1 /* $NetBSD: uvm_page.c,v 1.71 2001/11/10 07:37:00 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * Copyright (c) 1991, 1993, The Regents of the University of California. 6 * 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * The Mach Operating System project at Carnegie-Mellon University. 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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by Charles D. Cranor, 23 * Washington University, the University of California, Berkeley and 24 * its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)vm_page.c 8.3 (Berkeley) 3/21/94 42 * from: Id: uvm_page.c,v 1.1.2.18 1998/02/06 05:24:42 chs Exp 43 * 44 * 45 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 46 * All rights reserved. 47 * 48 * Permission to use, copy, modify and distribute this software and 49 * its documentation is hereby granted, provided that both the copyright 50 * notice and this permission notice appear in all copies of the 51 * software, derivative works or modified versions, and any portions 52 * thereof, and that both notices appear in supporting documentation. 53 * 54 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 55 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 56 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 57 * 58 * Carnegie Mellon requests users of this software to return to 59 * 60 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 61 * School of Computer Science 62 * Carnegie Mellon University 63 * Pittsburgh PA 15213-3890 64 * 65 * any improvements or extensions that they make and grant Carnegie the 66 * rights to redistribute these changes. 67 */ 68 69 /* 70 * uvm_page.c: page ops. 71 */ 72 73 #include <sys/cdefs.h> 74 __KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.71 2001/11/10 07:37:00 lukem Exp $"); 75 76 #include "opt_uvmhist.h" 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/malloc.h> 81 #include <sys/sched.h> 82 #include <sys/kernel.h> 83 #include <sys/vnode.h> 84 #include <sys/proc.h> 85 86 #define UVM_PAGE /* pull in uvm_page.h functions */ 87 #include <uvm/uvm.h> 88 89 /* 90 * global vars... XXXCDC: move to uvm. structure. 91 */ 92 93 /* 94 * physical memory config is stored in vm_physmem. 95 */ 96 97 struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; /* XXXCDC: uvm.physmem */ 98 int vm_nphysseg = 0; /* XXXCDC: uvm.nphysseg */ 99 100 /* 101 * Some supported CPUs in a given architecture don't support all 102 * of the things necessary to do idle page zero'ing efficiently. 103 * We therefore provide a way to disable it from machdep code here. 104 */ 105 /* 106 * XXX disabled until we can find a way to do this without causing 107 * problems for either cpu caches or DMA latency. 108 */ 109 boolean_t vm_page_zero_enable = FALSE; 110 111 /* 112 * local variables 113 */ 114 115 /* 116 * these variables record the values returned by vm_page_bootstrap, 117 * for debugging purposes. The implementation of uvm_pageboot_alloc 118 * and pmap_startup here also uses them internally. 119 */ 120 121 static vaddr_t virtual_space_start; 122 static vaddr_t virtual_space_end; 123 124 /* 125 * we use a hash table with only one bucket during bootup. we will 126 * later rehash (resize) the hash table once the allocator is ready. 127 * we static allocate the one bootstrap bucket below... 128 */ 129 130 static struct pglist uvm_bootbucket; 131 132 /* 133 * we allocate an initial number of page colors in uvm_page_init(), 134 * and remember them. We may re-color pages as cache sizes are 135 * discovered during the autoconfiguration phase. But we can never 136 * free the initial set of buckets, since they are allocated using 137 * uvm_pageboot_alloc(). 138 */ 139 140 static boolean_t have_recolored_pages /* = FALSE */; 141 142 /* 143 * local prototypes 144 */ 145 146 static void uvm_pageinsert __P((struct vm_page *)); 147 static void uvm_pageremove __P((struct vm_page *)); 148 149 /* 150 * inline functions 151 */ 152 153 /* 154 * uvm_pageinsert: insert a page in the object and the hash table 155 * 156 * => caller must lock object 157 * => caller must lock page queues 158 * => call should have already set pg's object and offset pointers 159 * and bumped the version counter 160 */ 161 162 __inline static void 163 uvm_pageinsert(pg) 164 struct vm_page *pg; 165 { 166 struct pglist *buck; 167 struct uvm_object *uobj = pg->uobject; 168 169 KASSERT((pg->flags & PG_TABLED) == 0); 170 buck = &uvm.page_hash[uvm_pagehash(uobj, pg->offset)]; 171 simple_lock(&uvm.hashlock); 172 TAILQ_INSERT_TAIL(buck, pg, hashq); 173 simple_unlock(&uvm.hashlock); 174 175 TAILQ_INSERT_TAIL(&uobj->memq, pg, listq); 176 pg->flags |= PG_TABLED; 177 uobj->uo_npages++; 178 } 179 180 /* 181 * uvm_page_remove: remove page from object and hash 182 * 183 * => caller must lock object 184 * => caller must lock page queues 185 */ 186 187 static __inline void 188 uvm_pageremove(pg) 189 struct vm_page *pg; 190 { 191 struct pglist *buck; 192 struct uvm_object *uobj = pg->uobject; 193 194 KASSERT(pg->flags & PG_TABLED); 195 buck = &uvm.page_hash[uvm_pagehash(uobj ,pg->offset)]; 196 simple_lock(&uvm.hashlock); 197 TAILQ_REMOVE(buck, pg, hashq); 198 simple_unlock(&uvm.hashlock); 199 200 if (UVM_OBJ_IS_VTEXT(uobj)) { 201 uvmexp.vtextpages--; 202 } else if (UVM_OBJ_IS_VNODE(uobj)) { 203 uvmexp.vnodepages--; 204 } 205 206 /* object should be locked */ 207 uobj->uo_npages--; 208 TAILQ_REMOVE(&uobj->memq, pg, listq); 209 pg->flags &= ~PG_TABLED; 210 pg->uobject = NULL; 211 } 212 213 static void 214 uvm_page_init_buckets(struct pgfreelist *pgfl) 215 { 216 int color, i; 217 218 for (color = 0; color < uvmexp.ncolors; color++) { 219 for (i = 0; i < PGFL_NQUEUES; i++) { 220 TAILQ_INIT(&pgfl->pgfl_buckets[ 221 color].pgfl_queues[i]); 222 } 223 } 224 } 225 226 /* 227 * uvm_page_init: init the page system. called from uvm_init(). 228 * 229 * => we return the range of kernel virtual memory in kvm_startp/kvm_endp 230 */ 231 232 void 233 uvm_page_init(kvm_startp, kvm_endp) 234 vaddr_t *kvm_startp, *kvm_endp; 235 { 236 vsize_t freepages, pagecount, bucketcount, n; 237 struct pgflbucket *bucketarray; 238 struct vm_page *pagearray; 239 int lcv, i; 240 paddr_t paddr; 241 242 /* 243 * init the page queues and page queue locks, except the free 244 * list; we allocate that later (with the initial vm_page 245 * structures). 246 */ 247 248 TAILQ_INIT(&uvm.page_active); 249 TAILQ_INIT(&uvm.page_inactive); 250 simple_lock_init(&uvm.pageqlock); 251 simple_lock_init(&uvm.fpageqlock); 252 253 /* 254 * init the <obj,offset> => <page> hash table. for now 255 * we just have one bucket (the bootstrap bucket). later on we 256 * will allocate new buckets as we dynamically resize the hash table. 257 */ 258 259 uvm.page_nhash = 1; /* 1 bucket */ 260 uvm.page_hashmask = 0; /* mask for hash function */ 261 uvm.page_hash = &uvm_bootbucket; /* install bootstrap bucket */ 262 TAILQ_INIT(uvm.page_hash); /* init hash table */ 263 simple_lock_init(&uvm.hashlock); /* init hash table lock */ 264 265 /* 266 * allocate vm_page structures. 267 */ 268 269 /* 270 * sanity check: 271 * before calling this function the MD code is expected to register 272 * some free RAM with the uvm_page_physload() function. our job 273 * now is to allocate vm_page structures for this memory. 274 */ 275 276 if (vm_nphysseg == 0) 277 panic("uvm_page_bootstrap: no memory pre-allocated"); 278 279 /* 280 * first calculate the number of free pages... 281 * 282 * note that we use start/end rather than avail_start/avail_end. 283 * this allows us to allocate extra vm_page structures in case we 284 * want to return some memory to the pool after booting. 285 */ 286 287 freepages = 0; 288 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 289 freepages += (vm_physmem[lcv].end - vm_physmem[lcv].start); 290 291 /* 292 * Let MD code initialize the number of colors, or default 293 * to 1 color if MD code doesn't care. 294 */ 295 if (uvmexp.ncolors == 0) 296 uvmexp.ncolors = 1; 297 uvmexp.colormask = uvmexp.ncolors - 1; 298 299 /* 300 * we now know we have (PAGE_SIZE * freepages) bytes of memory we can 301 * use. for each page of memory we use we need a vm_page structure. 302 * thus, the total number of pages we can use is the total size of 303 * the memory divided by the PAGE_SIZE plus the size of the vm_page 304 * structure. we add one to freepages as a fudge factor to avoid 305 * truncation errors (since we can only allocate in terms of whole 306 * pages). 307 */ 308 309 bucketcount = uvmexp.ncolors * VM_NFREELIST; 310 pagecount = ((freepages + 1) << PAGE_SHIFT) / 311 (PAGE_SIZE + sizeof(struct vm_page)); 312 313 bucketarray = (void *)uvm_pageboot_alloc((bucketcount * 314 sizeof(struct pgflbucket)) + (pagecount * 315 sizeof(struct vm_page))); 316 pagearray = (struct vm_page *)(bucketarray + bucketcount); 317 318 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 319 uvm.page_free[lcv].pgfl_buckets = 320 (bucketarray + (lcv * uvmexp.ncolors)); 321 uvm_page_init_buckets(&uvm.page_free[lcv]); 322 } 323 memset(pagearray, 0, pagecount * sizeof(struct vm_page)); 324 325 /* 326 * init the vm_page structures and put them in the correct place. 327 */ 328 329 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 330 n = vm_physmem[lcv].end - vm_physmem[lcv].start; 331 332 /* set up page array pointers */ 333 vm_physmem[lcv].pgs = pagearray; 334 pagearray += n; 335 pagecount -= n; 336 vm_physmem[lcv].lastpg = vm_physmem[lcv].pgs + (n - 1); 337 338 /* init and free vm_pages (we've already zeroed them) */ 339 paddr = ptoa(vm_physmem[lcv].start); 340 for (i = 0 ; i < n ; i++, paddr += PAGE_SIZE) { 341 vm_physmem[lcv].pgs[i].phys_addr = paddr; 342 #ifdef __HAVE_VM_PAGE_MD 343 VM_MDPAGE_INIT(&vm_physmem[lcv].pgs[i]); 344 #endif 345 if (atop(paddr) >= vm_physmem[lcv].avail_start && 346 atop(paddr) <= vm_physmem[lcv].avail_end) { 347 uvmexp.npages++; 348 /* add page to free pool */ 349 uvm_pagefree(&vm_physmem[lcv].pgs[i]); 350 } 351 } 352 } 353 354 /* 355 * pass up the values of virtual_space_start and 356 * virtual_space_end (obtained by uvm_pageboot_alloc) to the upper 357 * layers of the VM. 358 */ 359 360 *kvm_startp = round_page(virtual_space_start); 361 *kvm_endp = trunc_page(virtual_space_end); 362 363 /* 364 * init locks for kernel threads 365 */ 366 367 simple_lock_init(&uvm.pagedaemon_lock); 368 simple_lock_init(&uvm.aiodoned_lock); 369 370 /* 371 * init various thresholds. 372 * XXXCDC - values may need adjusting 373 */ 374 375 uvmexp.reserve_pagedaemon = 1; 376 uvmexp.reserve_kernel = 5; 377 uvmexp.anonminpct = 10; 378 uvmexp.vnodeminpct = 10; 379 uvmexp.vtextminpct = 5; 380 uvmexp.anonmin = uvmexp.anonminpct * 256 / 100; 381 uvmexp.vnodemin = uvmexp.vnodeminpct * 256 / 100; 382 uvmexp.vtextmin = uvmexp.vtextminpct * 256 / 100; 383 384 /* 385 * determine if we should zero pages in the idle loop. 386 */ 387 388 uvm.page_idle_zero = vm_page_zero_enable; 389 390 /* 391 * done! 392 */ 393 394 uvm.page_init_done = TRUE; 395 } 396 397 /* 398 * uvm_setpagesize: set the page size 399 * 400 * => sets page_shift and page_mask from uvmexp.pagesize. 401 */ 402 403 void 404 uvm_setpagesize() 405 { 406 if (uvmexp.pagesize == 0) 407 uvmexp.pagesize = DEFAULT_PAGE_SIZE; 408 uvmexp.pagemask = uvmexp.pagesize - 1; 409 if ((uvmexp.pagemask & uvmexp.pagesize) != 0) 410 panic("uvm_setpagesize: page size not a power of two"); 411 for (uvmexp.pageshift = 0; ; uvmexp.pageshift++) 412 if ((1 << uvmexp.pageshift) == uvmexp.pagesize) 413 break; 414 } 415 416 /* 417 * uvm_pageboot_alloc: steal memory from physmem for bootstrapping 418 */ 419 420 vaddr_t 421 uvm_pageboot_alloc(size) 422 vsize_t size; 423 { 424 static boolean_t initialized = FALSE; 425 vaddr_t addr; 426 #if !defined(PMAP_STEAL_MEMORY) 427 vaddr_t vaddr; 428 paddr_t paddr; 429 #endif 430 431 /* 432 * on first call to this function, initialize ourselves. 433 */ 434 if (initialized == FALSE) { 435 pmap_virtual_space(&virtual_space_start, &virtual_space_end); 436 437 /* round it the way we like it */ 438 virtual_space_start = round_page(virtual_space_start); 439 virtual_space_end = trunc_page(virtual_space_end); 440 441 initialized = TRUE; 442 } 443 444 /* round to page size */ 445 size = round_page(size); 446 447 #if defined(PMAP_STEAL_MEMORY) 448 449 /* 450 * defer bootstrap allocation to MD code (it may want to allocate 451 * from a direct-mapped segment). pmap_steal_memory should adjust 452 * virtual_space_start/virtual_space_end if necessary. 453 */ 454 455 addr = pmap_steal_memory(size, &virtual_space_start, 456 &virtual_space_end); 457 458 return(addr); 459 460 #else /* !PMAP_STEAL_MEMORY */ 461 462 /* 463 * allocate virtual memory for this request 464 */ 465 if (virtual_space_start == virtual_space_end || 466 (virtual_space_end - virtual_space_start) < size) 467 panic("uvm_pageboot_alloc: out of virtual space"); 468 469 addr = virtual_space_start; 470 471 #ifdef PMAP_GROWKERNEL 472 /* 473 * If the kernel pmap can't map the requested space, 474 * then allocate more resources for it. 475 */ 476 if (uvm_maxkaddr < (addr + size)) { 477 uvm_maxkaddr = pmap_growkernel(addr + size); 478 if (uvm_maxkaddr < (addr + size)) 479 panic("uvm_pageboot_alloc: pmap_growkernel() failed"); 480 } 481 #endif 482 483 virtual_space_start += size; 484 485 /* 486 * allocate and mapin physical pages to back new virtual pages 487 */ 488 489 for (vaddr = round_page(addr) ; vaddr < addr + size ; 490 vaddr += PAGE_SIZE) { 491 492 if (!uvm_page_physget(&paddr)) 493 panic("uvm_pageboot_alloc: out of memory"); 494 495 /* 496 * Note this memory is no longer managed, so using 497 * pmap_kenter is safe. 498 */ 499 pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE); 500 } 501 pmap_update(pmap_kernel()); 502 return(addr); 503 #endif /* PMAP_STEAL_MEMORY */ 504 } 505 506 #if !defined(PMAP_STEAL_MEMORY) 507 /* 508 * uvm_page_physget: "steal" one page from the vm_physmem structure. 509 * 510 * => attempt to allocate it off the end of a segment in which the "avail" 511 * values match the start/end values. if we can't do that, then we 512 * will advance both values (making them equal, and removing some 513 * vm_page structures from the non-avail area). 514 * => return false if out of memory. 515 */ 516 517 /* subroutine: try to allocate from memory chunks on the specified freelist */ 518 static boolean_t uvm_page_physget_freelist __P((paddr_t *, int)); 519 520 static boolean_t 521 uvm_page_physget_freelist(paddrp, freelist) 522 paddr_t *paddrp; 523 int freelist; 524 { 525 int lcv, x; 526 527 /* pass 1: try allocating from a matching end */ 528 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 529 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 530 #else 531 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 532 #endif 533 { 534 535 if (uvm.page_init_done == TRUE) 536 panic("uvm_page_physget: called _after_ bootstrap"); 537 538 if (vm_physmem[lcv].free_list != freelist) 539 continue; 540 541 /* try from front */ 542 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].start && 543 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 544 *paddrp = ptoa(vm_physmem[lcv].avail_start); 545 vm_physmem[lcv].avail_start++; 546 vm_physmem[lcv].start++; 547 /* nothing left? nuke it */ 548 if (vm_physmem[lcv].avail_start == 549 vm_physmem[lcv].end) { 550 if (vm_nphysseg == 1) 551 panic("vum_page_physget: out of memory!"); 552 vm_nphysseg--; 553 for (x = lcv ; x < vm_nphysseg ; x++) 554 /* structure copy */ 555 vm_physmem[x] = vm_physmem[x+1]; 556 } 557 return (TRUE); 558 } 559 560 /* try from rear */ 561 if (vm_physmem[lcv].avail_end == vm_physmem[lcv].end && 562 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 563 *paddrp = ptoa(vm_physmem[lcv].avail_end - 1); 564 vm_physmem[lcv].avail_end--; 565 vm_physmem[lcv].end--; 566 /* nothing left? nuke it */ 567 if (vm_physmem[lcv].avail_end == 568 vm_physmem[lcv].start) { 569 if (vm_nphysseg == 1) 570 panic("uvm_page_physget: out of memory!"); 571 vm_nphysseg--; 572 for (x = lcv ; x < vm_nphysseg ; x++) 573 /* structure copy */ 574 vm_physmem[x] = vm_physmem[x+1]; 575 } 576 return (TRUE); 577 } 578 } 579 580 /* pass2: forget about matching ends, just allocate something */ 581 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 582 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 583 #else 584 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 585 #endif 586 { 587 588 /* any room in this bank? */ 589 if (vm_physmem[lcv].avail_start >= vm_physmem[lcv].avail_end) 590 continue; /* nope */ 591 592 *paddrp = ptoa(vm_physmem[lcv].avail_start); 593 vm_physmem[lcv].avail_start++; 594 /* truncate! */ 595 vm_physmem[lcv].start = vm_physmem[lcv].avail_start; 596 597 /* nothing left? nuke it */ 598 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].end) { 599 if (vm_nphysseg == 1) 600 panic("uvm_page_physget: out of memory!"); 601 vm_nphysseg--; 602 for (x = lcv ; x < vm_nphysseg ; x++) 603 /* structure copy */ 604 vm_physmem[x] = vm_physmem[x+1]; 605 } 606 return (TRUE); 607 } 608 609 return (FALSE); /* whoops! */ 610 } 611 612 boolean_t 613 uvm_page_physget(paddrp) 614 paddr_t *paddrp; 615 { 616 int i; 617 618 /* try in the order of freelist preference */ 619 for (i = 0; i < VM_NFREELIST; i++) 620 if (uvm_page_physget_freelist(paddrp, i) == TRUE) 621 return (TRUE); 622 return (FALSE); 623 } 624 #endif /* PMAP_STEAL_MEMORY */ 625 626 /* 627 * uvm_page_physload: load physical memory into VM system 628 * 629 * => all args are PFs 630 * => all pages in start/end get vm_page structures 631 * => areas marked by avail_start/avail_end get added to the free page pool 632 * => we are limited to VM_PHYSSEG_MAX physical memory segments 633 */ 634 635 void 636 uvm_page_physload(start, end, avail_start, avail_end, free_list) 637 paddr_t start, end, avail_start, avail_end; 638 int free_list; 639 { 640 int preload, lcv; 641 psize_t npages; 642 struct vm_page *pgs; 643 struct vm_physseg *ps; 644 645 if (uvmexp.pagesize == 0) 646 panic("uvm_page_physload: page size not set!"); 647 if (free_list >= VM_NFREELIST || free_list < VM_FREELIST_DEFAULT) 648 panic("uvm_page_physload: bad free list %d\n", free_list); 649 if (start >= end) 650 panic("uvm_page_physload: start >= end"); 651 652 /* 653 * do we have room? 654 */ 655 656 if (vm_nphysseg == VM_PHYSSEG_MAX) { 657 printf("uvm_page_physload: unable to load physical memory " 658 "segment\n"); 659 printf("\t%d segments allocated, ignoring 0x%llx -> 0x%llx\n", 660 VM_PHYSSEG_MAX, (long long)start, (long long)end); 661 printf("\tincrease VM_PHYSSEG_MAX\n"); 662 return; 663 } 664 665 /* 666 * check to see if this is a "preload" (i.e. uvm_mem_init hasn't been 667 * called yet, so malloc is not available). 668 */ 669 670 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 671 if (vm_physmem[lcv].pgs) 672 break; 673 } 674 preload = (lcv == vm_nphysseg); 675 676 /* 677 * if VM is already running, attempt to malloc() vm_page structures 678 */ 679 680 if (!preload) { 681 #if defined(VM_PHYSSEG_NOADD) 682 panic("uvm_page_physload: tried to add RAM after vm_mem_init"); 683 #else 684 /* XXXCDC: need some sort of lockout for this case */ 685 paddr_t paddr; 686 npages = end - start; /* # of pages */ 687 pgs = malloc(sizeof(struct vm_page) * npages, 688 M_VMPAGE, M_NOWAIT); 689 if (pgs == NULL) { 690 printf("uvm_page_physload: can not malloc vm_page " 691 "structs for segment\n"); 692 printf("\tignoring 0x%lx -> 0x%lx\n", start, end); 693 return; 694 } 695 /* zero data, init phys_addr and free_list, and free pages */ 696 memset(pgs, 0, sizeof(struct vm_page) * npages); 697 for (lcv = 0, paddr = ptoa(start) ; 698 lcv < npages ; lcv++, paddr += PAGE_SIZE) { 699 pgs[lcv].phys_addr = paddr; 700 pgs[lcv].free_list = free_list; 701 if (atop(paddr) >= avail_start && 702 atop(paddr) <= avail_end) 703 uvm_pagefree(&pgs[lcv]); 704 } 705 /* XXXCDC: incomplete: need to update uvmexp.free, what else? */ 706 /* XXXCDC: need hook to tell pmap to rebuild pv_list, etc... */ 707 #endif 708 } else { 709 pgs = NULL; 710 npages = 0; 711 } 712 713 /* 714 * now insert us in the proper place in vm_physmem[] 715 */ 716 717 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_RANDOM) 718 /* random: put it at the end (easy!) */ 719 ps = &vm_physmem[vm_nphysseg]; 720 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH) 721 { 722 int x; 723 /* sort by address for binary search */ 724 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 725 if (start < vm_physmem[lcv].start) 726 break; 727 ps = &vm_physmem[lcv]; 728 /* move back other entries, if necessary ... */ 729 for (x = vm_nphysseg ; x > lcv ; x--) 730 /* structure copy */ 731 vm_physmem[x] = vm_physmem[x - 1]; 732 } 733 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 734 { 735 int x; 736 /* sort by largest segment first */ 737 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 738 if ((end - start) > 739 (vm_physmem[lcv].end - vm_physmem[lcv].start)) 740 break; 741 ps = &vm_physmem[lcv]; 742 /* move back other entries, if necessary ... */ 743 for (x = vm_nphysseg ; x > lcv ; x--) 744 /* structure copy */ 745 vm_physmem[x] = vm_physmem[x - 1]; 746 } 747 #else 748 panic("uvm_page_physload: unknown physseg strategy selected!"); 749 #endif 750 751 ps->start = start; 752 ps->end = end; 753 ps->avail_start = avail_start; 754 ps->avail_end = avail_end; 755 if (preload) { 756 ps->pgs = NULL; 757 } else { 758 ps->pgs = pgs; 759 ps->lastpg = pgs + npages - 1; 760 } 761 ps->free_list = free_list; 762 vm_nphysseg++; 763 764 if (!preload) 765 uvm_page_rehash(); 766 } 767 768 /* 769 * uvm_page_rehash: reallocate hash table based on number of free pages. 770 */ 771 772 void 773 uvm_page_rehash() 774 { 775 int freepages, lcv, bucketcount, oldcount; 776 struct pglist *newbuckets, *oldbuckets; 777 struct vm_page *pg; 778 size_t newsize, oldsize; 779 780 /* 781 * compute number of pages that can go in the free pool 782 */ 783 784 freepages = 0; 785 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 786 freepages += 787 (vm_physmem[lcv].avail_end - vm_physmem[lcv].avail_start); 788 789 /* 790 * compute number of buckets needed for this number of pages 791 */ 792 793 bucketcount = 1; 794 while (bucketcount < freepages) 795 bucketcount = bucketcount * 2; 796 797 /* 798 * compute the size of the current table and new table. 799 */ 800 801 oldbuckets = uvm.page_hash; 802 oldcount = uvm.page_nhash; 803 oldsize = round_page(sizeof(struct pglist) * oldcount); 804 newsize = round_page(sizeof(struct pglist) * bucketcount); 805 806 /* 807 * allocate the new buckets 808 */ 809 810 newbuckets = (struct pglist *) uvm_km_alloc(kernel_map, newsize); 811 if (newbuckets == NULL) { 812 printf("uvm_page_physrehash: WARNING: could not grow page " 813 "hash table\n"); 814 return; 815 } 816 for (lcv = 0 ; lcv < bucketcount ; lcv++) 817 TAILQ_INIT(&newbuckets[lcv]); 818 819 /* 820 * now replace the old buckets with the new ones and rehash everything 821 */ 822 823 simple_lock(&uvm.hashlock); 824 uvm.page_hash = newbuckets; 825 uvm.page_nhash = bucketcount; 826 uvm.page_hashmask = bucketcount - 1; /* power of 2 */ 827 828 /* ... and rehash */ 829 for (lcv = 0 ; lcv < oldcount ; lcv++) { 830 while ((pg = oldbuckets[lcv].tqh_first) != NULL) { 831 TAILQ_REMOVE(&oldbuckets[lcv], pg, hashq); 832 TAILQ_INSERT_TAIL( 833 &uvm.page_hash[uvm_pagehash(pg->uobject, pg->offset)], 834 pg, hashq); 835 } 836 } 837 simple_unlock(&uvm.hashlock); 838 839 /* 840 * free old bucket array if is not the boot-time table 841 */ 842 843 if (oldbuckets != &uvm_bootbucket) 844 uvm_km_free(kernel_map, (vaddr_t) oldbuckets, oldsize); 845 } 846 847 /* 848 * uvm_page_recolor: Recolor the pages if the new bucket count is 849 * larger than the old one. 850 */ 851 852 void 853 uvm_page_recolor(int newncolors) 854 { 855 struct pgflbucket *bucketarray, *oldbucketarray; 856 struct pgfreelist pgfl; 857 struct vm_page *pg; 858 vsize_t bucketcount; 859 int s, lcv, color, i, ocolors; 860 861 if (newncolors <= uvmexp.ncolors) 862 return; 863 864 bucketcount = newncolors * VM_NFREELIST; 865 bucketarray = malloc(bucketcount * sizeof(struct pgflbucket), 866 M_VMPAGE, M_NOWAIT); 867 if (bucketarray == NULL) { 868 printf("WARNING: unable to allocate %ld page color buckets\n", 869 (long) bucketcount); 870 return; 871 } 872 873 s = uvm_lock_fpageq(); 874 875 /* Make sure we should still do this. */ 876 if (newncolors <= uvmexp.ncolors) { 877 uvm_unlock_fpageq(s); 878 free(bucketarray, M_VMPAGE); 879 return; 880 } 881 882 oldbucketarray = uvm.page_free[0].pgfl_buckets; 883 ocolors = uvmexp.ncolors; 884 885 uvmexp.ncolors = newncolors; 886 uvmexp.colormask = uvmexp.ncolors - 1; 887 888 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 889 pgfl.pgfl_buckets = (bucketarray + (lcv * newncolors)); 890 uvm_page_init_buckets(&pgfl); 891 for (color = 0; color < ocolors; color++) { 892 for (i = 0; i < PGFL_NQUEUES; i++) { 893 while ((pg = TAILQ_FIRST(&uvm.page_free[ 894 lcv].pgfl_buckets[color].pgfl_queues[i])) 895 != NULL) { 896 TAILQ_REMOVE(&uvm.page_free[ 897 lcv].pgfl_buckets[ 898 color].pgfl_queues[i], pg, pageq); 899 TAILQ_INSERT_TAIL(&pgfl.pgfl_buckets[ 900 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[ 901 i], pg, pageq); 902 } 903 } 904 } 905 uvm.page_free[lcv].pgfl_buckets = pgfl.pgfl_buckets; 906 } 907 908 if (have_recolored_pages) { 909 uvm_unlock_fpageq(s); 910 free(oldbucketarray, M_VMPAGE); 911 return; 912 } 913 914 have_recolored_pages = TRUE; 915 uvm_unlock_fpageq(s); 916 } 917 918 /* 919 * uvm_pagealloc_pgfl: helper routine for uvm_pagealloc_strat 920 */ 921 922 static __inline struct vm_page * 923 uvm_pagealloc_pgfl(struct pgfreelist *pgfl, int try1, int try2, 924 int *trycolorp) 925 { 926 struct pglist *freeq; 927 struct vm_page *pg; 928 int color, trycolor = *trycolorp; 929 930 color = trycolor; 931 do { 932 if ((pg = TAILQ_FIRST((freeq = 933 &pgfl->pgfl_buckets[color].pgfl_queues[try1]))) != NULL) 934 goto gotit; 935 if ((pg = TAILQ_FIRST((freeq = 936 &pgfl->pgfl_buckets[color].pgfl_queues[try2]))) != NULL) 937 goto gotit; 938 color = (color + 1) & uvmexp.colormask; 939 } while (color != trycolor); 940 941 return (NULL); 942 943 gotit: 944 TAILQ_REMOVE(freeq, pg, pageq); 945 uvmexp.free--; 946 947 /* update zero'd page count */ 948 if (pg->flags & PG_ZERO) 949 uvmexp.zeropages--; 950 951 if (color == trycolor) 952 uvmexp.colorhit++; 953 else { 954 uvmexp.colormiss++; 955 *trycolorp = color; 956 } 957 958 return (pg); 959 } 960 961 /* 962 * uvm_pagealloc_strat: allocate vm_page from a particular free list. 963 * 964 * => return null if no pages free 965 * => wake up pagedaemon if number of free pages drops below low water mark 966 * => if obj != NULL, obj must be locked (to put in hash) 967 * => if anon != NULL, anon must be locked (to put in anon) 968 * => only one of obj or anon can be non-null 969 * => caller must activate/deactivate page if it is not wired. 970 * => free_list is ignored if strat == UVM_PGA_STRAT_NORMAL. 971 * => policy decision: it is more important to pull a page off of the 972 * appropriate priority free list than it is to get a zero'd or 973 * unknown contents page. This is because we live with the 974 * consequences of a bad free list decision for the entire 975 * lifetime of the page, e.g. if the page comes from memory that 976 * is slower to access. 977 */ 978 979 struct vm_page * 980 uvm_pagealloc_strat(obj, off, anon, flags, strat, free_list) 981 struct uvm_object *obj; 982 voff_t off; 983 int flags; 984 struct vm_anon *anon; 985 int strat, free_list; 986 { 987 int lcv, try1, try2, s, zeroit = 0, color; 988 struct vm_page *pg; 989 boolean_t use_reserve; 990 991 KASSERT(obj == NULL || anon == NULL); 992 KASSERT(off == trunc_page(off)); 993 LOCK_ASSERT(obj == NULL || simple_lock_held(&obj->vmobjlock)); 994 LOCK_ASSERT(anon == NULL || simple_lock_held(&anon->an_lock)); 995 996 s = uvm_lock_fpageq(); 997 998 /* 999 * This implements a global round-robin page coloring 1000 * algorithm. 1001 * 1002 * XXXJRT: Should we make the `nextcolor' per-cpu? 1003 * XXXJRT: What about virtually-indexed caches? 1004 */ 1005 1006 color = uvm.page_free_nextcolor; 1007 1008 /* 1009 * check to see if we need to generate some free pages waking 1010 * the pagedaemon. 1011 */ 1012 1013 UVM_KICK_PDAEMON(); 1014 1015 /* 1016 * fail if any of these conditions is true: 1017 * [1] there really are no free pages, or 1018 * [2] only kernel "reserved" pages remain and 1019 * the page isn't being allocated to a kernel object. 1020 * [3] only pagedaemon "reserved" pages remain and 1021 * the requestor isn't the pagedaemon. 1022 */ 1023 1024 use_reserve = (flags & UVM_PGA_USERESERVE) || 1025 (obj && UVM_OBJ_IS_KERN_OBJECT(obj)); 1026 if ((uvmexp.free <= uvmexp.reserve_kernel && !use_reserve) || 1027 (uvmexp.free <= uvmexp.reserve_pagedaemon && 1028 !(use_reserve && curproc == uvm.pagedaemon_proc))) 1029 goto fail; 1030 1031 #if PGFL_NQUEUES != 2 1032 #error uvm_pagealloc_strat needs to be updated 1033 #endif 1034 1035 /* 1036 * If we want a zero'd page, try the ZEROS queue first, otherwise 1037 * we try the UNKNOWN queue first. 1038 */ 1039 if (flags & UVM_PGA_ZERO) { 1040 try1 = PGFL_ZEROS; 1041 try2 = PGFL_UNKNOWN; 1042 } else { 1043 try1 = PGFL_UNKNOWN; 1044 try2 = PGFL_ZEROS; 1045 } 1046 1047 again: 1048 switch (strat) { 1049 case UVM_PGA_STRAT_NORMAL: 1050 /* Check all freelists in descending priority order. */ 1051 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 1052 pg = uvm_pagealloc_pgfl(&uvm.page_free[lcv], 1053 try1, try2, &color); 1054 if (pg != NULL) 1055 goto gotit; 1056 } 1057 1058 /* No pages free! */ 1059 goto fail; 1060 1061 case UVM_PGA_STRAT_ONLY: 1062 case UVM_PGA_STRAT_FALLBACK: 1063 /* Attempt to allocate from the specified free list. */ 1064 KASSERT(free_list >= 0 && free_list < VM_NFREELIST); 1065 pg = uvm_pagealloc_pgfl(&uvm.page_free[free_list], 1066 try1, try2, &color); 1067 if (pg != NULL) 1068 goto gotit; 1069 1070 /* Fall back, if possible. */ 1071 if (strat == UVM_PGA_STRAT_FALLBACK) { 1072 strat = UVM_PGA_STRAT_NORMAL; 1073 goto again; 1074 } 1075 1076 /* No pages free! */ 1077 goto fail; 1078 1079 default: 1080 panic("uvm_pagealloc_strat: bad strat %d", strat); 1081 /* NOTREACHED */ 1082 } 1083 1084 gotit: 1085 /* 1086 * We now know which color we actually allocated from; set 1087 * the next color accordingly. 1088 */ 1089 1090 uvm.page_free_nextcolor = (color + 1) & uvmexp.colormask; 1091 1092 /* 1093 * update allocation statistics and remember if we have to 1094 * zero the page 1095 */ 1096 1097 if (flags & UVM_PGA_ZERO) { 1098 if (pg->flags & PG_ZERO) { 1099 uvmexp.pga_zerohit++; 1100 zeroit = 0; 1101 } else { 1102 uvmexp.pga_zeromiss++; 1103 zeroit = 1; 1104 } 1105 } 1106 uvm_unlock_fpageq(s); 1107 1108 pg->offset = off; 1109 pg->uobject = obj; 1110 pg->uanon = anon; 1111 pg->flags = PG_BUSY|PG_CLEAN|PG_FAKE; 1112 if (anon) { 1113 anon->u.an_page = pg; 1114 pg->pqflags = PQ_ANON; 1115 uvmexp.anonpages++; 1116 } else { 1117 if (obj) { 1118 uvm_pageinsert(pg); 1119 } 1120 pg->pqflags = 0; 1121 } 1122 #if defined(UVM_PAGE_TRKOWN) 1123 pg->owner_tag = NULL; 1124 #endif 1125 UVM_PAGE_OWN(pg, "new alloc"); 1126 1127 if (flags & UVM_PGA_ZERO) { 1128 /* 1129 * A zero'd page is not clean. If we got a page not already 1130 * zero'd, then we have to zero it ourselves. 1131 */ 1132 pg->flags &= ~PG_CLEAN; 1133 if (zeroit) 1134 pmap_zero_page(VM_PAGE_TO_PHYS(pg)); 1135 } 1136 1137 return(pg); 1138 1139 fail: 1140 uvm_unlock_fpageq(s); 1141 return (NULL); 1142 } 1143 1144 /* 1145 * uvm_pagerealloc: reallocate a page from one object to another 1146 * 1147 * => both objects must be locked 1148 */ 1149 1150 void 1151 uvm_pagerealloc(pg, newobj, newoff) 1152 struct vm_page *pg; 1153 struct uvm_object *newobj; 1154 voff_t newoff; 1155 { 1156 /* 1157 * remove it from the old object 1158 */ 1159 1160 if (pg->uobject) { 1161 uvm_pageremove(pg); 1162 } 1163 1164 /* 1165 * put it in the new object 1166 */ 1167 1168 if (newobj) { 1169 pg->uobject = newobj; 1170 pg->offset = newoff; 1171 uvm_pageinsert(pg); 1172 } 1173 } 1174 1175 /* 1176 * uvm_pagefree: free page 1177 * 1178 * => erase page's identity (i.e. remove from hash/object) 1179 * => put page on free list 1180 * => caller must lock owning object (either anon or uvm_object) 1181 * => caller must lock page queues 1182 * => assumes all valid mappings of pg are gone 1183 */ 1184 1185 void 1186 uvm_pagefree(pg) 1187 struct vm_page *pg; 1188 { 1189 int s; 1190 1191 KASSERT((pg->flags & PG_PAGEOUT) == 0); 1192 LOCK_ASSERT(simple_lock_held(&uvm.pageqlock) || 1193 (pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) == 0); 1194 LOCK_ASSERT(pg->uobject == NULL || 1195 simple_lock_held(&pg->uobject->vmobjlock)); 1196 LOCK_ASSERT(pg->uobject != NULL || pg->uanon == NULL || 1197 simple_lock_held(&pg->uanon->an_lock)); 1198 1199 #ifdef DEBUG 1200 if (pg->uobject == (void *)0xdeadbeef && 1201 pg->uanon == (void *)0xdeadbeef) { 1202 panic("uvm_pagefree: freeing free page %p\n", pg); 1203 } 1204 #endif 1205 1206 /* 1207 * if the page is loaned, resolve the loan instead of freeing. 1208 */ 1209 1210 if (pg->loan_count) { 1211 KASSERT(pg->wire_count == 0); 1212 1213 /* 1214 * if the page is owned by an anon then we just want to 1215 * drop anon ownership. the kernel will free the page when 1216 * it is done with it. if the page is owned by an object, 1217 * remove it from the object and mark it dirty for the benefit 1218 * of possible anon owners. 1219 * 1220 * regardless of previous ownership, wakeup any waiters, 1221 * unbusy the page, and we're done. 1222 */ 1223 1224 if (pg->pqflags & PQ_ANON) { 1225 pg->pqflags &= ~PQ_ANON; 1226 pg->uanon = NULL; 1227 } else if (pg->flags & PG_TABLED) { 1228 uvm_pageremove(pg); 1229 pg->flags &= ~PG_CLEAN; 1230 } 1231 if (pg->flags & PG_WANTED) { 1232 wakeup(pg); 1233 } 1234 pg->flags &= ~(PG_WANTED|PG_BUSY); 1235 #ifdef UVM_PAGE_TRKOWN 1236 pg->owner_tag = NULL; 1237 #endif 1238 return; 1239 } 1240 1241 /* 1242 * remove page from its object or anon. 1243 * adjust swpgonly if the page is swap-backed. 1244 */ 1245 1246 if (pg->flags & PG_TABLED) { 1247 uvm_pageremove(pg); 1248 } else if (pg->pqflags & PQ_ANON) { 1249 pg->uanon->u.an_page = NULL; 1250 } 1251 1252 /* 1253 * now remove the page from the queues. 1254 */ 1255 1256 uvm_pagedequeue(pg); 1257 1258 /* 1259 * if the page was wired, unwire it now. 1260 */ 1261 1262 if (pg->wire_count) { 1263 pg->wire_count = 0; 1264 uvmexp.wired--; 1265 } 1266 if (pg->pqflags & PQ_ANON) { 1267 uvmexp.anonpages--; 1268 } 1269 1270 /* 1271 * and put on free queue 1272 */ 1273 1274 pg->flags &= ~PG_ZERO; 1275 1276 s = uvm_lock_fpageq(); 1277 TAILQ_INSERT_TAIL(&uvm.page_free[ 1278 uvm_page_lookup_freelist(pg)].pgfl_buckets[ 1279 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[PGFL_UNKNOWN], pg, pageq); 1280 pg->pqflags = PQ_FREE; 1281 #ifdef DEBUG 1282 pg->uobject = (void *)0xdeadbeef; 1283 pg->offset = 0xdeadbeef; 1284 pg->uanon = (void *)0xdeadbeef; 1285 #endif 1286 uvmexp.free++; 1287 1288 if (uvmexp.zeropages < UVM_PAGEZERO_TARGET) 1289 uvm.page_idle_zero = vm_page_zero_enable; 1290 1291 uvm_unlock_fpageq(s); 1292 } 1293 1294 /* 1295 * uvm_page_unbusy: unbusy an array of pages. 1296 * 1297 * => pages must either all belong to the same object, or all belong to anons. 1298 * => if pages are object-owned, object must be locked. 1299 * => if pages are anon-owned, anons must be locked. 1300 */ 1301 1302 void 1303 uvm_page_unbusy(pgs, npgs) 1304 struct vm_page **pgs; 1305 int npgs; 1306 { 1307 struct vm_page *pg; 1308 int i; 1309 UVMHIST_FUNC("uvm_page_unbusy"); UVMHIST_CALLED(ubchist); 1310 1311 for (i = 0; i < npgs; i++) { 1312 pg = pgs[i]; 1313 if (pg == NULL) { 1314 continue; 1315 } 1316 if (pg->flags & PG_WANTED) { 1317 wakeup(pg); 1318 } 1319 if (pg->flags & PG_RELEASED) { 1320 UVMHIST_LOG(ubchist, "releasing pg %p", pg,0,0,0); 1321 pg->flags &= ~PG_RELEASED; 1322 uvm_pagefree(pg); 1323 } else { 1324 UVMHIST_LOG(ubchist, "unbusying pg %p", pg,0,0,0); 1325 pg->flags &= ~(PG_WANTED|PG_BUSY); 1326 UVM_PAGE_OWN(pg, NULL); 1327 } 1328 } 1329 } 1330 1331 #if defined(UVM_PAGE_TRKOWN) 1332 /* 1333 * uvm_page_own: set or release page ownership 1334 * 1335 * => this is a debugging function that keeps track of who sets PG_BUSY 1336 * and where they do it. it can be used to track down problems 1337 * such a process setting "PG_BUSY" and never releasing it. 1338 * => page's object [if any] must be locked 1339 * => if "tag" is NULL then we are releasing page ownership 1340 */ 1341 void 1342 uvm_page_own(pg, tag) 1343 struct vm_page *pg; 1344 char *tag; 1345 { 1346 KASSERT((pg->flags & (PG_PAGEOUT|PG_RELEASED)) == 0); 1347 1348 /* gain ownership? */ 1349 if (tag) { 1350 if (pg->owner_tag) { 1351 printf("uvm_page_own: page %p already owned " 1352 "by proc %d [%s]\n", pg, 1353 pg->owner, pg->owner_tag); 1354 panic("uvm_page_own"); 1355 } 1356 pg->owner = (curproc) ? curproc->p_pid : (pid_t) -1; 1357 pg->owner_tag = tag; 1358 return; 1359 } 1360 1361 /* drop ownership */ 1362 if (pg->owner_tag == NULL) { 1363 printf("uvm_page_own: dropping ownership of an non-owned " 1364 "page (%p)\n", pg); 1365 panic("uvm_page_own"); 1366 } 1367 pg->owner_tag = NULL; 1368 KASSERT((pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) || 1369 (pg->uanon == NULL && pg->uobject == NULL) || 1370 pg->uobject == uvm.kernel_object || 1371 pg->wire_count > 0 || 1372 (pg->loan_count == 1 && pg->uanon == NULL) || 1373 pg->loan_count > 1); 1374 return; 1375 } 1376 #endif 1377 1378 /* 1379 * uvm_pageidlezero: zero free pages while the system is idle. 1380 * 1381 * => try to complete one color bucket at a time, to reduce our impact 1382 * on the CPU cache. 1383 * => we loop until we either reach the target or whichqs indicates that 1384 * there is a process ready to run. 1385 */ 1386 void 1387 uvm_pageidlezero() 1388 { 1389 struct vm_page *pg; 1390 struct pgfreelist *pgfl; 1391 int free_list, s, firstbucket; 1392 static int nextbucket; 1393 1394 s = uvm_lock_fpageq(); 1395 firstbucket = nextbucket; 1396 do { 1397 if (sched_whichqs != 0) { 1398 uvm_unlock_fpageq(s); 1399 return; 1400 } 1401 if (uvmexp.zeropages >= UVM_PAGEZERO_TARGET) { 1402 uvm.page_idle_zero = FALSE; 1403 uvm_unlock_fpageq(s); 1404 return; 1405 } 1406 for (free_list = 0; free_list < VM_NFREELIST; free_list++) { 1407 pgfl = &uvm.page_free[free_list]; 1408 while ((pg = TAILQ_FIRST(&pgfl->pgfl_buckets[ 1409 nextbucket].pgfl_queues[PGFL_UNKNOWN])) != NULL) { 1410 if (sched_whichqs != 0) { 1411 uvm_unlock_fpageq(s); 1412 return; 1413 } 1414 1415 TAILQ_REMOVE(&pgfl->pgfl_buckets[ 1416 nextbucket].pgfl_queues[PGFL_UNKNOWN], 1417 pg, pageq); 1418 uvmexp.free--; 1419 uvm_unlock_fpageq(s); 1420 #ifdef PMAP_PAGEIDLEZERO 1421 if (!PMAP_PAGEIDLEZERO(VM_PAGE_TO_PHYS(pg))) { 1422 1423 /* 1424 * The machine-dependent code detected 1425 * some reason for us to abort zeroing 1426 * pages, probably because there is a 1427 * process now ready to run. 1428 */ 1429 1430 s = uvm_lock_fpageq(); 1431 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[ 1432 nextbucket].pgfl_queues[ 1433 PGFL_UNKNOWN], pg, pageq); 1434 uvmexp.free++; 1435 uvmexp.zeroaborts++; 1436 uvm_unlock_fpageq(s); 1437 return; 1438 } 1439 #else 1440 pmap_zero_page(VM_PAGE_TO_PHYS(pg)); 1441 #endif /* PMAP_PAGEIDLEZERO */ 1442 pg->flags |= PG_ZERO; 1443 1444 s = uvm_lock_fpageq(); 1445 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[ 1446 nextbucket].pgfl_queues[PGFL_ZEROS], 1447 pg, pageq); 1448 uvmexp.free++; 1449 uvmexp.zeropages++; 1450 } 1451 } 1452 nextbucket = (nextbucket + 1) & uvmexp.colormask; 1453 } while (nextbucket != firstbucket); 1454 uvm_unlock_fpageq(s); 1455 } 1456