1 /* 2 * Copyright (c) 2003-2019 The DragonFly Project. All rights reserved. 3 * Copyright (c) 1991 Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * The Mach Operating System project at Carnegie-Mellon University. 8 * 9 * This code is derived from software contributed to The DragonFly Project 10 * by Matthew Dillon <dillon@backplane.com> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 37 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $ 38 */ 39 40 /* 41 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 42 * All rights reserved. 43 * 44 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 45 * 46 * Permission to use, copy, modify and distribute this software and 47 * its documentation is hereby granted, provided that both the copyright 48 * notice and this permission notice appear in all copies of the 49 * software, derivative works or modified versions, and any portions 50 * thereof, and that both notices appear in supporting documentation. 51 * 52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 55 * 56 * Carnegie Mellon requests users of this software to return to 57 * 58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 59 * School of Computer Science 60 * Carnegie Mellon University 61 * Pittsburgh PA 15213-3890 62 * 63 * any improvements or extensions that they make and grant Carnegie the 64 * rights to redistribute these changes. 65 */ 66 /* 67 * Resident memory management module. The module manipulates 'VM pages'. 68 * A VM page is the core building block for memory management. 69 */ 70 71 #include <sys/param.h> 72 #include <sys/systm.h> 73 #include <sys/malloc.h> 74 #include <sys/proc.h> 75 #include <sys/vmmeter.h> 76 #include <sys/vnode.h> 77 #include <sys/kernel.h> 78 #include <sys/alist.h> 79 #include <sys/sysctl.h> 80 #include <sys/cpu_topology.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <sys/lock.h> 85 #include <vm/vm_kern.h> 86 #include <vm/pmap.h> 87 #include <vm/vm_map.h> 88 #include <vm/vm_object.h> 89 #include <vm/vm_page.h> 90 #include <vm/vm_pageout.h> 91 #include <vm/vm_pager.h> 92 #include <vm/vm_extern.h> 93 #include <vm/swap_pager.h> 94 95 #include <machine/inttypes.h> 96 #include <machine/md_var.h> 97 #include <machine/specialreg.h> 98 #include <machine/bus_dma.h> 99 100 #include <vm/vm_page2.h> 101 #include <sys/spinlock2.h> 102 103 /* 104 * Cache necessary elements in the hash table itself to avoid indirecting 105 * through random vm_page's when doing a lookup. The hash table is 106 * heuristical and it is ok for races to mess up any or all fields. 107 */ 108 struct vm_page_hash_elm { 109 vm_page_t m; 110 vm_object_t object; /* heuristical */ 111 vm_pindex_t pindex; /* heuristical */ 112 int ticks; 113 int unused; 114 }; 115 116 #define VM_PAGE_HASH_SET 4 /* power of 2, set-assoc */ 117 #define VM_PAGE_HASH_MAX (8 * 1024 * 1024) /* power of 2, max size */ 118 119 /* 120 * SET - Minimum required set associative size, must be a power of 2. We 121 * want this to match or exceed the set-associativeness of the cpu, 122 * up to a reasonable limit (we will use 16). 123 */ 124 __read_mostly static int set_assoc_mask = 16 - 1; 125 126 static void vm_page_queue_init(void); 127 static void vm_page_free_wakeup(void); 128 static vm_page_t vm_page_select_cache(u_short pg_color); 129 static vm_page_t _vm_page_list_find_wide(int basequeue, int index, int *lastp); 130 static vm_page_t _vm_page_list_find2_wide(int bq1, int bq2, int index, 131 int *lastp1, int *lastp); 132 static void _vm_page_deactivate_locked(vm_page_t m, int athead); 133 static void vm_numa_add_topology_mem(cpu_node_t *cpup, int physid, long bytes); 134 135 /* 136 * Array of tailq lists 137 */ 138 struct vpgqueues vm_page_queues[PQ_COUNT]; 139 140 static volatile int vm_pages_waiting; 141 static struct alist vm_contig_alist; 142 static struct almeta vm_contig_ameta[ALIST_RECORDS_65536]; 143 static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin, "vm_contig_spin"); 144 145 __read_mostly static int vm_page_hash_vnode_only; 146 __read_mostly static int vm_page_hash_size; 147 __read_mostly static struct vm_page_hash_elm *vm_page_hash; 148 149 static u_long vm_dma_reserved = 0; 150 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved); 151 SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0, 152 "Memory reserved for DMA"); 153 SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD, 154 &vm_contig_alist.bl_free, 0, "Memory reserved for DMA"); 155 156 SYSCTL_INT(_vm, OID_AUTO, page_hash_vnode_only, CTLFLAG_RW, 157 &vm_page_hash_vnode_only, 0, "Only hash vnode pages"); 158 #if 0 159 static int vm_page_hash_debug; 160 SYSCTL_INT(_vm, OID_AUTO, page_hash_debug, CTLFLAG_RW, 161 &vm_page_hash_debug, 0, "Only hash vnode pages"); 162 #endif 163 164 static int vm_contig_verbose = 0; 165 TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose); 166 167 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, 168 vm_pindex_t, pindex); 169 170 static void 171 vm_page_queue_init(void) 172 { 173 int i; 174 175 for (i = 0; i < PQ_L2_SIZE; i++) 176 vm_page_queues[PQ_FREE+i].cnt_offset = 177 offsetof(struct vmstats, v_free_count); 178 for (i = 0; i < PQ_L2_SIZE; i++) 179 vm_page_queues[PQ_CACHE+i].cnt_offset = 180 offsetof(struct vmstats, v_cache_count); 181 for (i = 0; i < PQ_L2_SIZE; i++) 182 vm_page_queues[PQ_INACTIVE+i].cnt_offset = 183 offsetof(struct vmstats, v_inactive_count); 184 for (i = 0; i < PQ_L2_SIZE; i++) 185 vm_page_queues[PQ_ACTIVE+i].cnt_offset = 186 offsetof(struct vmstats, v_active_count); 187 for (i = 0; i < PQ_L2_SIZE; i++) 188 vm_page_queues[PQ_HOLD+i].cnt_offset = 189 offsetof(struct vmstats, v_active_count); 190 /* PQ_NONE has no queue */ 191 192 for (i = 0; i < PQ_COUNT; i++) { 193 struct vpgqueues *vpq; 194 195 vpq = &vm_page_queues[i]; 196 vpq->lastq = -1; 197 TAILQ_INIT(&vpq->pl); 198 spin_init(&vpq->spin, "vm_page_queue_init"); 199 } 200 } 201 202 /* 203 * note: place in initialized data section? Is this necessary? 204 */ 205 vm_pindex_t first_page = 0; 206 vm_pindex_t vm_page_array_size = 0; 207 vm_page_t vm_page_array = NULL; 208 vm_paddr_t vm_low_phys_reserved; 209 210 /* 211 * (low level boot) 212 * 213 * Sets the page size, perhaps based upon the memory size. 214 * Must be called before any use of page-size dependent functions. 215 */ 216 void 217 vm_set_page_size(void) 218 { 219 if (vmstats.v_page_size == 0) 220 vmstats.v_page_size = PAGE_SIZE; 221 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0) 222 panic("vm_set_page_size: page size not a power of two"); 223 } 224 225 /* 226 * (low level boot) 227 * 228 * Add a new page to the freelist for use by the system. New pages 229 * are added to both the head and tail of the associated free page 230 * queue in a bottom-up fashion, so both zero'd and non-zero'd page 231 * requests pull 'recent' adds (higher physical addresses) first. 232 * 233 * Beware that the page zeroing daemon will also be running soon after 234 * boot, moving pages from the head to the tail of the PQ_FREE queues. 235 * 236 * Must be called in a critical section. 237 */ 238 static void 239 vm_add_new_page(vm_paddr_t pa, int *badcountp) 240 { 241 struct vpgqueues *vpq; 242 vm_page_t m; 243 244 m = PHYS_TO_VM_PAGE(pa); 245 246 /* 247 * Make sure it isn't a duplicate (due to BIOS page range overlaps, 248 * which we consider bugs... but don't crash). Note that m->phys_addr 249 * is pre-initialized, so use m->queue as a check. 250 */ 251 if (m->queue) { 252 if (*badcountp < 10) { 253 kprintf("vm_add_new_page: duplicate pa %016jx\n", 254 (intmax_t)pa); 255 ++*badcountp; 256 } else if (*badcountp == 10) { 257 kprintf("vm_add_new_page: duplicate pa (many more)\n"); 258 ++*badcountp; 259 } 260 return; 261 } 262 263 m->phys_addr = pa; 264 m->flags = 0; 265 m->pat_mode = PAT_WRITE_BACK; 266 m->pc = (pa >> PAGE_SHIFT); 267 268 /* 269 * Twist for cpu localization in addition to page coloring, so 270 * different cpus selecting by m->queue get different page colors. 271 */ 272 m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE); 273 m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)); 274 m->pc &= PQ_L2_MASK; 275 276 /* 277 * Reserve a certain number of contiguous low memory pages for 278 * contigmalloc() to use. 279 * 280 * Even though these pages represent real ram and can be 281 * reverse-mapped, we set PG_FICTITIOUS and PG_UNQUEUED 282 * because their use is special-cased. 283 * 284 * WARNING! Once PG_FICTITIOUS is set, vm_page_wire*() 285 * and vm_page_unwire*() calls have no effect. 286 */ 287 if (pa < vm_low_phys_reserved) { 288 atomic_add_long(&vmstats.v_page_count, 1); 289 atomic_add_long(&vmstats.v_dma_pages, 1); 290 m->flags |= PG_FICTITIOUS | PG_UNQUEUED; 291 m->queue = PQ_NONE; 292 m->wire_count = 1; 293 atomic_add_long(&vmstats.v_wire_count, 1); 294 alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1); 295 return; 296 } 297 298 /* 299 * General page 300 */ 301 m->queue = m->pc + PQ_FREE; 302 KKASSERT(m->dirty == 0); 303 304 atomic_add_long(&vmstats.v_page_count, 1); 305 atomic_add_long(&vmstats.v_free_count, 1); 306 vpq = &vm_page_queues[m->queue]; 307 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); 308 ++vpq->lcnt; 309 } 310 311 /* 312 * (low level boot) 313 * 314 * Initializes the resident memory module. 315 * 316 * Preallocates memory for critical VM structures and arrays prior to 317 * kernel_map becoming available. 318 * 319 * Memory is allocated from (virtual2_start, virtual2_end) if available, 320 * otherwise memory is allocated from (virtual_start, virtual_end). 321 * 322 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be 323 * large enough to hold vm_page_array & other structures for machines with 324 * large amounts of ram, so we want to use virtual2* when available. 325 */ 326 void 327 vm_page_startup(void) 328 { 329 vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start; 330 vm_offset_t mapped; 331 vm_pindex_t npages; 332 vm_paddr_t page_range; 333 vm_paddr_t new_end; 334 int i; 335 vm_paddr_t pa; 336 vm_paddr_t last_pa; 337 vm_paddr_t end; 338 vm_paddr_t biggestone, biggestsize; 339 vm_paddr_t total; 340 vm_page_t m; 341 int badcount; 342 343 total = 0; 344 badcount = 0; 345 biggestsize = 0; 346 biggestone = 0; 347 vaddr = round_page(vaddr); 348 349 /* 350 * Make sure ranges are page-aligned. 351 */ 352 for (i = 0; phys_avail[i].phys_end; ++i) { 353 phys_avail[i].phys_beg = round_page64(phys_avail[i].phys_beg); 354 phys_avail[i].phys_end = trunc_page64(phys_avail[i].phys_end); 355 if (phys_avail[i].phys_end < phys_avail[i].phys_beg) 356 phys_avail[i].phys_end = phys_avail[i].phys_beg; 357 } 358 359 /* 360 * Locate largest block 361 */ 362 for (i = 0; phys_avail[i].phys_end; ++i) { 363 vm_paddr_t size = phys_avail[i].phys_end - 364 phys_avail[i].phys_beg; 365 366 if (size > biggestsize) { 367 biggestone = i; 368 biggestsize = size; 369 } 370 total += size; 371 } 372 --i; /* adjust to last entry for use down below */ 373 374 end = phys_avail[biggestone].phys_end; 375 end = trunc_page(end); 376 377 /* 378 * Initialize the queue headers for the free queue, the active queue 379 * and the inactive queue. 380 */ 381 vm_page_queue_init(); 382 383 #if !defined(_KERNEL_VIRTUAL) 384 /* 385 * VKERNELs don't support minidumps and as such don't need 386 * vm_page_dump 387 * 388 * Allocate a bitmap to indicate that a random physical page 389 * needs to be included in a minidump. 390 * 391 * The amd64 port needs this to indicate which direct map pages 392 * need to be dumped, via calls to dump_add_page()/dump_drop_page(). 393 * 394 * However, x86 still needs this workspace internally within the 395 * minidump code. In theory, they are not needed on x86, but are 396 * included should the sf_buf code decide to use them. 397 */ 398 page_range = phys_avail[i].phys_end / PAGE_SIZE; 399 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); 400 end -= vm_page_dump_size; 401 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size, 402 VM_PROT_READ | VM_PROT_WRITE); 403 bzero((void *)vm_page_dump, vm_page_dump_size); 404 #endif 405 /* 406 * Compute the number of pages of memory that will be available for 407 * use (taking into account the overhead of a page structure per 408 * page). 409 */ 410 first_page = phys_avail[0].phys_beg / PAGE_SIZE; 411 page_range = phys_avail[i].phys_end / PAGE_SIZE - first_page; 412 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE; 413 414 #ifndef _KERNEL_VIRTUAL 415 /* 416 * (only applies to real kernels) 417 * 418 * Reserve a large amount of low memory for potential 32-bit DMA 419 * space allocations. Once device initialization is complete we 420 * release most of it, but keep (vm_dma_reserved) memory reserved 421 * for later use. Typically for X / graphics. Through trial and 422 * error we find that GPUs usually requires ~60-100MB or so. 423 * 424 * By default, 128M is left in reserve on machines with 2G+ of ram. 425 */ 426 vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT; 427 if (vm_low_phys_reserved > total / 4) 428 vm_low_phys_reserved = total / 4; 429 if (vm_dma_reserved == 0) { 430 vm_dma_reserved = 128 * 1024 * 1024; /* 128MB */ 431 if (vm_dma_reserved > total / 16) 432 vm_dma_reserved = total / 16; 433 } 434 #endif 435 alist_init(&vm_contig_alist, 65536, vm_contig_ameta, 436 ALIST_RECORDS_65536); 437 438 /* 439 * Initialize the mem entry structures now, and put them in the free 440 * queue. 441 */ 442 if (bootverbose && ctob(physmem) >= 400LL*1024*1024*1024) 443 kprintf("initializing vm_page_array "); 444 new_end = trunc_page(end - page_range * sizeof(struct vm_page)); 445 mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE); 446 vm_page_array = (vm_page_t)mapped; 447 448 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL) 449 /* 450 * since pmap_map on amd64 returns stuff out of a direct-map region, 451 * we have to manually add these pages to the minidump tracking so 452 * that they can be dumped, including the vm_page_array. 453 */ 454 for (pa = new_end; 455 pa < phys_avail[biggestone].phys_end; 456 pa += PAGE_SIZE) { 457 dump_add_page(pa); 458 } 459 #endif 460 461 /* 462 * Clear all of the page structures, run basic initialization so 463 * PHYS_TO_VM_PAGE() operates properly even on pages not in the 464 * map. 465 */ 466 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); 467 vm_page_array_size = page_range; 468 if (bootverbose && ctob(physmem) >= 400LL*1024*1024*1024) 469 kprintf("size = 0x%zx\n", vm_page_array_size); 470 471 m = &vm_page_array[0]; 472 pa = ptoa(first_page); 473 for (i = 0; i < page_range; ++i) { 474 spin_init(&m->spin, "vm_page"); 475 m->phys_addr = pa; 476 pa += PAGE_SIZE; 477 ++m; 478 } 479 480 /* 481 * Construct the free queue(s) in ascending order (by physical 482 * address) so that the first 16MB of physical memory is allocated 483 * last rather than first. On large-memory machines, this avoids 484 * the exhaustion of low physical memory before isa_dma_init has run. 485 */ 486 vmstats.v_page_count = 0; 487 vmstats.v_free_count = 0; 488 for (i = 0; phys_avail[i].phys_end && npages > 0; ++i) { 489 pa = phys_avail[i].phys_beg; 490 if (i == biggestone) 491 last_pa = new_end; 492 else 493 last_pa = phys_avail[i].phys_end; 494 while (pa < last_pa && npages-- > 0) { 495 vm_add_new_page(pa, &badcount); 496 pa += PAGE_SIZE; 497 } 498 } 499 if (virtual2_start) 500 virtual2_start = vaddr; 501 else 502 virtual_start = vaddr; 503 mycpu->gd_vmstats = vmstats; 504 } 505 506 /* 507 * (called from early boot only) 508 * 509 * Reorganize VM pages based on numa data. May be called as many times as 510 * necessary. Will reorganize the vm_page_t page color and related queue(s) 511 * to allow vm_page_alloc() to choose pages based on socket affinity. 512 * 513 * NOTE: This function is only called while we are still in UP mode, so 514 * we only need a critical section to protect the queues (which 515 * saves a lot of time, there are likely a ton of pages). 516 */ 517 void 518 vm_numa_organize(vm_paddr_t ran_beg, vm_paddr_t bytes, int physid) 519 { 520 vm_paddr_t scan_beg; 521 vm_paddr_t scan_end; 522 vm_paddr_t ran_end; 523 struct vpgqueues *vpq; 524 vm_page_t m; 525 vm_page_t mend; 526 int socket_mod; 527 int socket_value; 528 int i; 529 530 /* 531 * Check if no physical information, or there was only one socket 532 * (so don't waste time doing nothing!). 533 */ 534 if (cpu_topology_phys_ids <= 1 || 535 cpu_topology_core_ids == 0) { 536 return; 537 } 538 539 /* 540 * Setup for our iteration. Note that ACPI may iterate CPU 541 * sockets starting at 0 or 1 or some other number. The 542 * cpu_topology code mod's it against the socket count. 543 */ 544 ran_end = ran_beg + bytes; 545 546 socket_mod = PQ_L2_SIZE / cpu_topology_phys_ids; 547 socket_value = (physid % cpu_topology_phys_ids) * socket_mod; 548 mend = &vm_page_array[vm_page_array_size]; 549 550 crit_enter(); 551 552 /* 553 * Adjust cpu_topology's phys_mem parameter 554 */ 555 if (root_cpu_node) 556 vm_numa_add_topology_mem(root_cpu_node, physid, (long)bytes); 557 558 /* 559 * Adjust vm_page->pc and requeue all affected pages. The 560 * allocator will then be able to localize memory allocations 561 * to some degree. 562 */ 563 for (i = 0; phys_avail[i].phys_end; ++i) { 564 scan_beg = phys_avail[i].phys_beg; 565 scan_end = phys_avail[i].phys_end; 566 if (scan_end <= ran_beg) 567 continue; 568 if (scan_beg >= ran_end) 569 continue; 570 if (scan_beg < ran_beg) 571 scan_beg = ran_beg; 572 if (scan_end > ran_end) 573 scan_end = ran_end; 574 if (atop(scan_end) > first_page + vm_page_array_size) 575 scan_end = ptoa(first_page + vm_page_array_size); 576 577 m = PHYS_TO_VM_PAGE(scan_beg); 578 while (scan_beg < scan_end) { 579 KKASSERT(m < mend); 580 if (m->queue != PQ_NONE) { 581 vpq = &vm_page_queues[m->queue]; 582 TAILQ_REMOVE(&vpq->pl, m, pageq); 583 --vpq->lcnt; 584 /* queue doesn't change, no need to adj cnt */ 585 m->queue -= m->pc; 586 m->pc %= socket_mod; 587 m->pc += socket_value; 588 m->pc &= PQ_L2_MASK; 589 m->queue += m->pc; 590 vpq = &vm_page_queues[m->queue]; 591 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); 592 ++vpq->lcnt; 593 /* queue doesn't change, no need to adj cnt */ 594 } else { 595 m->pc %= socket_mod; 596 m->pc += socket_value; 597 m->pc &= PQ_L2_MASK; 598 } 599 scan_beg += PAGE_SIZE; 600 ++m; 601 } 602 } 603 604 crit_exit(); 605 } 606 607 /* 608 * (called from early boot only) 609 * 610 * Don't allow the NUMA organization to leave vm_page_queues[] nodes 611 * completely empty for a logical cpu. Doing so would force allocations 612 * on that cpu to always borrow from a nearby cpu, create unnecessary 613 * contention, and cause vm_page_alloc() to iterate more queues and run more 614 * slowly. 615 * 616 * This situation can occur when memory sticks are not entirely populated, 617 * populated at different densities, or in naturally assymetric systems 618 * such as the 2990WX. There could very well be many vm_page_queues[] 619 * entries with *NO* pages assigned to them. 620 * 621 * Fixing this up ensures that each logical CPU has roughly the same 622 * sized memory pool, and more importantly ensures that logical CPUs 623 * do not wind up with an empty memory pool. 624 * 625 * At them moment we just iterate the other queues and borrow pages, 626 * moving them into the queues for cpus with severe deficits even though 627 * the memory might not be local to those cpus. I am not doing this in 628 * a 'smart' way, its effectively UMA style (sorta, since its page-by-page 629 * whereas real UMA typically exchanges address bits 8-10 with high address 630 * bits). But it works extremely well and gives us fairly good deterministic 631 * results on the cpu cores associated with these secondary nodes. 632 */ 633 void 634 vm_numa_organize_finalize(void) 635 { 636 struct vpgqueues *vpq; 637 vm_page_t m; 638 long lcnt_lo; 639 long lcnt_hi; 640 int iter; 641 int i; 642 int scale_lim; 643 644 crit_enter(); 645 646 /* 647 * Machines might not use an exact power of 2 for phys_ids, 648 * core_ids, ht_ids, etc. This can slightly reduce the actual 649 * range of indices in vm_page_queues[] that are nominally used. 650 */ 651 if (cpu_topology_ht_ids) { 652 scale_lim = PQ_L2_SIZE / cpu_topology_phys_ids; 653 scale_lim = scale_lim / cpu_topology_core_ids; 654 scale_lim = scale_lim / cpu_topology_ht_ids; 655 scale_lim = scale_lim * cpu_topology_ht_ids; 656 scale_lim = scale_lim * cpu_topology_core_ids; 657 scale_lim = scale_lim * cpu_topology_phys_ids; 658 } else { 659 scale_lim = PQ_L2_SIZE; 660 } 661 662 /* 663 * Calculate an average, set hysteresis for balancing from 664 * 10% below the average to the average. 665 */ 666 lcnt_hi = 0; 667 for (i = 0; i < scale_lim; ++i) { 668 lcnt_hi += vm_page_queues[i].lcnt; 669 } 670 lcnt_hi /= scale_lim; 671 lcnt_lo = lcnt_hi - lcnt_hi / 10; 672 673 kprintf("vm_page: avg %ld pages per queue, %d queues\n", 674 lcnt_hi, scale_lim); 675 676 iter = 0; 677 for (i = 0; i < scale_lim; ++i) { 678 vpq = &vm_page_queues[PQ_FREE + i]; 679 while (vpq->lcnt < lcnt_lo) { 680 struct vpgqueues *vptmp; 681 682 iter = (iter + 1) & PQ_L2_MASK; 683 vptmp = &vm_page_queues[PQ_FREE + iter]; 684 if (vptmp->lcnt < lcnt_hi) 685 continue; 686 m = TAILQ_FIRST(&vptmp->pl); 687 KKASSERT(m->queue == PQ_FREE + iter); 688 TAILQ_REMOVE(&vptmp->pl, m, pageq); 689 --vptmp->lcnt; 690 /* queue doesn't change, no need to adj cnt */ 691 m->queue -= m->pc; 692 m->pc = i; 693 m->queue += m->pc; 694 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); 695 ++vpq->lcnt; 696 } 697 } 698 crit_exit(); 699 } 700 701 static 702 void 703 vm_numa_add_topology_mem(cpu_node_t *cpup, int physid, long bytes) 704 { 705 int cpuid; 706 int i; 707 708 switch(cpup->type) { 709 case PACKAGE_LEVEL: 710 cpup->phys_mem += bytes; 711 break; 712 case CHIP_LEVEL: 713 /* 714 * All members should have the same chipid, so we only need 715 * to pull out one member. 716 */ 717 if (CPUMASK_TESTNZERO(cpup->members)) { 718 cpuid = BSFCPUMASK(cpup->members); 719 if (physid == 720 get_chip_ID_from_APICID(CPUID_TO_APICID(cpuid))) { 721 cpup->phys_mem += bytes; 722 } 723 } 724 break; 725 case CORE_LEVEL: 726 case THREAD_LEVEL: 727 /* 728 * Just inherit from the parent node 729 */ 730 cpup->phys_mem = cpup->parent_node->phys_mem; 731 break; 732 } 733 for (i = 0; i < MAXCPU && cpup->child_node[i]; ++i) 734 vm_numa_add_topology_mem(cpup->child_node[i], physid, bytes); 735 } 736 737 /* 738 * We tended to reserve a ton of memory for contigmalloc(). Now that most 739 * drivers have initialized we want to return most the remaining free 740 * reserve back to the VM page queues so they can be used for normal 741 * allocations. 742 * 743 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool. 744 */ 745 static void 746 vm_page_startup_finish(void *dummy __unused) 747 { 748 alist_blk_t blk; 749 alist_blk_t rblk; 750 alist_blk_t count; 751 alist_blk_t xcount; 752 alist_blk_t bfree; 753 vm_page_t m; 754 struct vm_page_hash_elm *mp; 755 int mask; 756 757 /* 758 * Set the set_assoc_mask based on the fitted number of CPUs. 759 * This is a mask, so we subject 1. 760 * 761 * w/PQ_L2_SIZE = 1024, Don't let the associativity drop below 8. 762 * So if we have 256 CPUs, two hyper-threads will wind up sharing. 763 * 764 * The maximum is PQ_L2_SIZE. However, we limit the starting 765 * maximum to 16 (mask = 15) in order to improve the cache locality 766 * of related kernel data structures. 767 */ 768 mask = PQ_L2_SIZE / ncpus_fit - 1; 769 if (mask < 7) /* minimum is 8-way w/256 CPU threads */ 770 mask = 7; 771 if (mask < 15) 772 mask = 15; 773 cpu_ccfence(); 774 set_assoc_mask = mask; 775 776 /* 777 * Return part of the initial reserve back to the system 778 */ 779 spin_lock(&vm_contig_spin); 780 for (;;) { 781 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 782 if (bfree <= vm_dma_reserved / PAGE_SIZE) 783 break; 784 if (count == 0) 785 break; 786 787 /* 788 * Figure out how much of the initial reserve we have to 789 * free in order to reach our target. 790 */ 791 bfree -= vm_dma_reserved / PAGE_SIZE; 792 if (count > bfree) { 793 blk += count - bfree; 794 count = bfree; 795 } 796 797 /* 798 * Calculate the nearest power of 2 <= count. 799 */ 800 for (xcount = 1; xcount <= count; xcount <<= 1) 801 ; 802 xcount >>= 1; 803 blk += count - xcount; 804 count = xcount; 805 806 /* 807 * Allocate the pages from the alist, then free them to 808 * the normal VM page queues. 809 * 810 * Pages allocated from the alist are wired. We have to 811 * busy, unwire, and free them. We must also adjust 812 * vm_low_phys_reserved before freeing any pages to prevent 813 * confusion. 814 */ 815 rblk = alist_alloc(&vm_contig_alist, blk, count); 816 if (rblk != blk) { 817 kprintf("vm_page_startup_finish: Unable to return " 818 "dma space @0x%08x/%d -> 0x%08x\n", 819 blk, count, rblk); 820 break; 821 } 822 atomic_add_long(&vmstats.v_dma_pages, -(long)count); 823 spin_unlock(&vm_contig_spin); 824 825 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 826 vm_low_phys_reserved = VM_PAGE_TO_PHYS(m); 827 while (count) { 828 vm_page_flag_clear(m, PG_FICTITIOUS | PG_UNQUEUED); 829 vm_page_busy_wait(m, FALSE, "cpgfr"); 830 vm_page_unwire(m, 0); 831 vm_page_free(m); 832 --count; 833 ++m; 834 } 835 spin_lock(&vm_contig_spin); 836 } 837 spin_unlock(&vm_contig_spin); 838 839 /* 840 * Print out how much DMA space drivers have already allocated and 841 * how much is left over. 842 */ 843 kprintf("DMA space used: %jdk, remaining available: %jdk\n", 844 (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) * 845 (PAGE_SIZE / 1024), 846 (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024)); 847 848 /* 849 * Power of 2 850 */ 851 vm_page_hash_size = 4096; 852 while (vm_page_hash_size < (vm_page_array_size / 16)) 853 vm_page_hash_size <<= 1; 854 if (vm_page_hash_size > VM_PAGE_HASH_MAX) 855 vm_page_hash_size = VM_PAGE_HASH_MAX; 856 857 /* 858 * hash table for vm_page_lookup_quick() 859 */ 860 mp = (void *)kmem_alloc3(&kernel_map, 861 (vm_page_hash_size + VM_PAGE_HASH_SET) * 862 sizeof(*vm_page_hash), 863 VM_SUBSYS_VMPGHASH, KM_CPU(0)); 864 bzero(mp, (vm_page_hash_size + VM_PAGE_HASH_SET) * sizeof(*mp)); 865 cpu_sfence(); 866 vm_page_hash = mp; 867 } 868 SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY, 869 vm_page_startup_finish, NULL); 870 871 872 /* 873 * Scan comparison function for Red-Black tree scans. An inclusive 874 * (start,end) is expected. Other fields are not used. 875 */ 876 int 877 rb_vm_page_scancmp(struct vm_page *p, void *data) 878 { 879 struct rb_vm_page_scan_info *info = data; 880 881 if (p->pindex < info->start_pindex) 882 return(-1); 883 if (p->pindex > info->end_pindex) 884 return(1); 885 return(0); 886 } 887 888 int 889 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2) 890 { 891 if (p1->pindex < p2->pindex) 892 return(-1); 893 if (p1->pindex > p2->pindex) 894 return(1); 895 return(0); 896 } 897 898 void 899 vm_page_init(vm_page_t m) 900 { 901 /* do nothing for now. Called from pmap_page_init() */ 902 } 903 904 /* 905 * Each page queue has its own spin lock, which is fairly optimal for 906 * allocating and freeing pages at least. 907 * 908 * The caller must hold the vm_page_spin_lock() before locking a vm_page's 909 * queue spinlock via this function. Also note that m->queue cannot change 910 * unless both the page and queue are locked. 911 */ 912 static __inline 913 void 914 _vm_page_queue_spin_lock(vm_page_t m) 915 { 916 u_short queue; 917 918 queue = m->queue; 919 if (queue != PQ_NONE) { 920 spin_lock(&vm_page_queues[queue].spin); 921 KKASSERT(queue == m->queue); 922 } 923 } 924 925 static __inline 926 void 927 _vm_page_queue_spin_unlock(vm_page_t m) 928 { 929 u_short queue; 930 931 queue = m->queue; 932 cpu_ccfence(); 933 if (queue != PQ_NONE) 934 spin_unlock(&vm_page_queues[queue].spin); 935 } 936 937 static __inline 938 void 939 _vm_page_queues_spin_lock(u_short queue) 940 { 941 cpu_ccfence(); 942 if (queue != PQ_NONE) 943 spin_lock(&vm_page_queues[queue].spin); 944 } 945 946 947 static __inline 948 void 949 _vm_page_queues_spin_unlock(u_short queue) 950 { 951 cpu_ccfence(); 952 if (queue != PQ_NONE) 953 spin_unlock(&vm_page_queues[queue].spin); 954 } 955 956 void 957 vm_page_queue_spin_lock(vm_page_t m) 958 { 959 _vm_page_queue_spin_lock(m); 960 } 961 962 void 963 vm_page_queues_spin_lock(u_short queue) 964 { 965 _vm_page_queues_spin_lock(queue); 966 } 967 968 void 969 vm_page_queue_spin_unlock(vm_page_t m) 970 { 971 _vm_page_queue_spin_unlock(m); 972 } 973 974 void 975 vm_page_queues_spin_unlock(u_short queue) 976 { 977 _vm_page_queues_spin_unlock(queue); 978 } 979 980 /* 981 * This locks the specified vm_page and its queue in the proper order 982 * (page first, then queue). The queue may change so the caller must 983 * recheck on return. 984 */ 985 static __inline 986 void 987 _vm_page_and_queue_spin_lock(vm_page_t m) 988 { 989 vm_page_spin_lock(m); 990 _vm_page_queue_spin_lock(m); 991 } 992 993 static __inline 994 void 995 _vm_page_and_queue_spin_unlock(vm_page_t m) 996 { 997 _vm_page_queues_spin_unlock(m->queue); 998 vm_page_spin_unlock(m); 999 } 1000 1001 void 1002 vm_page_and_queue_spin_unlock(vm_page_t m) 1003 { 1004 _vm_page_and_queue_spin_unlock(m); 1005 } 1006 1007 void 1008 vm_page_and_queue_spin_lock(vm_page_t m) 1009 { 1010 _vm_page_and_queue_spin_lock(m); 1011 } 1012 1013 /* 1014 * Helper function removes vm_page from its current queue. 1015 * Returns the base queue the page used to be on. 1016 * 1017 * The vm_page and the queue must be spinlocked. 1018 * This function will unlock the queue but leave the page spinlocked. 1019 */ 1020 static __inline u_short 1021 _vm_page_rem_queue_spinlocked(vm_page_t m) 1022 { 1023 struct vpgqueues *pq; 1024 u_short queue; 1025 u_short oqueue; 1026 long *cnt_adj; 1027 long *cnt_gd; 1028 1029 queue = m->queue; 1030 if (queue != PQ_NONE) { 1031 pq = &vm_page_queues[queue]; 1032 TAILQ_REMOVE(&pq->pl, m, pageq); 1033 1034 /* 1035 * Primarily adjust our pcpu stats for rollup, which is 1036 * (mycpu->gd_vmstats_adj + offset). This is normally 1037 * synchronized on every hardclock(). 1038 * 1039 * However, in order for the nominal low-memory algorithms 1040 * to work properly if the unsynchronized adjustment gets 1041 * too negative and might trigger the pageout daemon, we 1042 * immediately synchronize with the global structure. 1043 * 1044 * The idea here is to reduce unnecessary SMP cache mastership 1045 * changes in the global vmstats, which can be particularly 1046 * bad in multi-socket systems. 1047 * 1048 * WARNING! In systems with low amounts of memory the 1049 * vm_paging_needed(-1024 * ncpus) test could 1050 * wind up testing a value above the paging target, 1051 * meaning it would almost always return TRUE. In 1052 * that situation we synchronize every time the 1053 * cumulative adjustment falls below -1024. 1054 */ 1055 cnt_adj = (long *)((char *)&mycpu->gd_vmstats_adj + 1056 pq->cnt_offset); 1057 cnt_gd = (long *)((char *)&mycpu->gd_vmstats + 1058 pq->cnt_offset); 1059 atomic_add_long(cnt_adj, -1); 1060 atomic_add_long(cnt_gd, -1); 1061 1062 if (*cnt_adj < -1024 && vm_paging_start(-1024 * ncpus)) { 1063 u_long copy = atomic_swap_long(cnt_adj, 0); 1064 cnt_adj = (long *)((char *)&vmstats + pq->cnt_offset); 1065 atomic_add_long(cnt_adj, copy); 1066 } 1067 pq->lcnt--; 1068 m->queue = PQ_NONE; 1069 oqueue = queue; 1070 queue -= m->pc; 1071 vm_page_queues_spin_unlock(oqueue); /* intended */ 1072 } 1073 return queue; 1074 } 1075 1076 /* 1077 * Helper function places the vm_page on the specified queue. Generally 1078 * speaking only PQ_FREE pages are placed at the head, to allow them to 1079 * be allocated sooner rather than later on the assumption that they 1080 * are cache-hot. 1081 * 1082 * The vm_page must be spinlocked. 1083 * The vm_page must NOT be FICTITIOUS (that would be a disaster) 1084 * This function will return with both the page and the queue locked. 1085 */ 1086 static __inline void 1087 _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead) 1088 { 1089 struct vpgqueues *pq; 1090 u_long *cnt_adj; 1091 u_long *cnt_gd; 1092 1093 KKASSERT(m->queue == PQ_NONE && 1094 (m->flags & (PG_FICTITIOUS | PG_UNQUEUED)) == 0); 1095 1096 if (queue != PQ_NONE) { 1097 vm_page_queues_spin_lock(queue); 1098 pq = &vm_page_queues[queue]; 1099 ++pq->lcnt; 1100 1101 /* 1102 * Adjust our pcpu stats. If a system entity really needs 1103 * to incorporate the count it will call vmstats_rollup() 1104 * to roll it all up into the global vmstats strufture. 1105 */ 1106 cnt_adj = (long *)((char *)&mycpu->gd_vmstats_adj + 1107 pq->cnt_offset); 1108 cnt_gd = (long *)((char *)&mycpu->gd_vmstats + 1109 pq->cnt_offset); 1110 atomic_add_long(cnt_adj, 1); 1111 atomic_add_long(cnt_gd, 1); 1112 1113 /* 1114 * PQ_FREE is always handled LIFO style to try to provide 1115 * cache-hot pages to programs. 1116 */ 1117 m->queue = queue; 1118 if (queue - m->pc == PQ_FREE) { 1119 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 1120 } else if (athead) { 1121 TAILQ_INSERT_HEAD(&pq->pl, m, pageq); 1122 } else { 1123 TAILQ_INSERT_TAIL(&pq->pl, m, pageq); 1124 } 1125 /* leave the queue spinlocked */ 1126 } 1127 } 1128 1129 /* 1130 * Wait until page is no longer BUSY. If also_m_busy is TRUE we wait 1131 * until the page is no longer BUSY or SBUSY (busy_count field is 0). 1132 * 1133 * Returns TRUE if it had to sleep, FALSE if we did not. Only one sleep 1134 * call will be made before returning. 1135 * 1136 * This function does NOT busy the page and on return the page is not 1137 * guaranteed to be available. 1138 */ 1139 void 1140 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 1141 { 1142 u_int32_t busy_count; 1143 1144 for (;;) { 1145 busy_count = m->busy_count; 1146 cpu_ccfence(); 1147 1148 if ((busy_count & PBUSY_LOCKED) == 0 && 1149 (also_m_busy == 0 || (busy_count & PBUSY_MASK) == 0)) { 1150 break; 1151 } 1152 tsleep_interlock(m, 0); 1153 if (atomic_cmpset_int(&m->busy_count, busy_count, 1154 busy_count | PBUSY_WANTED)) { 1155 atomic_set_int(&m->flags, PG_REFERENCED); 1156 tsleep(m, PINTERLOCKED, msg, 0); 1157 break; 1158 } 1159 } 1160 } 1161 1162 /* 1163 * This calculates and returns a page color given an optional VM object and 1164 * either a pindex or an iterator. We attempt to return a cpu-localized 1165 * pg_color that is still roughly 16-way set-associative. The CPU topology 1166 * is used if it was probed. 1167 * 1168 * The caller may use the returned value to index into e.g. PQ_FREE when 1169 * allocating a page in order to nominally obtain pages that are hopefully 1170 * already localized to the requesting cpu. This function is not able to 1171 * provide any sort of guarantee of this, but does its best to improve 1172 * hardware cache management performance. 1173 * 1174 * WARNING! The caller must mask the returned value with PQ_L2_MASK. 1175 */ 1176 u_short 1177 vm_get_pg_color(int cpuid, vm_object_t object, vm_pindex_t pindex) 1178 { 1179 u_short pg_color; 1180 int object_pg_color; 1181 1182 /* 1183 * WARNING! cpu_topology_core_ids might not be a power of two. 1184 * We also shouldn't make assumptions about 1185 * cpu_topology_phys_ids either. 1186 * 1187 * WARNING! ncpus might not be known at this time (during early 1188 * boot), and might be set to 1. 1189 * 1190 * General format: [phys_id][core_id][cpuid][set-associativity] 1191 * (but uses modulo, so not necessarily precise bit masks) 1192 */ 1193 object_pg_color = object ? object->pg_color : 0; 1194 1195 if (cpu_topology_ht_ids) { 1196 int phys_id; 1197 int core_id; 1198 int ht_id; 1199 int physcale; 1200 int grpscale; 1201 int cpuscale; 1202 1203 /* 1204 * Translate cpuid to socket, core, and hyperthread id. 1205 */ 1206 phys_id = get_cpu_phys_id(cpuid); 1207 core_id = get_cpu_core_id(cpuid); 1208 ht_id = get_cpu_ht_id(cpuid); 1209 1210 /* 1211 * Calculate pg_color for our array index. 1212 * 1213 * physcale - socket multiplier. 1214 * grpscale - core multiplier (cores per socket) 1215 * cpu* - cpus per core 1216 * 1217 * WARNING! In early boot, ncpus has not yet been 1218 * initialized and may be set to (1). 1219 * 1220 * WARNING! physcale must match the organization that 1221 * vm_numa_organize() creates to ensure that 1222 * we properly localize allocations to the 1223 * requested cpuid. 1224 */ 1225 physcale = PQ_L2_SIZE / cpu_topology_phys_ids; 1226 grpscale = physcale / cpu_topology_core_ids; 1227 cpuscale = grpscale / cpu_topology_ht_ids; 1228 1229 pg_color = phys_id * physcale; 1230 pg_color += core_id * grpscale; 1231 pg_color += ht_id * cpuscale; 1232 pg_color += (pindex + object_pg_color) % cpuscale; 1233 1234 #if 0 1235 if (grpsize >= 8) { 1236 pg_color += (pindex + object_pg_color) % grpsize; 1237 } else { 1238 if (grpsize <= 2) { 1239 grpsize = 8; 1240 } else { 1241 /* 3->9, 4->8, 5->10, 6->12, 7->14 */ 1242 grpsize += grpsize; 1243 if (grpsize < 8) 1244 grpsize += grpsize; 1245 } 1246 pg_color += (pindex + object_pg_color) % grpsize; 1247 } 1248 #endif 1249 } else { 1250 /* 1251 * Unknown topology, distribute things evenly. 1252 * 1253 * WARNING! In early boot, ncpus has not yet been 1254 * initialized and may be set to (1). 1255 */ 1256 int cpuscale; 1257 1258 cpuscale = PQ_L2_SIZE / ncpus; 1259 1260 pg_color = cpuid * cpuscale; 1261 pg_color += (pindex + object_pg_color) % cpuscale; 1262 } 1263 return (pg_color & PQ_L2_MASK); 1264 } 1265 1266 /* 1267 * Wait until BUSY can be set, then set it. If also_m_busy is TRUE we 1268 * also wait for m->busy_count to become 0 before setting PBUSY_LOCKED. 1269 */ 1270 void 1271 VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m, 1272 int also_m_busy, const char *msg 1273 VM_PAGE_DEBUG_ARGS) 1274 { 1275 u_int32_t busy_count; 1276 1277 for (;;) { 1278 busy_count = m->busy_count; 1279 cpu_ccfence(); 1280 if (busy_count & PBUSY_LOCKED) { 1281 tsleep_interlock(m, 0); 1282 if (atomic_cmpset_int(&m->busy_count, busy_count, 1283 busy_count | PBUSY_WANTED)) { 1284 atomic_set_int(&m->flags, PG_REFERENCED); 1285 tsleep(m, PINTERLOCKED, msg, 0); 1286 } 1287 } else if (also_m_busy && busy_count) { 1288 tsleep_interlock(m, 0); 1289 if (atomic_cmpset_int(&m->busy_count, busy_count, 1290 busy_count | PBUSY_WANTED)) { 1291 atomic_set_int(&m->flags, PG_REFERENCED); 1292 tsleep(m, PINTERLOCKED, msg, 0); 1293 } 1294 } else { 1295 if (atomic_cmpset_int(&m->busy_count, busy_count, 1296 busy_count | PBUSY_LOCKED)) { 1297 #ifdef VM_PAGE_DEBUG 1298 m->busy_func = func; 1299 m->busy_line = lineno; 1300 #endif 1301 break; 1302 } 1303 } 1304 } 1305 } 1306 1307 /* 1308 * Attempt to set BUSY. If also_m_busy is TRUE we only succeed if 1309 * m->busy_count is also 0. 1310 * 1311 * Returns non-zero on failure. 1312 */ 1313 int 1314 VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy 1315 VM_PAGE_DEBUG_ARGS) 1316 { 1317 u_int32_t busy_count; 1318 1319 for (;;) { 1320 busy_count = m->busy_count; 1321 cpu_ccfence(); 1322 if (busy_count & PBUSY_LOCKED) 1323 return TRUE; 1324 if (also_m_busy && (busy_count & PBUSY_MASK) != 0) 1325 return TRUE; 1326 if (atomic_cmpset_int(&m->busy_count, busy_count, 1327 busy_count | PBUSY_LOCKED)) { 1328 #ifdef VM_PAGE_DEBUG 1329 m->busy_func = func; 1330 m->busy_line = lineno; 1331 #endif 1332 return FALSE; 1333 } 1334 } 1335 } 1336 1337 /* 1338 * Clear the BUSY flag and return non-zero to indicate to the caller 1339 * that a wakeup() should be performed. 1340 * 1341 * (inline version) 1342 */ 1343 static __inline 1344 int 1345 _vm_page_wakeup(vm_page_t m) 1346 { 1347 u_int32_t busy_count; 1348 1349 busy_count = m->busy_count; 1350 cpu_ccfence(); 1351 for (;;) { 1352 if (atomic_fcmpset_int(&m->busy_count, &busy_count, 1353 busy_count & 1354 ~(PBUSY_LOCKED | PBUSY_WANTED))) { 1355 return((int)(busy_count & PBUSY_WANTED)); 1356 } 1357 } 1358 /* not reached */ 1359 } 1360 1361 /* 1362 * Clear the BUSY flag and wakeup anyone waiting for the page. This 1363 * is typically the last call you make on a page before moving onto 1364 * other things. 1365 */ 1366 void 1367 vm_page_wakeup(vm_page_t m) 1368 { 1369 KASSERT(m->busy_count & PBUSY_LOCKED, 1370 ("vm_page_wakeup: page not busy!!!")); 1371 if (_vm_page_wakeup(m)) 1372 wakeup(m); 1373 } 1374 1375 /* 1376 * Hold a page, preventing reuse. This is typically only called on pages 1377 * in a known state (either held busy, special, or interlocked in some 1378 * manner). Holding a page does not ensure that it remains valid, it only 1379 * prevents reuse. The page must not already be on the FREE queue or in 1380 * any danger of being moved to the FREE queue concurrent with this call. 1381 * 1382 * Other parts of the system can still disassociate the page from its object 1383 * and attempt to free it, or perform read or write I/O on it and/or otherwise 1384 * manipulate the page, but if the page is held the VM system will leave the 1385 * page and its data intact and not cycle it through the FREE queue until 1386 * the last hold has been released. 1387 * 1388 * (see vm_page_wire() if you want to prevent the page from being 1389 * disassociated from its object too). 1390 */ 1391 void 1392 vm_page_hold(vm_page_t m) 1393 { 1394 atomic_add_int(&m->hold_count, 1); 1395 KKASSERT(m->queue - m->pc != PQ_FREE); 1396 } 1397 1398 /* 1399 * The opposite of vm_page_hold(). If the page is on the HOLD queue 1400 * it was freed while held and must be moved back to the FREE queue. 1401 * 1402 * To avoid racing against vm_page_free*() we must re-test conditions 1403 * after obtaining the spin-lock. The initial test can also race a 1404 * vm_page_free*() that is in the middle of moving a page to PQ_HOLD, 1405 * leaving the page on PQ_HOLD with hold_count == 0. Rather than 1406 * throw a spin-lock in the critical path, we rely on the pageout 1407 * daemon to clean-up these loose ends. 1408 * 1409 * More critically, the 'easy movement' between queues without busying 1410 * a vm_page is only allowed for PQ_FREE<->PQ_HOLD. 1411 */ 1412 void 1413 vm_page_unhold(vm_page_t m) 1414 { 1415 KASSERT(m->hold_count > 0 && m->queue - m->pc != PQ_FREE, 1416 ("vm_page_unhold: pg %p illegal hold_count (%d) or " 1417 "on FREE queue (%d)", 1418 m, m->hold_count, m->queue - m->pc)); 1419 1420 if (atomic_fetchadd_int(&m->hold_count, -1) == 1 && 1421 m->queue - m->pc == PQ_HOLD) { 1422 vm_page_spin_lock(m); 1423 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) { 1424 _vm_page_queue_spin_lock(m); 1425 _vm_page_rem_queue_spinlocked(m); 1426 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 1); 1427 _vm_page_queue_spin_unlock(m); 1428 } 1429 vm_page_spin_unlock(m); 1430 } 1431 } 1432 1433 /* 1434 * Create a fictitious page with the specified physical address and 1435 * memory attribute. The memory attribute is the only the machine- 1436 * dependent aspect of a fictitious page that must be initialized. 1437 */ 1438 void 1439 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr) 1440 { 1441 /* 1442 * The page's memattr might have changed since the 1443 * previous initialization. Update the pmap to the 1444 * new memattr. 1445 */ 1446 if ((m->flags & PG_FICTITIOUS) != 0) 1447 goto memattr; 1448 m->phys_addr = paddr; 1449 m->queue = PQ_NONE; 1450 /* Fictitious pages don't use "segind". */ 1451 /* Fictitious pages don't use "order" or "pool". */ 1452 m->flags = PG_FICTITIOUS | PG_UNQUEUED; 1453 m->busy_count = PBUSY_LOCKED; 1454 m->wire_count = 1; 1455 spin_init(&m->spin, "fake_page"); 1456 pmap_page_init(m); 1457 memattr: 1458 pmap_page_set_memattr(m, memattr); 1459 } 1460 1461 /* 1462 * Inserts the given vm_page into the object and object list. 1463 * 1464 * The pagetables are not updated but will presumably fault the page 1465 * in if necessary, or if a kernel page the caller will at some point 1466 * enter the page into the kernel's pmap. We are not allowed to block 1467 * here so we *can't* do this anyway. 1468 * 1469 * This routine may not block. 1470 * This routine must be called with the vm_object held. 1471 * This routine must be called with a critical section held. 1472 * 1473 * This routine returns TRUE if the page was inserted into the object 1474 * successfully, and FALSE if the page already exists in the object. 1475 */ 1476 int 1477 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) 1478 { 1479 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object)); 1480 if (m->object != NULL) 1481 panic("vm_page_insert: already inserted"); 1482 1483 atomic_add_int(&object->generation, 1); 1484 1485 /* 1486 * Associate the VM page with an (object, offset). 1487 * 1488 * The vm_page spin lock is required for interactions with the pmap. 1489 * XXX vm_page_spin_lock() might not be needed for this any more. 1490 */ 1491 vm_page_spin_lock(m); 1492 m->object = object; 1493 m->pindex = pindex; 1494 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) { 1495 m->object = NULL; 1496 m->pindex = 0; 1497 vm_page_spin_unlock(m); 1498 return FALSE; 1499 } 1500 ++object->resident_page_count; 1501 ++mycpu->gd_vmtotal.t_rm; 1502 vm_page_spin_unlock(m); 1503 1504 /* 1505 * Since we are inserting a new and possibly dirty page, 1506 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. 1507 */ 1508 if ((m->valid & m->dirty) || 1509 (m->flags & (PG_WRITEABLE | PG_NEED_COMMIT))) 1510 vm_object_set_writeable_dirty(object); 1511 1512 /* 1513 * Checks for a swap assignment and sets PG_SWAPPED if appropriate. 1514 */ 1515 swap_pager_page_inserted(m); 1516 return TRUE; 1517 } 1518 1519 /* 1520 * Removes the given vm_page_t from the (object,index) table 1521 * 1522 * The page must be BUSY and will remain BUSY on return. 1523 * No other requirements. 1524 * 1525 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave 1526 * it busy. 1527 * 1528 * NOTE: Caller is responsible for any pmap disposition prior to the 1529 * rename (as the pmap code will not be able to find the entries 1530 * once the object has been disassociated). The caller may choose 1531 * to leave the pmap association intact if this routine is being 1532 * called as part of a rename between shadowed objects. 1533 * 1534 * This routine may not block. 1535 */ 1536 void 1537 vm_page_remove(vm_page_t m) 1538 { 1539 vm_object_t object; 1540 1541 if (m->object == NULL) { 1542 return; 1543 } 1544 1545 if ((m->busy_count & PBUSY_LOCKED) == 0) 1546 panic("vm_page_remove: page not busy"); 1547 1548 object = m->object; 1549 1550 vm_object_hold(object); 1551 1552 /* 1553 * Remove the page from the object and update the object. 1554 * 1555 * The vm_page spin lock is required for interactions with the pmap. 1556 * XXX vm_page_spin_lock() might not be needed for this any more. 1557 */ 1558 vm_page_spin_lock(m); 1559 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); 1560 --object->resident_page_count; 1561 --mycpu->gd_vmtotal.t_rm; 1562 m->object = NULL; 1563 atomic_add_int(&object->generation, 1); 1564 vm_page_spin_unlock(m); 1565 1566 vm_object_drop(object); 1567 } 1568 1569 /* 1570 * Calculate the hash position for the vm_page hash heuristic. Generally 1571 * speaking we want to localize sequential lookups to reduce memory stalls. 1572 * 1573 * Mask by ~3 to offer 4-way set-assoc 1574 */ 1575 static __inline 1576 struct vm_page_hash_elm * 1577 vm_page_hash_hash(vm_object_t object, vm_pindex_t pindex) 1578 { 1579 size_t hi; 1580 1581 hi = iscsi_crc32(&object, sizeof(object)) << 2; 1582 hi ^= hi >> (23 - 2); 1583 hi += pindex * VM_PAGE_HASH_SET; 1584 #if 0 1585 /* mix it up */ 1586 hi = (intptr_t)object ^ object->pg_color ^ pindex; 1587 hi += object->pg_color * pindex; 1588 hi = hi ^ (hi >> 20); 1589 #endif 1590 hi &= vm_page_hash_size - 1; /* bounds */ 1591 1592 return (&vm_page_hash[hi]); 1593 } 1594 1595 /* 1596 * Heuristical page lookup that does not require any locks. Returns 1597 * a soft-busied page on success, NULL on failure. 1598 * 1599 * Caller must lookup the page the slow way if NULL is returned. 1600 */ 1601 vm_page_t 1602 vm_page_hash_get(vm_object_t object, vm_pindex_t pindex) 1603 { 1604 struct vm_page_hash_elm *mp; 1605 vm_page_t m; 1606 int i; 1607 1608 if (__predict_false(vm_page_hash == NULL)) 1609 return NULL; 1610 mp = vm_page_hash_hash(object, pindex); 1611 for (i = 0; i < VM_PAGE_HASH_SET; ++i, ++mp) { 1612 if (mp->object != object || 1613 mp->pindex != pindex) { 1614 continue; 1615 } 1616 m = mp->m; 1617 cpu_ccfence(); 1618 if (m == NULL) 1619 continue; 1620 if (m->object != object || m->pindex != pindex) 1621 continue; 1622 if (vm_page_sbusy_try(m)) 1623 continue; 1624 if (m->object == object && m->pindex == pindex) { 1625 /* 1626 * On-match optimization - do not update ticks 1627 * unless we have to (reduce cache coherency traffic) 1628 */ 1629 if (mp->ticks != ticks) 1630 mp->ticks = ticks; 1631 return m; 1632 } 1633 vm_page_sbusy_drop(m); 1634 } 1635 return NULL; 1636 } 1637 1638 /* 1639 * Enter page onto vm_page_hash[]. This is a heuristic, SMP collisions 1640 * are allowed. 1641 */ 1642 static __inline 1643 void 1644 vm_page_hash_enter(vm_page_t m) 1645 { 1646 struct vm_page_hash_elm *mp; 1647 struct vm_page_hash_elm *best; 1648 vm_object_t object; 1649 vm_pindex_t pindex; 1650 int best_delta; 1651 int delta; 1652 int i; 1653 1654 /* 1655 * Only enter type-stable vm_pages with well-shared objects. 1656 */ 1657 if ((m->flags & PG_MAPPEDMULTI) == 0) 1658 return; 1659 if (__predict_false(vm_page_hash == NULL || 1660 m < &vm_page_array[0] || 1661 m >= &vm_page_array[vm_page_array_size])) { 1662 return; 1663 } 1664 if (__predict_false(m->object == NULL)) 1665 return; 1666 #if 0 1667 /* 1668 * Disabled at the moment, there are some degenerate conditions 1669 * with often-exec'd programs that get ignored. In particular, 1670 * the kernel's elf loader does a vn_rdwr() on the first page of 1671 * a binary. 1672 */ 1673 if (m->object->ref_count <= 2 || (m->object->flags & OBJ_ONEMAPPING)) 1674 return; 1675 #endif 1676 if (vm_page_hash_vnode_only && m->object->type != OBJT_VNODE) 1677 return; 1678 1679 /* 1680 * Find best entry 1681 */ 1682 object = m->object; 1683 pindex = m->pindex; 1684 1685 mp = vm_page_hash_hash(object, pindex); 1686 best = mp; 1687 best_delta = ticks - best->ticks; 1688 1689 for (i = 0; i < VM_PAGE_HASH_SET; ++i, ++mp) { 1690 if (mp->m == m && 1691 mp->object == object && 1692 mp->pindex == pindex) { 1693 /* 1694 * On-match optimization - do not update ticks 1695 * unless we have to (reduce cache coherency traffic) 1696 */ 1697 if (mp->ticks != ticks) 1698 mp->ticks = ticks; 1699 return; 1700 } 1701 1702 /* 1703 * The best choice is the oldest entry. 1704 * 1705 * Also check for a field overflow, using -1 instead of 0 1706 * to deal with SMP races on accessing the 'ticks' global. 1707 */ 1708 delta = ticks - mp->ticks; 1709 if (delta < -1) 1710 best = mp; 1711 if (best_delta < delta) 1712 best = mp; 1713 } 1714 1715 /* 1716 * Load the entry. Copy a few elements to the hash entry itself 1717 * to reduce memory stalls due to memory indirects on lookups. 1718 */ 1719 best->m = m; 1720 best->object = object; 1721 best->pindex = pindex; 1722 best->ticks = ticks; 1723 } 1724 1725 /* 1726 * Locate and return the page at (object, pindex), or NULL if the 1727 * page could not be found. 1728 * 1729 * The caller must hold the vm_object token. 1730 */ 1731 vm_page_t 1732 vm_page_lookup(vm_object_t object, vm_pindex_t pindex) 1733 { 1734 vm_page_t m; 1735 1736 /* 1737 * Search the hash table for this object/offset pair 1738 */ 1739 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1740 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1741 if (m) { 1742 KKASSERT(m->object == object && m->pindex == pindex); 1743 vm_page_hash_enter(m); 1744 } 1745 return(m); 1746 } 1747 1748 vm_page_t 1749 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object, 1750 vm_pindex_t pindex, 1751 int also_m_busy, const char *msg 1752 VM_PAGE_DEBUG_ARGS) 1753 { 1754 u_int32_t busy_count; 1755 vm_page_t m; 1756 1757 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1758 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1759 while (m) { 1760 KKASSERT(m->object == object && m->pindex == pindex); 1761 busy_count = m->busy_count; 1762 cpu_ccfence(); 1763 if (busy_count & PBUSY_LOCKED) { 1764 tsleep_interlock(m, 0); 1765 if (atomic_cmpset_int(&m->busy_count, busy_count, 1766 busy_count | PBUSY_WANTED)) { 1767 atomic_set_int(&m->flags, PG_REFERENCED); 1768 tsleep(m, PINTERLOCKED, msg, 0); 1769 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1770 pindex); 1771 } 1772 } else if (also_m_busy && busy_count) { 1773 tsleep_interlock(m, 0); 1774 if (atomic_cmpset_int(&m->busy_count, busy_count, 1775 busy_count | PBUSY_WANTED)) { 1776 atomic_set_int(&m->flags, PG_REFERENCED); 1777 tsleep(m, PINTERLOCKED, msg, 0); 1778 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, 1779 pindex); 1780 } 1781 } else if (atomic_cmpset_int(&m->busy_count, busy_count, 1782 busy_count | PBUSY_LOCKED)) { 1783 #ifdef VM_PAGE_DEBUG 1784 m->busy_func = func; 1785 m->busy_line = lineno; 1786 #endif 1787 vm_page_hash_enter(m); 1788 break; 1789 } 1790 } 1791 return m; 1792 } 1793 1794 /* 1795 * Attempt to lookup and busy a page. 1796 * 1797 * Returns NULL if the page could not be found 1798 * 1799 * Returns a vm_page and error == TRUE if the page exists but could not 1800 * be busied. 1801 * 1802 * Returns a vm_page and error == FALSE on success. 1803 */ 1804 vm_page_t 1805 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object, 1806 vm_pindex_t pindex, 1807 int also_m_busy, int *errorp 1808 VM_PAGE_DEBUG_ARGS) 1809 { 1810 u_int32_t busy_count; 1811 vm_page_t m; 1812 1813 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1814 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1815 *errorp = FALSE; 1816 while (m) { 1817 KKASSERT(m->object == object && m->pindex == pindex); 1818 busy_count = m->busy_count; 1819 cpu_ccfence(); 1820 if (busy_count & PBUSY_LOCKED) { 1821 *errorp = TRUE; 1822 break; 1823 } 1824 if (also_m_busy && busy_count) { 1825 *errorp = TRUE; 1826 break; 1827 } 1828 if (atomic_cmpset_int(&m->busy_count, busy_count, 1829 busy_count | PBUSY_LOCKED)) { 1830 #ifdef VM_PAGE_DEBUG 1831 m->busy_func = func; 1832 m->busy_line = lineno; 1833 #endif 1834 vm_page_hash_enter(m); 1835 break; 1836 } 1837 } 1838 return m; 1839 } 1840 1841 /* 1842 * Returns a page that is only soft-busied for use by the caller in 1843 * a read-only fashion. Returns NULL if the page could not be found, 1844 * the soft busy could not be obtained, or the page data is invalid. 1845 * 1846 * XXX Doesn't handle PG_FICTITIOUS pages at the moment, but there is 1847 * no reason why we couldn't. 1848 */ 1849 vm_page_t 1850 vm_page_lookup_sbusy_try(struct vm_object *object, vm_pindex_t pindex, 1851 int pgoff, int pgbytes) 1852 { 1853 vm_page_t m; 1854 1855 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 1856 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); 1857 if (m) { 1858 if ((m->valid != VM_PAGE_BITS_ALL && 1859 !vm_page_is_valid(m, pgoff, pgbytes)) || 1860 (m->flags & PG_FICTITIOUS)) { 1861 m = NULL; 1862 } else if (vm_page_sbusy_try(m)) { 1863 m = NULL; 1864 } else if ((m->valid != VM_PAGE_BITS_ALL && 1865 !vm_page_is_valid(m, pgoff, pgbytes)) || 1866 (m->flags & PG_FICTITIOUS)) { 1867 vm_page_sbusy_drop(m); 1868 m = NULL; 1869 } else { 1870 vm_page_hash_enter(m); 1871 } 1872 } 1873 return m; 1874 } 1875 1876 /* 1877 * Caller must hold the related vm_object 1878 */ 1879 vm_page_t 1880 vm_page_next(vm_page_t m) 1881 { 1882 vm_page_t next; 1883 1884 next = vm_page_rb_tree_RB_NEXT(m); 1885 if (next && next->pindex != m->pindex + 1) 1886 next = NULL; 1887 return (next); 1888 } 1889 1890 /* 1891 * vm_page_rename() 1892 * 1893 * Move the given vm_page from its current object to the specified 1894 * target object/offset. The page must be busy and will remain so 1895 * on return. 1896 * 1897 * new_object must be held. 1898 * This routine might block. XXX ? 1899 * 1900 * NOTE: Swap associated with the page must be invalidated by the move. We 1901 * have to do this for several reasons: (1) we aren't freeing the 1902 * page, (2) we are dirtying the page, (3) the VM system is probably 1903 * moving the page from object A to B, and will then later move 1904 * the backing store from A to B and we can't have a conflict. 1905 * 1906 * NOTE: We *always* dirty the page. It is necessary both for the 1907 * fact that we moved it, and because we may be invalidating 1908 * swap. If the page is on the cache, we have to deactivate it 1909 * or vm_page_dirty() will panic. Dirty pages are not allowed 1910 * on the cache. 1911 * 1912 * NOTE: Caller is responsible for any pmap disposition prior to the 1913 * rename (as the pmap code will not be able to find the entries 1914 * once the object has been disassociated or changed). Nominally 1915 * the caller is moving a page between shadowed objects and so the 1916 * pmap association is retained without having to remove the page 1917 * from it. 1918 */ 1919 void 1920 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) 1921 { 1922 KKASSERT(m->busy_count & PBUSY_LOCKED); 1923 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object)); 1924 if (m->object) { 1925 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m->object)); 1926 vm_page_remove(m); 1927 } 1928 if (vm_page_insert(m, new_object, new_pindex) == FALSE) { 1929 panic("vm_page_rename: target exists (%p,%"PRIu64")", 1930 new_object, new_pindex); 1931 } 1932 if (m->queue - m->pc == PQ_CACHE) 1933 vm_page_deactivate(m); 1934 vm_page_dirty(m); 1935 } 1936 1937 /* 1938 * vm_page_unqueue() without any wakeup. This routine is used when a page 1939 * is to remain BUSYied by the caller. 1940 * 1941 * This routine may not block. 1942 */ 1943 void 1944 vm_page_unqueue_nowakeup(vm_page_t m) 1945 { 1946 vm_page_and_queue_spin_lock(m); 1947 (void)_vm_page_rem_queue_spinlocked(m); 1948 vm_page_spin_unlock(m); 1949 } 1950 1951 /* 1952 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon 1953 * if necessary. 1954 * 1955 * This routine may not block. 1956 */ 1957 void 1958 vm_page_unqueue(vm_page_t m) 1959 { 1960 u_short queue; 1961 1962 vm_page_and_queue_spin_lock(m); 1963 queue = _vm_page_rem_queue_spinlocked(m); 1964 if (queue == PQ_FREE || queue == PQ_CACHE) { 1965 vm_page_spin_unlock(m); 1966 pagedaemon_wakeup(); 1967 } else { 1968 vm_page_spin_unlock(m); 1969 } 1970 } 1971 1972 /* 1973 * vm_page_list_find() 1974 * 1975 * Find a page on the specified queue with color optimization. 1976 * 1977 * The page coloring optimization attempts to locate a page that does 1978 * not overload other nearby pages in the object in the cpu's L1 or L2 1979 * caches. We need this optimization because cpu caches tend to be 1980 * physical caches, while object spaces tend to be virtual. 1981 * 1982 * The page coloring optimization also, very importantly, tries to localize 1983 * memory to cpus and physical sockets. 1984 * 1985 * Each PQ_FREE and PQ_CACHE color queue has its own spinlock and the 1986 * algorithm is adjusted to localize allocations on a per-core basis. 1987 * This is done by 'twisting' the colors. 1988 * 1989 * The page is returned spinlocked and removed from its queue (it will 1990 * be on PQ_NONE), or NULL. The page is not BUSY'd. The caller 1991 * is responsible for dealing with the busy-page case (usually by 1992 * deactivating the page and looping). 1993 * 1994 * NOTE: This routine is carefully inlined. A non-inlined version 1995 * is available for outside callers but the only critical path is 1996 * from within this source file. 1997 * 1998 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE 1999 * represent stable storage, allowing us to order our locks vm_page 2000 * first, then queue. 2001 * 2002 * WARNING! The returned page is not busied and may race other busying 2003 * operations, callers must check that the page is in the state they 2004 * want after busying. 2005 */ 2006 static __inline 2007 vm_page_t 2008 _vm_page_list_find(int basequeue, int index) 2009 { 2010 struct vpgqueues *pq; 2011 vm_page_t m; 2012 2013 index &= PQ_L2_MASK; 2014 pq = &vm_page_queues[basequeue + index]; 2015 2016 /* 2017 * Try this cpu's colored queue first. Test for a page unlocked, 2018 * then lock the queue and locate a page. Note that the lock order 2019 * is reversed, but we do not want to dwadle on the page spinlock 2020 * anyway as it is held significantly longer than the queue spinlock. 2021 */ 2022 if (TAILQ_FIRST(&pq->pl)) { 2023 spin_lock(&pq->spin); 2024 TAILQ_FOREACH(m, &pq->pl, pageq) { 2025 if (spin_trylock(&m->spin) == 0) 2026 continue; 2027 KKASSERT(m->queue == basequeue + index); 2028 pq->lastq = -1; 2029 return(m); 2030 } 2031 spin_unlock(&pq->spin); 2032 } 2033 2034 m = _vm_page_list_find_wide(basequeue, index, &pq->lastq); 2035 2036 return(m); 2037 } 2038 2039 /* 2040 * If we could not find the page in the desired queue try to find it in 2041 * a nearby (NUMA-aware) queue, spreading out as we go. 2042 */ 2043 static vm_page_t 2044 _vm_page_list_find_wide(int basequeue, int index, int *lastp) 2045 { 2046 struct vpgqueues *pq; 2047 vm_page_t m = NULL; 2048 int pqmask = set_assoc_mask >> 1; 2049 int pqi; 2050 int range; 2051 int skip_start; 2052 int skip_next; 2053 int count; 2054 2055 /* 2056 * Avoid re-searching empty queues over and over again skip to 2057 * pq->last if appropriate. 2058 */ 2059 if (*lastp >= 0) 2060 index = *lastp; 2061 2062 index &= PQ_L2_MASK; 2063 pq = &vm_page_queues[basequeue]; 2064 count = 0; 2065 skip_start = -1; 2066 skip_next = -1; 2067 2068 /* 2069 * Run local sets of 16, 32, 64, 128, up to the entire queue if all 2070 * else fails (PQ_L2_MASK). 2071 * 2072 * pqmask is a mask, 15, 31, 63, etc. 2073 * 2074 * Test each queue unlocked first, then lock the queue and locate 2075 * a page. Note that the lock order is reversed, but we do not want 2076 * to dwadle on the page spinlock anyway as it is held significantly 2077 * longer than the queue spinlock. 2078 */ 2079 do { 2080 pqmask = (pqmask << 1) | 1; 2081 2082 pqi = index; 2083 range = pqmask + 1; 2084 2085 while (range > 0) { 2086 if (pqi >= skip_start && pqi < skip_next) { 2087 range -= skip_next - pqi; 2088 pqi = (pqi & ~pqmask) | (skip_next & pqmask); 2089 } 2090 if (range > 0 && TAILQ_FIRST(&pq[pqi].pl)) { 2091 spin_lock(&pq[pqi].spin); 2092 TAILQ_FOREACH(m, &pq[pqi].pl, pageq) { 2093 if (spin_trylock(&m->spin) == 0) 2094 continue; 2095 KKASSERT(m->queue == basequeue + pqi); 2096 2097 /* 2098 * If we had to wander too far, set 2099 * *lastp to skip past empty queues. 2100 */ 2101 if (count >= 8) 2102 *lastp = pqi & PQ_L2_MASK; 2103 return(m); 2104 } 2105 spin_unlock(&pq[pqi].spin); 2106 } 2107 --range; 2108 ++count; 2109 pqi = (pqi & ~pqmask) | ((pqi + 1) & pqmask); 2110 } 2111 skip_start = pqi & ~pqmask; 2112 skip_next = (pqi | pqmask) + 1; 2113 } while (pqmask != PQ_L2_MASK); 2114 2115 return(m); 2116 } 2117 2118 static __inline 2119 vm_page_t 2120 _vm_page_list_find2(int bq1, int bq2, int index) 2121 { 2122 struct vpgqueues *pq1; 2123 struct vpgqueues *pq2; 2124 vm_page_t m; 2125 2126 index &= PQ_L2_MASK; 2127 pq1 = &vm_page_queues[bq1 + index]; 2128 pq2 = &vm_page_queues[bq2 + index]; 2129 2130 /* 2131 * Try this cpu's colored queue first. Test for a page unlocked, 2132 * then lock the queue and locate a page. Note that the lock order 2133 * is reversed, but we do not want to dwadle on the page spinlock 2134 * anyway as it is held significantly longer than the queue spinlock. 2135 */ 2136 if (TAILQ_FIRST(&pq1->pl)) { 2137 spin_lock(&pq1->spin); 2138 TAILQ_FOREACH(m, &pq1->pl, pageq) { 2139 if (spin_trylock(&m->spin) == 0) 2140 continue; 2141 KKASSERT(m->queue == bq1 + index); 2142 pq1->lastq = -1; 2143 pq2->lastq = -1; 2144 return(m); 2145 } 2146 spin_unlock(&pq1->spin); 2147 } 2148 2149 m = _vm_page_list_find2_wide(bq1, bq2, index, &pq1->lastq, &pq2->lastq); 2150 2151 return(m); 2152 } 2153 2154 2155 /* 2156 * This version checks two queues at the same time, widening its search 2157 * as we progress. prefering basequeue1 2158 * and starting on basequeue2 after exhausting the first set. The idea 2159 * is to try to stay localized to the cpu. 2160 */ 2161 static vm_page_t 2162 _vm_page_list_find2_wide(int basequeue1, int basequeue2, int index, 2163 int *lastp1, int *lastp2) 2164 { 2165 struct vpgqueues *pq1; 2166 struct vpgqueues *pq2; 2167 vm_page_t m = NULL; 2168 int pqmask1, pqmask2; 2169 int pqi; 2170 int range; 2171 int skip_start1, skip_start2; 2172 int skip_next1, skip_next2; 2173 int count1, count2; 2174 2175 /* 2176 * Avoid re-searching empty queues over and over again skip to 2177 * pq->last if appropriate. 2178 */ 2179 if (*lastp1 >= 0) 2180 index = *lastp1; 2181 2182 index &= PQ_L2_MASK; 2183 2184 pqmask1 = set_assoc_mask >> 1; 2185 pq1 = &vm_page_queues[basequeue1]; 2186 count1 = 0; 2187 skip_start1 = -1; 2188 skip_next1 = -1; 2189 2190 pqmask2 = set_assoc_mask >> 1; 2191 pq2 = &vm_page_queues[basequeue2]; 2192 count2 = 0; 2193 skip_start2 = -1; 2194 skip_next2 = -1; 2195 2196 /* 2197 * Run local sets of 16, 32, 64, 128, up to the entire queue if all 2198 * else fails (PQ_L2_MASK). 2199 * 2200 * pqmask is a mask, 15, 31, 63, etc. 2201 * 2202 * Test each queue unlocked first, then lock the queue and locate 2203 * a page. Note that the lock order is reversed, but we do not want 2204 * to dwadle on the page spinlock anyway as it is held significantly 2205 * longer than the queue spinlock. 2206 */ 2207 do { 2208 if (pqmask1 == PQ_L2_MASK) 2209 goto skip2; 2210 2211 pqmask1 = (pqmask1 << 1) | 1; 2212 pqi = index; 2213 range = pqmask1 + 1; 2214 2215 while (range > 0) { 2216 if (pqi >= skip_start1 && pqi < skip_next1) { 2217 range -= skip_next1 - pqi; 2218 pqi = (pqi & ~pqmask1) | (skip_next1 & pqmask1); 2219 } 2220 if (range > 0 && TAILQ_FIRST(&pq1[pqi].pl)) { 2221 spin_lock(&pq1[pqi].spin); 2222 TAILQ_FOREACH(m, &pq1[pqi].pl, pageq) { 2223 if (spin_trylock(&m->spin) == 0) 2224 continue; 2225 KKASSERT(m->queue == basequeue1 + pqi); 2226 2227 /* 2228 * If we had to wander too far, set 2229 * *lastp to skip past empty queues. 2230 */ 2231 if (count1 >= 8) 2232 *lastp1 = pqi & PQ_L2_MASK; 2233 return(m); 2234 } 2235 spin_unlock(&pq1[pqi].spin); 2236 } 2237 --range; 2238 ++count1; 2239 pqi = (pqi & ~pqmask1) | ((pqi + 1) & pqmask1); 2240 } 2241 skip_start1 = pqi & ~pqmask1; 2242 skip_next1 = (pqi | pqmask1) + 1; 2243 skip2: 2244 if (pqmask1 < ((set_assoc_mask << 1) | 1)) 2245 continue; 2246 2247 pqmask2 = (pqmask2 << 1) | 1; 2248 pqi = index; 2249 range = pqmask2 + 1; 2250 2251 while (range > 0) { 2252 if (pqi >= skip_start2 && pqi < skip_next2) { 2253 range -= skip_next2 - pqi; 2254 pqi = (pqi & ~pqmask2) | (skip_next2 & pqmask2); 2255 } 2256 if (range > 0 && TAILQ_FIRST(&pq2[pqi].pl)) { 2257 spin_lock(&pq2[pqi].spin); 2258 TAILQ_FOREACH(m, &pq2[pqi].pl, pageq) { 2259 if (spin_trylock(&m->spin) == 0) 2260 continue; 2261 KKASSERT(m->queue == basequeue2 + pqi); 2262 2263 /* 2264 * If we had to wander too far, set 2265 * *lastp to skip past empty queues. 2266 */ 2267 if (count2 >= 8) 2268 *lastp2 = pqi & PQ_L2_MASK; 2269 return(m); 2270 } 2271 spin_unlock(&pq2[pqi].spin); 2272 } 2273 --range; 2274 ++count2; 2275 pqi = (pqi & ~pqmask2) | ((pqi + 1) & pqmask2); 2276 } 2277 skip_start2 = pqi & ~pqmask2; 2278 skip_next2 = (pqi | pqmask2) + 1; 2279 } while (pqmask1 != PQ_L2_MASK && pqmask2 != PQ_L2_MASK); 2280 2281 return(m); 2282 } 2283 2284 /* 2285 * Returns a vm_page candidate for allocation. The page is not busied so 2286 * it can move around. The caller must busy the page (and typically 2287 * deactivate it if it cannot be busied!) 2288 * 2289 * Returns a spinlocked vm_page that has been removed from its queue. 2290 * (note that _vm_page_list_find() does not remove the page from its 2291 * queue). 2292 */ 2293 vm_page_t 2294 vm_page_list_find(int basequeue, int index) 2295 { 2296 vm_page_t m; 2297 2298 m = _vm_page_list_find(basequeue, index); 2299 if (m) 2300 _vm_page_rem_queue_spinlocked(m); 2301 return m; 2302 } 2303 2304 /* 2305 * Find a page on the cache queue with color optimization, remove it 2306 * from the queue, and busy it. The returned page will not be spinlocked. 2307 * 2308 * A candidate failure will be deactivated. Candidates can fail due to 2309 * being busied by someone else, in which case they will be deactivated. 2310 * 2311 * This routine may not block. 2312 * 2313 */ 2314 static vm_page_t 2315 vm_page_select_cache(u_short pg_color) 2316 { 2317 vm_page_t m; 2318 2319 for (;;) { 2320 m = _vm_page_list_find(PQ_CACHE, pg_color); 2321 if (m == NULL) 2322 break; 2323 /* 2324 * (m) has been spinlocked 2325 */ 2326 _vm_page_rem_queue_spinlocked(m); 2327 if (vm_page_busy_try(m, TRUE)) { 2328 _vm_page_deactivate_locked(m, 0); 2329 vm_page_spin_unlock(m); 2330 } else { 2331 /* 2332 * We successfully busied the page. This can race 2333 * vm_page_lookup() + busy ops so make sure the 2334 * page is in the state we want. 2335 */ 2336 if ((m->flags & (PG_NEED_COMMIT | PG_MAPPED)) == 0 && 2337 m->hold_count == 0 && 2338 m->wire_count == 0 && 2339 (m->dirty & m->valid) == 0) { 2340 vm_page_spin_unlock(m); 2341 KKASSERT((m->flags & PG_UNQUEUED) == 0); 2342 pagedaemon_wakeup(); 2343 return(m); 2344 } 2345 2346 /* 2347 * The page cannot be recycled, deactivate it. 2348 */ 2349 _vm_page_deactivate_locked(m, 0); 2350 if (_vm_page_wakeup(m)) { 2351 vm_page_spin_unlock(m); 2352 wakeup(m); 2353 } else { 2354 vm_page_spin_unlock(m); 2355 } 2356 } 2357 } 2358 return (m); 2359 } 2360 2361 /* 2362 * Find a free page. We attempt to inline the nominal case and fall back 2363 * to _vm_page_select_free() otherwise. A busied page is removed from 2364 * the queue and returned. 2365 * 2366 * This routine may not block. 2367 */ 2368 static __inline vm_page_t 2369 vm_page_select_free(u_short pg_color) 2370 { 2371 vm_page_t m; 2372 2373 for (;;) { 2374 m = _vm_page_list_find(PQ_FREE, pg_color); 2375 if (m == NULL) 2376 break; 2377 _vm_page_rem_queue_spinlocked(m); 2378 if (vm_page_busy_try(m, TRUE)) { 2379 /* 2380 * Various mechanisms such as a pmap_collect can 2381 * result in a busy page on the free queue. We 2382 * have to move the page out of the way so we can 2383 * retry the allocation. If the other thread is not 2384 * allocating the page then m->valid will remain 0 and 2385 * the pageout daemon will free the page later on. 2386 * 2387 * Since we could not busy the page, however, we 2388 * cannot make assumptions as to whether the page 2389 * will be allocated by the other thread or not, 2390 * so all we can do is deactivate it to move it out 2391 * of the way. In particular, if the other thread 2392 * wires the page it may wind up on the inactive 2393 * queue and the pageout daemon will have to deal 2394 * with that case too. 2395 */ 2396 _vm_page_deactivate_locked(m, 0); 2397 vm_page_spin_unlock(m); 2398 } else { 2399 /* 2400 * Theoretically if we are able to busy the page 2401 * atomic with the queue removal (using the vm_page 2402 * lock) nobody else should have been able to mess 2403 * with the page before us. 2404 * 2405 * Assert the page state. Note that even though 2406 * wiring doesn't adjust queues, a page on the free 2407 * queue should never be wired at this point. 2408 */ 2409 KKASSERT((m->flags & (PG_UNQUEUED | 2410 PG_NEED_COMMIT)) == 0); 2411 KASSERT(m->hold_count == 0, 2412 ("m->hold_count is not zero " 2413 "pg %p q=%d flags=%08x hold=%d wire=%d", 2414 m, m->queue, m->flags, 2415 m->hold_count, m->wire_count)); 2416 KKASSERT(m->wire_count == 0); 2417 vm_page_spin_unlock(m); 2418 pagedaemon_wakeup(); 2419 2420 /* return busied and removed page */ 2421 return(m); 2422 } 2423 } 2424 return(m); 2425 } 2426 2427 static __inline vm_page_t 2428 vm_page_select_free_or_cache(u_short pg_color, int *fromcachep) 2429 { 2430 vm_page_t m; 2431 2432 *fromcachep = 0; 2433 for (;;) { 2434 m = _vm_page_list_find2(PQ_FREE, PQ_CACHE, pg_color); 2435 if (m == NULL) 2436 break; 2437 if (vm_page_busy_try(m, TRUE)) { 2438 _vm_page_rem_queue_spinlocked(m); 2439 _vm_page_deactivate_locked(m, 0); 2440 vm_page_spin_unlock(m); 2441 } else if (m->queue - m->pc == PQ_FREE) { 2442 /* 2443 * We successfully busied the page, PQ_FREE case 2444 */ 2445 _vm_page_rem_queue_spinlocked(m); 2446 KKASSERT((m->flags & (PG_UNQUEUED | 2447 PG_NEED_COMMIT)) == 0); 2448 KASSERT(m->hold_count == 0, 2449 ("m->hold_count is not zero " 2450 "pg %p q=%d flags=%08x hold=%d wire=%d", 2451 m, m->queue, m->flags, 2452 m->hold_count, m->wire_count)); 2453 KKASSERT(m->wire_count == 0); 2454 vm_page_spin_unlock(m); 2455 pagedaemon_wakeup(); 2456 2457 /* return busied and removed page */ 2458 return(m); 2459 } else { 2460 /* 2461 * We successfully busied the page, PQ_CACHE case 2462 * 2463 * This can race vm_page_lookup() + busy ops, so make 2464 * sure the page is in the state we want. 2465 */ 2466 _vm_page_rem_queue_spinlocked(m); 2467 if ((m->flags & (PG_NEED_COMMIT | PG_MAPPED)) == 0 && 2468 m->hold_count == 0 && 2469 m->wire_count == 0 && 2470 (m->dirty & m->valid) == 0) { 2471 vm_page_spin_unlock(m); 2472 KKASSERT((m->flags & PG_UNQUEUED) == 0); 2473 pagedaemon_wakeup(); 2474 *fromcachep = 1; 2475 return(m); 2476 } 2477 2478 /* 2479 * The page cannot be recycled, deactivate it. 2480 */ 2481 _vm_page_deactivate_locked(m, 0); 2482 if (_vm_page_wakeup(m)) { 2483 vm_page_spin_unlock(m); 2484 wakeup(m); 2485 } else { 2486 vm_page_spin_unlock(m); 2487 } 2488 } 2489 } 2490 return(m); 2491 } 2492 2493 /* 2494 * vm_page_alloc() 2495 * 2496 * Allocate and return a memory cell associated with this VM object/offset 2497 * pair. If object is NULL an unassociated page will be allocated. 2498 * 2499 * The returned page will be busied and removed from its queues. This 2500 * routine can block and may return NULL if a race occurs and the page 2501 * is found to already exist at the specified (object, pindex). 2502 * 2503 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain 2504 * VM_ALLOC_QUICK like normal but cannot use cache 2505 * VM_ALLOC_SYSTEM greater free drain 2506 * VM_ALLOC_INTERRUPT allow free list to be completely drained 2507 * VM_ALLOC_ZERO advisory request for pre-zero'd page only 2508 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only 2509 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision 2510 * (see vm_page_grab()) 2511 * VM_ALLOC_USE_GD ok to use per-gd cache 2512 * 2513 * VM_ALLOC_CPU(n) allocate using specified cpu localization 2514 * 2515 * The object must be held if not NULL 2516 * This routine may not block 2517 * 2518 * Additional special handling is required when called from an interrupt 2519 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache 2520 * in this case. 2521 */ 2522 vm_page_t 2523 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req) 2524 { 2525 globaldata_t gd; 2526 vm_object_t obj; 2527 vm_page_t m; 2528 u_short pg_color; 2529 int cpuid_local; 2530 int fromcache; 2531 2532 #if 0 2533 /* 2534 * Special per-cpu free VM page cache. The pages are pre-busied 2535 * and pre-zerod for us. 2536 */ 2537 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) { 2538 crit_enter_gd(gd); 2539 if (gd->gd_vmpg_count) { 2540 m = gd->gd_vmpg_array[--gd->gd_vmpg_count]; 2541 crit_exit_gd(gd); 2542 goto done; 2543 } 2544 crit_exit_gd(gd); 2545 } 2546 #endif 2547 m = NULL; 2548 2549 /* 2550 * CPU LOCALIZATION 2551 * 2552 * CPU localization algorithm. Break the page queues up by physical 2553 * id and core id (note that two cpu threads will have the same core 2554 * id, and core_id != gd_cpuid). 2555 * 2556 * This is nowhere near perfect, for example the last pindex in a 2557 * subgroup will overflow into the next cpu or package. But this 2558 * should get us good page reuse locality in heavy mixed loads. 2559 * 2560 * (may be executed before the APs are started, so other GDs might 2561 * not exist!) 2562 */ 2563 if (page_req & VM_ALLOC_CPU_SPEC) 2564 cpuid_local = VM_ALLOC_GETCPU(page_req); 2565 else 2566 cpuid_local = mycpu->gd_cpuid; 2567 2568 pg_color = vm_get_pg_color(cpuid_local, object, pindex); 2569 2570 KKASSERT(page_req & 2571 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK| 2572 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 2573 2574 /* 2575 * Certain system threads (pageout daemon, buf_daemon's) are 2576 * allowed to eat deeper into the free page list. 2577 */ 2578 if (curthread->td_flags & TDF_SYSTHREAD) 2579 page_req |= VM_ALLOC_SYSTEM; 2580 2581 /* 2582 * To avoid live-locks only compare against v_free_reserved. The 2583 * pageout daemon has extra tests for this. 2584 */ 2585 loop: 2586 gd = mycpu; 2587 if (gd->gd_vmstats.v_free_count >= gd->gd_vmstats.v_free_reserved || 2588 ((page_req & VM_ALLOC_INTERRUPT) && 2589 gd->gd_vmstats.v_free_count > 0) || 2590 ((page_req & VM_ALLOC_SYSTEM) && 2591 gd->gd_vmstats.v_cache_count == 0 && 2592 gd->gd_vmstats.v_free_count > 2593 gd->gd_vmstats.v_interrupt_free_min) 2594 ) { 2595 /* 2596 * The free queue has sufficient free pages to take one out. 2597 * 2598 * However, if the free queue is strained the scan may widen 2599 * to the entire queue and cause a great deal of SMP 2600 * contention, so we use a double-queue-scan if we can 2601 * to avoid this. 2602 */ 2603 if (page_req & VM_ALLOC_NORMAL) { 2604 m = vm_page_select_free_or_cache(pg_color, &fromcache); 2605 if (m && fromcache) 2606 goto found_cache; 2607 } else { 2608 m = vm_page_select_free(pg_color); 2609 } 2610 } else if (page_req & VM_ALLOC_NORMAL) { 2611 /* 2612 * Allocatable from the cache (non-interrupt only). On 2613 * success, we must free the page and try again, thus 2614 * ensuring that vmstats.v_*_free_min counters are replenished. 2615 */ 2616 #ifdef INVARIANTS 2617 if (curthread->td_preempted) { 2618 kprintf("vm_page_alloc(): warning, attempt to allocate" 2619 " cache page from preempting interrupt\n"); 2620 m = NULL; 2621 } else { 2622 m = vm_page_select_cache(pg_color); 2623 } 2624 #else 2625 m = vm_page_select_cache(pg_color); 2626 #endif 2627 /* 2628 * On success move the page into the free queue and loop. 2629 * 2630 * Only do this if we can safely acquire the vm_object lock, 2631 * because this is effectively a random page and the caller 2632 * might be holding the lock shared, we don't want to 2633 * deadlock. 2634 */ 2635 if (m != NULL) { 2636 found_cache: 2637 KASSERT(m->dirty == 0, 2638 ("Found dirty cache page %p", m)); 2639 if ((obj = m->object) != NULL) { 2640 if (vm_object_hold_try(obj)) { 2641 if (__predict_false((m->flags & (PG_MAPPED|PG_WRITEABLE)) != 0)) 2642 vm_page_protect(m, VM_PROT_NONE); 2643 vm_page_free(m); 2644 /* m->object NULL here */ 2645 vm_object_drop(obj); 2646 } else { 2647 vm_page_deactivate(m); 2648 vm_page_wakeup(m); 2649 } 2650 } else { 2651 if (__predict_false((m->flags & (PG_MAPPED|PG_WRITEABLE)) != 0)) 2652 vm_page_protect(m, VM_PROT_NONE); 2653 vm_page_free(m); 2654 } 2655 goto loop; 2656 } 2657 2658 /* 2659 * On failure return NULL 2660 */ 2661 atomic_add_int(&vm_pageout_deficit, 1); 2662 pagedaemon_wakeup(); 2663 return (NULL); 2664 } else { 2665 /* 2666 * No pages available, wakeup the pageout daemon and give up. 2667 */ 2668 atomic_add_int(&vm_pageout_deficit, 1); 2669 pagedaemon_wakeup(); 2670 return (NULL); 2671 } 2672 2673 /* 2674 * v_free_count can race so loop if we don't find the expected 2675 * page. 2676 */ 2677 if (m == NULL) { 2678 vmstats_rollup(); 2679 goto loop; 2680 } 2681 2682 /* 2683 * Good page found. The page has already been busied for us and 2684 * removed from its queues. 2685 */ 2686 KASSERT(m->dirty == 0, 2687 ("vm_page_alloc: free/cache page %p was dirty", m)); 2688 KKASSERT(m->queue == PQ_NONE); 2689 2690 #if 0 2691 done: 2692 #endif 2693 /* 2694 * Initialize the structure, inheriting some flags but clearing 2695 * all the rest. The page has already been busied for us. 2696 */ 2697 vm_page_flag_clear(m, ~PG_KEEP_NEWPAGE_MASK); 2698 2699 KKASSERT(m->wire_count == 0); 2700 KKASSERT((m->busy_count & PBUSY_MASK) == 0); 2701 m->act_count = 0; 2702 m->valid = 0; 2703 2704 /* 2705 * Caller must be holding the object lock (asserted by 2706 * vm_page_insert()). 2707 * 2708 * NOTE: Inserting a page here does not insert it into any pmaps 2709 * (which could cause us to block allocating memory). 2710 * 2711 * NOTE: If no object an unassociated page is allocated, m->pindex 2712 * can be used by the caller for any purpose. 2713 */ 2714 if (object) { 2715 if (vm_page_insert(m, object, pindex) == FALSE) { 2716 vm_page_free(m); 2717 if ((page_req & VM_ALLOC_NULL_OK) == 0) 2718 panic("PAGE RACE %p[%ld]/%p", 2719 object, (long)pindex, m); 2720 m = NULL; 2721 } 2722 } else { 2723 m->pindex = pindex; 2724 } 2725 2726 /* 2727 * Don't wakeup too often - wakeup the pageout daemon when 2728 * we would be nearly out of memory. 2729 */ 2730 pagedaemon_wakeup(); 2731 2732 /* 2733 * A BUSY page is returned. 2734 */ 2735 return (m); 2736 } 2737 2738 /* 2739 * Returns number of pages available in our DMA memory reserve 2740 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf) 2741 */ 2742 vm_size_t 2743 vm_contig_avail_pages(void) 2744 { 2745 alist_blk_t blk; 2746 alist_blk_t count; 2747 alist_blk_t bfree; 2748 spin_lock(&vm_contig_spin); 2749 bfree = alist_free_info(&vm_contig_alist, &blk, &count); 2750 spin_unlock(&vm_contig_spin); 2751 2752 return bfree; 2753 } 2754 2755 /* 2756 * Attempt to allocate contiguous physical memory with the specified 2757 * requirements. 2758 */ 2759 vm_page_t 2760 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high, 2761 unsigned long alignment, unsigned long boundary, 2762 unsigned long size, vm_memattr_t memattr) 2763 { 2764 alist_blk_t blk; 2765 vm_page_t m; 2766 vm_pindex_t i; 2767 #if 0 2768 static vm_pindex_t contig_rover; 2769 #endif 2770 2771 alignment >>= PAGE_SHIFT; 2772 if (alignment == 0) 2773 alignment = 1; 2774 boundary >>= PAGE_SHIFT; 2775 if (boundary == 0) 2776 boundary = 1; 2777 size = (size + PAGE_MASK) >> PAGE_SHIFT; 2778 2779 #if 0 2780 /* 2781 * Disabled temporarily until we find a solution for DRM (a flag 2782 * to always use the free space reserve, for performance). 2783 */ 2784 if (high == BUS_SPACE_MAXADDR && alignment <= PAGE_SIZE && 2785 boundary <= PAGE_SIZE && size == 1 && 2786 memattr == VM_MEMATTR_DEFAULT) { 2787 /* 2788 * Any page will work, use vm_page_alloc() 2789 * (e.g. when used from kmem_alloc_attr()) 2790 */ 2791 m = vm_page_alloc(NULL, (contig_rover++) & 0x7FFFFFFF, 2792 VM_ALLOC_NORMAL | VM_ALLOC_SYSTEM | 2793 VM_ALLOC_INTERRUPT); 2794 m->valid = VM_PAGE_BITS_ALL; 2795 vm_page_wire(m); 2796 vm_page_wakeup(m); 2797 } else 2798 #endif 2799 { 2800 /* 2801 * Use the low-memory dma reserve 2802 */ 2803 spin_lock(&vm_contig_spin); 2804 blk = alist_alloc(&vm_contig_alist, 0, size); 2805 if (blk == ALIST_BLOCK_NONE) { 2806 spin_unlock(&vm_contig_spin); 2807 if (bootverbose) { 2808 kprintf("vm_page_alloc_contig: %ldk nospace\n", 2809 (size << PAGE_SHIFT) / 1024); 2810 print_backtrace(5); 2811 } 2812 return(NULL); 2813 } 2814 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) { 2815 alist_free(&vm_contig_alist, blk, size); 2816 spin_unlock(&vm_contig_spin); 2817 if (bootverbose) { 2818 kprintf("vm_page_alloc_contig: %ldk high " 2819 "%016jx failed\n", 2820 (size << PAGE_SHIFT) / 1024, 2821 (intmax_t)high); 2822 } 2823 return(NULL); 2824 } 2825 spin_unlock(&vm_contig_spin); 2826 2827 /* 2828 * Base vm_page_t of range 2829 */ 2830 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); 2831 } 2832 if (vm_contig_verbose) { 2833 kprintf("vm_page_alloc_contig: %016jx/%ldk " 2834 "(%016jx-%016jx al=%lu bo=%lu pgs=%lu attr=%d\n", 2835 (intmax_t)m->phys_addr, 2836 (size << PAGE_SHIFT) / 1024, 2837 low, high, alignment, boundary, size, memattr); 2838 } 2839 if (memattr != VM_MEMATTR_DEFAULT) { 2840 for (i = 0; i < size; ++i) { 2841 KKASSERT(m[i].flags & PG_FICTITIOUS); 2842 pmap_page_set_memattr(&m[i], memattr); 2843 } 2844 } 2845 return m; 2846 } 2847 2848 /* 2849 * Free contiguously allocated pages. The pages will be wired but not busy. 2850 * When freeing to the alist we leave them wired and not busy. 2851 */ 2852 void 2853 vm_page_free_contig(vm_page_t m, unsigned long size) 2854 { 2855 vm_paddr_t pa = VM_PAGE_TO_PHYS(m); 2856 vm_pindex_t start = pa >> PAGE_SHIFT; 2857 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT; 2858 2859 if (vm_contig_verbose) { 2860 kprintf("vm_page_free_contig: %016jx/%ldk\n", 2861 (intmax_t)pa, size / 1024); 2862 } 2863 if (pa < vm_low_phys_reserved) { 2864 /* 2865 * Just assert check the first page for convenience. 2866 */ 2867 KKASSERT(m->wire_count == 1); 2868 KKASSERT(m->flags & PG_FICTITIOUS); 2869 KKASSERT(pa + size <= vm_low_phys_reserved); 2870 spin_lock(&vm_contig_spin); 2871 alist_free(&vm_contig_alist, start, pages); 2872 spin_unlock(&vm_contig_spin); 2873 } else { 2874 while (pages) { 2875 /* XXX FUTURE, maybe (pair with vm_pg_contig_alloc()) */ 2876 /*vm_page_flag_clear(m, PG_FICTITIOUS | PG_UNQUEUED);*/ 2877 vm_page_busy_wait(m, FALSE, "cpgfr"); 2878 vm_page_unwire(m, 0); 2879 vm_page_free(m); 2880 --pages; 2881 ++m; 2882 } 2883 2884 } 2885 } 2886 2887 2888 /* 2889 * Wait for sufficient free memory for nominal heavy memory use kernel 2890 * operations. 2891 * 2892 * WARNING! Be sure never to call this in any vm_pageout code path, which 2893 * will trivially deadlock the system. 2894 */ 2895 void 2896 vm_wait_nominal(void) 2897 { 2898 while (vm_paging_min()) 2899 vm_wait(0); 2900 } 2901 2902 /* 2903 * Test if vm_wait_nominal() would block. 2904 */ 2905 int 2906 vm_test_nominal(void) 2907 { 2908 if (vm_paging_min()) 2909 return(1); 2910 return(0); 2911 } 2912 2913 /* 2914 * Block until free pages are available for allocation, called in various 2915 * places before memory allocations, and occurs before the minimum is reached. 2916 * Typically in the I/O path. 2917 * 2918 * The caller may loop if vm_paging_min() is TRUE (free pages below minimum), 2919 * so we cannot be more generous then that. 2920 */ 2921 void 2922 vm_wait(int timo) 2923 { 2924 /* 2925 * never wait forever 2926 */ 2927 if (timo == 0) 2928 timo = hz; 2929 lwkt_gettoken(&vm_token); 2930 2931 if (curthread == pagethread || 2932 curthread == emergpager) { 2933 /* 2934 * The pageout daemon itself needs pages, this is bad. 2935 */ 2936 if (vm_paging_min()) { 2937 vm_pageout_pages_needed = 1; 2938 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo); 2939 } 2940 } else { 2941 /* 2942 * Wakeup the pageout daemon if necessary and wait. 2943 * 2944 * Do not wait indefinitely for the target to be reached, 2945 * as load might prevent it from being reached any time soon. 2946 * But wait a little to try to slow down page allocations 2947 * and to give more important threads (the pagedaemon) 2948 * allocation priority. 2949 * 2950 * The vm_paging_min() test is a safety. 2951 * 2952 * I/O waits are given a slightly lower priority (higher nice) 2953 * than VM waits. 2954 */ 2955 int nice; 2956 2957 nice = curthread->td_proc ? curthread->td_proc->p_nice : 0; 2958 /*if (vm_paging_wait() || vm_paging_min())*/ 2959 if (vm_paging_min_nice(nice + 1)) 2960 { 2961 if (vm_pages_needed <= 1) { 2962 ++vm_pages_needed; 2963 wakeup(&vm_pages_needed); 2964 } 2965 ++vm_pages_waiting; /* SMP race ok */ 2966 tsleep(&vmstats.v_free_count, 0, "vmwait", timo); 2967 } 2968 } 2969 lwkt_reltoken(&vm_token); 2970 } 2971 2972 /* 2973 * Block until free pages are available for allocation, called in the 2974 * page-fault code. We must stall indefinitely (except for certain 2975 * conditions) when the free page count becomes severe. 2976 * 2977 * Called only from vm_fault so that processes page faulting can be 2978 * easily tracked. 2979 * 2980 * The process nice value determines the trip point. This way niced 2981 * processes which are heavy memory users do not completely mess the 2982 * machine up for normal processes. 2983 */ 2984 void 2985 vm_wait_pfault(void) 2986 { 2987 int nice; 2988 2989 /* 2990 * Wakeup the pageout daemon if necessary and wait. 2991 * 2992 * Allow VM faults down to the minimum free page count, but only 2993 * stall once paging becomes severe. 2994 * 2995 * Do not wait indefinitely for the target to be reached, 2996 * as load might prevent it from being reached any time soon. 2997 * But wait a little to try to slow down page allocations 2998 * and to give more important threads (the pagedaemon) 2999 * allocation priority. 3000 */ 3001 nice = curthread->td_proc ? curthread->td_proc->p_nice : 0; 3002 3003 if (vm_paging_min_nice(nice)) { 3004 lwkt_gettoken(&vm_token); 3005 do { 3006 thread_t td; 3007 3008 if (vm_pages_needed <= 1) { 3009 ++vm_pages_needed; 3010 wakeup(&vm_pages_needed); 3011 } 3012 ++vm_pages_waiting; /* SMP race ok */ 3013 tsleep(&vmstats.v_free_count, 0, "pfault", 3014 hz / 10 + 1); 3015 3016 /* 3017 * Do not stay stuck in the loop if the system 3018 * is trying to kill the process. 3019 */ 3020 td = curthread; 3021 if (td->td_proc && 3022 (td->td_proc->p_flags & P_LOWMEMKILL)) 3023 { 3024 break; 3025 } 3026 } while (vm_paging_severe()); 3027 lwkt_reltoken(&vm_token); 3028 } 3029 } 3030 3031 /* 3032 * Put the specified page on the active list (if appropriate). Ensure 3033 * that act_count is at least ACT_INIT but do not otherwise mess with it. 3034 * 3035 * The caller should be holding the page busied ? XXX 3036 * This routine may not block. 3037 * 3038 * It is ok if the page is wired (so buffer cache operations don't have 3039 * to mess with the page queues). 3040 */ 3041 void 3042 vm_page_activate(vm_page_t m) 3043 { 3044 u_short oqueue; 3045 3046 /* 3047 * If already active or inappropriate, just set act_count and 3048 * return. We don't have to spin-lock the page. 3049 */ 3050 if (m->queue - m->pc == PQ_ACTIVE || 3051 (m->flags & (PG_FICTITIOUS | PG_UNQUEUED))) { 3052 if (m->act_count < ACT_INIT) 3053 m->act_count = ACT_INIT; 3054 return; 3055 } 3056 3057 vm_page_spin_lock(m); 3058 if (m->queue - m->pc != PQ_ACTIVE && 3059 (m->flags & (PG_FICTITIOUS | PG_UNQUEUED)) == 0) { 3060 _vm_page_queue_spin_lock(m); 3061 oqueue = _vm_page_rem_queue_spinlocked(m); 3062 /* page is left spinlocked, queue is unlocked */ 3063 3064 if (oqueue == PQ_CACHE) 3065 mycpu->gd_cnt.v_reactivated++; 3066 if (m->act_count < ACT_INIT) 3067 m->act_count = ACT_INIT; 3068 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); 3069 _vm_page_and_queue_spin_unlock(m); 3070 if (oqueue == PQ_CACHE || oqueue == PQ_FREE) 3071 pagedaemon_wakeup(); 3072 } else { 3073 if (m->act_count < ACT_INIT) 3074 m->act_count = ACT_INIT; 3075 vm_page_spin_unlock(m); 3076 } 3077 } 3078 3079 void 3080 vm_page_soft_activate(vm_page_t m) 3081 { 3082 if (m->queue - m->pc == PQ_ACTIVE || 3083 (m->flags & (PG_FICTITIOUS | PG_UNQUEUED))) { 3084 if (m->act_count < ACT_INIT) 3085 m->act_count = ACT_INIT; 3086 } else { 3087 vm_page_activate(m); 3088 } 3089 } 3090 3091 /* 3092 * Helper routine for vm_page_free_toq() and vm_page_cache(). This 3093 * routine is called when a page has been added to the cache or free 3094 * queues. 3095 * 3096 * This routine may not block. 3097 */ 3098 static __inline void 3099 vm_page_free_wakeup(void) 3100 { 3101 globaldata_t gd = mycpu; 3102 3103 /* 3104 * If the pageout daemon itself needs pages, then tell it that 3105 * there are some free. 3106 */ 3107 if (vm_pageout_pages_needed && 3108 gd->gd_vmstats.v_cache_count + gd->gd_vmstats.v_free_count >= 3109 gd->gd_vmstats.v_pageout_free_min 3110 ) { 3111 vm_pageout_pages_needed = 0; 3112 wakeup(&vm_pageout_pages_needed); 3113 } 3114 3115 /* 3116 * Wakeup processes that are waiting on memory. 3117 * 3118 * Generally speaking we want to wakeup stuck processes as soon as 3119 * possible. !vm_page_count_min(0) is the absolute minimum point 3120 * where we can do this. Wait a bit longer to reduce degenerate 3121 * re-blocking (vm_page_free_hysteresis). 3122 * 3123 * The target check is a safety to make sure the min-check 3124 * w/hysteresis does not exceed the normal target1. 3125 */ 3126 if (vm_pages_waiting) { 3127 if (!vm_paging_min_dnc(vm_page_free_hysteresis) || 3128 !vm_paging_target1()) 3129 { 3130 vm_pages_waiting = 0; 3131 wakeup(&vmstats.v_free_count); 3132 ++mycpu->gd_cnt.v_ppwakeups; 3133 } 3134 } 3135 } 3136 3137 /* 3138 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates 3139 * it from its VM object. 3140 * 3141 * The vm_page must be BUSY on entry. BUSY will be released on 3142 * return (the page will have been freed). 3143 */ 3144 void 3145 vm_page_free_toq(vm_page_t m) 3146 { 3147 /* 3148 * The page must not be mapped when freed, but we may have to call 3149 * pmap_mapped_sync() to validate this. 3150 */ 3151 mycpu->gd_cnt.v_tfree++; 3152 if (m->flags & (PG_MAPPED | PG_WRITEABLE)) 3153 pmap_mapped_sync(m); 3154 KKASSERT((m->flags & PG_MAPPED) == 0); 3155 KKASSERT(m->busy_count & PBUSY_LOCKED); 3156 3157 if ((m->busy_count & PBUSY_MASK) || ((m->queue - m->pc) == PQ_FREE)) { 3158 kprintf("vm_page_free: pindex(%lu), busy %08x, " 3159 "hold(%d)\n", 3160 (u_long)m->pindex, m->busy_count, m->hold_count); 3161 if ((m->queue - m->pc) == PQ_FREE) 3162 panic("vm_page_free: freeing free page"); 3163 else 3164 panic("vm_page_free: freeing busy page"); 3165 } 3166 3167 /* 3168 * Remove from object, spinlock the page and its queues and 3169 * remove from any queue. No queue spinlock will be held 3170 * after this section (because the page was removed from any 3171 * queue). 3172 */ 3173 vm_page_remove(m); 3174 3175 /* 3176 * No further management of fictitious pages occurs beyond object 3177 * and queue removal. 3178 */ 3179 if ((m->flags & PG_FICTITIOUS) != 0) { 3180 KKASSERT(m->queue == PQ_NONE); 3181 vm_page_wakeup(m); 3182 return; 3183 } 3184 vm_page_and_queue_spin_lock(m); 3185 _vm_page_rem_queue_spinlocked(m); 3186 3187 m->valid = 0; 3188 vm_page_undirty(m); 3189 3190 if (m->wire_count != 0) { 3191 if (m->wire_count > 1) { 3192 panic( 3193 "vm_page_free: invalid wire count (%d), pindex: 0x%lx", 3194 m->wire_count, (long)m->pindex); 3195 } 3196 panic("vm_page_free: freeing wired page"); 3197 } 3198 3199 if (!MD_PAGE_FREEABLE(m)) 3200 panic("vm_page_free: page %p is still mapped!", m); 3201 3202 /* 3203 * Clear the PG_NEED_COMMIT and the PG_UNQUEUED flags. The 3204 * page returns to normal operation and will be placed in 3205 * the PQ_HOLD or PQ_FREE queue. 3206 */ 3207 vm_page_flag_clear(m, PG_NEED_COMMIT | PG_UNQUEUED); 3208 3209 if (m->hold_count != 0) { 3210 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); 3211 } else { 3212 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 1); 3213 } 3214 3215 /* 3216 * This sequence allows us to clear BUSY while still holding 3217 * its spin lock, which reduces contention vs allocators. We 3218 * must not leave the queue locked or _vm_page_wakeup() may 3219 * deadlock. 3220 */ 3221 _vm_page_queue_spin_unlock(m); 3222 if (_vm_page_wakeup(m)) { 3223 vm_page_spin_unlock(m); 3224 wakeup(m); 3225 } else { 3226 vm_page_spin_unlock(m); 3227 } 3228 vm_page_free_wakeup(); 3229 } 3230 3231 /* 3232 * Mark this page as wired down by yet another map. We do not adjust the 3233 * queue the page is on, it will be checked for wiring as-needed. 3234 * 3235 * This function has no effect on fictitious pages. 3236 * 3237 * Caller must be holding the page busy. 3238 */ 3239 void 3240 vm_page_wire(vm_page_t m) 3241 { 3242 KKASSERT(m->busy_count & PBUSY_LOCKED); 3243 if ((m->flags & PG_FICTITIOUS) == 0) { 3244 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) { 3245 atomic_add_long(&mycpu->gd_vmstats_adj.v_wire_count, 1); 3246 } 3247 KASSERT(m->wire_count != 0, 3248 ("vm_page_wire: wire_count overflow m=%p", m)); 3249 } 3250 } 3251 3252 /* 3253 * Release one wiring of this page, potentially enabling it to be paged again. 3254 * 3255 * Note that wired pages are no longer unconditionally removed from the 3256 * paging queues, so the page may already be on a queue. Move the page 3257 * to the desired queue if necessary. 3258 * 3259 * Many pages placed on the inactive queue should actually go 3260 * into the cache, but it is difficult to figure out which. What 3261 * we do instead, if the inactive target is well met, is to put 3262 * clean pages at the head of the inactive queue instead of the tail. 3263 * This will cause them to be moved to the cache more quickly and 3264 * if not actively re-referenced, freed more quickly. If we just 3265 * stick these pages at the end of the inactive queue, heavy filesystem 3266 * meta-data accesses can cause an unnecessary paging load on memory bound 3267 * processes. This optimization causes one-time-use metadata to be 3268 * reused more quickly. 3269 * 3270 * Pages marked PG_NEED_COMMIT are always activated and never placed on 3271 * the inactive queue. This helps the pageout daemon determine memory 3272 * pressure and act on out-of-memory situations more quickly. 3273 * 3274 * BUT, if we are in a low-memory situation we have no choice but to 3275 * put clean pages on the cache queue. 3276 * 3277 * A number of routines use vm_page_unwire() to guarantee that the page 3278 * will go into either the inactive or active queues, and will NEVER 3279 * be placed in the cache - for example, just after dirtying a page. 3280 * dirty pages in the cache are not allowed. 3281 * 3282 * PG_FICTITIOUS or PG_UNQUEUED pages are never moved to any queue, and 3283 * the wire_count will not be adjusted in any way for a PG_FICTITIOUS 3284 * page. 3285 * 3286 * This routine may not block. 3287 */ 3288 void 3289 vm_page_unwire(vm_page_t m, int activate) 3290 { 3291 KKASSERT(m->busy_count & PBUSY_LOCKED); 3292 if (m->flags & PG_FICTITIOUS) { 3293 /* do nothing */ 3294 } else if ((int)m->wire_count <= 0) { 3295 panic("vm_page_unwire: invalid wire count: %d", m->wire_count); 3296 } else { 3297 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) { 3298 atomic_add_long(&mycpu->gd_vmstats_adj.v_wire_count,-1); 3299 if (m->flags & PG_UNQUEUED) { 3300 ; 3301 } else if (activate || (m->flags & PG_NEED_COMMIT)) { 3302 vm_page_activate(m); 3303 } else { 3304 vm_page_deactivate(m); 3305 } 3306 } 3307 } 3308 } 3309 3310 /* 3311 * Move the specified page to the inactive queue. 3312 * 3313 * Normally athead is 0 resulting in LRU operation. athead is set 3314 * to 1 if we want this page to be 'as if it were placed in the cache', 3315 * except without unmapping it from the process address space. 3316 * 3317 * vm_page's spinlock must be held on entry and will remain held on return. 3318 * This routine may not block. The caller does not have to hold the page 3319 * busied but should have some sort of interlock on its validity. 3320 * 3321 * It is ok if the page is wired (so buffer cache operations don't have 3322 * to mess with the page queues). 3323 */ 3324 static void 3325 _vm_page_deactivate_locked(vm_page_t m, int athead) 3326 { 3327 u_short oqueue; 3328 3329 /* 3330 * Ignore if already inactive. 3331 */ 3332 if (m->queue - m->pc == PQ_INACTIVE || 3333 (m->flags & (PG_FICTITIOUS | PG_UNQUEUED))) { 3334 return; 3335 } 3336 3337 _vm_page_queue_spin_lock(m); 3338 oqueue = _vm_page_rem_queue_spinlocked(m); 3339 3340 if ((m->flags & (PG_FICTITIOUS | PG_UNQUEUED)) == 0) { 3341 if (oqueue == PQ_CACHE) 3342 mycpu->gd_cnt.v_reactivated++; 3343 vm_page_flag_clear(m, PG_WINATCFLS); 3344 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead); 3345 if (athead == 0) { 3346 atomic_add_long( 3347 &vm_page_queues[PQ_INACTIVE + m->pc].adds, 1); 3348 } 3349 } 3350 /* NOTE: PQ_NONE if condition not taken */ 3351 _vm_page_queue_spin_unlock(m); 3352 /* leaves vm_page spinlocked */ 3353 } 3354 3355 /* 3356 * Attempt to deactivate a page. 3357 * 3358 * No requirements. We can pre-filter before getting the spinlock. 3359 * 3360 * It is ok if the page is wired (so buffer cache operations don't have 3361 * to mess with the page queues). 3362 */ 3363 void 3364 vm_page_deactivate(vm_page_t m) 3365 { 3366 if (m->queue - m->pc != PQ_INACTIVE && 3367 (m->flags & (PG_FICTITIOUS | PG_UNQUEUED)) == 0) { 3368 vm_page_spin_lock(m); 3369 _vm_page_deactivate_locked(m, 0); 3370 vm_page_spin_unlock(m); 3371 } 3372 } 3373 3374 void 3375 vm_page_deactivate_locked(vm_page_t m) 3376 { 3377 _vm_page_deactivate_locked(m, 0); 3378 } 3379 3380 /* 3381 * Attempt to move a busied page to PQ_CACHE, then unconditionally unbusy it. 3382 * 3383 * This function returns non-zero if it successfully moved the page to 3384 * PQ_CACHE. 3385 * 3386 * This function unconditionally unbusies the page on return. 3387 */ 3388 int 3389 vm_page_try_to_cache(vm_page_t m) 3390 { 3391 /* 3392 * Shortcut if we obviously cannot move the page, or if the 3393 * page is already on the cache queue, or it is ficitious. 3394 * 3395 * Never allow a wired page into the cache. 3396 */ 3397 if (m->dirty || m->hold_count || m->wire_count || 3398 m->queue - m->pc == PQ_CACHE || 3399 (m->flags & (PG_UNQUEUED | PG_NEED_COMMIT | PG_FICTITIOUS))) { 3400 vm_page_wakeup(m); 3401 return(0); 3402 } 3403 3404 /* 3405 * Page busied by us and no longer spinlocked. Dirty pages cannot 3406 * be moved to the cache, but can be deactivated. However, users 3407 * of this function want to move pages closer to the cache so we 3408 * only deactivate it if it is in PQ_ACTIVE. We do not re-deactivate. 3409 */ 3410 vm_page_test_dirty(m); 3411 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 3412 if (m->queue - m->pc == PQ_ACTIVE) 3413 vm_page_deactivate(m); 3414 vm_page_wakeup(m); 3415 return(0); 3416 } 3417 vm_page_cache(m); 3418 return(1); 3419 } 3420 3421 /* 3422 * Attempt to free the page. If we cannot free it, we do nothing. 3423 * 1 is returned on success, 0 on failure. 3424 * 3425 * The page can be in any state, including already being on the free 3426 * queue. Check to see if it really can be freed. Note that we disallow 3427 * this ad-hoc operation if the page is flagged PG_UNQUEUED. 3428 * 3429 * Caller provides an unlocked/non-busied page. 3430 * No requirements. 3431 */ 3432 int 3433 vm_page_try_to_free(vm_page_t m) 3434 { 3435 if (vm_page_busy_try(m, TRUE)) 3436 return(0); 3437 3438 if (m->dirty || /* can't free if it is dirty */ 3439 m->hold_count || /* or held (XXX may be wrong) */ 3440 m->wire_count || /* or wired */ 3441 (m->flags & (PG_UNQUEUED | /* or unqueued */ 3442 PG_NEED_COMMIT | /* or needs a commit */ 3443 PG_FICTITIOUS)) || /* or is fictitious */ 3444 m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */ 3445 m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */ 3446 vm_page_wakeup(m); 3447 return(0); 3448 } 3449 3450 /* 3451 * We can probably free the page. 3452 * 3453 * Page busied by us and no longer spinlocked. Dirty pages will 3454 * not be freed by this function. We have to re-test the 3455 * dirty bit after cleaning out the pmaps. 3456 */ 3457 vm_page_test_dirty(m); 3458 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 3459 vm_page_wakeup(m); 3460 return(0); 3461 } 3462 vm_page_protect(m, VM_PROT_NONE); 3463 if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 3464 vm_page_wakeup(m); 3465 return(0); 3466 } 3467 vm_page_free(m); 3468 return(1); 3469 } 3470 3471 /* 3472 * vm_page_cache 3473 * 3474 * Put the specified page onto the page cache queue (if appropriate). 3475 * 3476 * The page must be busy, and this routine will release the busy and 3477 * possibly even free the page. 3478 */ 3479 void 3480 vm_page_cache(vm_page_t m) 3481 { 3482 /* 3483 * Not suitable for the cache 3484 */ 3485 if ((m->flags & (PG_UNQUEUED | PG_NEED_COMMIT | PG_FICTITIOUS)) || 3486 (m->busy_count & PBUSY_MASK) || 3487 m->wire_count || m->hold_count) { 3488 vm_page_wakeup(m); 3489 return; 3490 } 3491 3492 /* 3493 * Already in the cache (and thus not mapped) 3494 */ 3495 if ((m->queue - m->pc) == PQ_CACHE) { 3496 KKASSERT((m->flags & PG_MAPPED) == 0); 3497 vm_page_wakeup(m); 3498 return; 3499 } 3500 3501 #if 0 3502 /* 3503 * REMOVED - it is possible for dirty to get set at any time as 3504 * long as the page is still mapped and writeable. 3505 * 3506 * Caller is required to test m->dirty, but note that the act of 3507 * removing the page from its maps can cause it to become dirty 3508 * on an SMP system due to another cpu running in usermode. 3509 */ 3510 if (m->dirty) { 3511 panic("vm_page_cache: caching a dirty page, pindex: %ld", 3512 (long)m->pindex); 3513 } 3514 #endif 3515 3516 /* 3517 * Remove all pmaps and indicate that the page is not 3518 * writeable or mapped. Our vm_page_protect() call may 3519 * have blocked (especially w/ VM_PROT_NONE), so recheck 3520 * everything. 3521 */ 3522 if (m->flags & (PG_MAPPED | PG_WRITEABLE)) { 3523 vm_page_protect(m, VM_PROT_NONE); 3524 pmap_mapped_sync(m); 3525 } 3526 if ((m->flags & (PG_UNQUEUED | PG_MAPPED)) || 3527 (m->busy_count & PBUSY_MASK) || 3528 m->wire_count || m->hold_count) { 3529 vm_page_wakeup(m); 3530 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) { 3531 vm_page_deactivate(m); 3532 vm_page_wakeup(m); 3533 } else { 3534 _vm_page_and_queue_spin_lock(m); 3535 _vm_page_rem_queue_spinlocked(m); 3536 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0); 3537 _vm_page_and_queue_spin_unlock(m); 3538 vm_page_wakeup(m); 3539 vm_page_free_wakeup(); 3540 } 3541 } 3542 3543 /* 3544 * vm_page_dontneed() 3545 * 3546 * Cache, deactivate, or do nothing as appropriate. This routine 3547 * is typically used by madvise() MADV_DONTNEED. 3548 * 3549 * Generally speaking we want to move the page into the cache so 3550 * it gets reused quickly. However, this can result in a silly syndrome 3551 * due to the page recycling too quickly. Small objects will not be 3552 * fully cached. On the otherhand, if we move the page to the inactive 3553 * queue we wind up with a problem whereby very large objects 3554 * unnecessarily blow away our inactive and cache queues. 3555 * 3556 * The solution is to move the pages based on a fixed weighting. We 3557 * either leave them alone, deactivate them, or move them to the cache, 3558 * where moving them to the cache has the highest weighting. 3559 * By forcing some pages into other queues we eventually force the 3560 * system to balance the queues, potentially recovering other unrelated 3561 * space from active. The idea is to not force this to happen too 3562 * often. 3563 * 3564 * The page must be busied. 3565 */ 3566 void 3567 vm_page_dontneed(vm_page_t m) 3568 { 3569 static int dnweight; 3570 int dnw; 3571 int head; 3572 3573 dnw = ++dnweight; 3574 3575 /* 3576 * occassionally leave the page alone 3577 */ 3578 if ((dnw & 0x01F0) == 0 || 3579 m->queue - m->pc == PQ_INACTIVE || 3580 m->queue - m->pc == PQ_CACHE 3581 ) { 3582 if (m->act_count >= ACT_INIT) 3583 --m->act_count; 3584 return; 3585 } 3586 3587 /* 3588 * If vm_page_dontneed() is inactivating a page, it must clear 3589 * the referenced flag; otherwise the pagedaemon will see references 3590 * on the page in the inactive queue and reactivate it. Until the 3591 * page can move to the cache queue, madvise's job is not done. 3592 */ 3593 vm_page_flag_clear(m, PG_REFERENCED); 3594 pmap_clear_reference(m); 3595 3596 if (m->dirty == 0) 3597 vm_page_test_dirty(m); 3598 3599 if (m->dirty || (dnw & 0x0070) == 0) { 3600 /* 3601 * Deactivate the page 3 times out of 32. 3602 */ 3603 head = 0; 3604 } else { 3605 /* 3606 * Cache the page 28 times out of every 32. Note that 3607 * the page is deactivated instead of cached, but placed 3608 * at the head of the queue instead of the tail. 3609 */ 3610 head = 1; 3611 } 3612 vm_page_spin_lock(m); 3613 _vm_page_deactivate_locked(m, head); 3614 vm_page_spin_unlock(m); 3615 } 3616 3617 /* 3618 * These routines manipulate the 'soft busy' count for a page. A soft busy 3619 * is almost like a hard BUSY except that it allows certain compatible 3620 * operations to occur on the page while it is busy. For example, a page 3621 * undergoing a write can still be mapped read-only. 3622 * 3623 * We also use soft-busy to quickly pmap_enter shared read-only pages 3624 * without having to hold the page locked. 3625 * 3626 * The soft-busy count can be > 1 in situations where multiple threads 3627 * are pmap_enter()ing the same page simultaneously, or when two buffer 3628 * cache buffers overlap the same page. 3629 * 3630 * The caller must hold the page BUSY when making these two calls. 3631 */ 3632 void 3633 vm_page_io_start(vm_page_t m) 3634 { 3635 uint32_t ocount; 3636 3637 ocount = atomic_fetchadd_int(&m->busy_count, 1); 3638 KKASSERT(ocount & PBUSY_LOCKED); 3639 } 3640 3641 void 3642 vm_page_io_finish(vm_page_t m) 3643 { 3644 uint32_t ocount; 3645 3646 ocount = atomic_fetchadd_int(&m->busy_count, -1); 3647 KKASSERT(ocount & PBUSY_MASK); 3648 #if 0 3649 if (((ocount - 1) & (PBUSY_LOCKED | PBUSY_MASK)) == 0) 3650 wakeup(m); 3651 #endif 3652 } 3653 3654 /* 3655 * Attempt to soft-busy a page. The page must not be PBUSY_LOCKED. 3656 * 3657 * We can't use fetchadd here because we might race a hard-busy and the 3658 * page freeing code asserts on a non-zero soft-busy count (even if only 3659 * temporary). 3660 * 3661 * Returns 0 on success, non-zero on failure. 3662 */ 3663 int 3664 vm_page_sbusy_try(vm_page_t m) 3665 { 3666 uint32_t ocount; 3667 3668 for (;;) { 3669 ocount = m->busy_count; 3670 cpu_ccfence(); 3671 if (ocount & PBUSY_LOCKED) 3672 return 1; 3673 if (atomic_cmpset_int(&m->busy_count, ocount, ocount + 1)) 3674 break; 3675 } 3676 return 0; 3677 #if 0 3678 if (m->busy_count & PBUSY_LOCKED) 3679 return 1; 3680 ocount = atomic_fetchadd_int(&m->busy_count, 1); 3681 if (ocount & PBUSY_LOCKED) { 3682 vm_page_sbusy_drop(m); 3683 return 1; 3684 } 3685 return 0; 3686 #endif 3687 } 3688 3689 /* 3690 * Indicate that a clean VM page requires a filesystem commit and cannot 3691 * be reused. Used by tmpfs. 3692 */ 3693 void 3694 vm_page_need_commit(vm_page_t m) 3695 { 3696 vm_page_flag_set(m, PG_NEED_COMMIT); 3697 vm_object_set_writeable_dirty(m->object); 3698 } 3699 3700 void 3701 vm_page_clear_commit(vm_page_t m) 3702 { 3703 vm_page_flag_clear(m, PG_NEED_COMMIT); 3704 } 3705 3706 /* 3707 * Grab a page, blocking if it is busy and allocating a page if necessary. 3708 * A busy page is returned or NULL. The page may or may not be valid and 3709 * might not be on a queue (the caller is responsible for the disposition of 3710 * the page). 3711 * 3712 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the 3713 * page will be zero'd and marked valid. 3714 * 3715 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked 3716 * valid even if it already exists. 3717 * 3718 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also 3719 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified. 3720 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified. 3721 * 3722 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is 3723 * always returned if we had blocked. 3724 * 3725 * This routine may not be called from an interrupt. 3726 * 3727 * No other requirements. 3728 */ 3729 vm_page_t 3730 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) 3731 { 3732 vm_page_t m; 3733 int error; 3734 int shared = 1; 3735 3736 KKASSERT(allocflags & 3737 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); 3738 vm_object_hold_shared(object); 3739 for (;;) { 3740 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error); 3741 if (error) { 3742 vm_page_sleep_busy(m, TRUE, "pgrbwt"); 3743 if ((allocflags & VM_ALLOC_RETRY) == 0) { 3744 m = NULL; 3745 break; 3746 } 3747 /* retry */ 3748 } else if (m == NULL) { 3749 if (shared) { 3750 vm_object_upgrade(object); 3751 shared = 0; 3752 } 3753 if (allocflags & VM_ALLOC_RETRY) 3754 allocflags |= VM_ALLOC_NULL_OK; 3755 m = vm_page_alloc(object, pindex, 3756 allocflags & ~VM_ALLOC_RETRY); 3757 if (m) 3758 break; 3759 vm_wait(0); 3760 if ((allocflags & VM_ALLOC_RETRY) == 0) 3761 goto failed; 3762 } else { 3763 /* m found */ 3764 break; 3765 } 3766 } 3767 3768 /* 3769 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid. 3770 * 3771 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set 3772 * valid even if already valid. 3773 * 3774 * NOTE! We have removed all of the PG_ZERO optimizations and also 3775 * removed the idle zeroing code. These optimizations actually 3776 * slow things down on modern cpus because the zerod area is 3777 * likely uncached, placing a memory-access burden on the 3778 * accesors taking the fault. 3779 * 3780 * By always zeroing the page in-line with the fault, no 3781 * dynamic ram reads are needed and the caches are hot, ready 3782 * for userland to access the memory. 3783 */ 3784 if (m->valid == 0) { 3785 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) { 3786 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 3787 m->valid = VM_PAGE_BITS_ALL; 3788 } 3789 } else if (allocflags & VM_ALLOC_FORCE_ZERO) { 3790 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 3791 m->valid = VM_PAGE_BITS_ALL; 3792 } 3793 failed: 3794 vm_object_drop(object); 3795 return(m); 3796 } 3797 3798 /* 3799 * Mapping function for valid bits or for dirty bits in 3800 * a page. May not block. 3801 * 3802 * Inputs are required to range within a page. 3803 * 3804 * No requirements. 3805 * Non blocking. 3806 */ 3807 int 3808 vm_page_bits(int base, int size) 3809 { 3810 int first_bit; 3811 int last_bit; 3812 3813 KASSERT( 3814 base + size <= PAGE_SIZE, 3815 ("vm_page_bits: illegal base/size %d/%d", base, size) 3816 ); 3817 3818 if (size == 0) /* handle degenerate case */ 3819 return(0); 3820 3821 first_bit = base >> DEV_BSHIFT; 3822 last_bit = (base + size - 1) >> DEV_BSHIFT; 3823 3824 return ((2 << last_bit) - (1 << first_bit)); 3825 } 3826 3827 /* 3828 * Sets portions of a page valid and clean. The arguments are expected 3829 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive 3830 * of any partial chunks touched by the range. The invalid portion of 3831 * such chunks will be zero'd. 3832 * 3833 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically 3834 * align base to DEV_BSIZE so as not to mark clean a partially 3835 * truncated device block. Otherwise the dirty page status might be 3836 * lost. 3837 * 3838 * This routine may not block. 3839 * 3840 * (base + size) must be less then or equal to PAGE_SIZE. 3841 */ 3842 static void 3843 _vm_page_zero_valid(vm_page_t m, int base, int size) 3844 { 3845 int frag; 3846 int endoff; 3847 3848 if (size == 0) /* handle degenerate case */ 3849 return; 3850 3851 /* 3852 * If the base is not DEV_BSIZE aligned and the valid 3853 * bit is clear, we have to zero out a portion of the 3854 * first block. 3855 */ 3856 3857 if ((frag = rounddown2(base, DEV_BSIZE)) != base && 3858 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 3859 ) { 3860 pmap_zero_page_area( 3861 VM_PAGE_TO_PHYS(m), 3862 frag, 3863 base - frag 3864 ); 3865 } 3866 3867 /* 3868 * If the ending offset is not DEV_BSIZE aligned and the 3869 * valid bit is clear, we have to zero out a portion of 3870 * the last block. 3871 */ 3872 3873 endoff = base + size; 3874 3875 if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff && 3876 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 3877 ) { 3878 pmap_zero_page_area( 3879 VM_PAGE_TO_PHYS(m), 3880 endoff, 3881 DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) 3882 ); 3883 } 3884 } 3885 3886 /* 3887 * Set valid, clear dirty bits. If validating the entire 3888 * page we can safely clear the pmap modify bit. We also 3889 * use this opportunity to clear the PG_NOSYNC flag. If a process 3890 * takes a write fault on a MAP_NOSYNC memory area the flag will 3891 * be set again. 3892 * 3893 * We set valid bits inclusive of any overlap, but we can only 3894 * clear dirty bits for DEV_BSIZE chunks that are fully within 3895 * the range. 3896 * 3897 * Page must be busied? 3898 * No other requirements. 3899 */ 3900 void 3901 vm_page_set_valid(vm_page_t m, int base, int size) 3902 { 3903 _vm_page_zero_valid(m, base, size); 3904 m->valid |= vm_page_bits(base, size); 3905 } 3906 3907 3908 /* 3909 * Set valid bits and clear dirty bits. 3910 * 3911 * Page must be busied by caller. 3912 * 3913 * NOTE: This function does not clear the pmap modified bit. 3914 * Also note that e.g. NFS may use a byte-granular base 3915 * and size. 3916 * 3917 * No other requirements. 3918 */ 3919 void 3920 vm_page_set_validclean(vm_page_t m, int base, int size) 3921 { 3922 int pagebits; 3923 3924 _vm_page_zero_valid(m, base, size); 3925 pagebits = vm_page_bits(base, size); 3926 m->valid |= pagebits; 3927 m->dirty &= ~pagebits; 3928 if (base == 0 && size == PAGE_SIZE) { 3929 /*pmap_clear_modify(m);*/ 3930 vm_page_flag_clear(m, PG_NOSYNC); 3931 } 3932 } 3933 3934 /* 3935 * Set valid & dirty. Used by buwrite() 3936 * 3937 * Page must be busied by caller. 3938 */ 3939 void 3940 vm_page_set_validdirty(vm_page_t m, int base, int size) 3941 { 3942 int pagebits; 3943 3944 pagebits = vm_page_bits(base, size); 3945 m->valid |= pagebits; 3946 m->dirty |= pagebits; 3947 if (m->object) 3948 vm_object_set_writeable_dirty(m->object); 3949 } 3950 3951 /* 3952 * Clear dirty bits. 3953 * 3954 * NOTE: This function does not clear the pmap modified bit. 3955 * Also note that e.g. NFS may use a byte-granular base 3956 * and size. 3957 * 3958 * Page must be busied? 3959 * No other requirements. 3960 */ 3961 void 3962 vm_page_clear_dirty(vm_page_t m, int base, int size) 3963 { 3964 m->dirty &= ~vm_page_bits(base, size); 3965 if (base == 0 && size == PAGE_SIZE) { 3966 /*pmap_clear_modify(m);*/ 3967 vm_page_flag_clear(m, PG_NOSYNC); 3968 } 3969 } 3970 3971 /* 3972 * Make the page all-dirty. 3973 * 3974 * Also make sure the related object and vnode reflect the fact that the 3975 * object may now contain a dirty page. 3976 * 3977 * Page must be busied? 3978 * No other requirements. 3979 */ 3980 void 3981 vm_page_dirty(vm_page_t m) 3982 { 3983 #ifdef INVARIANTS 3984 int pqtype = m->queue - m->pc; 3985 #endif 3986 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE, 3987 ("vm_page_dirty: page in free/cache queue!")); 3988 if (m->dirty != VM_PAGE_BITS_ALL) { 3989 m->dirty = VM_PAGE_BITS_ALL; 3990 if (m->object) 3991 vm_object_set_writeable_dirty(m->object); 3992 } 3993 } 3994 3995 /* 3996 * Invalidates DEV_BSIZE'd chunks within a page. Both the 3997 * valid and dirty bits for the effected areas are cleared. 3998 * 3999 * Page must be busied? 4000 * Does not block. 4001 * No other requirements. 4002 */ 4003 void 4004 vm_page_set_invalid(vm_page_t m, int base, int size) 4005 { 4006 int bits; 4007 4008 bits = vm_page_bits(base, size); 4009 m->valid &= ~bits; 4010 m->dirty &= ~bits; 4011 atomic_add_int(&m->object->generation, 1); 4012 } 4013 4014 /* 4015 * The kernel assumes that the invalid portions of a page contain 4016 * garbage, but such pages can be mapped into memory by user code. 4017 * When this occurs, we must zero out the non-valid portions of the 4018 * page so user code sees what it expects. 4019 * 4020 * Pages are most often semi-valid when the end of a file is mapped 4021 * into memory and the file's size is not page aligned. 4022 * 4023 * Page must be busied? 4024 * No other requirements. 4025 */ 4026 void 4027 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) 4028 { 4029 int b; 4030 int i; 4031 4032 /* 4033 * Scan the valid bits looking for invalid sections that 4034 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the 4035 * valid bit may be set ) have already been zerod by 4036 * vm_page_set_validclean(). 4037 */ 4038 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { 4039 if (i == (PAGE_SIZE / DEV_BSIZE) || 4040 (m->valid & (1 << i)) 4041 ) { 4042 if (i > b) { 4043 pmap_zero_page_area( 4044 VM_PAGE_TO_PHYS(m), 4045 b << DEV_BSHIFT, 4046 (i - b) << DEV_BSHIFT 4047 ); 4048 } 4049 b = i + 1; 4050 } 4051 } 4052 4053 /* 4054 * setvalid is TRUE when we can safely set the zero'd areas 4055 * as being valid. We can do this if there are no cache consistency 4056 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. 4057 */ 4058 if (setvalid) 4059 m->valid = VM_PAGE_BITS_ALL; 4060 } 4061 4062 /* 4063 * Is a (partial) page valid? Note that the case where size == 0 4064 * will return FALSE in the degenerate case where the page is entirely 4065 * invalid, and TRUE otherwise. 4066 * 4067 * Does not block. 4068 * No other requirements. 4069 */ 4070 int 4071 vm_page_is_valid(vm_page_t m, int base, int size) 4072 { 4073 int bits = vm_page_bits(base, size); 4074 4075 if (m->valid && ((m->valid & bits) == bits)) 4076 return 1; 4077 else 4078 return 0; 4079 } 4080 4081 /* 4082 * Update dirty bits from pmap/mmu. May not block. 4083 * 4084 * Caller must hold the page busy 4085 * 4086 * WARNING! Unless the page has been unmapped, this function only 4087 * provides a likely dirty status. 4088 */ 4089 void 4090 vm_page_test_dirty(vm_page_t m) 4091 { 4092 if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m)) { 4093 vm_page_dirty(m); 4094 } 4095 } 4096 4097 #include "opt_ddb.h" 4098 #ifdef DDB 4099 #include <ddb/ddb.h> 4100 4101 DB_SHOW_COMMAND(page, vm_page_print_page_info) 4102 { 4103 db_printf("vmstats.v_free_count: %ld\n", vmstats.v_free_count); 4104 db_printf("vmstats.v_cache_count: %ld\n", vmstats.v_cache_count); 4105 db_printf("vmstats.v_inactive_count: %ld\n", vmstats.v_inactive_count); 4106 db_printf("vmstats.v_active_count: %ld\n", vmstats.v_active_count); 4107 db_printf("vmstats.v_wire_count: %ld\n", vmstats.v_wire_count); 4108 db_printf("vmstats.v_free_reserved: %ld\n", vmstats.v_free_reserved); 4109 db_printf("vmstats.v_free_min: %ld\n", vmstats.v_free_min); 4110 db_printf("vmstats.v_free_target: %ld\n", vmstats.v_free_target); 4111 db_printf("vmstats.v_inactive_target: %ld\n", 4112 vmstats.v_inactive_target); 4113 db_printf("vmstats.v_paging_wait: %ld\n", vmstats.v_paging_wait); 4114 db_printf("vmstats.v_paging_start: %ld\n", vmstats.v_paging_start); 4115 db_printf("vmstats.v_paging_target1: %ld\n", vmstats.v_paging_target1); 4116 db_printf("vmstats.v_paging_target2: %ld\n", vmstats.v_paging_target2); 4117 } 4118 4119 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) 4120 { 4121 int i; 4122 db_printf("PQ_FREE:"); 4123 for (i = 0; i < PQ_L2_SIZE; i++) { 4124 db_printf(" %ld", vm_page_queues[PQ_FREE + i].lcnt); 4125 } 4126 db_printf("\n"); 4127 4128 db_printf("PQ_CACHE:"); 4129 for(i = 0; i < PQ_L2_SIZE; i++) { 4130 db_printf(" %ld", vm_page_queues[PQ_CACHE + i].lcnt); 4131 } 4132 db_printf("\n"); 4133 4134 db_printf("PQ_ACTIVE:"); 4135 for(i = 0; i < PQ_L2_SIZE; i++) { 4136 db_printf(" %ld", vm_page_queues[PQ_ACTIVE + i].lcnt); 4137 } 4138 db_printf("\n"); 4139 4140 db_printf("PQ_INACTIVE:"); 4141 for(i = 0; i < PQ_L2_SIZE; i++) { 4142 db_printf(" %ld", vm_page_queues[PQ_INACTIVE + i].lcnt); 4143 } 4144 db_printf("\n"); 4145 } 4146 #endif /* DDB */ 4147