1 /* $NetBSD: uvm_page.c,v 1.89 2003/06/01 09:26:10 wiz 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 1.89 2003/06/01 09:26:10 wiz 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 MALLOC_DEFINE(M_VMPAGE, "VM page", "VM page"); 143 144 /* 145 * local prototypes 146 */ 147 148 static void uvm_pageinsert __P((struct vm_page *)); 149 static void uvm_pageremove __P((struct vm_page *)); 150 151 /* 152 * inline functions 153 */ 154 155 /* 156 * uvm_pageinsert: insert a page in the object and the hash table 157 * 158 * => caller must lock object 159 * => caller must lock page queues 160 * => call should have already set pg's object and offset pointers 161 * and bumped the version counter 162 */ 163 164 __inline static void 165 uvm_pageinsert(pg) 166 struct vm_page *pg; 167 { 168 struct pglist *buck; 169 struct uvm_object *uobj = pg->uobject; 170 171 KASSERT((pg->flags & PG_TABLED) == 0); 172 buck = &uvm.page_hash[uvm_pagehash(uobj, pg->offset)]; 173 simple_lock(&uvm.hashlock); 174 TAILQ_INSERT_TAIL(buck, pg, hashq); 175 simple_unlock(&uvm.hashlock); 176 177 if (UVM_OBJ_IS_VTEXT(uobj)) { 178 uvmexp.execpages++; 179 } else if (UVM_OBJ_IS_VNODE(uobj)) { 180 uvmexp.filepages++; 181 } else if (UVM_OBJ_IS_AOBJ(uobj)) { 182 uvmexp.anonpages++; 183 } 184 185 TAILQ_INSERT_TAIL(&uobj->memq, pg, listq); 186 pg->flags |= PG_TABLED; 187 uobj->uo_npages++; 188 } 189 190 /* 191 * uvm_page_remove: remove page from object and hash 192 * 193 * => caller must lock object 194 * => caller must lock page queues 195 */ 196 197 static __inline void 198 uvm_pageremove(pg) 199 struct vm_page *pg; 200 { 201 struct pglist *buck; 202 struct uvm_object *uobj = pg->uobject; 203 204 KASSERT(pg->flags & PG_TABLED); 205 buck = &uvm.page_hash[uvm_pagehash(uobj, pg->offset)]; 206 simple_lock(&uvm.hashlock); 207 TAILQ_REMOVE(buck, pg, hashq); 208 simple_unlock(&uvm.hashlock); 209 210 if (UVM_OBJ_IS_VTEXT(uobj)) { 211 uvmexp.execpages--; 212 } else if (UVM_OBJ_IS_VNODE(uobj)) { 213 uvmexp.filepages--; 214 } else if (UVM_OBJ_IS_AOBJ(uobj)) { 215 uvmexp.anonpages--; 216 } 217 218 /* object should be locked */ 219 uobj->uo_npages--; 220 TAILQ_REMOVE(&uobj->memq, pg, listq); 221 pg->flags &= ~PG_TABLED; 222 pg->uobject = NULL; 223 } 224 225 static void 226 uvm_page_init_buckets(struct pgfreelist *pgfl) 227 { 228 int color, i; 229 230 for (color = 0; color < uvmexp.ncolors; color++) { 231 for (i = 0; i < PGFL_NQUEUES; i++) { 232 TAILQ_INIT(&pgfl->pgfl_buckets[ 233 color].pgfl_queues[i]); 234 } 235 } 236 } 237 238 /* 239 * uvm_page_init: init the page system. called from uvm_init(). 240 * 241 * => we return the range of kernel virtual memory in kvm_startp/kvm_endp 242 */ 243 244 void 245 uvm_page_init(kvm_startp, kvm_endp) 246 vaddr_t *kvm_startp, *kvm_endp; 247 { 248 vsize_t freepages, pagecount, bucketcount, n; 249 struct pgflbucket *bucketarray; 250 struct vm_page *pagearray; 251 int lcv; 252 u_int i; 253 paddr_t paddr; 254 255 /* 256 * init the page queues and page queue locks, except the free 257 * list; we allocate that later (with the initial vm_page 258 * structures). 259 */ 260 261 TAILQ_INIT(&uvm.page_active); 262 TAILQ_INIT(&uvm.page_inactive); 263 simple_lock_init(&uvm.pageqlock); 264 simple_lock_init(&uvm.fpageqlock); 265 266 /* 267 * init the <obj,offset> => <page> hash table. for now 268 * we just have one bucket (the bootstrap bucket). later on we 269 * will allocate new buckets as we dynamically resize the hash table. 270 */ 271 272 uvm.page_nhash = 1; /* 1 bucket */ 273 uvm.page_hashmask = 0; /* mask for hash function */ 274 uvm.page_hash = &uvm_bootbucket; /* install bootstrap bucket */ 275 TAILQ_INIT(uvm.page_hash); /* init hash table */ 276 simple_lock_init(&uvm.hashlock); /* init hash table lock */ 277 278 /* 279 * allocate vm_page structures. 280 */ 281 282 /* 283 * sanity check: 284 * before calling this function the MD code is expected to register 285 * some free RAM with the uvm_page_physload() function. our job 286 * now is to allocate vm_page structures for this memory. 287 */ 288 289 if (vm_nphysseg == 0) 290 panic("uvm_page_bootstrap: no memory pre-allocated"); 291 292 /* 293 * first calculate the number of free pages... 294 * 295 * note that we use start/end rather than avail_start/avail_end. 296 * this allows us to allocate extra vm_page structures in case we 297 * want to return some memory to the pool after booting. 298 */ 299 300 freepages = 0; 301 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 302 freepages += (vm_physmem[lcv].end - vm_physmem[lcv].start); 303 304 /* 305 * Let MD code initialize the number of colors, or default 306 * to 1 color if MD code doesn't care. 307 */ 308 if (uvmexp.ncolors == 0) 309 uvmexp.ncolors = 1; 310 uvmexp.colormask = uvmexp.ncolors - 1; 311 312 /* 313 * we now know we have (PAGE_SIZE * freepages) bytes of memory we can 314 * use. for each page of memory we use we need a vm_page structure. 315 * thus, the total number of pages we can use is the total size of 316 * the memory divided by the PAGE_SIZE plus the size of the vm_page 317 * structure. we add one to freepages as a fudge factor to avoid 318 * truncation errors (since we can only allocate in terms of whole 319 * pages). 320 */ 321 322 bucketcount = uvmexp.ncolors * VM_NFREELIST; 323 pagecount = ((freepages + 1) << PAGE_SHIFT) / 324 (PAGE_SIZE + sizeof(struct vm_page)); 325 326 bucketarray = (void *)uvm_pageboot_alloc((bucketcount * 327 sizeof(struct pgflbucket)) + (pagecount * 328 sizeof(struct vm_page))); 329 pagearray = (struct vm_page *)(bucketarray + bucketcount); 330 331 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 332 uvm.page_free[lcv].pgfl_buckets = 333 (bucketarray + (lcv * uvmexp.ncolors)); 334 uvm_page_init_buckets(&uvm.page_free[lcv]); 335 } 336 memset(pagearray, 0, pagecount * sizeof(struct vm_page)); 337 338 /* 339 * init the vm_page structures and put them in the correct place. 340 */ 341 342 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 343 n = vm_physmem[lcv].end - vm_physmem[lcv].start; 344 345 /* set up page array pointers */ 346 vm_physmem[lcv].pgs = pagearray; 347 pagearray += n; 348 pagecount -= n; 349 vm_physmem[lcv].lastpg = vm_physmem[lcv].pgs + (n - 1); 350 351 /* init and free vm_pages (we've already zeroed them) */ 352 paddr = ptoa(vm_physmem[lcv].start); 353 for (i = 0 ; i < n ; i++, paddr += PAGE_SIZE) { 354 vm_physmem[lcv].pgs[i].phys_addr = paddr; 355 #ifdef __HAVE_VM_PAGE_MD 356 VM_MDPAGE_INIT(&vm_physmem[lcv].pgs[i]); 357 #endif 358 if (atop(paddr) >= vm_physmem[lcv].avail_start && 359 atop(paddr) <= vm_physmem[lcv].avail_end) { 360 uvmexp.npages++; 361 /* add page to free pool */ 362 uvm_pagefree(&vm_physmem[lcv].pgs[i]); 363 } 364 } 365 } 366 367 /* 368 * pass up the values of virtual_space_start and 369 * virtual_space_end (obtained by uvm_pageboot_alloc) to the upper 370 * layers of the VM. 371 */ 372 373 *kvm_startp = round_page(virtual_space_start); 374 *kvm_endp = trunc_page(virtual_space_end); 375 376 /* 377 * init locks for kernel threads 378 */ 379 380 simple_lock_init(&uvm.pagedaemon_lock); 381 simple_lock_init(&uvm.aiodoned_lock); 382 383 /* 384 * init various thresholds. 385 */ 386 387 uvmexp.reserve_pagedaemon = 1; 388 uvmexp.reserve_kernel = 5; 389 uvmexp.anonminpct = 10; 390 uvmexp.fileminpct = 10; 391 uvmexp.execminpct = 5; 392 uvmexp.anonmaxpct = 80; 393 uvmexp.filemaxpct = 50; 394 uvmexp.execmaxpct = 30; 395 uvmexp.anonmin = uvmexp.anonminpct * 256 / 100; 396 uvmexp.filemin = uvmexp.fileminpct * 256 / 100; 397 uvmexp.execmin = uvmexp.execminpct * 256 / 100; 398 uvmexp.anonmax = uvmexp.anonmaxpct * 256 / 100; 399 uvmexp.filemax = uvmexp.filemaxpct * 256 / 100; 400 uvmexp.execmax = uvmexp.execmaxpct * 256 / 100; 401 402 /* 403 * determine if we should zero pages in the idle loop. 404 */ 405 406 uvm.page_idle_zero = vm_page_zero_enable; 407 408 /* 409 * done! 410 */ 411 412 uvm.page_init_done = TRUE; 413 } 414 415 /* 416 * uvm_setpagesize: set the page size 417 * 418 * => sets page_shift and page_mask from uvmexp.pagesize. 419 */ 420 421 void 422 uvm_setpagesize() 423 { 424 425 /* 426 * If uvmexp.pagesize is 0 at this point, we expect PAGE_SIZE 427 * to be a constant (indicated by being a non-zero value). 428 */ 429 if (uvmexp.pagesize == 0) { 430 if (PAGE_SIZE == 0) 431 panic("uvm_setpagesize: uvmexp.pagesize not set"); 432 uvmexp.pagesize = PAGE_SIZE; 433 } 434 uvmexp.pagemask = uvmexp.pagesize - 1; 435 if ((uvmexp.pagemask & uvmexp.pagesize) != 0) 436 panic("uvm_setpagesize: page size not a power of two"); 437 for (uvmexp.pageshift = 0; ; uvmexp.pageshift++) 438 if ((1 << uvmexp.pageshift) == uvmexp.pagesize) 439 break; 440 } 441 442 /* 443 * uvm_pageboot_alloc: steal memory from physmem for bootstrapping 444 */ 445 446 vaddr_t 447 uvm_pageboot_alloc(size) 448 vsize_t size; 449 { 450 static boolean_t initialized = FALSE; 451 vaddr_t addr; 452 #if !defined(PMAP_STEAL_MEMORY) 453 vaddr_t vaddr; 454 paddr_t paddr; 455 #endif 456 457 /* 458 * on first call to this function, initialize ourselves. 459 */ 460 if (initialized == FALSE) { 461 pmap_virtual_space(&virtual_space_start, &virtual_space_end); 462 463 /* round it the way we like it */ 464 virtual_space_start = round_page(virtual_space_start); 465 virtual_space_end = trunc_page(virtual_space_end); 466 467 initialized = TRUE; 468 } 469 470 /* round to page size */ 471 size = round_page(size); 472 473 #if defined(PMAP_STEAL_MEMORY) 474 475 /* 476 * defer bootstrap allocation to MD code (it may want to allocate 477 * from a direct-mapped segment). pmap_steal_memory should adjust 478 * virtual_space_start/virtual_space_end if necessary. 479 */ 480 481 addr = pmap_steal_memory(size, &virtual_space_start, 482 &virtual_space_end); 483 484 return(addr); 485 486 #else /* !PMAP_STEAL_MEMORY */ 487 488 /* 489 * allocate virtual memory for this request 490 */ 491 if (virtual_space_start == virtual_space_end || 492 (virtual_space_end - virtual_space_start) < size) 493 panic("uvm_pageboot_alloc: out of virtual space"); 494 495 addr = virtual_space_start; 496 497 #ifdef PMAP_GROWKERNEL 498 /* 499 * If the kernel pmap can't map the requested space, 500 * then allocate more resources for it. 501 */ 502 if (uvm_maxkaddr < (addr + size)) { 503 uvm_maxkaddr = pmap_growkernel(addr + size); 504 if (uvm_maxkaddr < (addr + size)) 505 panic("uvm_pageboot_alloc: pmap_growkernel() failed"); 506 } 507 #endif 508 509 virtual_space_start += size; 510 511 /* 512 * allocate and mapin physical pages to back new virtual pages 513 */ 514 515 for (vaddr = round_page(addr) ; vaddr < addr + size ; 516 vaddr += PAGE_SIZE) { 517 518 if (!uvm_page_physget(&paddr)) 519 panic("uvm_pageboot_alloc: out of memory"); 520 521 /* 522 * Note this memory is no longer managed, so using 523 * pmap_kenter is safe. 524 */ 525 pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE); 526 } 527 pmap_update(pmap_kernel()); 528 return(addr); 529 #endif /* PMAP_STEAL_MEMORY */ 530 } 531 532 #if !defined(PMAP_STEAL_MEMORY) 533 /* 534 * uvm_page_physget: "steal" one page from the vm_physmem structure. 535 * 536 * => attempt to allocate it off the end of a segment in which the "avail" 537 * values match the start/end values. if we can't do that, then we 538 * will advance both values (making them equal, and removing some 539 * vm_page structures from the non-avail area). 540 * => return false if out of memory. 541 */ 542 543 /* subroutine: try to allocate from memory chunks on the specified freelist */ 544 static boolean_t uvm_page_physget_freelist __P((paddr_t *, int)); 545 546 static boolean_t 547 uvm_page_physget_freelist(paddrp, freelist) 548 paddr_t *paddrp; 549 int freelist; 550 { 551 int lcv, x; 552 553 /* pass 1: try allocating from a matching end */ 554 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 555 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 556 #else 557 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 558 #endif 559 { 560 561 if (uvm.page_init_done == TRUE) 562 panic("uvm_page_physget: called _after_ bootstrap"); 563 564 if (vm_physmem[lcv].free_list != freelist) 565 continue; 566 567 /* try from front */ 568 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].start && 569 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 570 *paddrp = ptoa(vm_physmem[lcv].avail_start); 571 vm_physmem[lcv].avail_start++; 572 vm_physmem[lcv].start++; 573 /* nothing left? nuke it */ 574 if (vm_physmem[lcv].avail_start == 575 vm_physmem[lcv].end) { 576 if (vm_nphysseg == 1) 577 panic("uvm_page_physget: out of memory!"); 578 vm_nphysseg--; 579 for (x = lcv ; x < vm_nphysseg ; x++) 580 /* structure copy */ 581 vm_physmem[x] = vm_physmem[x+1]; 582 } 583 return (TRUE); 584 } 585 586 /* try from rear */ 587 if (vm_physmem[lcv].avail_end == vm_physmem[lcv].end && 588 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 589 *paddrp = ptoa(vm_physmem[lcv].avail_end - 1); 590 vm_physmem[lcv].avail_end--; 591 vm_physmem[lcv].end--; 592 /* nothing left? nuke it */ 593 if (vm_physmem[lcv].avail_end == 594 vm_physmem[lcv].start) { 595 if (vm_nphysseg == 1) 596 panic("uvm_page_physget: out of memory!"); 597 vm_nphysseg--; 598 for (x = lcv ; x < vm_nphysseg ; x++) 599 /* structure copy */ 600 vm_physmem[x] = vm_physmem[x+1]; 601 } 602 return (TRUE); 603 } 604 } 605 606 /* pass2: forget about matching ends, just allocate something */ 607 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 608 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 609 #else 610 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 611 #endif 612 { 613 614 /* any room in this bank? */ 615 if (vm_physmem[lcv].avail_start >= vm_physmem[lcv].avail_end) 616 continue; /* nope */ 617 618 *paddrp = ptoa(vm_physmem[lcv].avail_start); 619 vm_physmem[lcv].avail_start++; 620 /* truncate! */ 621 vm_physmem[lcv].start = vm_physmem[lcv].avail_start; 622 623 /* nothing left? nuke it */ 624 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].end) { 625 if (vm_nphysseg == 1) 626 panic("uvm_page_physget: out of memory!"); 627 vm_nphysseg--; 628 for (x = lcv ; x < vm_nphysseg ; x++) 629 /* structure copy */ 630 vm_physmem[x] = vm_physmem[x+1]; 631 } 632 return (TRUE); 633 } 634 635 return (FALSE); /* whoops! */ 636 } 637 638 boolean_t 639 uvm_page_physget(paddrp) 640 paddr_t *paddrp; 641 { 642 int i; 643 644 /* try in the order of freelist preference */ 645 for (i = 0; i < VM_NFREELIST; i++) 646 if (uvm_page_physget_freelist(paddrp, i) == TRUE) 647 return (TRUE); 648 return (FALSE); 649 } 650 #endif /* PMAP_STEAL_MEMORY */ 651 652 /* 653 * uvm_page_physload: load physical memory into VM system 654 * 655 * => all args are PFs 656 * => all pages in start/end get vm_page structures 657 * => areas marked by avail_start/avail_end get added to the free page pool 658 * => we are limited to VM_PHYSSEG_MAX physical memory segments 659 */ 660 661 void 662 uvm_page_physload(start, end, avail_start, avail_end, free_list) 663 paddr_t start, end, avail_start, avail_end; 664 int free_list; 665 { 666 int preload, lcv; 667 psize_t npages; 668 struct vm_page *pgs; 669 struct vm_physseg *ps; 670 671 if (uvmexp.pagesize == 0) 672 panic("uvm_page_physload: page size not set!"); 673 if (free_list >= VM_NFREELIST || free_list < VM_FREELIST_DEFAULT) 674 panic("uvm_page_physload: bad free list %d", free_list); 675 if (start >= end) 676 panic("uvm_page_physload: start >= end"); 677 678 /* 679 * do we have room? 680 */ 681 682 if (vm_nphysseg == VM_PHYSSEG_MAX) { 683 printf("uvm_page_physload: unable to load physical memory " 684 "segment\n"); 685 printf("\t%d segments allocated, ignoring 0x%llx -> 0x%llx\n", 686 VM_PHYSSEG_MAX, (long long)start, (long long)end); 687 printf("\tincrease VM_PHYSSEG_MAX\n"); 688 return; 689 } 690 691 /* 692 * check to see if this is a "preload" (i.e. uvm_mem_init hasn't been 693 * called yet, so malloc is not available). 694 */ 695 696 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 697 if (vm_physmem[lcv].pgs) 698 break; 699 } 700 preload = (lcv == vm_nphysseg); 701 702 /* 703 * if VM is already running, attempt to malloc() vm_page structures 704 */ 705 706 if (!preload) { 707 #if defined(VM_PHYSSEG_NOADD) 708 panic("uvm_page_physload: tried to add RAM after vm_mem_init"); 709 #else 710 /* XXXCDC: need some sort of lockout for this case */ 711 paddr_t paddr; 712 npages = end - start; /* # of pages */ 713 pgs = malloc(sizeof(struct vm_page) * npages, 714 M_VMPAGE, M_NOWAIT); 715 if (pgs == NULL) { 716 printf("uvm_page_physload: can not malloc vm_page " 717 "structs for segment\n"); 718 printf("\tignoring 0x%lx -> 0x%lx\n", start, end); 719 return; 720 } 721 /* zero data, init phys_addr and free_list, and free pages */ 722 memset(pgs, 0, sizeof(struct vm_page) * npages); 723 for (lcv = 0, paddr = ptoa(start) ; 724 lcv < npages ; lcv++, paddr += PAGE_SIZE) { 725 pgs[lcv].phys_addr = paddr; 726 pgs[lcv].free_list = free_list; 727 if (atop(paddr) >= avail_start && 728 atop(paddr) <= avail_end) 729 uvm_pagefree(&pgs[lcv]); 730 } 731 /* XXXCDC: incomplete: need to update uvmexp.free, what else? */ 732 /* XXXCDC: need hook to tell pmap to rebuild pv_list, etc... */ 733 #endif 734 } else { 735 pgs = NULL; 736 npages = 0; 737 } 738 739 /* 740 * now insert us in the proper place in vm_physmem[] 741 */ 742 743 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_RANDOM) 744 /* random: put it at the end (easy!) */ 745 ps = &vm_physmem[vm_nphysseg]; 746 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH) 747 { 748 int x; 749 /* sort by address for binary search */ 750 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 751 if (start < vm_physmem[lcv].start) 752 break; 753 ps = &vm_physmem[lcv]; 754 /* move back other entries, if necessary ... */ 755 for (x = vm_nphysseg ; x > lcv ; x--) 756 /* structure copy */ 757 vm_physmem[x] = vm_physmem[x - 1]; 758 } 759 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 760 { 761 int x; 762 /* sort by largest segment first */ 763 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 764 if ((end - start) > 765 (vm_physmem[lcv].end - vm_physmem[lcv].start)) 766 break; 767 ps = &vm_physmem[lcv]; 768 /* move back other entries, if necessary ... */ 769 for (x = vm_nphysseg ; x > lcv ; x--) 770 /* structure copy */ 771 vm_physmem[x] = vm_physmem[x - 1]; 772 } 773 #else 774 panic("uvm_page_physload: unknown physseg strategy selected!"); 775 #endif 776 777 ps->start = start; 778 ps->end = end; 779 ps->avail_start = avail_start; 780 ps->avail_end = avail_end; 781 if (preload) { 782 ps->pgs = NULL; 783 } else { 784 ps->pgs = pgs; 785 ps->lastpg = pgs + npages - 1; 786 } 787 ps->free_list = free_list; 788 vm_nphysseg++; 789 790 if (!preload) 791 uvm_page_rehash(); 792 } 793 794 /* 795 * uvm_page_rehash: reallocate hash table based on number of free pages. 796 */ 797 798 void 799 uvm_page_rehash() 800 { 801 int freepages, lcv, bucketcount, oldcount; 802 struct pglist *newbuckets, *oldbuckets; 803 struct vm_page *pg; 804 size_t newsize, oldsize; 805 806 /* 807 * compute number of pages that can go in the free pool 808 */ 809 810 freepages = 0; 811 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 812 freepages += 813 (vm_physmem[lcv].avail_end - vm_physmem[lcv].avail_start); 814 815 /* 816 * compute number of buckets needed for this number of pages 817 */ 818 819 bucketcount = 1; 820 while (bucketcount < freepages) 821 bucketcount = bucketcount * 2; 822 823 /* 824 * compute the size of the current table and new table. 825 */ 826 827 oldbuckets = uvm.page_hash; 828 oldcount = uvm.page_nhash; 829 oldsize = round_page(sizeof(struct pglist) * oldcount); 830 newsize = round_page(sizeof(struct pglist) * bucketcount); 831 832 /* 833 * allocate the new buckets 834 */ 835 836 newbuckets = (struct pglist *) uvm_km_alloc(kernel_map, newsize); 837 if (newbuckets == NULL) { 838 printf("uvm_page_physrehash: WARNING: could not grow page " 839 "hash table\n"); 840 return; 841 } 842 for (lcv = 0 ; lcv < bucketcount ; lcv++) 843 TAILQ_INIT(&newbuckets[lcv]); 844 845 /* 846 * now replace the old buckets with the new ones and rehash everything 847 */ 848 849 simple_lock(&uvm.hashlock); 850 uvm.page_hash = newbuckets; 851 uvm.page_nhash = bucketcount; 852 uvm.page_hashmask = bucketcount - 1; /* power of 2 */ 853 854 /* ... and rehash */ 855 for (lcv = 0 ; lcv < oldcount ; lcv++) { 856 while ((pg = oldbuckets[lcv].tqh_first) != NULL) { 857 TAILQ_REMOVE(&oldbuckets[lcv], pg, hashq); 858 TAILQ_INSERT_TAIL( 859 &uvm.page_hash[uvm_pagehash(pg->uobject, pg->offset)], 860 pg, hashq); 861 } 862 } 863 simple_unlock(&uvm.hashlock); 864 865 /* 866 * free old bucket array if is not the boot-time table 867 */ 868 869 if (oldbuckets != &uvm_bootbucket) 870 uvm_km_free(kernel_map, (vaddr_t) oldbuckets, oldsize); 871 } 872 873 /* 874 * uvm_page_recolor: Recolor the pages if the new bucket count is 875 * larger than the old one. 876 */ 877 878 void 879 uvm_page_recolor(int newncolors) 880 { 881 struct pgflbucket *bucketarray, *oldbucketarray; 882 struct pgfreelist pgfl; 883 struct vm_page *pg; 884 vsize_t bucketcount; 885 int s, lcv, color, i, ocolors; 886 887 if (newncolors <= uvmexp.ncolors) 888 return; 889 890 if (uvm.page_init_done == FALSE) { 891 uvmexp.ncolors = newncolors; 892 return; 893 } 894 895 bucketcount = newncolors * VM_NFREELIST; 896 bucketarray = malloc(bucketcount * sizeof(struct pgflbucket), 897 M_VMPAGE, M_NOWAIT); 898 if (bucketarray == NULL) { 899 printf("WARNING: unable to allocate %ld page color buckets\n", 900 (long) bucketcount); 901 return; 902 } 903 904 s = uvm_lock_fpageq(); 905 906 /* Make sure we should still do this. */ 907 if (newncolors <= uvmexp.ncolors) { 908 uvm_unlock_fpageq(s); 909 free(bucketarray, M_VMPAGE); 910 return; 911 } 912 913 oldbucketarray = uvm.page_free[0].pgfl_buckets; 914 ocolors = uvmexp.ncolors; 915 916 uvmexp.ncolors = newncolors; 917 uvmexp.colormask = uvmexp.ncolors - 1; 918 919 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 920 pgfl.pgfl_buckets = (bucketarray + (lcv * newncolors)); 921 uvm_page_init_buckets(&pgfl); 922 for (color = 0; color < ocolors; color++) { 923 for (i = 0; i < PGFL_NQUEUES; i++) { 924 while ((pg = TAILQ_FIRST(&uvm.page_free[ 925 lcv].pgfl_buckets[color].pgfl_queues[i])) 926 != NULL) { 927 TAILQ_REMOVE(&uvm.page_free[ 928 lcv].pgfl_buckets[ 929 color].pgfl_queues[i], pg, pageq); 930 TAILQ_INSERT_TAIL(&pgfl.pgfl_buckets[ 931 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[ 932 i], pg, pageq); 933 } 934 } 935 } 936 uvm.page_free[lcv].pgfl_buckets = pgfl.pgfl_buckets; 937 } 938 939 if (have_recolored_pages) { 940 uvm_unlock_fpageq(s); 941 free(oldbucketarray, M_VMPAGE); 942 return; 943 } 944 945 have_recolored_pages = TRUE; 946 uvm_unlock_fpageq(s); 947 } 948 949 /* 950 * uvm_pagealloc_pgfl: helper routine for uvm_pagealloc_strat 951 */ 952 953 static __inline struct vm_page * 954 uvm_pagealloc_pgfl(struct pgfreelist *pgfl, int try1, int try2, 955 int *trycolorp) 956 { 957 struct pglist *freeq; 958 struct vm_page *pg; 959 int color, trycolor = *trycolorp; 960 961 color = trycolor; 962 do { 963 if ((pg = TAILQ_FIRST((freeq = 964 &pgfl->pgfl_buckets[color].pgfl_queues[try1]))) != NULL) 965 goto gotit; 966 if ((pg = TAILQ_FIRST((freeq = 967 &pgfl->pgfl_buckets[color].pgfl_queues[try2]))) != NULL) 968 goto gotit; 969 color = (color + 1) & uvmexp.colormask; 970 } while (color != trycolor); 971 972 return (NULL); 973 974 gotit: 975 TAILQ_REMOVE(freeq, pg, pageq); 976 uvmexp.free--; 977 978 /* update zero'd page count */ 979 if (pg->flags & PG_ZERO) 980 uvmexp.zeropages--; 981 982 if (color == trycolor) 983 uvmexp.colorhit++; 984 else { 985 uvmexp.colormiss++; 986 *trycolorp = color; 987 } 988 989 return (pg); 990 } 991 992 /* 993 * uvm_pagealloc_strat: allocate vm_page from a particular free list. 994 * 995 * => return null if no pages free 996 * => wake up pagedaemon if number of free pages drops below low water mark 997 * => if obj != NULL, obj must be locked (to put in hash) 998 * => if anon != NULL, anon must be locked (to put in anon) 999 * => only one of obj or anon can be non-null 1000 * => caller must activate/deactivate page if it is not wired. 1001 * => free_list is ignored if strat == UVM_PGA_STRAT_NORMAL. 1002 * => policy decision: it is more important to pull a page off of the 1003 * appropriate priority free list than it is to get a zero'd or 1004 * unknown contents page. This is because we live with the 1005 * consequences of a bad free list decision for the entire 1006 * lifetime of the page, e.g. if the page comes from memory that 1007 * is slower to access. 1008 */ 1009 1010 struct vm_page * 1011 uvm_pagealloc_strat(obj, off, anon, flags, strat, free_list) 1012 struct uvm_object *obj; 1013 voff_t off; 1014 int flags; 1015 struct vm_anon *anon; 1016 int strat, free_list; 1017 { 1018 int lcv, try1, try2, s, zeroit = 0, color; 1019 struct vm_page *pg; 1020 boolean_t use_reserve; 1021 1022 KASSERT(obj == NULL || anon == NULL); 1023 KASSERT(off == trunc_page(off)); 1024 LOCK_ASSERT(obj == NULL || simple_lock_held(&obj->vmobjlock)); 1025 LOCK_ASSERT(anon == NULL || simple_lock_held(&anon->an_lock)); 1026 1027 s = uvm_lock_fpageq(); 1028 1029 /* 1030 * This implements a global round-robin page coloring 1031 * algorithm. 1032 * 1033 * XXXJRT: Should we make the `nextcolor' per-cpu? 1034 * XXXJRT: What about virtually-indexed caches? 1035 */ 1036 1037 color = uvm.page_free_nextcolor; 1038 1039 /* 1040 * check to see if we need to generate some free pages waking 1041 * the pagedaemon. 1042 */ 1043 1044 UVM_KICK_PDAEMON(); 1045 1046 /* 1047 * fail if any of these conditions is true: 1048 * [1] there really are no free pages, or 1049 * [2] only kernel "reserved" pages remain and 1050 * the page isn't being allocated to a kernel object. 1051 * [3] only pagedaemon "reserved" pages remain and 1052 * the requestor isn't the pagedaemon. 1053 */ 1054 1055 use_reserve = (flags & UVM_PGA_USERESERVE) || 1056 (obj && UVM_OBJ_IS_KERN_OBJECT(obj)); 1057 if ((uvmexp.free <= uvmexp.reserve_kernel && !use_reserve) || 1058 (uvmexp.free <= uvmexp.reserve_pagedaemon && 1059 !(use_reserve && curproc == uvm.pagedaemon_proc))) 1060 goto fail; 1061 1062 #if PGFL_NQUEUES != 2 1063 #error uvm_pagealloc_strat needs to be updated 1064 #endif 1065 1066 /* 1067 * If we want a zero'd page, try the ZEROS queue first, otherwise 1068 * we try the UNKNOWN queue first. 1069 */ 1070 if (flags & UVM_PGA_ZERO) { 1071 try1 = PGFL_ZEROS; 1072 try2 = PGFL_UNKNOWN; 1073 } else { 1074 try1 = PGFL_UNKNOWN; 1075 try2 = PGFL_ZEROS; 1076 } 1077 1078 again: 1079 switch (strat) { 1080 case UVM_PGA_STRAT_NORMAL: 1081 /* Check all freelists in descending priority order. */ 1082 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 1083 pg = uvm_pagealloc_pgfl(&uvm.page_free[lcv], 1084 try1, try2, &color); 1085 if (pg != NULL) 1086 goto gotit; 1087 } 1088 1089 /* No pages free! */ 1090 goto fail; 1091 1092 case UVM_PGA_STRAT_ONLY: 1093 case UVM_PGA_STRAT_FALLBACK: 1094 /* Attempt to allocate from the specified free list. */ 1095 KASSERT(free_list >= 0 && free_list < VM_NFREELIST); 1096 pg = uvm_pagealloc_pgfl(&uvm.page_free[free_list], 1097 try1, try2, &color); 1098 if (pg != NULL) 1099 goto gotit; 1100 1101 /* Fall back, if possible. */ 1102 if (strat == UVM_PGA_STRAT_FALLBACK) { 1103 strat = UVM_PGA_STRAT_NORMAL; 1104 goto again; 1105 } 1106 1107 /* No pages free! */ 1108 goto fail; 1109 1110 default: 1111 panic("uvm_pagealloc_strat: bad strat %d", strat); 1112 /* NOTREACHED */ 1113 } 1114 1115 gotit: 1116 /* 1117 * We now know which color we actually allocated from; set 1118 * the next color accordingly. 1119 */ 1120 1121 uvm.page_free_nextcolor = (color + 1) & uvmexp.colormask; 1122 1123 /* 1124 * update allocation statistics and remember if we have to 1125 * zero the page 1126 */ 1127 1128 if (flags & UVM_PGA_ZERO) { 1129 if (pg->flags & PG_ZERO) { 1130 uvmexp.pga_zerohit++; 1131 zeroit = 0; 1132 } else { 1133 uvmexp.pga_zeromiss++; 1134 zeroit = 1; 1135 } 1136 } 1137 uvm_unlock_fpageq(s); 1138 1139 pg->offset = off; 1140 pg->uobject = obj; 1141 pg->uanon = anon; 1142 pg->flags = PG_BUSY|PG_CLEAN|PG_FAKE; 1143 if (anon) { 1144 anon->u.an_page = pg; 1145 pg->pqflags = PQ_ANON; 1146 uvmexp.anonpages++; 1147 } else { 1148 if (obj) { 1149 uvm_pageinsert(pg); 1150 } 1151 pg->pqflags = 0; 1152 } 1153 #if defined(UVM_PAGE_TRKOWN) 1154 pg->owner_tag = NULL; 1155 #endif 1156 UVM_PAGE_OWN(pg, "new alloc"); 1157 1158 if (flags & UVM_PGA_ZERO) { 1159 /* 1160 * A zero'd page is not clean. If we got a page not already 1161 * zero'd, then we have to zero it ourselves. 1162 */ 1163 pg->flags &= ~PG_CLEAN; 1164 if (zeroit) 1165 pmap_zero_page(VM_PAGE_TO_PHYS(pg)); 1166 } 1167 1168 return(pg); 1169 1170 fail: 1171 uvm_unlock_fpageq(s); 1172 return (NULL); 1173 } 1174 1175 /* 1176 * uvm_pagerealloc: reallocate a page from one object to another 1177 * 1178 * => both objects must be locked 1179 */ 1180 1181 void 1182 uvm_pagerealloc(pg, newobj, newoff) 1183 struct vm_page *pg; 1184 struct uvm_object *newobj; 1185 voff_t newoff; 1186 { 1187 /* 1188 * remove it from the old object 1189 */ 1190 1191 if (pg->uobject) { 1192 uvm_pageremove(pg); 1193 } 1194 1195 /* 1196 * put it in the new object 1197 */ 1198 1199 if (newobj) { 1200 pg->uobject = newobj; 1201 pg->offset = newoff; 1202 uvm_pageinsert(pg); 1203 } 1204 } 1205 1206 /* 1207 * uvm_pagefree: free page 1208 * 1209 * => erase page's identity (i.e. remove from hash/object) 1210 * => put page on free list 1211 * => caller must lock owning object (either anon or uvm_object) 1212 * => caller must lock page queues 1213 * => assumes all valid mappings of pg are gone 1214 */ 1215 1216 void 1217 uvm_pagefree(pg) 1218 struct vm_page *pg; 1219 { 1220 int s; 1221 1222 KASSERT((pg->flags & PG_PAGEOUT) == 0); 1223 LOCK_ASSERT(simple_lock_held(&uvm.pageqlock) || 1224 (pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) == 0); 1225 LOCK_ASSERT(pg->uobject == NULL || 1226 simple_lock_held(&pg->uobject->vmobjlock)); 1227 LOCK_ASSERT(pg->uobject != NULL || pg->uanon == NULL || 1228 simple_lock_held(&pg->uanon->an_lock)); 1229 1230 #ifdef DEBUG 1231 if (pg->uobject == (void *)0xdeadbeef && 1232 pg->uanon == (void *)0xdeadbeef) { 1233 panic("uvm_pagefree: freeing free page %p", pg); 1234 } 1235 #endif 1236 1237 /* 1238 * if the page is loaned, resolve the loan instead of freeing. 1239 */ 1240 1241 if (pg->loan_count) { 1242 KASSERT(pg->wire_count == 0); 1243 1244 /* 1245 * if the page is owned by an anon then we just want to 1246 * drop anon ownership. the kernel will free the page when 1247 * it is done with it. if the page is owned by an object, 1248 * remove it from the object and mark it dirty for the benefit 1249 * of possible anon owners. 1250 * 1251 * regardless of previous ownership, wakeup any waiters, 1252 * unbusy the page, and we're done. 1253 */ 1254 1255 if (pg->uobject != NULL) { 1256 uvm_pageremove(pg); 1257 pg->flags &= ~PG_CLEAN; 1258 } else if (pg->uanon != NULL) { 1259 if ((pg->pqflags & PQ_ANON) == 0) { 1260 pg->loan_count--; 1261 } else { 1262 pg->pqflags &= ~PQ_ANON; 1263 } 1264 pg->uanon = NULL; 1265 } 1266 if (pg->flags & PG_WANTED) { 1267 wakeup(pg); 1268 } 1269 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_RELEASED|PG_PAGER1); 1270 #ifdef UVM_PAGE_TRKOWN 1271 pg->owner_tag = NULL; 1272 #endif 1273 if (pg->loan_count) { 1274 uvm_pagedequeue(pg); 1275 return; 1276 } 1277 } 1278 1279 /* 1280 * remove page from its object or anon. 1281 */ 1282 1283 if (pg->uobject != NULL) { 1284 uvm_pageremove(pg); 1285 } else if (pg->uanon != NULL) { 1286 pg->uanon->u.an_page = NULL; 1287 uvmexp.anonpages--; 1288 } 1289 1290 /* 1291 * now remove the page from the queues. 1292 */ 1293 1294 uvm_pagedequeue(pg); 1295 1296 /* 1297 * if the page was wired, unwire it now. 1298 */ 1299 1300 if (pg->wire_count) { 1301 pg->wire_count = 0; 1302 uvmexp.wired--; 1303 } 1304 1305 /* 1306 * and put on free queue 1307 */ 1308 1309 pg->flags &= ~PG_ZERO; 1310 1311 s = uvm_lock_fpageq(); 1312 TAILQ_INSERT_TAIL(&uvm.page_free[ 1313 uvm_page_lookup_freelist(pg)].pgfl_buckets[ 1314 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[PGFL_UNKNOWN], pg, pageq); 1315 pg->pqflags = PQ_FREE; 1316 #ifdef DEBUG 1317 pg->uobject = (void *)0xdeadbeef; 1318 pg->offset = 0xdeadbeef; 1319 pg->uanon = (void *)0xdeadbeef; 1320 #endif 1321 uvmexp.free++; 1322 1323 if (uvmexp.zeropages < UVM_PAGEZERO_TARGET) 1324 uvm.page_idle_zero = vm_page_zero_enable; 1325 1326 uvm_unlock_fpageq(s); 1327 } 1328 1329 /* 1330 * uvm_page_unbusy: unbusy an array of pages. 1331 * 1332 * => pages must either all belong to the same object, or all belong to anons. 1333 * => if pages are object-owned, object must be locked. 1334 * => if pages are anon-owned, anons must be locked. 1335 * => caller must lock page queues if pages may be released. 1336 */ 1337 1338 void 1339 uvm_page_unbusy(pgs, npgs) 1340 struct vm_page **pgs; 1341 int npgs; 1342 { 1343 struct vm_page *pg; 1344 int i; 1345 UVMHIST_FUNC("uvm_page_unbusy"); UVMHIST_CALLED(ubchist); 1346 1347 for (i = 0; i < npgs; i++) { 1348 pg = pgs[i]; 1349 if (pg == NULL || pg == PGO_DONTCARE) { 1350 continue; 1351 } 1352 if (pg->flags & PG_WANTED) { 1353 wakeup(pg); 1354 } 1355 if (pg->flags & PG_RELEASED) { 1356 UVMHIST_LOG(ubchist, "releasing pg %p", pg,0,0,0); 1357 pg->flags &= ~PG_RELEASED; 1358 uvm_pagefree(pg); 1359 } else { 1360 UVMHIST_LOG(ubchist, "unbusying pg %p", pg,0,0,0); 1361 pg->flags &= ~(PG_WANTED|PG_BUSY); 1362 UVM_PAGE_OWN(pg, NULL); 1363 } 1364 } 1365 } 1366 1367 #if defined(UVM_PAGE_TRKOWN) 1368 /* 1369 * uvm_page_own: set or release page ownership 1370 * 1371 * => this is a debugging function that keeps track of who sets PG_BUSY 1372 * and where they do it. it can be used to track down problems 1373 * such a process setting "PG_BUSY" and never releasing it. 1374 * => page's object [if any] must be locked 1375 * => if "tag" is NULL then we are releasing page ownership 1376 */ 1377 void 1378 uvm_page_own(pg, tag) 1379 struct vm_page *pg; 1380 char *tag; 1381 { 1382 KASSERT((pg->flags & (PG_PAGEOUT|PG_RELEASED)) == 0); 1383 1384 /* gain ownership? */ 1385 if (tag) { 1386 if (pg->owner_tag) { 1387 printf("uvm_page_own: page %p already owned " 1388 "by proc %d [%s]\n", pg, 1389 pg->owner, pg->owner_tag); 1390 panic("uvm_page_own"); 1391 } 1392 pg->owner = (curproc) ? curproc->p_pid : (pid_t) -1; 1393 pg->owner_tag = tag; 1394 return; 1395 } 1396 1397 /* drop ownership */ 1398 if (pg->owner_tag == NULL) { 1399 printf("uvm_page_own: dropping ownership of an non-owned " 1400 "page (%p)\n", pg); 1401 panic("uvm_page_own"); 1402 } 1403 KASSERT((pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) || 1404 (pg->uanon == NULL && pg->uobject == NULL) || 1405 pg->uobject == uvm.kernel_object || 1406 pg->wire_count > 0 || 1407 (pg->loan_count == 1 && pg->uanon == NULL) || 1408 pg->loan_count > 1); 1409 pg->owner_tag = NULL; 1410 } 1411 #endif 1412 1413 /* 1414 * uvm_pageidlezero: zero free pages while the system is idle. 1415 * 1416 * => try to complete one color bucket at a time, to reduce our impact 1417 * on the CPU cache. 1418 * => we loop until we either reach the target or whichqs indicates that 1419 * there is a process ready to run. 1420 */ 1421 void 1422 uvm_pageidlezero() 1423 { 1424 struct vm_page *pg; 1425 struct pgfreelist *pgfl; 1426 int free_list, s, firstbucket; 1427 static int nextbucket; 1428 1429 s = uvm_lock_fpageq(); 1430 firstbucket = nextbucket; 1431 do { 1432 if (sched_whichqs != 0) { 1433 uvm_unlock_fpageq(s); 1434 return; 1435 } 1436 if (uvmexp.zeropages >= UVM_PAGEZERO_TARGET) { 1437 uvm.page_idle_zero = FALSE; 1438 uvm_unlock_fpageq(s); 1439 return; 1440 } 1441 for (free_list = 0; free_list < VM_NFREELIST; free_list++) { 1442 pgfl = &uvm.page_free[free_list]; 1443 while ((pg = TAILQ_FIRST(&pgfl->pgfl_buckets[ 1444 nextbucket].pgfl_queues[PGFL_UNKNOWN])) != NULL) { 1445 if (sched_whichqs != 0) { 1446 uvm_unlock_fpageq(s); 1447 return; 1448 } 1449 1450 TAILQ_REMOVE(&pgfl->pgfl_buckets[ 1451 nextbucket].pgfl_queues[PGFL_UNKNOWN], 1452 pg, pageq); 1453 uvmexp.free--; 1454 uvm_unlock_fpageq(s); 1455 #ifdef PMAP_PAGEIDLEZERO 1456 if (!PMAP_PAGEIDLEZERO(VM_PAGE_TO_PHYS(pg))) { 1457 1458 /* 1459 * The machine-dependent code detected 1460 * some reason for us to abort zeroing 1461 * pages, probably because there is a 1462 * process now ready to run. 1463 */ 1464 1465 s = uvm_lock_fpageq(); 1466 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[ 1467 nextbucket].pgfl_queues[ 1468 PGFL_UNKNOWN], pg, pageq); 1469 uvmexp.free++; 1470 uvmexp.zeroaborts++; 1471 uvm_unlock_fpageq(s); 1472 return; 1473 } 1474 #else 1475 pmap_zero_page(VM_PAGE_TO_PHYS(pg)); 1476 #endif /* PMAP_PAGEIDLEZERO */ 1477 pg->flags |= PG_ZERO; 1478 1479 s = uvm_lock_fpageq(); 1480 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[ 1481 nextbucket].pgfl_queues[PGFL_ZEROS], 1482 pg, pageq); 1483 uvmexp.free++; 1484 uvmexp.zeropages++; 1485 } 1486 } 1487 nextbucket = (nextbucket + 1) & uvmexp.colormask; 1488 } while (nextbucket != firstbucket); 1489 uvm_unlock_fpageq(s); 1490 } 1491