_color += (pindex + object_pg_color) % 785 (grpsize / cpu_topology_core_ids); 786 } else { 787 /* 788 * Not enough space, split up by physical package, 789 * then split up by core id but only down to a 790 * 16-set. If all else fails, force a 16-set. 791 */ 792 pg_color = phys_id * grpsize; 793 if (grpsize > 16) { 794 pg_color += 16 * (core_id % (grpsize / 16)); 795 grpsize = 16; 796 } else { 797 grpsize = 16; 798 } 799 pg_color += (pindex + object_pg_color) % 800 grpsize; 801 } 802 } else { 803 /* 804 * Unknown topology, distribute things evenly. 805 */ 806 pg_color = gd->gd_cpuid * PQ_L2_SIZE / ncpus; 807 pg_color += pindex + object_pg_color; 808 } 809 return pg_color; 810 } 811 812 /* 813 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we 814 * also wait for m->busy to become 0 before setting PG_BUSY. 815 */ 816 void 817 VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m, 818 int also_m_busy, const char *msg 819 VM_PAGE_DEBUG_ARGS) 820 { 821 u_int32_t flags; 822 823 for (;;) { 824 flags = m->flags; 825 cpu_ccfence(); 826 if (flags & PG_BUSY) { 827 tsleep_interlock(m, 0); 828 if (atomic_cmpset_int(&m->flags, flags, 829 flags | PG_WANTED | PG_REFERENCED)) { 830 tsleep(m, PINTERLOCKED, msg, 0); 831 } 832 } else if (also_m_busy && (flags & PG_SBUSY)) { 833 tsleep_interlock(m, 0); 834 if (atomic_cmpset_int(&m->flags, flags, 835 flags | PG_WANTED | PG_REFERENCED)) { 836 tsleep(m, PINTERLOCKED, msg, 0); 837 } 838 } else { 839 if (atomic_cmpset_int(&m->flags, flags, 840 flags | PG_BUSY)) { 841 #ifdef VM_PAGE_DEBUG 842 m->busy_func = func; 843 m->busy_line = lineno; 844 #endif 845 break; 846 } 847 } 848 } 849 } 850 851 /* 852 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy 853 * is also 0. 854 * 855 * Returns non-zero on failure. 856 */ 857 int 858 VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy 859 VM_PAGE_DEBUG_ARGS) 860 { 861 u_int32_t flags; 862 863 for (;;) { 864 flags = m->flags; 865 cpu_ccfence(); 866 if (flags & PG_BUSY) 867 return TRUE; 868 if (also_m_busy && (flags & PG_SBUSY)) 869 return TRUE; 870 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { 871 #ifdef VM_PAGE_DEBUG 872 m->busy_func = func; 873 m->busy_line = lineno; 874 #endif 875 return FALSE; 876 } 877 } 878 } 879 880 /* 881 * Clear the PG_BUSY flag and return non-zero to indicate to the caller 882 * that a wakeup() should be performed. 883 * 884 * The vm_page must be spinlocked and will remain spinlocked on return. 885 * The related queue must NOT be spinlocked (which could deadlock us). 886 * 887 * (inline version) 888 */ 889 static __inline 890 int 891 _vm_page_wakeup(vm_page_t m) 892 { 893 u_int32_t flags; 894 895 for (;;) { 896 flags = m->flags; 897 cpu_ccfence(); 898 if (atomic_cmpset_int(&m->flags, flags, 899 flags & ~(PG_BUSY | PG_WANTED))) { 900 break; 901 } 902 } 903 return(flags & PG_WANTED); 904 } 905 906 /* 907 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This 908 * is typically the last call you make on a page before moving onto 909 * other things. 910 */ 911 void 912 vm_page_wakeup(vm_page_t m) 913 { 914 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 915 vm_page_spin_lock(m); 916 if (_vm_page_wakeup(m)) { 917 vm_page_spin_unlock(m); 918 wakeup(m); 919 } else { 920 vm_page_spin_unlock(m); 921 } 922 } 923 924 /* 925 * Holding a page keeps it from being reused. Other parts of the system 926 * can still disassociate the page from its current object and free it, or 927 * perform read or write I/O on it and/or otherwise manipulate the page, 928 * but if the page is held the VM system will leave the page and its data 929 * intact and not reuse the page for other purposes until the last hold 930 * reference is released. (see vm_page_wire() if you want to prevent the 931 * page from being disassociated from its object too). 932 * 933 * The caller must still validate the contents of the page and, if necessary, 934 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete 935 * before manipulating the page. 936 * 937 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary 938 */ 939 void 940 vm_page_hold(vm_page_t m) 941 { 942 vm_page_spin_lock(m); 943 atomic_add_int(&m->hold_count, 1); 944 if (m->queue - m->pc == PQ_FREE) { 945 _vm_page_queue_spin_lock(m); 946 _vm_page_rem_queue_spinlocked(m); 947 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); 948 _vm_page_queue_spin_unlock(m); 949 } 950 vm_page_spin_unlock(m); 951 } 952 953 /* 954 * The opposite of vm_page_hold(). If the page is on the HOLD queue 955 * it was freed while held and must be moved back to the FREE queue. 956 */ 957 void 958 vm_page_unhold(vm_page_t m) 959 { 960 KASSERT(m->hold_count > 0 && m->queue - m->pc != PQ_FREE, 961 ("vm_page_unhold: pg %p illegal hold_count (%d) or on FREE queue (%d)", 962 m, m->hold_count, m->queue - m->pc)); 963 vm_page_spin_lock(m); 964 atomic_add_int(&m->hold_count, -1); 965 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) { 966 _vm_page_queue_spin_lock(m); 967 _vm_page_rem_queue_spinlocked(m); 968 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); 969 _vm_page_queue_spin_unlock(m); 970 } 971 vm_page_spin_unlock(m); 972 } 973 974 /* 975 * vm_page_getfake: 976 * 977 * Create a fictitious page with the specified physical address and 978 * memory attribute. The memory attribute is the only the machine- 979 * dependent aspect of a fictitious page that must be initialized. 980 */ 981 982 void 983 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 984 { 985 986 if ((m->flags & PG_FICTITIOUS) != 0) { 987 /* 988 * The page's memattr might have changed since the 989 * previous initialization. Update the pmap to the 990 * new memattr. 991 */ 992 goto memattr; 993 } 994 m->phys_addr = paddr; 995 m->queue = PQ_NONE; 996 /* Fictitious pages don't use "segind". */ 997 /* Fictitious pages don't use "order" or "pool". */ 998 m->flags = PG_FICTITIOUS | PG_UNMANAGED | PG_BUSY; 999 m->wire_count = 1; 1000 pmap_page_init(m); 1001 memattr: 1002 pmap_page_set_memattr(m, memattr); 1003 } 1004 1005 /* 1006 * Inserts the given vm_page into the object and object list. 1007 * 1008 * The pagetables are not updated but will presumably fault the page 1009 * in if necessary, or if a kernel page the caller will at some point 1010 * enter the page into the kernel's pmap. We are not allowed to block 1011 * here so we *can't* do this anyway. 1012 * 1013 * This routine may not block. 1014 * This routine must be called with the vm_object held. 1015 * This routine must be called with a critical section held. 1016 * 1017 * This routine returns TRUE if the page was inserted into the object 1018 * successfully, and FALSE if the page already exists in the object. 1019 */ 1020 int 1021 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 1022 { 1023 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object)); 1024 if (m->object != NULL) 1025 panic("vm_page_insert: already inserted"); 1026 1027 object->generation++; 1028 1029 /* 1030 * Record the object/offset pair in this page and add the 1031 * pv_list_count of the page to the object. 1032 * 1033 * The vm_page spin lock is required for interactions with the pmap. 1034 */ 1035 vm_page_spin_lock(m); 1036 m->object = object; 1037 m->pindex = pindex; 1038 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) { 1039 m->object = NULL; 1040 m->pindex = 0; 1041 vm_page_spin_unlock(m); 1042 return FALSE; 1043 } 1044 ++object->resident_page_count; 1045 ++mycpu->gd_vmtotal.t_rm; 1046 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */ 1047 vm_page_spin_unlock(m); 1048 1049 /* 1050 * Since we are inserting a new and possibly dirty page, 1051 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 1052 */ 1053 if ((m->valid & m->dirty) || 1054 (m->flags & (PG_WRITEABLE | PG_NEED_COMMIT))) 1055 vm_object_set_writeable_dirty(object); 1056 1057 /* 1058 * Checks for a swap assignment and sets PG_SWAPPED if appropriate. 1059 */ 1060 swap_pager_page_inserted(m); 1061 return TRUE; 1062 } 1063 1064 /* 1065 * Removes the given vm_page_t from the (object,index) table 1066 * 1067 * The underlying pmap entry (if any) is NOT removed here. 1068 * This routine may not block. 1069 * 1070 * The page must be BUSY and will remain BUSY on return. 1071 * No other requirements. 1072 * 1073 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave 1074 * it busy. 1075 */ 1076 void 1077 vm_page_remove(vm_page_t m) 1078 { 1079 vm_object_t object; 1080 1081 if (m->object == NULL) { 1082 return; 1083 } 1084 1085 if ((m->flags & PG_BUSY) == 0) 1086 panic("vm_page_remove: page not busy"); 1087 1088 object = m->object; 1089 1090 vm_object_hold(object); 1091 1092 /* 1093 * Remove the page from the object and update the object. 1094 * 1095 * The vm_page spin lock is required for interactions with the pmap. 1096 */ 1097 vm_page_spin_lock(m); 1098 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); 1099 --object->resident_page_count; 1100 --mycpu->gd_vmtotal.t_rm; 1101 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */ 1102 m->object = NULL; 1103 vm_page_spin_unlock(m); 1104 1105 object->generation++; 1106 1107 vm_object_drop(object); 1108 } 1109 1110 /* 1111 * Locate and return the page at (object, pindex), or NULL if the 1112 * page could not be found. 1113 * 1114 * The caller must hold the vm_object token. 1115 */ 1116 vm_page_t 1117 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 1118 { 1119 vm_page_t m; 1120 1121 /* 1122 * Search the hash table for this object/offset pair 1123 */ 1124 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1125 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1126 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex)); 1127 return(m); 1128 } 1129 1130 vm_page_t 1131 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object, 1132 vm_pindex_t pindex, 1133 int also_m_busy, const char *msg 1134 VM_PAGE_DEBUG_ARGS) 1135 { 1136 u_int32_t flags; 1137 vm_page_t m; 1138 1139 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1140 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1141 while (m) { 1142 KKASSERT(m->object == object && m->pindex == pindex); 1143 flags = m->flags; 1144 cpu_ccfence(); 1145 if (flags & PG_BUSY) { 1146 tsleep_interlock(m, 0); 1147 if (atomic_cmpset_int(&m->flags, flags, 1148 flags | PG_WANTED | PG_REFERENCED)) { 1149 tsleep(m, PINTERLOCKED, msg, 0); 1150 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1151 pindex); 1152 } 1153 } else if (also_m_busy && (flags & PG_SBUSY)) { 1154 tsleep_interlock(m, 0); 1155 if (atomic_cmpset_int(&m->flags, flags, 1156 flags | PG_WANTED | PG_REFERENCED)) { 1157 tsleep(m, PINTERLOCKED, msg, 0); 1158 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1159 pindex); 1160 } 1161 } else if (atomic_cmpset_int(&m->flags, flags, 1162 flags | PG_BUSY)) { 1163 #ifdef VM_PAGE_DEBUG 1164 m->busy_func = func; 1165 m->busy_line = lineno; 1166 #endif 1167 break; 1168 } 1169 } 1170 return m; 1171 } 1172 1173 /* 1174 * Attempt to lookup and busy a page. 1175 * 1176 * Returns NULL if the page could not be found 1177 * 1178 * Returns a vm_page and error == TRUE if the page exists but could not 1179 * be busied. 1180 * 1181 * Returns a vm_page and error == FALSE on success. 1182 */ 1183 vm_page_t 1184 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object, 1185 vm_pindex_t pindex, 1186 int also_m_busy, int *errorp 1187 VM_PAGE_DEBUG_ARGS) 1188 { 1189 u_int32_t flags; 1190 vm_page_t m; 1191 1192 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1193 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1194 *errorp = FALSE; 1195 while (m) { 1196 KKASSERT(m->object == object && m->pindex == pindex); 1197 flags = m->flags; 1198 cpu_ccfence(); 1199 if (flags & PG_BUSY) { 1200 *errorp = TRUE; 1201 break; 1202 } 1203 if (also_m_busy && (flags & PG_SBUSY)) { 1204 *errorp = TRUE; 1205 break; 1206 } 1207 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { 1208 #ifdef VM_PAGE_DEBUG 1209 m->busy_func = func; 1210 m->busy_line = lineno; 1211 #endif 1212 break; 1213 } 1214 } 1215 return m; 1216 } 1217 1218 /* 1219 * Attempt to repurpose the passed-in page. If the passed-in page cannot 1220 * be repurposed it will be released, *must_reenter will be set to 1, and 1221 * this function will fall-through to vm_page_lookup_busy_try(). 1222 * 1223 * The passed-in page must be wired and not busy. The returned page will 1224 * be busied and not wired. 1225 * 1226 * A different page may be returned. The returned page will be busied and 1227 * not wired. 1228 * 1229 * NULL can be returned. If so, the required page could not be busied. 1230 * The passed-in page will be unwired. 1231 */ 1232 vm_page_t 1233 vm_page_repurpose(struct vm_object *object, vm_pindex_t pindex, 1234 int also_m_busy, int *errorp, vm_page_t m, 1235 int *must_reenter, int *iswired) 1236 { 1237 if (m) { 1238 vm_page_busy_wait(m, TRUE, "biodep"); 1239 if ((m->flags & (PG_UNMANAGED | PG_MAPPED | PG_FICTITIOUS)) || 1240 m->busy || m->wire_count != 1 || m->hold_count) { 1241 vm_page_unwire(m, 0); 1242 vm_page_wakeup(m); 1243 /* fall through to normal lookup */ 1244 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 1245 vm_page_unwire(m, 0); 1246 vm_page_deactivate(m); 1247 vm_page_wakeup(m); 1248 /* fall through to normal lookup */ 1249 } else { 1250 /* 1251 * We can safely repurpose the page. It should 1252 * already be unqueued. 1253 */ 1254 KKASSERT(m->queue == PQ_NONE && m->dirty == 0); 1255 vm_page_remove(m); 1256 m->valid = 0; 1257 m->act_count = 0; 1258 if (vm_page_insert(m, object, pindex)) { 1259 *errorp = 0; 1260 *iswired = 1; 1261 1262 return m; 1263 } 1264 vm_page_unwire(m, 0); 1265 vm_page_free(m); 1266 /* fall through to normal lookup */ 1267 } 1268 } 1269 *must_reenter = 1; 1270 *iswired = 0; 1271 m = vm_page_lookup_busy_try(object, pindex, also_m_busy, errorp); 1272 1273 return m; 1274 } 1275 1276 /* 1277 * Caller must hold the related vm_object 1278 */ 1279 vm_page_t 1280 vm_page_next(vm_page_t m) 1281 { 1282 vm_page_t next; 1283 1284 next = vm_page_rb_tree_RB_NEXT(m); 1285 if (next && next->pindex != m->pindex + 1) 1286 next = NULL; 1287 return (next); 1288 } 1289 1290 /* 1291 * vm_page_rename() 1292 * 1293 * Move the given vm_page from its current object to the specified 1294 * target object/offset. The page must be busy and will remain so 1295 * on return. 1296 * 1297 * new_object must be held. 1298 * This routine might block. XXX ? 1299 * 1300 * NOTE: Swap associated with the page must be invalidated by the move. We 1301 * have to do this for several reasons: (1) we aren't freeing the 1302 * page, (2) we are dirtying the page, (3) the VM system is probably 1303 * moving the page from object A to B, and will then later move 1304 * the backing store from A to B and we can't have a conflict. 1305 * 1306 * NOTE: We *always* dirty the page. It is necessary both for the 1307 * fact that we moved it, and because we may be invalidating 1308 * swap. If the page is on the cache, we have to deactivate it 1309 * or vm_page_dirty() will panic. Dirty pages are not allowed 1310 * on the cache. 1311 */ 1312 void 1313 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1314 { 1315 KKASSERT(m->flags & PG_BUSY); 1316 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object)); 1317 if (m->object) { 1318 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m->object)); 1319 vm_page_remove(m); 1320 } 1321 if (vm_page_insert(m, new_object, new_pindex) == FALSE) { 1322 panic("vm_page_rename: target exists (%p,%"PRIu64")", 1323 new_object, new_pindex); 1324 } 1325 if (m->queue - m->pc == PQ_CACHE) 1326 vm_page_deactivate(m); 1327 vm_page_dirty(m); 1328 } 1329 1330 /* 1331 * vm_page_unqueue() without any wakeup. This routine is used when a page 1332 * is to remain BUSYied by the caller. 1333 * 1334 * This routine may not block. 1335 */ 1336 void 1337 vm_page_unqueue_nowakeup(vm_page_t m) 1338 { 1339 vm_page_and_queue_spin_lock(m); 1340 (void)_vm_page_rem_queue_spinlocked(m); 1341 vm_page_spin_unlock(m); 1342 } 1343 1344 /* 1345 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon 1346 * if necessary. 1347 * 1348 * This routine may not block. 1349 */ 1350 void 1351 vm_page_unqueue(vm_page_t m) 1352 { 1353 u_short queue; 1354 1355 vm_page_and_queue_spin_lock(m); 1356 queue = _vm_page_rem_queue_spinlocked(m); 1357 if (queue == PQ_FREE || queue == PQ_CACHE) { 1358 vm_page_spin_unlock(m); 1359 pagedaemon_wakeup(); 1360 } else { 1361 vm_page_spin_unlock(m); 1362 } 1363 } 1364 1365 /* 1366 * vm_page_list_find() 1367 * 1368 * Find a page on the specified queue with color optimization. 1369 * 1370 * The page coloring optimization attempts to locate a page that does 1371 * not overload other nearby pages in the object in the cpu's L1 or L2 1372 * caches. We need this optimization because cpu caches tend to be 1373 * physical caches, while object spaces tend to be virtual. 1374 * 1375 * The page coloring optimization also, very importantly, tries to localize 1376 * memory to cpus and physical sockets. 1377 * 1378 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock 1379 * and the algorithm is adjusted to localize allocations on a per-core basis. 1380 * This is done by 'twisting' the colors. 1381 * 1382 * The page is returned spinlocked and removed from its queue (it will 1383 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller 1384 * is responsible for dealing with the busy-page case (usually by 1385 * deactivating the page and looping). 1386 * 1387 * NOTE: This routine is carefully inlined. A non-inlined version 1388 * is available for outside callers but the only critical path is 1389 * from within this source file. 1390 * 1391 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE 1392 * represent stable storage, allowing us to order our locks vm_page 1393 * first, then queue. 1394 */ 1395 static __inline 1396 vm_page_t 1397 _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) 1398 { 1399 vm_page_t m; 1400 1401 for (;;) { 1402 if (prefer_zero) { 1403 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, 1404 pglist); 1405 } else { 1406 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl); 1407 } 1408 if (m == NULL) { 1409 m = _vm_page_list_find2(basequeue, index); 1410 return(m); 1411 } 1412 vm_page_and_queue_spin_lock(m); 1413 if (m->queue == basequeue + index) { 1414 _vm_page_rem_queue_spinlocked(m); 1415 /* vm_page_t spin held, no queue spin */ 1416 break; 1417 } 1418 vm_page_and_queue_spin_unlock(m); 1419 } 1420 return(m); 1421 } 1422 1423 /* 1424 * If we could not find the page in the desired queue try to find it in 1425 * a nearby queue. 1426 */ 1427 static vm_page_t 1428 _vm_page_list_find2(int basequeue, int index) 1429 { 1430 struct vpgqueues *pq; 1431 vm_page_t m = NULL; 1432 int pqmask = PQ_SET_ASSOC_MASK >> 1; 1433 int pqi; 1434 int i; 1435 1436 index &= PQ_L2_MASK; 1437 pq = &vm_page_queues[basequeue]; 1438 1439 /* 1440 * Run local sets of 16, 32, 64, 128, and the whole queue if all 1441 * else fails (PQ_L2_MASK which is 255). 1442 */ 1443 do { 1444 pqmask = (pqmask << 1) | 1; 1445 for (i = 0; i <= pqmask; ++i) { 1446 pqi = (index & ~pqmask) | ((index + i) & pqmask); 1447 m = TAILQ_FIRST(&pq[pqi].pl); 1448 if (m) { 1449 _vm_page_and_queue_spin_lock(m); 1450 if (m->queue == basequeue + pqi) { 1451 _vm_page_rem_queue_spinlocked(m); 1452 return(m); 1453 } 1454 _vm_page_and_queue_spin_unlock(m); 1455 --i; 1456 continue; 1457 } 1458 } 1459 } while (pqmask != PQ_L2_MASK); 1460 1461 return(m); 1462 } 1463 1464 /* 1465 * Returns a vm_page candidate for allocation. The page is not busied so 1466 * it can move around. The caller must busy the page (and typically 1467 * deactivate it if it cannot be busied!) 1468 * 1469 * Returns a spinlocked vm_page that has been removed from its queue. 1470 */ 1471 vm_page_t 1472 vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) 1473 { 1474 return(_vm_page_list_find(basequeue, index, prefer_zero)); 1475 } 1476 1477 /* 1478 * Find a page on the cache queue with color optimization, remove it 1479 * from the queue, and busy it. The returned page will not be spinlocked. 1480 * 1481 * A candidate failure will be deactivated. Candidates can fail due to 1482 * being busied by someone else, in which case they will be deactivated. 1483 * 1484 * This routine may not block. 1485 * 1486 */ 1487 static vm_page_t 1488 vm_page_select_cache(u_short pg_color) 1489 { 1490 vm_page_t m; 1491 1492 for (;;) { 1493 m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK, FALSE); 1494 if (m == NULL) 1495 break; 1496 /* 1497 * (m) has been removed from its queue and spinlocked 1498 */ 1499 if (vm_page_busy_try(m, TRUE)) { 1500 _vm_page_deactivate_locked(m, 0); 1501 vm_page_spin_unlock(m); 1502 } else { 1503 /* 1504 * We successfully busied the page 1505 */ 1506 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) == 0 && 1507 m->hold_count == 0 && 1508 m->wire_count == 0 && 1509 (m->dirty & m->valid) == 0) { 1510 vm_page_spin_unlock(m); 1511 pagedaemon_wakeup(); 1512 return(m); 1513 } 1514 1515 /* 1516 * The page cannot be recycled, deactivate it. 1517 */ 1518 _vm_page_deactivate_locked(m, 0); 1519 if (_vm_page_wakeup(m)) { 1520 vm_page_spin_unlock(m); 1521 wakeup(m); 1522 } else { 1523 vm_page_spin_unlock(m); 1524 } 1525 } 1526 } 1527 return (m); 1528 } 1529 1530 /* 1531 * Find a free or zero page, with specified preference. We attempt to 1532 * inline the nominal case and fall back to _vm_page_select_free() 1533 * otherwise. A busied page is removed from the queue and returned. 1534 * 1535 * This routine may not block. 1536 */ 1537 static __inline vm_page_t 1538 vm_page_select_free(u_short pg_color, boolean_t prefer_zero) 1539 { 1540 vm_page_t m; 1541 1542 for (;;) { 1543 m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK, 1544 prefer_zero); 1545 if (m == NULL) 1546 break; 1547 if (vm_page_busy_try(m, TRUE)) { 1548 /* 1549 * Various mechanisms such as a pmap_collect can 1550 * result in a busy page on the free queue. We 1551 * have to move the page out of the way so we can 1552 * retry the allocation. If the other thread is not 1553 * allocating the page then m->valid will remain 0 and 1554 * the pageout daemon will free the page later on. 1555 * 1556 * Since we could not busy the page, however, we 1557 * cannot make assumptions as to whether the page 1558 * will be allocated by the other thread or not, 1559 * so all we can do is deactivate it to move it out 1560 * of the way. In particular, if the other thread 1561 * wires the page it may wind up on the inactive 1562 * queue and the pageout daemon will have to deal 1563 * with that case too. 1564 */ 1565 _vm_page_deactivate_locked(m, 0); 1566 vm_page_spin_unlock(m); 1567 } else { 1568 /* 1569 * Theoretically if we are able to busy the page 1570 * atomic with the queue removal (using the vm_page 1571 * lock) nobody else should be able to mess with the 1572 * page before us. 1573 */ 1574 KKASSERT((m->flags & (PG_UNMANAGED | 1575 PG_NEED_COMMIT)) == 0); 1576 KASSERT(m->hold_count == 0, ("m->hold_count is not zero " 1577 "pg %p q=%d flags=%08x hold=%d wire=%d", 1578 m, m->queue, m->flags, m->hold_count, m->wire_count)); 1579 KKASSERT(m->wire_count == 0); 1580 vm_page_spin_unlock(m); 1581 pagedaemon_wakeup(); 1582 1583 /* return busied and removed page */ 1584 return(m); 1585 } 1586 } 1587 return(m); 1588 } 1589 1590 /* 1591 * vm_page_alloc() 1592 * 1593 * Allocate and return a memory cell associated with this VM object/offset 1594 * pair. If object is NULL an unassociated page will be allocated. 1595 * 1596 * The returned page will be busied and removed from its queues. This 1597 * routine can block and may return NULL if a race occurs and the page 1598 * is found to already exist at the specified (object, pindex). 1599 * 1600 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain 1601 * VM_ALLOC_QUICK like normal but cannot use cache 1602 * VM_ALLOC_SYSTEM greater free drain 1603 * VM_ALLOC_INTERRUPT allow free list to be completely drained 1604 * VM_ALLOC_ZERO advisory request for pre-zero'd page only 1605 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only 1606 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision 1607 * (see vm_page_grab()) 1608 * VM_ALLOC_USE_GD ok to use per-gd cache 1609 * 1610 * The object must be held if not NULL 1611 * This routine may not block 1612 * 1613 * Additional special handling is required when called from an interrupt 1614 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache 1615 * in this case. 1616 */ 1617 vm_page_t 1618 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req) 1619 { 1620 globaldata_t gd = mycpu; 1621 vm_object_t obj; 1622 vm_page_t m; 1623 u_short pg_color; 1624 1625 #if 0 1626 /* 1627 * Special per-cpu free VM page cache. The pages are pre-busied 1628 * and pre-zerod for us. 1629 */ 1630 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) { 1631 crit_enter_gd(gd); 1632 if (gd->gd_vmpg_count) { 1633 m = gd->gd_vmpg_array[--gd->gd_vmpg_count]; 1634 crit_exit_gd(gd); 1635 goto done; 1636 } 1637 crit_exit_gd(gd); 1638 } 1639 #endif 1640 m = NULL; 1641 1642 /* 1643 * CPU LOCALIZATION 1644 * 1645 * CPU localization algorithm. Break the page queues up by physical 1646 * id and core id (note that two cpu threads will have the same core 1647 * id, and core_id != gd_cpuid). 1648 * 1649 * This is nowhere near perfect, for example the last pindex in a 1650 * subgroup will overflow into the next cpu or package. But this 1651 * should get us good page reuse locality in heavy mixed loads. 1652 */ 1653 pg_color = vm_get_pg_color(gd, object, pindex); 1654 1655 KKASSERT(page_req & 1656 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK| 1657 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 1658 1659 /* 1660 * Certain system threads (pageout daemon, buf_daemon's) are 1661 * allowed to eat deeper into the free page list. 1662 */ 1663 if (curthread->td_flags & TDF_SYSTHREAD) 1664 page_req |= VM_ALLOC_SYSTEM; 1665 1666 /* 1667 * Impose various limitations. Note that the v_free_reserved test 1668 * must match the opposite of vm_page_count_target() to avoid 1669 * livelocks, be careful. 1670 */ 1671 loop: 1672 if (vmstats.v_free_count >= vmstats.v_free_reserved || 1673 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) || 1674 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 && 1675 vmstats.v_free_count > vmstats.v_interrupt_free_min) 1676 ) { 1677 /* 1678 * The free queue has sufficient free pages to take one out. 1679 */ 1680 if (page_req & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) 1681 m = vm_page_select_free(pg_color, TRUE); 1682 else 1683 m = vm_page_select_free(pg_color, FALSE); 1684 } else if (page_req & VM_ALLOC_NORMAL) { 1685 /* 1686 * Allocatable from the cache (non-interrupt only). On 1687 * success, we must free the page and try again, thus 1688 * ensuring that vmstats.v_*_free_min counters are replenished. 1689 */ 1690 #ifdef INVARIANTS 1691 if (curthread->td_preempted) { 1692 kprintf("vm_page_alloc(): warning, attempt to allocate" 1693 " cache page from preempting interrupt\n"); 1694 m = NULL; 1695 } else { 1696 m = vm_page_select_cache(pg_color); 1697 } 1698 #else 1699 m = vm_page_select_cache(pg_color); 1700 #endif 1701 /* 1702 * On success move the page into the free queue and loop. 1703 * 1704 * Only do this if we can safely acquire the vm_object lock, 1705 * because this is effectively a random page and the caller 1706 * might be holding the lock shared, we don't want to 1707 * deadlock. 1708 */ 1709 if (m != NULL) { 1710 KASSERT(m->dirty == 0, 1711 ("Found dirty cache page %p", m)); 1712 if ((obj = m->object) != NULL) { 1713 if (vm_object_hold_try(obj)) { 1714 vm_page_protect(m, VM_PROT_NONE); 1715 vm_page_free(m); 1716 /* m->object NULL here */ 1717 vm_object_drop(obj); 1718 } else { 1719 vm_page_deactivate(m); 1720 vm_page_wakeup(m); 1721 } 1722 } else { 1723 vm_page_protect(m, VM_PROT_NONE); 1724 vm_page_free(m); 1725 } 1726 goto loop; 1727 } 1728 1729 /* 1730 * On failure return NULL 1731 */ 1732 #if defined(DIAGNOSTIC) 1733 if (vmstats.v_cache_count > 0) 1734 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count); 1735 #endif 1736 vm_pageout_deficit++; 1737 pagedaemon_wakeup(); 1738 return (NULL); 1739 } else { 1740 /* 1741 * No pages available, wakeup the pageout daemon and give up. 1742 */ 1743 vm_pageout_deficit++; 1744 pagedaemon_wakeup(); 1745 return (NULL); 1746 } 1747 1748 /* 1749 * v_free_count can race so loop if we don't find the expected 1750 * page. 1751 */ 1752 if (m == NULL) 1753 goto loop; 1754 1755 /* 1756 * Good page found. The page has already been busied for us and 1757 * removed from its queues. 1758 */ 1759 KASSERT(m->dirty == 0, 1760 ("vm_page_alloc: free/cache page %p was dirty", m)); 1761 KKASSERT(m->queue == PQ_NONE); 1762 1763 #if 0 1764 done: 1765 #endif 1766 /* 1767 * Initialize the structure, inheriting some flags but clearing 1768 * all the rest. The page has already been busied for us. 1769 */ 1770 vm_page_flag_clear(m, ~(PG_BUSY | PG_SBUSY)); 1771 KKASSERT(m->wire_count == 0); 1772 KKASSERT(m->busy == 0); 1773 m->act_count = 0; 1774 m->valid = 0; 1775 1776 /* 1777 * Caller must be holding the object lock (asserted by 1778 * vm_page_insert()). 1779 * 1780 * NOTE: Inserting a page here does not insert it into any pmaps 1781 * (which could cause us to block allocating memory). 1782 * 1783 * NOTE: If no object an unassociated page is allocated, m->pindex 1784 * can be used by the caller for any purpose. 1785 */ 1786 if (object) { 1787 if (vm_page_insert(m, object, pindex) == FALSE) { 1788 vm_page_free(m); 1789 if ((page_req & VM_ALLOC_NULL_OK) == 0) 1790 panic("PAGE RACE %p[%ld]/%p", 1791 object, (long)pindex, m); 1792 m = NULL; 1793 } 1794 } else { 1795 m->pindex = pindex; 1796 } 1797 1798 /* 1799 * Don't wakeup too often - wakeup the pageout daemon when 1800 * we would be nearly out of memory. 1801 */ 1802 pagedaemon_wakeup(); 1803 1804 /* 1805 * A PG_BUSY page is returned. 1806 */ 1807 return (m); 1808 } 1809 1810 /* 1811 * Returns number of pages available in our DMA memory reserve 1812 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf) 1813 */ 1814 vm_size_t 1815 vm_contig_avail_pages(void) 1816 { 1817 alist_blk_t blk; 1818 alist_blk_t count; 1819 alist_blk_t bfree; 1820 spin_lock(&vm_contig_spin); 1821 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 1822 spin_unlock(&vm_contig_spin); 1823 1824 return bfree; 1825 } 1826 1827 /* 1828 * Attempt to allocate contiguous physical memory with the specified 1829 * requirements. 1830 */ 1831 vm_page_t 1832 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high, 1833 unsigned long alignment, unsigned long boundary, 1834 unsigned long size, vm_memattr_t memattr) 1835 { 1836 alist_blk_t blk; 1837 vm_page_t m; 1838 int i; 1839 1840 alignment >>= PAGE_SHIFT; 1841 if (alignment == 0) 1842 alignment = 1; 1843 boundary >>= PAGE_SHIFT; 1844 if (boundary == 0) 1845 boundary = 1; 1846 size = (size + PAGE_MASK) >> PAGE_SHIFT; 1847 1848 spin_lock(&vm_contig_spin); 1849 blk = alist_alloc(&vm_contig_alist, 0, size); 1850 if (blk == ALIST_BLOCK_NONE) { 1851 spin_unlock(&vm_contig_spin); 1852 if (bootverbose) { 1853 kprintf("vm_page_alloc_contig: %ldk nospace\n", 1854 (size + PAGE_MASK) * (PAGE_SIZE / 1024)); 1855 } 1856 return(NULL); 1857 } 1858 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) { 1859 alist_free(&vm_contig_alist, blk, size); 1860 spin_unlock(&vm_contig_spin); 1861 if (bootverbose) { 1862 kprintf("vm_page_alloc_contig: %ldk high " 1863 "%016jx failed\n", 1864 (size + PAGE_MASK) * (PAGE_SIZE / 1024), 1865 (intmax_t)high); 1866 } 1867 return(NULL); 1868 } 1869 spin_unlock(&vm_contig_spin); 1870 if (vm_contig_verbose) { 1871 kprintf("vm_page_alloc_contig: %016jx/%ldk\n", 1872 (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT, 1873 (size + PAGE_MASK) * (PAGE_SIZE / 1024)); 1874 } 1875 1876 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 1877 if (memattr != VM_MEMATTR_DEFAULT) 1878 for (i = 0;i < size;i++) 1879 pmap_page_set_memattr(&m[i], memattr); 1880 return m; 1881 } 1882 1883 /* 1884 * Free contiguously allocated pages. The pages will be wired but not busy. 1885 * When freeing to the alist we leave them wired and not busy. 1886 */ 1887 void 1888 vm_page_free_contig(vm_page_t m, unsigned long size) 1889 { 1890 vm_paddr_t pa = VM_PAGE_TO_PHYS(m); 1891 vm_pindex_t start = pa >> PAGE_SHIFT; 1892 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT; 1893 1894 if (vm_contig_verbose) { 1895 kprintf("vm_page_free_contig: %016jx/%ldk\n", 1896 (intmax_t)pa, size / 1024); 1897 } 1898 if (pa < vm_low_phys_reserved) { 1899 KKASSERT(pa + size <= vm_low_phys_reserved); 1900 spin_lock(&vm_contig_spin); 1901 alist_free(&vm_contig_alist, start, pages); 1902 spin_unlock(&vm_contig_spin); 1903 } else { 1904 while (pages) { 1905 vm_page_busy_wait(m, FALSE, "cpgfr"); 1906 vm_page_unwire(m, 0); 1907 vm_page_free(m); 1908 --pages; 1909 ++m; 1910 } 1911 1912 } 1913 } 1914 1915 1916 /* 1917 * Wait for sufficient free memory for nominal heavy memory use kernel 1918 * operations. 1919 * 1920 * WARNING! Be sure never to call this in any vm_pageout code path, which 1921 * will trivially deadlock the system. 1922 */ 1923 void 1924 vm_wait_nominal(void) 1925 { 1926 while (vm_page_count_min(0)) 1927 vm_wait(0); 1928 } 1929 1930 /* 1931 * Test if vm_wait_nominal() would block. 1932 */ 1933 int 1934 vm_test_nominal(void) 1935 { 1936 if (vm_page_count_min(0)) 1937 return(1); 1938 return(0); 1939 } 1940 1941 /* 1942 * Block until free pages are available for allocation, called in various 1943 * places before memory allocations. 1944 * 1945 * The caller may loop if vm_page_count_min() == FALSE so we cannot be 1946 * more generous then that. 1947 */ 1948 void 1949 vm_wait(int timo) 1950 { 1951 /* 1952 * never wait forever 1953 */ 1954 if (timo == 0) 1955 timo = hz; 1956 lwkt_gettoken(&vm_token); 1957 1958 if (curthread == pagethread) { 1959 /* 1960 * The pageout daemon itself needs pages, this is bad. 1961 */ 1962 if (vm_page_count_min(0)) { 1963 vm_pageout_pages_needed = 1; 1964 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo); 1965 } 1966 } else { 1967 /* 1968 * Wakeup the pageout daemon if necessary and wait. 1969 * 1970 * Do not wait indefinitely for the target to be reached, 1971 * as load might prevent it from being reached any time soon. 1972 * But wait a little to try to slow down page allocations 1973 * and to give more important threads (the pagedaemon) 1974 * allocation priority. 1975 */ 1976 if (vm_page_count_target()) { 1977 if (vm_pages_needed == 0) { 1978 vm_pages_needed = 1; 1979 wakeup(&vm_pages_needed); 1980 } 1981 ++vm_pages_waiting; /* SMP race ok */ 1982 tsleep(&vmstats.v_free_count, 0, "vmwait", timo); 1983 } 1984 } 1985 lwkt_reltoken(&vm_token); 1986 } 1987 1988 /* 1989 * Block until free pages are available for allocation 1990 * 1991 * Called only from vm_fault so that processes page faulting can be 1992 * easily tracked. 1993 */ 1994 void 1995 vm_wait_pfault(void) 1996 { 1997 /* 1998 * Wakeup the pageout daemon if necessary and wait. 1999 * 2000 * Do not wait indefinitely for the target to be reached, 2001 * as load might prevent it from being reached any time soon. 2002 * But wait a little to try to slow down page allocations 2003 * and to give more important threads (the pagedaemon) 2004 * allocation priority. 2005 */ 2006 if (vm_page_count_min(0)) { 2007 lwkt_gettoken(&vm_token); 2008 while (vm_page_count_severe()) { 2009 if (vm_page_count_target()) { 2010 if (vm_pages_needed == 0) { 2011 vm_pages_needed = 1; 2012 wakeup(&vm_pages_needed); 2013 } 2014 ++vm_pages_waiting; /* SMP race ok */ 2015 tsleep(&vmstats.v_free_count, 0, "pfault", hz); 2016 } 2017 } 2018 lwkt_reltoken(&vm_token); 2019 } 2020 } 2021 2022 /* 2023 * Put the specified page on the active list (if appropriate). Ensure 2024 * that act_count is at least ACT_INIT but do not otherwise mess with it. 2025 * 2026 * The caller should be holding the page busied ? XXX 2027 * This routine may not block. 2028 */ 2029 void 2030 vm_page_activate(vm_page_t m) 2031 { 2032 u_short oqueue; 2033 2034 vm_page_spin_lock(m); 2035 if (m->queue - m->pc != PQ_ACTIVE) { 2036 _vm_page_queue_spin_lock(m); 2037 oqueue = _vm_page_rem_queue_spinlocked(m); 2038 /* page is left spinlocked, queue is unlocked */ 2039 2040 if (oqueue == PQ_CACHE) 2041 mycpu->gd_cnt.v_reactivated++; 2042 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 2043 if (m->act_count < ACT_INIT) 2044 m->act_count = ACT_INIT; 2045 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); 2046 } 2047 _vm_page_and_queue_spin_unlock(m); 2048 if (oqueue == PQ_CACHE || oqueue == PQ_FREE) 2049 pagedaemon_wakeup(); 2050 } else { 2051 if (m->act_count < ACT_INIT) 2052 m->act_count = ACT_INIT; 2053 vm_page_spin_unlock(m); 2054 } 2055 } 2056 2057 /* 2058 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 2059 * routine is called when a page has been added to the cache or free 2060 * queues. 2061 * 2062 * This routine may not block. 2063 */ 2064 static __inline void 2065 vm_page_free_wakeup(void) 2066 { 2067 /* 2068 * If the pageout daemon itself needs pages, then tell it that 2069 * there are some free. 2070 */ 2071 if (vm_pageout_pages_needed && 2072 vmstats.v_cache_count + vmstats.v_free_count >= 2073 vmstats.v_pageout_free_min 2074 ) { 2075 vm_pageout_pages_needed = 0; 2076 wakeup(&vm_pageout_pages_needed); 2077 } 2078 2079 /* 2080 * Wakeup processes that are waiting on memory. 2081 * 2082 * Generally speaking we want to wakeup stuck processes as soon as 2083 * possible. !vm_page_count_min(0) is the absolute minimum point 2084 * where we can do this. Wait a bit longer to reduce degenerate 2085 * re-blocking (vm_page_free_hysteresis). The target check is just 2086 * to make sure the min-check w/hysteresis does not exceed the 2087 * normal target. 2088 */ 2089 if (vm_pages_waiting) { 2090 if (!vm_page_count_min(vm_page_free_hysteresis) || 2091 !vm_page_count_target()) { 2092 vm_pages_waiting = 0; 2093 wakeup(&vmstats.v_free_count); 2094 ++mycpu->gd_cnt.v_ppwakeups; 2095 } 2096 #if 0 2097 if (!vm_page_count_target()) { 2098 /* 2099 * Plenty of pages are free, wakeup everyone. 2100 */ 2101 vm_pages_waiting = 0; 2102 wakeup(&vmstats.v_free_count); 2103 ++mycpu->gd_cnt.v_ppwakeups; 2104 } else if (!vm_page_count_min(0)) { 2105 /* 2106 * Some pages are free, wakeup someone. 2107 */ 2108 int wcount = vm_pages_waiting; 2109 if (wcount > 0) 2110 --wcount; 2111 vm_pages_waiting = wcount; 2112 wakeup_one(&vmstats.v_free_count); 2113 ++mycpu->gd_cnt.v_ppwakeups; 2114 } 2115 #endif 2116 } 2117 } 2118 2119 /* 2120 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates 2121 * it from its VM object. 2122 * 2123 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on 2124 * return (the page will have been freed). 2125 */ 2126 void 2127 vm_page_free_toq(vm_page_t m) 2128 { 2129 mycpu->gd_cnt.v_tfree++; 2130 KKASSERT((m->flags & PG_MAPPED) == 0); 2131 KKASSERT(m->flags & PG_BUSY); 2132 2133 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { 2134 kprintf("vm_page_free: pindex(%lu), busy(%d), " 2135 "PG_BUSY(%d), hold(%d)\n", 2136 (u_long)m->pindex, m->busy, 2137 ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count); 2138 if ((m->queue - m->pc) == PQ_FREE) 2139 panic("vm_page_free: freeing free page"); 2140 else 2141 panic("vm_page_free: freeing busy page"); 2142 } 2143 2144 /* 2145 * Remove from object, spinlock the page and its queues and 2146 * remove from any queue. No queue spinlock will be held 2147 * after this section (because the page was removed from any 2148 * queue). 2149 */ 2150 vm_page_remove(m); 2151 vm_page_and_queue_spin_lock(m); 2152 _vm_page_rem_queue_spinlocked(m); 2153 2154 /* 2155 * No further management of fictitious pages occurs beyond object 2156 * and queue removal. 2157 */ 2158 if ((m->flags & PG_FICTITIOUS) != 0) { 2159 vm_page_spin_unlock(m); 2160 vm_page_wakeup(m); 2161 return; 2162 } 2163 2164 m->valid = 0; 2165 vm_page_undirty(m); 2166 2167 if (m->wire_count != 0) { 2168 if (m->wire_count > 1) { 2169 panic( 2170 "vm_page_free: invalid wire count (%d), pindex: 0x%lx", 2171 m->wire_count, (long)m->pindex); 2172 } 2173 panic("vm_page_free: freeing wired page"); 2174 } 2175 2176 /* 2177 * Clear the UNMANAGED flag when freeing an unmanaged page. 2178 * Clear the NEED_COMMIT flag 2179 */ 2180 if (m->flags & PG_UNMANAGED) 2181 vm_page_flag_clear(m, PG_UNMANAGED); 2182 if (m->flags & PG_NEED_COMMIT) 2183 vm_page_flag_clear(m, PG_NEED_COMMIT); 2184 2185 if (m->hold_count != 0) { 2186 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); 2187 } else { 2188 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); 2189 } 2190 2191 /* 2192 * This sequence allows us to clear PG_BUSY while still holding 2193 * its spin lock, which reduces contention vs allocators. We 2194 * must not leave the queue locked or _vm_page_wakeup() may 2195 * deadlock. 2196 */ 2197 _vm_page_queue_spin_unlock(m); 2198 if (_vm_page_wakeup(m)) { 2199 vm_page_spin_unlock(m); 2200 wakeup(m); 2201 } else { 2202 vm_page_spin_unlock(m); 2203 } 2204 vm_page_free_wakeup(); 2205 } 2206 2207 /* 2208 * vm_page_unmanage() 2209 * 2210 * Prevent PV management from being done on the page. The page is 2211 * removed from the paging queues as if it were wired, and as a 2212 * consequence of no longer being managed the pageout daemon will not 2213 * touch it (since there is no way to locate the pte mappings for the 2214 * page). madvise() calls that mess with the pmap will also no longer 2215 * operate on the page. 2216 * 2217 * Beyond that the page is still reasonably 'normal'. Freeing the page 2218 * will clear the flag. 2219 * 2220 * This routine is used by OBJT_PHYS objects - objects using unswappable 2221 * physical memory as backing store rather then swap-backed memory and 2222 * will eventually be extended to support 4MB unmanaged physical 2223 * mappings. 2224 * 2225 * Caller must be holding the page busy. 2226 */ 2227 void 2228 vm_page_unmanage(vm_page_t m) 2229 { 2230 KKASSERT(m->flags & PG_BUSY); 2231 if ((m->flags & PG_UNMANAGED) == 0) { 2232 if (m->wire_count == 0) 2233 vm_page_unqueue(m); 2234 } 2235 vm_page_flag_set(m, PG_UNMANAGED); 2236 } 2237 2238 /* 2239 * Mark this page as wired down by yet another map, removing it from 2240 * paging queues as necessary. 2241 * 2242 * Caller must be holding the page busy. 2243 */ 2244 void 2245 vm_page_wire(vm_page_t m) 2246 { 2247 /* 2248 * Only bump the wire statistics if the page is not already wired, 2249 * and only unqueue the page if it is on some queue (if it is unmanaged 2250 * it is already off the queues). Don't do anything with fictitious 2251 * pages because they are always wired. 2252 */ 2253 KKASSERT(m->flags & PG_BUSY); 2254 if ((m->flags & PG_FICTITIOUS) == 0) { 2255 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) { 2256 if ((m->flags & PG_UNMANAGED) == 0) 2257 vm_page_unqueue(m); 2258 atomic_add_int(&vmstats.v_wire_count, 1); 2259 } 2260 KASSERT(m->wire_count != 0, 2261 ("vm_page_wire: wire_count overflow m=%p", m)); 2262 } 2263 } 2264 2265 /* 2266 * Release one wiring of this page, potentially enabling it to be paged again. 2267 * 2268 * Many pages placed on the inactive queue should actually go 2269 * into the cache, but it is difficult to figure out which. What 2270 * we do instead, if the inactive target is well met, is to put 2271 * clean pages at the head of the inactive queue instead of the tail. 2272 * This will cause them to be moved to the cache more quickly and 2273 * if not actively re-referenced, freed more quickly. If we just 2274 * stick these pages at the end of the inactive queue, heavy filesystem 2275 * meta-data accesses can cause an unnecessary paging load on memory bound 2276 * processes. This optimization causes one-time-use metadata to be 2277 * reused more quickly. 2278 * 2279 * Pages marked PG_NEED_COMMIT are always activated and never placed on 2280 * the inactive queue. This helps the pageout daemon determine memory 2281 * pressure and act on out-of-memory situations more quickly. 2282 * 2283 * BUT, if we are in a low-memory situation we have no choice but to 2284 * put clean pages on the cache queue. 2285 * 2286 * A number of routines use vm_page_unwire() to guarantee that the page 2287 * will go into either the inactive or active queues, and will NEVER 2288 * be placed in the cache - for example, just after dirtying a page. 2289 * dirty pages in the cache are not allowed. 2290 * 2291 * This routine may not block. 2292 */ 2293 void 2294 vm_page_unwire(vm_page_t m, int activate) 2295 { 2296 KKASSERT(m->flags & PG_BUSY); 2297 if (m->flags & PG_FICTITIOUS) { 2298 /* do nothing */ 2299 } else if (m->wire_count <= 0) { 2300 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 2301 } else { 2302 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) { 2303 atomic_add_int(&vmstats.v_wire_count, -1); 2304 if (m->flags & PG_UNMANAGED) { 2305 ; 2306 } else if (activate || (m->flags & PG_NEED_COMMIT)) { 2307 vm_page_spin_lock(m); 2308 _vm_page_add_queue_spinlocked(m, 2309 PQ_ACTIVE + m->pc, 0); 2310 _vm_page_and_queue_spin_unlock(m); 2311 } else { 2312 vm_page_spin_lock(m); 2313 vm_page_flag_clear(m, PG_WINATCFLS); 2314 _vm_page_add_queue_spinlocked(m, 2315 PQ_INACTIVE + m->pc, 0); 2316 ++vm_swapcache_inactive_heuristic; 2317 _vm_page_and_queue_spin_unlock(m); 2318 } 2319 } 2320 } 2321 } 2322 2323 /* 2324 * Move the specified page to the inactive queue. If the page has 2325 * any associated swap, the swap is deallocated. 2326 * 2327 * Normally athead is 0 resulting in LRU operation. athead is set 2328 * to 1 if we want this page to be 'as if it were placed in the cache', 2329 * except without unmapping it from the process address space. 2330 * 2331 * vm_page's spinlock must be held on entry and will remain held on return. 2332 * This routine may not block. 2333 */ 2334 static void 2335 _vm_page_deactivate_locked(vm_page_t m, int athead) 2336 { 2337 u_short oqueue; 2338 2339 /* 2340 * Ignore if already inactive. 2341 */ 2342 if (m->queue - m->pc == PQ_INACTIVE) 2343 return; 2344 _vm_page_queue_spin_lock(m); 2345 oqueue = _vm_page_rem_queue_spinlocked(m); 2346 2347 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { 2348 if (oqueue == PQ_CACHE) 2349 mycpu->gd_cnt.v_reactivated++; 2350 vm_page_flag_clear(m, PG_WINATCFLS); 2351 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead); 2352 if (athead == 0) 2353 ++vm_swapcache_inactive_heuristic; 2354 } 2355 /* NOTE: PQ_NONE if condition not taken */ 2356 _vm_page_queue_spin_unlock(m); 2357 /* leaves vm_page spinlocked */ 2358 } 2359 2360 /* 2361 * Attempt to deactivate a page. 2362 * 2363 * No requirements. 2364 */ 2365 void 2366 vm_page_deactivate(vm_page_t m) 2367 { 2368 vm_page_spin_lock(m); 2369 _vm_page_deactivate_locked(m, 0); 2370 vm_page_spin_unlock(m); 2371 } 2372 2373 void 2374 vm_page_deactivate_locked(vm_page_t m) 2375 { 2376 _vm_page_deactivate_locked(m, 0); 2377 } 2378 2379 /* 2380 * Attempt to move a page to PQ_CACHE. 2381 * 2382 * Returns 0 on failure, 1 on success 2383 * 2384 * The page should NOT be busied by the caller. This function will validate 2385 * whether the page can be safely moved to the cache. 2386 */ 2387 int 2388 vm_page_try_to_cache(vm_page_t m) 2389 { 2390 vm_page_spin_lock(m); 2391 if (vm_page_busy_try(m, TRUE)) { 2392 vm_page_spin_unlock(m); 2393 return(0); 2394 } 2395 if (m->dirty || m->hold_count || m->wire_count || 2396 (m->flags & (PG_UNMANAGED | PG_NEED_COMMIT))) { 2397 if (_vm_page_wakeup(m)) { 2398 vm_page_spin_unlock(m); 2399 wakeup(m); 2400 } else { 2401 vm_page_spin_unlock(m); 2402 } 2403 return(0); 2404 } 2405 vm_page_spin_unlock(m); 2406 2407 /* 2408 * Page busied by us and no longer spinlocked. Dirty pages cannot 2409 * be moved to the cache. 2410 */ 2411 vm_page_test_dirty(m); 2412 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2413 vm_page_wakeup(m); 2414 return(0); 2415 } 2416 vm_page_cache(m); 2417 return(1); 2418 } 2419 2420 /* 2421 * Attempt to free the page. If we cannot free it, we do nothing. 2422 * 1 is returned on success, 0 on failure. 2423 * 2424 * No requirements. 2425 */ 2426 int 2427 vm_page_try_to_free(vm_page_t m) 2428 { 2429 vm_page_spin_lock(m); 2430 if (vm_page_busy_try(m, TRUE)) { 2431 vm_page_spin_unlock(m); 2432 return(0); 2433 } 2434 2435 /* 2436 * The page can be in any state, including already being on the free 2437 * queue. Check to see if it really can be freed. 2438 */ 2439 if (m->dirty || /* can't free if it is dirty */ 2440 m->hold_count || /* or held (XXX may be wrong) */ 2441 m->wire_count || /* or wired */ 2442 (m->flags & (PG_UNMANAGED | /* or unmanaged */ 2443 PG_NEED_COMMIT)) || /* or needs a commit */ 2444 m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */ 2445 m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */ 2446 if (_vm_page_wakeup(m)) { 2447 vm_page_spin_unlock(m); 2448 wakeup(m); 2449 } else { 2450 vm_page_spin_unlock(m); 2451 } 2452 return(0); 2453 } 2454 vm_page_spin_unlock(m); 2455 2456 /* 2457 * We can probably free the page. 2458 * 2459 * Page busied by us and no longer spinlocked. Dirty pages will 2460 * not be freed by this function. We have to re-test the 2461 * dirty bit after cleaning out the pmaps. 2462 */ 2463 vm_page_test_dirty(m); 2464 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2465 vm_page_wakeup(m); 2466 return(0); 2467 } 2468 vm_page_protect(m, VM_PROT_NONE); 2469 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2470 vm_page_wakeup(m); 2471 return(0); 2472 } 2473 vm_page_free(m); 2474 return(1); 2475 } 2476 2477 /* 2478 * vm_page_cache 2479 * 2480 * Put the specified page onto the page cache queue (if appropriate). 2481 * 2482 * The page must be busy, and this routine will release the busy and 2483 * possibly even free the page. 2484 */ 2485 void 2486 vm_page_cache(vm_page_t m) 2487 { 2488 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) || 2489 m->busy || m->wire_count || m->hold_count) { 2490 kprintf("vm_page_cache: attempting to cache busy/held page\n"); 2491 vm_page_wakeup(m); 2492 return; 2493 } 2494 2495 /* 2496 * Already in the cache (and thus not mapped) 2497 */ 2498 if ((m->queue - m->pc) == PQ_CACHE) { 2499 KKASSERT((m->flags & PG_MAPPED) == 0); 2500 vm_page_wakeup(m); 2501 return; 2502 } 2503 2504 /* 2505 * Caller is required to test m->dirty, but note that the act of 2506 * removing the page from its maps can cause it to become dirty 2507 * on an SMP system due to another cpu running in usermode. 2508 */ 2509 if (m->dirty) { 2510 panic("vm_page_cache: caching a dirty page, pindex: %ld", 2511 (long)m->pindex); 2512 } 2513 2514 /* 2515 * Remove all pmaps and indicate that the page is not 2516 * writeable or mapped. Our vm_page_protect() call may 2517 * have blocked (especially w/ VM_PROT_NONE), so recheck 2518 * everything. 2519 */ 2520 vm_page_protect(m, VM_PROT_NONE); 2521 if ((m->flags & (PG_UNMANAGED | PG_MAPPED)) || 2522 m->busy || m->wire_count || m->hold_count) { 2523 vm_page_wakeup(m); 2524 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 2525 vm_page_deactivate(m); 2526 vm_page_wakeup(m); 2527 } else { 2528 _vm_page_and_queue_spin_lock(m); 2529 _vm_page_rem_queue_spinlocked(m); 2530 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0); 2531 _vm_page_queue_spin_unlock(m); 2532 if (_vm_page_wakeup(m)) { 2533 vm_page_spin_unlock(m); 2534 wakeup(m); 2535 } else { 2536 vm_page_spin_unlock(m); 2537 } 2538 vm_page_free_wakeup(); 2539 } 2540 } 2541 2542 /* 2543 * vm_page_dontneed() 2544 * 2545 * Cache, deactivate, or do nothing as appropriate. This routine 2546 * is typically used by madvise() MADV_DONTNEED. 2547 * 2548 * Generally speaking we want to move the page into the cache so 2549 * it gets reused quickly. However, this can result in a silly syndrome 2550 * due to the page recycling too quickly. Small objects will not be 2551 * fully cached. On the otherhand, if we move the page to the inactive 2552 * queue we wind up with a problem whereby very large objects 2553 * unnecessarily blow away our inactive and cache queues. 2554 * 2555 * The solution is to move the pages based on a fixed weighting. We 2556 * either leave them alone, deactivate them, or move them to the cache, 2557 * where moving them to the cache has the highest weighting. 2558 * By forcing some pages into other queues we eventually force the 2559 * system to balance the queues, potentially recovering other unrelated 2560 * space from active. The idea is to not force this to happen too 2561 * often. 2562 * 2563 * The page must be busied. 2564 */ 2565 void 2566 vm_page_dontneed(vm_page_t m) 2567 { 2568 static int dnweight; 2569 int dnw; 2570 int head; 2571 2572 dnw = ++dnweight; 2573 2574 /* 2575 * occassionally leave the page alone 2576 */ 2577 if ((dnw & 0x01F0) == 0 || 2578 m->queue - m->pc == PQ_INACTIVE || 2579 m->queue - m->pc == PQ_CACHE 2580 ) { 2581 if (m->act_count >= ACT_INIT) 2582 --m->act_count; 2583 return; 2584 } 2585 2586 /* 2587 * If vm_page_dontneed() is inactivating a page, it must clear 2588 * the referenced flag; otherwise the pagedaemon will see references 2589 * on the page in the inactive queue and reactivate it. Until the 2590 * page can move to the cache queue, madvise's job is not done. 2591 */ 2592 vm_page_flag_clear(m, PG_REFERENCED); 2593 pmap_clear_reference(m); 2594 2595 if (m->dirty == 0) 2596 vm_page_test_dirty(m); 2597 2598 if (m->dirty || (dnw & 0x0070) == 0) { 2599 /* 2600 * Deactivate the page 3 times out of 32. 2601 */ 2602 head = 0; 2603 } else { 2604 /* 2605 * Cache the page 28 times out of every 32. Note that 2606 * the page is deactivated instead of cached, but placed 2607 * at the head of the queue instead of the tail. 2608 */ 2609 head = 1; 2610 } 2611 vm_page_spin_lock(m); 2612 _vm_page_deactivate_locked(m, head); 2613 vm_page_spin_unlock(m); 2614 } 2615 2616 /* 2617 * These routines manipulate the 'soft busy' count for a page. A soft busy 2618 * is almost like PG_BUSY except that it allows certain compatible operations 2619 * to occur on the page while it is busy. For example, a page undergoing a 2620 * write can still be mapped read-only. 2621 * 2622 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only 2623 * adjusted while the vm_page is PG_BUSY so the flash will occur when the 2624 * busy bit is cleared. 2625 */ 2626 void 2627 vm_page_io_start(vm_page_t m) 2628 { 2629 KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!")); 2630 atomic_add_char(&m->busy, 1); 2631 vm_page_flag_set(m, PG_SBUSY); 2632 } 2633 2634 void 2635 vm_page_io_finish(vm_page_t m) 2636 { 2637 KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!")); 2638 atomic_subtract_char(&m->busy, 1); 2639 if (m->busy == 0) 2640 vm_page_flag_clear(m, PG_SBUSY); 2641 } 2642 2643 /* 2644 * Indicate that a clean VM page requires a filesystem commit and cannot 2645 * be reused. Used by tmpfs. 2646 */ 2647 void 2648 vm_page_need_commit(vm_page_t m) 2649 { 2650 vm_page_flag_set(m, PG_NEED_COMMIT); 2651 vm_object_set_writeable_dirty(m->object); 2652 } 2653 2654 void 2655 vm_page_clear_commit(vm_page_t m) 2656 { 2657 vm_page_flag_clear(m, PG_NEED_COMMIT); 2658 } 2659 2660 /* 2661 * Grab a page, blocking if it is busy and allocating a page if necessary. 2662 * A busy page is returned or NULL. The page may or may not be valid and 2663 * might not be on a queue (the caller is responsible for the disposition of 2664 * the page). 2665 * 2666 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the 2667 * page will be zero'd and marked valid. 2668 * 2669 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked 2670 * valid even if it already exists. 2671 * 2672 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also 2673 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified. 2674 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified. 2675 * 2676 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is 2677 * always returned if we had blocked. 2678 * 2679 * This routine may not be called from an interrupt. 2680 * 2681 * No other requirements. 2682 */ 2683 vm_page_t 2684 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 2685 { 2686 vm_page_t m; 2687 int error; 2688 int shared = 1; 2689 2690 KKASSERT(allocflags & 2691 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 2692 vm_object_hold_shared(object); 2693 for (;;) { 2694 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error); 2695 if (error) { 2696 vm_page_sleep_busy(m, TRUE, "pgrbwt"); 2697 if ((allocflags & VM_ALLOC_RETRY) == 0) { 2698 m = NULL; 2699 break; 2700 } 2701 /* retry */ 2702 } else if (m == NULL) { 2703 if (shared) { 2704 vm_object_upgrade(object); 2705 shared = 0; 2706 } 2707 if (allocflags & VM_ALLOC_RETRY) 2708 allocflags |= VM_ALLOC_NULL_OK; 2709 m = vm_page_alloc(object, pindex, 2710 allocflags & ~VM_ALLOC_RETRY); 2711 if (m) 2712 break; 2713 vm_wait(0); 2714 if ((allocflags & VM_ALLOC_RETRY) == 0) 2715 goto failed; 2716 } else { 2717 /* m found */ 2718 break; 2719 } 2720 } 2721 2722 /* 2723 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid. 2724 * 2725 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set 2726 * valid even if already valid. 2727 * 2728 * NOTE! We have removed all of the PG_ZERO optimizations and also 2729 * removed the idle zeroing code. These optimizations actually 2730 * slow things down on modern cpus because the zerod area is 2731 * likely uncached, placing a memory-access burden on the 2732 * accesors taking the fault. 2733 * 2734 * By always zeroing the page in-line with the fault, no 2735 * dynamic ram reads are needed and the caches are hot, ready 2736 * for userland to access the memory. 2737 */ 2738 if (m->valid == 0) { 2739 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) { 2740 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 2741 m->valid = VM_PAGE_BITS_ALL; 2742 } 2743 } else if (allocflags & VM_ALLOC_FORCE_ZERO) { 2744 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 2745 m->valid = VM_PAGE_BITS_ALL; 2746 } 2747 failed: 2748 vm_object_drop(object); 2749 return(m); 2750 } 2751 2752 /* 2753 * Mapping function for valid bits or for dirty bits in 2754 * a page. May not block. 2755 * 2756 * Inputs are required to range within a page. 2757 * 2758 * No requirements. 2759 * Non blocking. 2760 */ 2761 int 2762 vm_page_bits(int base, int size) 2763 { 2764 int first_bit; 2765 int last_bit; 2766 2767 KASSERT( 2768 base + size <= PAGE_SIZE, 2769 ("vm_page_bits: illegal base/size %d/%d", base, size) 2770 ); 2771 2772 if (size == 0) /* handle degenerate case */ 2773 return(0); 2774 2775 first_bit = base >> DEV_BSHIFT; 2776 last_bit = (base + size - 1) >> DEV_BSHIFT; 2777 2778 return ((2 << last_bit) - (1 << first_bit)); 2779 } 2780 2781 /* 2782 * Sets portions of a page valid and clean. The arguments are expected 2783 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 2784 * of any partial chunks touched by the range. The invalid portion of 2785 * such chunks will be zero'd. 2786 * 2787 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically 2788 * align base to DEV_BSIZE so as not to mark clean a partially 2789 * truncated device block. Otherwise the dirty page status might be 2790 * lost. 2791 * 2792 * This routine may not block. 2793 * 2794 * (base + size) must be less then or equal to PAGE_SIZE. 2795 */ 2796 static void 2797 _vm_page_zero_valid(vm_page_t m, int base, int size) 2798 { 2799 int frag; 2800 int endoff; 2801 2802 if (size == 0) /* handle degenerate case */ 2803 return; 2804 2805 /* 2806 * If the base is not DEV_BSIZE aligned and the valid 2807 * bit is clear, we have to zero out a portion of the 2808 * first block. 2809 */ 2810 2811 if ((frag = base & ~(DEV_BSIZE - 1)) != base && 2812 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 2813 ) { 2814 pmap_zero_page_area( 2815 VM_PAGE_TO_PHYS(m), 2816 frag, 2817 base - frag 2818 ); 2819 } 2820 2821 /* 2822 * If the ending offset is not DEV_BSIZE aligned and the 2823 * valid bit is clear, we have to zero out a portion of 2824 * the last block. 2825 */ 2826 2827 endoff = base + size; 2828 2829 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && 2830 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 2831 ) { 2832 pmap_zero_page_area( 2833 VM_PAGE_TO_PHYS(m), 2834 endoff, 2835 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 2836 ); 2837 } 2838 } 2839 2840 /* 2841 * Set valid, clear dirty bits. If validating the entire 2842 * page we can safely clear the pmap modify bit. We also 2843 * use this opportunity to clear the PG_NOSYNC flag. If a process 2844 * takes a write fault on a MAP_NOSYNC memory area the flag will 2845 * be set again. 2846 * 2847 * We set valid bits inclusive of any overlap, but we can only 2848 * clear dirty bits for DEV_BSIZE chunks that are fully within 2849 * the range. 2850 * 2851 * Page must be busied? 2852 * No other requirements. 2853 */ 2854 void 2855 vm_page_set_valid(vm_page_t m, int base, int size) 2856 { 2857 _vm_page_zero_valid(m, base, size); 2858 m->valid |= vm_page_bits(base, size); 2859 } 2860 2861 2862 /* 2863 * Set valid bits and clear dirty bits. 2864 * 2865 * NOTE: This function does not clear the pmap modified bit. 2866 * Also note that e.g. NFS may use a byte-granular base 2867 * and size. 2868 * 2869 * WARNING: Page must be busied? But vfs_clean_one_page() will call 2870 * this without necessarily busying the page (via bdwrite()). 2871 * So for now vm_token must also be held. 2872 * 2873 * No other requirements. 2874 */ 2875 void 2876 vm_page_set_validclean(vm_page_t m, int base, int size) 2877 { 2878 int pagebits; 2879 2880 _vm_page_zero_valid(m, base, size); 2881 pagebits = vm_page_bits(base, size); 2882 m->valid |= pagebits; 2883 m->dirty &= ~pagebits; 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 * Set valid & dirty. Used by buwrite() 2892 * 2893 * WARNING: Page must be busied? But vfs_dirty_one_page() will 2894 * call this function in buwrite() so for now vm_token must 2895 * be held. 2896 * 2897 * No other requirements. 2898 */ 2899 void 2900 vm_page_set_validdirty(vm_page_t m, int base, int size) 2901 { 2902 int pagebits; 2903 2904 pagebits = vm_page_bits(base, size); 2905 m->valid |= pagebits; 2906 m->dirty |= pagebits; 2907 if (m->object) 2908 vm_object_set_writeable_dirty(m->object); 2909 } 2910 2911 /* 2912 * Clear dirty bits. 2913 * 2914 * NOTE: This function does not clear the pmap modified bit. 2915 * Also note that e.g. NFS may use a byte-granular base 2916 * and size. 2917 * 2918 * Page must be busied? 2919 * No other requirements. 2920 */ 2921 void 2922 vm_page_clear_dirty(vm_page_t m, int base, int size) 2923 { 2924 m->dirty &= ~vm_page_bits(base, size); 2925 if (base == 0 && size == PAGE_SIZE) { 2926 /*pmap_clear_modify(m);*/ 2927 vm_page_flag_clear(m, PG_NOSYNC); 2928 } 2929 } 2930 2931 /* 2932 * Make the page all-dirty. 2933 * 2934 * Also make sure the related object and vnode reflect the fact that the 2935 * object may now contain a dirty page. 2936 * 2937 * Page must be busied? 2938 * No other requirements. 2939 */ 2940 void 2941 vm_page_dirty(vm_page_t m) 2942 { 2943 #ifdef INVARIANTS 2944 int pqtype = m->queue - m->pc; 2945 #endif 2946 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE, 2947 ("vm_page_dirty: page in free/cache queue!")); 2948 if (m->dirty != VM_PAGE_BITS_ALL) { 2949 m->dirty = VM_PAGE_BITS_ALL; 2950 if (m->object) 2951 vm_object_set_writeable_dirty(m->object); 2952 } 2953 } 2954 2955 /* 2956 * Invalidates DEV_BSIZE'd chunks within a page. Both the 2957 * valid and dirty bits for the effected areas are cleared. 2958 * 2959 * Page must be busied? 2960 * Does not block. 2961 * No other requirements. 2962 */ 2963 void 2964 vm_page_set_invalid(vm_page_t m, int base, int size) 2965 { 2966 int bits; 2967 2968 bits = vm_page_bits(base, size); 2969 m->valid &= ~bits; 2970 m->dirty &= ~bits; 2971 m->object->generation++; 2972 } 2973 2974 /* 2975 * The kernel assumes that the invalid portions of a page contain 2976 * garbage, but such pages can be mapped into memory by user code. 2977 * When this occurs, we must zero out the non-valid portions of the 2978 * page so user code sees what it expects. 2979 * 2980 * Pages are most often semi-valid when the end of a file is mapped 2981 * into memory and the file's size is not page aligned. 2982 * 2983 * Page must be busied? 2984 * No other requirements. 2985 */ 2986 void 2987 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 2988 { 2989 int b; 2990 int i; 2991 2992 /* 2993 * Scan the valid bits looking for invalid sections that 2994 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 2995 * valid bit may be set ) have already been zerod by 2996 * vm_page_set_validclean(). 2997 */ 2998 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 2999 if (i == (PAGE_SIZE / DEV_BSIZE) || 3000 (m->valid & (1 << i)) 3001 ) { 3002 if (i > b) { 3003 pmap_zero_page_area( 3004 VM_PAGE_TO_PHYS(m), 3005 b << DEV_BSHIFT, 3006 (i - b) << DEV_BSHIFT 3007 ); 3008 } 3009 b = i + 1; 3010 } 3011 } 3012 3013 /* 3014 * setvalid is TRUE when we can safely set the zero'd areas 3015 * as being valid. We can do this if there are no cache consistency 3016 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 3017 */ 3018 if (setvalid) 3019 m->valid = VM_PAGE_BITS_ALL; 3020 } 3021 3022 /* 3023 * Is a (partial) page valid? Note that the case where size == 0 3024 * will return FALSE in the degenerate case where the page is entirely 3025 * invalid, and TRUE otherwise. 3026 * 3027 * Does not block. 3028 * No other requirements. 3029 */ 3030 int 3031 vm_page_is_valid(vm_page_t m, int base, int size) 3032 { 3033 int bits = vm_page_bits(base, size); 3034 3035 if (m->valid && ((m->valid & bits) == bits)) 3036 return 1; 3037 else 3038 return 0; 3039 } 3040 3041 /* 3042 * update dirty bits from pmap/mmu. May not block. 3043 * 3044 * Caller must hold the page busy 3045 */ 3046 void 3047 vm_page_test_dirty(vm_page_t m) 3048 { 3049 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { 3050 vm_page_dirty(m); 3051 } 3052 } 3053 3054 /* 3055 * Register an action, associating it with its vm_page 3056 */ 3057 void 3058 vm_page_register_action(vm_page_action_t action, vm_page_event_t event) 3059 { 3060 struct vm_page_action_list *list; 3061 int hv; 3062 3063 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; 3064 list = &action_list[hv]; 3065 3066 lwkt_gettoken(&vm_token); 3067 vm_page_flag_set(action->m, PG_ACTIONLIST); 3068 action->event = event; 3069 LIST_INSERT_HEAD(list, action, entry); 3070 lwkt_reltoken(&vm_token); 3071 } 3072 3073 /* 3074 * Unregister an action, disassociating it from its related vm_page 3075 */ 3076 void 3077 vm_page_unregister_action(vm_page_action_t action) 3078 { 3079 struct vm_page_action_list *list; 3080 int hv; 3081 3082 lwkt_gettoken(&vm_token); 3083 if (action->event != VMEVENT_NONE) { 3084 action->event = VMEVENT_NONE; 3085 LIST_REMOVE(action, entry); 3086 3087 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; 3088 list = &action_list[hv]; 3089 if (LIST_EMPTY(list)) 3090 vm_page_flag_clear(action->m, PG_ACTIONLIST); 3091 } 3092 lwkt_reltoken(&vm_token); 3093 } 3094 3095 /* 3096 * Issue an event on a VM page. Corresponding action structures are 3097 * removed from the page's list and called. 3098 * 3099 * If the vm_page has no more pending action events we clear its 3100 * PG_ACTIONLIST flag. 3101 */ 3102 void 3103 vm_page_event_internal(vm_page_t m, vm_page_event_t event) 3104 { 3105 struct vm_page_action_list *list; 3106 struct vm_page_action *scan; 3107 struct vm_page_action *next; 3108 int hv; 3109 int all; 3110 3111 hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK; 3112 list = &action_list[hv]; 3113 all = 1; 3114 3115 lwkt_gettoken(&vm_token); 3116 LIST_FOREACH_MUTABLE(scan, list, entry, next) { 3117 if (scan->m == m) { 3118 if (scan->event == event) { 3119 scan->event = VMEVENT_NONE; 3120 LIST_REMOVE(scan, entry); 3121 scan->func(m, scan); 3122 /* XXX */ 3123 } else { 3124 all = 0; 3125 } 3126 } 3127 } 3128 if (all) 3129 vm_page_flag_clear(m, PG_ACTIONLIST); 3130 lwkt_reltoken(&vm_token); 3131 } 3132 3133 #include "opt_ddb.h" 3134 #ifdef DDB 3135 #include <sys/kernel.h> 3136 3137 #include <ddb/ddb.h> 3138 3139 DB_SHOW_COMMAND(page, vm_page_print_page_info) 3140 { 3141 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count); 3142 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count); 3143 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count); 3144 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count); 3145 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count); 3146 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved); 3147 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min); 3148 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target); 3149 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min); 3150 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target); 3151 } 3152 3153 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 3154 { 3155 int i; 3156 db_printf("PQ_FREE:"); 3157 for(i=0;i<PQ_L2_SIZE;i++) { 3158 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); 3159 } 3160 db_printf("\n"); 3161 3162 db_printf("PQ_CACHE:"); 3163 for(i=0;i<PQ_L2_SIZE;i++) { 3164 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); 3165 } 3166 db_printf("\n"); 3167 3168 db_printf("PQ_ACTIVE:"); 3169 for(i=0;i<PQ_L2_SIZE;i++) { 3170 db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt); 3171 } 3172 db_printf("\n"); 3173 3174 db_printf("PQ_INACTIVE:"); 3175 for(i=0;i<PQ_L2_SIZE;i++) { 3176 db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt); 3177 } 3178 db_printf("\n"); 3179 } 3180 #endif /* DDB */ 3181