| 1 | /* |
| 2 | * (MPSAFE) |
| 3 | * |
| 4 | * Copyright (c) 1991 Regents of the University of California. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to Berkeley by |
| 8 | * The Mach Operating System project at Carnegie-Mellon University. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * 4. Neither the name of the University nor the names of its contributors |
| 19 | * may be used to endorse or promote products derived from this software |
| 20 | * without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 32 | * SUCH DAMAGE. |
| 33 | * |
| 34 | * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 |
| 35 | * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $ |
| 36 | */ |
| 37 | |
| 38 | /* |
| 39 | * Copyright (c) 1987, 1990 Carnegie-Mellon University. |
| 40 | * All rights reserved. |
| 41 | * |
| 42 | * Authors: Avadis Tevanian, Jr., Michael Wayne Young |
| 43 | * |
| 44 | * Permission to use, copy, modify and distribute this software and |
| 45 | * its documentation is hereby granted, provided that both the copyright |
| 46 | * notice and this permission notice appear in all copies of the |
| 47 | * software, derivative works or modified versions, and any portions |
| 48 | * thereof, and that both notices appear in supporting documentation. |
| 49 | * |
| 50 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
| 51 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND |
| 52 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
| 53 | * |
| 54 | * Carnegie Mellon requests users of this software to return to |
| 55 | * |
| 56 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
| 57 | * School of Computer Science |
| 58 | * Carnegie Mellon University |
| 59 | * Pittsburgh PA 15213-3890 |
| 60 | * |
| 61 | * any improvements or extensions that they make and grant Carnegie the |
| 62 | * rights to redistribute these changes. |
| 63 | */ |
| 64 | /* |
| 65 | * Resident memory management module. The module manipulates 'VM pages'. |
| 66 | * A VM page is the core building block for memory management. |
| 67 | */ |
| 68 | |
| 69 | #include <sys/param.h> |
| 70 | #include <sys/systm.h> |
| 71 | #include <sys/malloc.h> |
| 72 | #include <sys/proc.h> |
| 73 | #include <sys/vmmeter.h> |
| 74 | #include <sys/vnode.h> |
| 75 | #include <sys/kernel.h> |
| 76 | #include <sys/alist.h> |
| 77 | #include <sys/sysctl.h> |
| 78 | |
| 79 | #include <vm/vm.h> |
| 80 | #include <vm/vm_param.h> |
| 81 | #include <sys/lock.h> |
| 82 | #include <vm/vm_kern.h> |
| 83 | #include <vm/pmap.h> |
| 84 | #include <vm/vm_map.h> |
| 85 | #include <vm/vm_object.h> |
| 86 | #include <vm/vm_page.h> |
| 87 | #include <vm/vm_pageout.h> |
| 88 | #include <vm/vm_pager.h> |
| 89 | #include <vm/vm_extern.h> |
| 90 | #include <vm/swap_pager.h> |
| 91 | |
| 92 | #include <machine/inttypes.h> |
| 93 | #include <machine/md_var.h> |
| 94 | |
| 95 | #include <vm/vm_page2.h> |
| 96 | #include <sys/spinlock2.h> |
| 97 | |
| 98 | #define VMACTION_HSIZE 256 |
| 99 | #define VMACTION_HMASK (VMACTION_HSIZE - 1) |
| 100 | |
| 101 | static void vm_page_queue_init(void); |
| 102 | static void vm_page_free_wakeup(void); |
| 103 | static vm_page_t vm_page_select_cache(u_short pg_color); |
| 104 | static vm_page_t _vm_page_list_find2(int basequeue, int index); |
| 105 | static void _vm_page_deactivate_locked(vm_page_t m, int athead); |
| 106 | |
| 107 | /* |
| 108 | * Array of tailq lists |
| 109 | */ |
| 110 | __cachealign struct vpgqueues vm_page_queues[PQ_COUNT]; |
| 111 | |
| 112 | LIST_HEAD(vm_page_action_list, vm_page_action); |
| 113 | struct vm_page_action_list action_list[VMACTION_HSIZE]; |
| 114 | static volatile int vm_pages_waiting; |
| 115 | |
| 116 | static struct alist vm_contig_alist; |
| 117 | static struct almeta vm_contig_ameta[ALIST_RECORDS_65536]; |
| 118 | static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin); |
| 119 | |
| 120 | static u_long vm_dma_reserved = 0; |
| 121 | TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved); |
| 122 | SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0, |
| 123 | "Memory reserved for DMA"); |
| 124 | SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD, |
| 125 | &vm_contig_alist.bl_free, 0, "Memory reserved for DMA"); |
| 126 | |
| 127 | static int vm_contig_verbose = 0; |
| 128 | TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose); |
| 129 | |
| 130 | RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, |
| 131 | vm_pindex_t, pindex); |
| 132 | |
| 133 | static void |
| 134 | vm_page_queue_init(void) |
| 135 | { |
| 136 | int i; |
| 137 | |
| 138 | for (i = 0; i < PQ_L2_SIZE; i++) |
| 139 | vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count; |
| 140 | for (i = 0; i < PQ_L2_SIZE; i++) |
| 141 | vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count; |
| 142 | for (i = 0; i < PQ_L2_SIZE; i++) |
| 143 | vm_page_queues[PQ_INACTIVE+i].cnt = &vmstats.v_inactive_count; |
| 144 | for (i = 0; i < PQ_L2_SIZE; i++) |
| 145 | vm_page_queues[PQ_ACTIVE+i].cnt = &vmstats.v_active_count; |
| 146 | for (i = 0; i < PQ_L2_SIZE; i++) |
| 147 | vm_page_queues[PQ_HOLD+i].cnt = &vmstats.v_active_count; |
| 148 | /* PQ_NONE has no queue */ |
| 149 | |
| 150 | for (i = 0; i < PQ_COUNT; i++) { |
| 151 | TAILQ_INIT(&vm_page_queues[i].pl); |
| 152 | spin_init(&vm_page_queues[i].spin); |
| 153 | } |
| 154 | |
| 155 | for (i = 0; i < VMACTION_HSIZE; i++) |
| 156 | LIST_INIT(&action_list[i]); |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * note: place in initialized data section? Is this necessary? |
| 161 | */ |
| 162 | long first_page = 0; |
| 163 | int vm_page_array_size = 0; |
| 164 | int vm_page_zero_count = 0; |
| 165 | vm_page_t vm_page_array = NULL; |
| 166 | vm_paddr_t vm_low_phys_reserved; |
| 167 | |
| 168 | /* |
| 169 | * (low level boot) |
| 170 | * |
| 171 | * Sets the page size, perhaps based upon the memory size. |
| 172 | * Must be called before any use of page-size dependent functions. |
| 173 | */ |
| 174 | void |
| 175 | vm_set_page_size(void) |
| 176 | { |
| 177 | if (vmstats.v_page_size == 0) |
| 178 | vmstats.v_page_size = PAGE_SIZE; |
| 179 | if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0) |
| 180 | panic("vm_set_page_size: page size not a power of two"); |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * (low level boot) |
| 185 | * |
| 186 | * Add a new page to the freelist for use by the system. New pages |
| 187 | * are added to both the head and tail of the associated free page |
| 188 | * queue in a bottom-up fashion, so both zero'd and non-zero'd page |
| 189 | * requests pull 'recent' adds (higher physical addresses) first. |
| 190 | * |
| 191 | * Beware that the page zeroing daemon will also be running soon after |
| 192 | * boot, moving pages from the head to the tail of the PQ_FREE queues. |
| 193 | * |
| 194 | * Must be called in a critical section. |
| 195 | */ |
| 196 | static void |
| 197 | vm_add_new_page(vm_paddr_t pa) |
| 198 | { |
| 199 | struct vpgqueues *vpq; |
| 200 | vm_page_t m; |
| 201 | |
| 202 | m = PHYS_TO_VM_PAGE(pa); |
| 203 | m->phys_addr = pa; |
| 204 | m->flags = 0; |
| 205 | m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; |
| 206 | /* |
| 207 | * Twist for cpu localization in addition to page coloring, so |
| 208 | * different cpus selecting by m->queue get different page colors. |
| 209 | */ |
| 210 | m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE) & PQ_L2_MASK; |
| 211 | m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)) & PQ_L2_MASK; |
| 212 | /* |
| 213 | * Reserve a certain number of contiguous low memory pages for |
| 214 | * contigmalloc() to use. |
| 215 | */ |
| 216 | if (pa < vm_low_phys_reserved) { |
| 217 | atomic_add_int(&vmstats.v_page_count, 1); |
| 218 | atomic_add_int(&vmstats.v_dma_pages, 1); |
| 219 | m->queue = PQ_NONE; |
| 220 | m->wire_count = 1; |
| 221 | atomic_add_int(&vmstats.v_wire_count, 1); |
| 222 | alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1); |
| 223 | return; |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * General page |
| 228 | */ |
| 229 | m->queue = m->pc + PQ_FREE; |
| 230 | KKASSERT(m->dirty == 0); |
| 231 | |
| 232 | atomic_add_int(&vmstats.v_page_count, 1); |
| 233 | atomic_add_int(&vmstats.v_free_count, 1); |
| 234 | vpq = &vm_page_queues[m->queue]; |
| 235 | if ((vpq->flipflop & 15) == 0) { |
| 236 | pmap_zero_page(VM_PAGE_TO_PHYS(m)); |
| 237 | m->flags |= PG_ZERO; |
| 238 | TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); |
| 239 | atomic_add_int(&vm_page_zero_count, 1); |
| 240 | } else { |
| 241 | TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); |
| 242 | } |
| 243 | ++vpq->flipflop; |
| 244 | ++vpq->lcnt; |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * (low level boot) |
| 249 | * |
| 250 | * Initializes the resident memory module. |
| 251 | * |
| 252 | * Preallocates memory for critical VM structures and arrays prior to |
| 253 | * kernel_map becoming available. |
| 254 | * |
| 255 | * Memory is allocated from (virtual2_start, virtual2_end) if available, |
| 256 | * otherwise memory is allocated from (virtual_start, virtual_end). |
| 257 | * |
| 258 | * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be |
| 259 | * large enough to hold vm_page_array & other structures for machines with |
| 260 | * large amounts of ram, so we want to use virtual2* when available. |
| 261 | */ |
| 262 | void |
| 263 | vm_page_startup(void) |
| 264 | { |
| 265 | vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start; |
| 266 | vm_offset_t mapped; |
| 267 | vm_size_t npages; |
| 268 | vm_paddr_t page_range; |
| 269 | vm_paddr_t new_end; |
| 270 | int i; |
| 271 | vm_paddr_t pa; |
| 272 | int nblocks; |
| 273 | vm_paddr_t last_pa; |
| 274 | vm_paddr_t end; |
| 275 | vm_paddr_t biggestone, biggestsize; |
| 276 | vm_paddr_t total; |
| 277 | |
| 278 | total = 0; |
| 279 | biggestsize = 0; |
| 280 | biggestone = 0; |
| 281 | nblocks = 0; |
| 282 | vaddr = round_page(vaddr); |
| 283 | |
| 284 | for (i = 0; phys_avail[i + 1]; i += 2) { |
| 285 | phys_avail[i] = round_page64(phys_avail[i]); |
| 286 | phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]); |
| 287 | } |
| 288 | |
| 289 | for (i = 0; phys_avail[i + 1]; i += 2) { |
| 290 | vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; |
| 291 | |
| 292 | if (size > biggestsize) { |
| 293 | biggestone = i; |
| 294 | biggestsize = size; |
| 295 | } |
| 296 | ++nblocks; |
| 297 | total += size; |
| 298 | } |
| 299 | |
| 300 | end = phys_avail[biggestone+1]; |
| 301 | end = trunc_page(end); |
| 302 | |
| 303 | /* |
| 304 | * Initialize the queue headers for the free queue, the active queue |
| 305 | * and the inactive queue. |
| 306 | */ |
| 307 | vm_page_queue_init(); |
| 308 | |
| 309 | #if !defined(_KERNEL_VIRTUAL) |
| 310 | /* |
| 311 | * VKERNELs don't support minidumps and as such don't need |
| 312 | * vm_page_dump |
| 313 | * |
| 314 | * Allocate a bitmap to indicate that a random physical page |
| 315 | * needs to be included in a minidump. |
| 316 | * |
| 317 | * The amd64 port needs this to indicate which direct map pages |
| 318 | * need to be dumped, via calls to dump_add_page()/dump_drop_page(). |
| 319 | * |
| 320 | * However, i386 still needs this workspace internally within the |
| 321 | * minidump code. In theory, they are not needed on i386, but are |
| 322 | * included should the sf_buf code decide to use them. |
| 323 | */ |
| 324 | page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; |
| 325 | vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); |
| 326 | end -= vm_page_dump_size; |
| 327 | vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size, |
| 328 | VM_PROT_READ | VM_PROT_WRITE); |
| 329 | bzero((void *)vm_page_dump, vm_page_dump_size); |
| 330 | #endif |
| 331 | /* |
| 332 | * Compute the number of pages of memory that will be available for |
| 333 | * use (taking into account the overhead of a page structure per |
| 334 | * page). |
| 335 | */ |
| 336 | first_page = phys_avail[0] / PAGE_SIZE; |
| 337 | page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; |
| 338 | npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE; |
| 339 | |
| 340 | #ifndef _KERNEL_VIRTUAL |
| 341 | /* |
| 342 | * (only applies to real kernels) |
| 343 | * |
| 344 | * Initialize the contiguous reserve map. We initially reserve up |
| 345 | * to 1/4 available physical memory or 65536 pages (~256MB), whichever |
| 346 | * is lower. |
| 347 | * |
| 348 | * Once device initialization is complete we return most of the |
| 349 | * reserved memory back to the normal page queues but leave some |
| 350 | * in reserve for things like usb attachments. |
| 351 | */ |
| 352 | vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT; |
| 353 | if (vm_low_phys_reserved > total / 4) |
| 354 | vm_low_phys_reserved = total / 4; |
| 355 | if (vm_dma_reserved == 0) { |
| 356 | vm_dma_reserved = 16 * 1024 * 1024; /* 16MB */ |
| 357 | if (vm_dma_reserved > total / 16) |
| 358 | vm_dma_reserved = total / 16; |
| 359 | } |
| 360 | #endif |
| 361 | alist_init(&vm_contig_alist, 65536, vm_contig_ameta, |
| 362 | ALIST_RECORDS_65536); |
| 363 | |
| 364 | /* |
| 365 | * Initialize the mem entry structures now, and put them in the free |
| 366 | * queue. |
| 367 | */ |
| 368 | new_end = trunc_page(end - page_range * sizeof(struct vm_page)); |
| 369 | mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE); |
| 370 | vm_page_array = (vm_page_t)mapped; |
| 371 | |
| 372 | #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL) |
| 373 | /* |
| 374 | * since pmap_map on amd64 returns stuff out of a direct-map region, |
| 375 | * we have to manually add these pages to the minidump tracking so |
| 376 | * that they can be dumped, including the vm_page_array. |
| 377 | */ |
| 378 | for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) |
| 379 | dump_add_page(pa); |
| 380 | #endif |
| 381 | |
| 382 | /* |
| 383 | * Clear all of the page structures |
| 384 | */ |
| 385 | bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page)); |
| 386 | vm_page_array_size = page_range; |
| 387 | |
| 388 | /* |
| 389 | * Construct the free queue(s) in ascending order (by physical |
| 390 | * address) so that the first 16MB of physical memory is allocated |
| 391 | * last rather than first. On large-memory machines, this avoids |
| 392 | * the exhaustion of low physical memory before isa_dmainit has run. |
| 393 | */ |
| 394 | vmstats.v_page_count = 0; |
| 395 | vmstats.v_free_count = 0; |
| 396 | for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { |
| 397 | pa = phys_avail[i]; |
| 398 | if (i == biggestone) |
| 399 | last_pa = new_end; |
| 400 | else |
| 401 | last_pa = phys_avail[i + 1]; |
| 402 | while (pa < last_pa && npages-- > 0) { |
| 403 | vm_add_new_page(pa); |
| 404 | pa += PAGE_SIZE; |
| 405 | } |
| 406 | } |
| 407 | if (virtual2_start) |
| 408 | virtual2_start = vaddr; |
| 409 | else |
| 410 | virtual_start = vaddr; |
| 411 | } |
| 412 | |
| 413 | /* |
| 414 | * We tended to reserve a ton of memory for contigmalloc(). Now that most |
| 415 | * drivers have initialized we want to return most the remaining free |
| 416 | * reserve back to the VM page queues so they can be used for normal |
| 417 | * allocations. |
| 418 | * |
| 419 | * We leave vm_dma_reserved bytes worth of free pages in the reserve pool. |
| 420 | */ |
| 421 | static void |
| 422 | vm_page_startup_finish(void *dummy __unused) |
| 423 | { |
| 424 | alist_blk_t blk; |
| 425 | alist_blk_t rblk; |
| 426 | alist_blk_t count; |
| 427 | alist_blk_t xcount; |
| 428 | alist_blk_t bfree; |
| 429 | vm_page_t m; |
| 430 | |
| 431 | spin_lock(&vm_contig_spin); |
| 432 | for (;;) { |
| 433 | bfree = alist_free_info(&vm_contig_alist, &blk, &count); |
| 434 | if (bfree <= vm_dma_reserved / PAGE_SIZE) |
| 435 | break; |
| 436 | if (count == 0) |
| 437 | break; |
| 438 | |
| 439 | /* |
| 440 | * Figure out how much of the initial reserve we have to |
| 441 | * free in order to reach our target. |
| 442 | */ |
| 443 | bfree -= vm_dma_reserved / PAGE_SIZE; |
| 444 | if (count > bfree) { |
| 445 | blk += count - bfree; |
| 446 | count = bfree; |
| 447 | } |
| 448 | |
| 449 | /* |
| 450 | * Calculate the nearest power of 2 <= count. |
| 451 | */ |
| 452 | for (xcount = 1; xcount <= count; xcount <<= 1) |
| 453 | ; |
| 454 | xcount >>= 1; |
| 455 | blk += count - xcount; |
| 456 | count = xcount; |
| 457 | |
| 458 | /* |
| 459 | * Allocate the pages from the alist, then free them to |
| 460 | * the normal VM page queues. |
| 461 | * |
| 462 | * Pages allocated from the alist are wired. We have to |
| 463 | * busy, unwire, and free them. We must also adjust |
| 464 | * vm_low_phys_reserved before freeing any pages to prevent |
| 465 | * confusion. |
| 466 | */ |
| 467 | rblk = alist_alloc(&vm_contig_alist, blk, count); |
| 468 | if (rblk != blk) { |
| 469 | kprintf("vm_page_startup_finish: Unable to return " |
| 470 | "dma space @0x%08x/%d -> 0x%08x\n", |
| 471 | blk, count, rblk); |
| 472 | break; |
| 473 | } |
| 474 | atomic_add_int(&vmstats.v_dma_pages, -count); |
| 475 | spin_unlock(&vm_contig_spin); |
| 476 | |
| 477 | m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); |
| 478 | vm_low_phys_reserved = VM_PAGE_TO_PHYS(m); |
| 479 | while (count) { |
| 480 | vm_page_busy_wait(m, FALSE, "cpgfr"); |
| 481 | vm_page_unwire(m, 0); |
| 482 | vm_page_free(m); |
| 483 | --count; |
| 484 | ++m; |
| 485 | } |
| 486 | spin_lock(&vm_contig_spin); |
| 487 | } |
| 488 | spin_unlock(&vm_contig_spin); |
| 489 | |
| 490 | /* |
| 491 | * Print out how much DMA space drivers have already allocated and |
| 492 | * how much is left over. |
| 493 | */ |
| 494 | kprintf("DMA space used: %jdk, remaining available: %jdk\n", |
| 495 | (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) * |
| 496 | (PAGE_SIZE / 1024), |
| 497 | (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024)); |
| 498 | } |
| 499 | SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY, |
| 500 | vm_page_startup_finish, NULL) |
| 501 | |
| 502 | |
| 503 | /* |
| 504 | * Scan comparison function for Red-Black tree scans. An inclusive |
| 505 | * (start,end) is expected. Other fields are not used. |
| 506 | */ |
| 507 | int |
| 508 | rb_vm_page_scancmp(struct vm_page *p, void *data) |
| 509 | { |
| 510 | struct rb_vm_page_scan_info *info = data; |
| 511 | |
| 512 | if (p->pindex < info->start_pindex) |
| 513 | return(-1); |
| 514 | if (p->pindex > info->end_pindex) |
| 515 | return(1); |
| 516 | return(0); |
| 517 | } |
| 518 | |
| 519 | int |
| 520 | rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2) |
| 521 | { |
| 522 | if (p1->pindex < p2->pindex) |
| 523 | return(-1); |
| 524 | if (p1->pindex > p2->pindex) |
| 525 | return(1); |
| 526 | return(0); |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * Each page queue has its own spin lock, which is fairly optimal for |
| 531 | * allocating and freeing pages at least. |
| 532 | * |
| 533 | * The caller must hold the vm_page_spin_lock() before locking a vm_page's |
| 534 | * queue spinlock via this function. Also note that m->queue cannot change |
| 535 | * unless both the page and queue are locked. |
| 536 | */ |
| 537 | static __inline |
| 538 | void |
| 539 | _vm_page_queue_spin_lock(vm_page_t m) |
| 540 | { |
| 541 | u_short queue; |
| 542 | |
| 543 | queue = m->queue; |
| 544 | if (queue != PQ_NONE) { |
| 545 | spin_lock(&vm_page_queues[queue].spin); |
| 546 | KKASSERT(queue == m->queue); |
| 547 | } |
| 548 | } |
| 549 | |
| 550 | static __inline |
| 551 | void |
| 552 | _vm_page_queue_spin_unlock(vm_page_t m) |
| 553 | { |
| 554 | u_short queue; |
| 555 | |
| 556 | queue = m->queue; |
| 557 | cpu_ccfence(); |
| 558 | if (queue != PQ_NONE) |
| 559 | spin_unlock(&vm_page_queues[queue].spin); |
| 560 | } |
| 561 | |
| 562 | static __inline |
| 563 | void |
| 564 | _vm_page_queues_spin_lock(u_short queue) |
| 565 | { |
| 566 | cpu_ccfence(); |
| 567 | if (queue != PQ_NONE) |
| 568 | spin_lock(&vm_page_queues[queue].spin); |
| 569 | } |
| 570 | |
| 571 | |
| 572 | static __inline |
| 573 | void |
| 574 | _vm_page_queues_spin_unlock(u_short queue) |
| 575 | { |
| 576 | cpu_ccfence(); |
| 577 | if (queue != PQ_NONE) |
| 578 | spin_unlock(&vm_page_queues[queue].spin); |
| 579 | } |
| 580 | |
| 581 | void |
| 582 | vm_page_queue_spin_lock(vm_page_t m) |
| 583 | { |
| 584 | _vm_page_queue_spin_lock(m); |
| 585 | } |
| 586 | |
| 587 | void |
| 588 | vm_page_queues_spin_lock(u_short queue) |
| 589 | { |
| 590 | _vm_page_queues_spin_lock(queue); |
| 591 | } |
| 592 | |
| 593 | void |
| 594 | vm_page_queue_spin_unlock(vm_page_t m) |
| 595 | { |
| 596 | _vm_page_queue_spin_unlock(m); |
| 597 | } |
| 598 | |
| 599 | void |
| 600 | vm_page_queues_spin_unlock(u_short queue) |
| 601 | { |
| 602 | _vm_page_queues_spin_unlock(queue); |
| 603 | } |
| 604 | |
| 605 | /* |
| 606 | * This locks the specified vm_page and its queue in the proper order |
| 607 | * (page first, then queue). The queue may change so the caller must |
| 608 | * recheck on return. |
| 609 | */ |
| 610 | static __inline |
| 611 | void |
| 612 | _vm_page_and_queue_spin_lock(vm_page_t m) |
| 613 | { |
| 614 | vm_page_spin_lock(m); |
| 615 | _vm_page_queue_spin_lock(m); |
| 616 | } |
| 617 | |
| 618 | static __inline |
| 619 | void |
| 620 | _vm_page_and_queue_spin_unlock(vm_page_t m) |
| 621 | { |
| 622 | _vm_page_queues_spin_unlock(m->queue); |
| 623 | vm_page_spin_unlock(m); |
| 624 | } |
| 625 | |
| 626 | void |
| 627 | vm_page_and_queue_spin_unlock(vm_page_t m) |
| 628 | { |
| 629 | _vm_page_and_queue_spin_unlock(m); |
| 630 | } |
| 631 | |
| 632 | void |
| 633 | vm_page_and_queue_spin_lock(vm_page_t m) |
| 634 | { |
| 635 | _vm_page_and_queue_spin_lock(m); |
| 636 | } |
| 637 | |
| 638 | /* |
| 639 | * Helper function removes vm_page from its current queue. |
| 640 | * Returns the base queue the page used to be on. |
| 641 | * |
| 642 | * The vm_page and the queue must be spinlocked. |
| 643 | * This function will unlock the queue but leave the page spinlocked. |
| 644 | */ |
| 645 | static __inline u_short |
| 646 | _vm_page_rem_queue_spinlocked(vm_page_t m) |
| 647 | { |
| 648 | struct vpgqueues *pq; |
| 649 | u_short queue; |
| 650 | |
| 651 | queue = m->queue; |
| 652 | if (queue != PQ_NONE) { |
| 653 | pq = &vm_page_queues[queue]; |
| 654 | TAILQ_REMOVE(&pq->pl, m, pageq); |
| 655 | atomic_add_int(pq->cnt, -1); |
| 656 | pq->lcnt--; |
| 657 | m->queue = PQ_NONE; |
| 658 | vm_page_queues_spin_unlock(queue); |
| 659 | if ((queue - m->pc) == PQ_FREE && (m->flags & PG_ZERO)) |
| 660 | atomic_subtract_int(&vm_page_zero_count, 1); |
| 661 | if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE) |
| 662 | return (queue - m->pc); |
| 663 | } |
| 664 | return queue; |
| 665 | } |
| 666 | |
| 667 | /* |
| 668 | * Helper function places the vm_page on the specified queue. |
| 669 | * |
| 670 | * The vm_page must be spinlocked. |
| 671 | * This function will return with both the page and the queue locked. |
| 672 | */ |
| 673 | static __inline void |
| 674 | _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead) |
| 675 | { |
| 676 | struct vpgqueues *pq; |
| 677 | |
| 678 | KKASSERT(m->queue == PQ_NONE); |
| 679 | |
| 680 | if (queue != PQ_NONE) { |
| 681 | vm_page_queues_spin_lock(queue); |
| 682 | pq = &vm_page_queues[queue]; |
| 683 | ++pq->lcnt; |
| 684 | atomic_add_int(pq->cnt, 1); |
| 685 | m->queue = queue; |
| 686 | |
| 687 | /* |
| 688 | * Put zero'd pages on the end ( where we look for zero'd pages |
| 689 | * first ) and non-zerod pages at the head. |
| 690 | */ |
| 691 | if (queue - m->pc == PQ_FREE) { |
| 692 | if (m->flags & PG_ZERO) { |
| 693 | TAILQ_INSERT_TAIL(&pq->pl, m, pageq); |
| 694 | atomic_add_int(&vm_page_zero_count, 1); |
| 695 | } else { |
| 696 | TAILQ_INSERT_HEAD(&pq->pl, m, pageq); |
| 697 | } |
| 698 | } else if (athead) { |
| 699 | TAILQ_INSERT_HEAD(&pq->pl, m, pageq); |
| 700 | } else { |
| 701 | TAILQ_INSERT_TAIL(&pq->pl, m, pageq); |
| 702 | } |
| 703 | /* leave the queue spinlocked */ |
| 704 | } |
| 705 | } |
| 706 | |
| 707 | /* |
| 708 | * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) |
| 709 | * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we |
| 710 | * did not. Only one sleep call will be made before returning. |
| 711 | * |
| 712 | * This function does NOT busy the page and on return the page is not |
| 713 | * guaranteed to be available. |
| 714 | */ |
| 715 | void |
| 716 | vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) |
| 717 | { |
| 718 | u_int32_t flags; |
| 719 | |
| 720 | for (;;) { |
| 721 | flags = m->flags; |
| 722 | cpu_ccfence(); |
| 723 | |
| 724 | if ((flags & PG_BUSY) == 0 && |
| 725 | (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) { |
| 726 | break; |
| 727 | } |
| 728 | tsleep_interlock(m, 0); |
| 729 | if (atomic_cmpset_int(&m->flags, flags, |
| 730 | flags | PG_WANTED | PG_REFERENCED)) { |
| 731 | tsleep(m, PINTERLOCKED, msg, 0); |
| 732 | break; |
| 733 | } |
| 734 | } |
| 735 | } |
| 736 | |
| 737 | /* |
| 738 | * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we |
| 739 | * also wait for m->busy to become 0 before setting PG_BUSY. |
| 740 | */ |
| 741 | void |
| 742 | VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m, |
| 743 | int also_m_busy, const char *msg |
| 744 | VM_PAGE_DEBUG_ARGS) |
| 745 | { |
| 746 | u_int32_t flags; |
| 747 | |
| 748 | for (;;) { |
| 749 | flags = m->flags; |
| 750 | cpu_ccfence(); |
| 751 | if (flags & PG_BUSY) { |
| 752 | tsleep_interlock(m, 0); |
| 753 | if (atomic_cmpset_int(&m->flags, flags, |
| 754 | flags | PG_WANTED | PG_REFERENCED)) { |
| 755 | tsleep(m, PINTERLOCKED, msg, 0); |
| 756 | } |
| 757 | } else if (also_m_busy && (flags & PG_SBUSY)) { |
| 758 | tsleep_interlock(m, 0); |
| 759 | if (atomic_cmpset_int(&m->flags, flags, |
| 760 | flags | PG_WANTED | PG_REFERENCED)) { |
| 761 | tsleep(m, PINTERLOCKED, msg, 0); |
| 762 | } |
| 763 | } else { |
| 764 | if (atomic_cmpset_int(&m->flags, flags, |
| 765 | flags | PG_BUSY)) { |
| 766 | #ifdef VM_PAGE_DEBUG |
| 767 | m->busy_func = func; |
| 768 | m->busy_line = lineno; |
| 769 | #endif |
| 770 | break; |
| 771 | } |
| 772 | } |
| 773 | } |
| 774 | } |
| 775 | |
| 776 | /* |
| 777 | * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy |
| 778 | * is also 0. |
| 779 | * |
| 780 | * Returns non-zero on failure. |
| 781 | */ |
| 782 | int |
| 783 | VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy |
| 784 | VM_PAGE_DEBUG_ARGS) |
| 785 | { |
| 786 | u_int32_t flags; |
| 787 | |
| 788 | for (;;) { |
| 789 | flags = m->flags; |
| 790 | cpu_ccfence(); |
| 791 | if (flags & PG_BUSY) |
| 792 | return TRUE; |
| 793 | if (also_m_busy && (flags & PG_SBUSY)) |
| 794 | return TRUE; |
| 795 | if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { |
| 796 | #ifdef VM_PAGE_DEBUG |
| 797 | m->busy_func = func; |
| 798 | m->busy_line = lineno; |
| 799 | #endif |
| 800 | return FALSE; |
| 801 | } |
| 802 | } |
| 803 | } |
| 804 | |
| 805 | /* |
| 806 | * Clear the PG_BUSY flag and return non-zero to indicate to the caller |
| 807 | * that a wakeup() should be performed. |
| 808 | * |
| 809 | * The vm_page must be spinlocked and will remain spinlocked on return. |
| 810 | * The related queue must NOT be spinlocked (which could deadlock us). |
| 811 | * |
| 812 | * (inline version) |
| 813 | */ |
| 814 | static __inline |
| 815 | int |
| 816 | _vm_page_wakeup(vm_page_t m) |
| 817 | { |
| 818 | u_int32_t flags; |
| 819 | |
| 820 | for (;;) { |
| 821 | flags = m->flags; |
| 822 | cpu_ccfence(); |
| 823 | if (atomic_cmpset_int(&m->flags, flags, |
| 824 | flags & ~(PG_BUSY | PG_WANTED))) { |
| 825 | break; |
| 826 | } |
| 827 | } |
| 828 | return(flags & PG_WANTED); |
| 829 | } |
| 830 | |
| 831 | /* |
| 832 | * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This |
| 833 | * is typically the last call you make on a page before moving onto |
| 834 | * other things. |
| 835 | */ |
| 836 | void |
| 837 | vm_page_wakeup(vm_page_t m) |
| 838 | { |
| 839 | KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); |
| 840 | vm_page_spin_lock(m); |
| 841 | if (_vm_page_wakeup(m)) { |
| 842 | vm_page_spin_unlock(m); |
| 843 | wakeup(m); |
| 844 | } else { |
| 845 | vm_page_spin_unlock(m); |
| 846 | } |
| 847 | } |
| 848 | |
| 849 | /* |
| 850 | * Holding a page keeps it from being reused. Other parts of the system |
| 851 | * can still disassociate the page from its current object and free it, or |
| 852 | * perform read or write I/O on it and/or otherwise manipulate the page, |
| 853 | * but if the page is held the VM system will leave the page and its data |
| 854 | * intact and not reuse the page for other purposes until the last hold |
| 855 | * reference is released. (see vm_page_wire() if you want to prevent the |
| 856 | * page from being disassociated from its object too). |
| 857 | * |
| 858 | * The caller must still validate the contents of the page and, if necessary, |
| 859 | * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete |
| 860 | * before manipulating the page. |
| 861 | * |
| 862 | * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary |
| 863 | */ |
| 864 | void |
| 865 | vm_page_hold(vm_page_t m) |
| 866 | { |
| 867 | vm_page_spin_lock(m); |
| 868 | atomic_add_int(&m->hold_count, 1); |
| 869 | if (m->queue - m->pc == PQ_FREE) { |
| 870 | _vm_page_queue_spin_lock(m); |
| 871 | _vm_page_rem_queue_spinlocked(m); |
| 872 | _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); |
| 873 | _vm_page_queue_spin_unlock(m); |
| 874 | } |
| 875 | vm_page_spin_unlock(m); |
| 876 | } |
| 877 | |
| 878 | /* |
| 879 | * The opposite of vm_page_hold(). A page can be freed while being held, |
| 880 | * which places it on the PQ_HOLD queue. If we are able to busy the page |
| 881 | * after the hold count drops to zero we will move the page to the |
| 882 | * appropriate PQ_FREE queue by calling vm_page_free_toq(). |
| 883 | */ |
| 884 | void |
| 885 | vm_page_unhold(vm_page_t m) |
| 886 | { |
| 887 | vm_page_spin_lock(m); |
| 888 | atomic_add_int(&m->hold_count, -1); |
| 889 | if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) { |
| 890 | _vm_page_queue_spin_lock(m); |
| 891 | _vm_page_rem_queue_spinlocked(m); |
| 892 | _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); |
| 893 | _vm_page_queue_spin_unlock(m); |
| 894 | } |
| 895 | vm_page_spin_unlock(m); |
| 896 | } |
| 897 | |
| 898 | /* |
| 899 | * Inserts the given vm_page into the object and object list. |
| 900 | * |
| 901 | * The pagetables are not updated but will presumably fault the page |
| 902 | * in if necessary, or if a kernel page the caller will at some point |
| 903 | * enter the page into the kernel's pmap. We are not allowed to block |
| 904 | * here so we *can't* do this anyway. |
| 905 | * |
| 906 | * This routine may not block. |
| 907 | * This routine must be called with the vm_object held. |
| 908 | * This routine must be called with a critical section held. |
| 909 | * |
| 910 | * This routine returns TRUE if the page was inserted into the object |
| 911 | * successfully, and FALSE if the page already exists in the object. |
| 912 | */ |
| 913 | int |
| 914 | vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) |
| 915 | { |
| 916 | ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); |
| 917 | if (m->object != NULL) |
| 918 | panic("vm_page_insert: already inserted"); |
| 919 | |
| 920 | object->generation++; |
| 921 | |
| 922 | /* |
| 923 | * Record the object/offset pair in this page and add the |
| 924 | * pv_list_count of the page to the object. |
| 925 | * |
| 926 | * The vm_page spin lock is required for interactions with the pmap. |
| 927 | */ |
| 928 | vm_page_spin_lock(m); |
| 929 | m->object = object; |
| 930 | m->pindex = pindex; |
| 931 | if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) { |
| 932 | m->object = NULL; |
| 933 | m->pindex = 0; |
| 934 | vm_page_spin_unlock(m); |
| 935 | return FALSE; |
| 936 | } |
| 937 | object->resident_page_count++; |
| 938 | /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */ |
| 939 | vm_page_spin_unlock(m); |
| 940 | |
| 941 | /* |
| 942 | * Since we are inserting a new and possibly dirty page, |
| 943 | * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. |
| 944 | */ |
| 945 | if ((m->valid & m->dirty) || (m->flags & PG_WRITEABLE)) |
| 946 | vm_object_set_writeable_dirty(object); |
| 947 | |
| 948 | /* |
| 949 | * Checks for a swap assignment and sets PG_SWAPPED if appropriate. |
| 950 | */ |
| 951 | swap_pager_page_inserted(m); |
| 952 | return TRUE; |
| 953 | } |
| 954 | |
| 955 | /* |
| 956 | * Removes the given vm_page_t from the (object,index) table |
| 957 | * |
| 958 | * The underlying pmap entry (if any) is NOT removed here. |
| 959 | * This routine may not block. |
| 960 | * |
| 961 | * The page must be BUSY and will remain BUSY on return. |
| 962 | * No other requirements. |
| 963 | * |
| 964 | * NOTE: FreeBSD side effect was to unbusy the page on return. We leave |
| 965 | * it busy. |
| 966 | */ |
| 967 | void |
| 968 | vm_page_remove(vm_page_t m) |
| 969 | { |
| 970 | vm_object_t object; |
| 971 | |
| 972 | if (m->object == NULL) { |
| 973 | return; |
| 974 | } |
| 975 | |
| 976 | if ((m->flags & PG_BUSY) == 0) |
| 977 | panic("vm_page_remove: page not busy"); |
| 978 | |
| 979 | object = m->object; |
| 980 | |
| 981 | vm_object_hold(object); |
| 982 | |
| 983 | /* |
| 984 | * Remove the page from the object and update the object. |
| 985 | * |
| 986 | * The vm_page spin lock is required for interactions with the pmap. |
| 987 | */ |
| 988 | vm_page_spin_lock(m); |
| 989 | vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); |
| 990 | object->resident_page_count--; |
| 991 | /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */ |
| 992 | m->object = NULL; |
| 993 | vm_page_spin_unlock(m); |
| 994 | |
| 995 | object->generation++; |
| 996 | |
| 997 | vm_object_drop(object); |
| 998 | } |
| 999 | |
| 1000 | /* |
| 1001 | * Locate and return the page at (object, pindex), or NULL if the |
| 1002 | * page could not be found. |
| 1003 | * |
| 1004 | * The caller must hold the vm_object token. |
| 1005 | */ |
| 1006 | vm_page_t |
| 1007 | vm_page_lookup(vm_object_t object, vm_pindex_t pindex) |
| 1008 | { |
| 1009 | vm_page_t m; |
| 1010 | |
| 1011 | /* |
| 1012 | * Search the hash table for this object/offset pair |
| 1013 | */ |
| 1014 | ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); |
| 1015 | m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); |
| 1016 | KKASSERT(m == NULL || (m->object == object && m->pindex == pindex)); |
| 1017 | return(m); |
| 1018 | } |
| 1019 | |
| 1020 | vm_page_t |
| 1021 | VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object, |
| 1022 | vm_pindex_t pindex, |
| 1023 | int also_m_busy, const char *msg |
| 1024 | VM_PAGE_DEBUG_ARGS) |
| 1025 | { |
| 1026 | u_int32_t flags; |
| 1027 | vm_page_t m; |
| 1028 | |
| 1029 | ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); |
| 1030 | m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); |
| 1031 | while (m) { |
| 1032 | KKASSERT(m->object == object && m->pindex == pindex); |
| 1033 | flags = m->flags; |
| 1034 | cpu_ccfence(); |
| 1035 | if (flags & PG_BUSY) { |
| 1036 | tsleep_interlock(m, 0); |
| 1037 | if (atomic_cmpset_int(&m->flags, flags, |
| 1038 | flags | PG_WANTED | PG_REFERENCED)) { |
| 1039 | tsleep(m, PINTERLOCKED, msg, 0); |
| 1040 | m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, |
| 1041 | pindex); |
| 1042 | } |
| 1043 | } else if (also_m_busy && (flags & PG_SBUSY)) { |
| 1044 | tsleep_interlock(m, 0); |
| 1045 | if (atomic_cmpset_int(&m->flags, flags, |
| 1046 | flags | PG_WANTED | PG_REFERENCED)) { |
| 1047 | tsleep(m, PINTERLOCKED, msg, 0); |
| 1048 | m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, |
| 1049 | pindex); |
| 1050 | } |
| 1051 | } else if (atomic_cmpset_int(&m->flags, flags, |
| 1052 | flags | PG_BUSY)) { |
| 1053 | #ifdef VM_PAGE_DEBUG |
| 1054 | m->busy_func = func; |
| 1055 | m->busy_line = lineno; |
| 1056 | #endif |
| 1057 | break; |
| 1058 | } |
| 1059 | } |
| 1060 | return m; |
| 1061 | } |
| 1062 | |
| 1063 | /* |
| 1064 | * Attempt to lookup and busy a page. |
| 1065 | * |
| 1066 | * Returns NULL if the page could not be found |
| 1067 | * |
| 1068 | * Returns a vm_page and error == TRUE if the page exists but could not |
| 1069 | * be busied. |
| 1070 | * |
| 1071 | * Returns a vm_page and error == FALSE on success. |
| 1072 | */ |
| 1073 | vm_page_t |
| 1074 | VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object, |
| 1075 | vm_pindex_t pindex, |
| 1076 | int also_m_busy, int *errorp |
| 1077 | VM_PAGE_DEBUG_ARGS) |
| 1078 | { |
| 1079 | u_int32_t flags; |
| 1080 | vm_page_t m; |
| 1081 | |
| 1082 | ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); |
| 1083 | m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); |
| 1084 | *errorp = FALSE; |
| 1085 | while (m) { |
| 1086 | KKASSERT(m->object == object && m->pindex == pindex); |
| 1087 | flags = m->flags; |
| 1088 | cpu_ccfence(); |
| 1089 | if (flags & PG_BUSY) { |
| 1090 | *errorp = TRUE; |
| 1091 | break; |
| 1092 | } |
| 1093 | if (also_m_busy && (flags & PG_SBUSY)) { |
| 1094 | *errorp = TRUE; |
| 1095 | break; |
| 1096 | } |
| 1097 | if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { |
| 1098 | #ifdef VM_PAGE_DEBUG |
| 1099 | m->busy_func = func; |
| 1100 | m->busy_line = lineno; |
| 1101 | #endif |
| 1102 | break; |
| 1103 | } |
| 1104 | } |
| 1105 | return m; |
| 1106 | } |
| 1107 | |
| 1108 | /* |
| 1109 | * Caller must hold the related vm_object |
| 1110 | */ |
| 1111 | vm_page_t |
| 1112 | vm_page_next(vm_page_t m) |
| 1113 | { |
| 1114 | vm_page_t next; |
| 1115 | |
| 1116 | next = vm_page_rb_tree_RB_NEXT(m); |
| 1117 | if (next && next->pindex != m->pindex + 1) |
| 1118 | next = NULL; |
| 1119 | return (next); |
| 1120 | } |
| 1121 | |
| 1122 | /* |
| 1123 | * vm_page_rename() |
| 1124 | * |
| 1125 | * Move the given vm_page from its current object to the specified |
| 1126 | * target object/offset. The page must be busy and will remain so |
| 1127 | * on return. |
| 1128 | * |
| 1129 | * new_object must be held. |
| 1130 | * This routine might block. XXX ? |
| 1131 | * |
| 1132 | * NOTE: Swap associated with the page must be invalidated by the move. We |
| 1133 | * have to do this for several reasons: (1) we aren't freeing the |
| 1134 | * page, (2) we are dirtying the page, (3) the VM system is probably |
| 1135 | * moving the page from object A to B, and will then later move |
| 1136 | * the backing store from A to B and we can't have a conflict. |
| 1137 | * |
| 1138 | * NOTE: We *always* dirty the page. It is necessary both for the |
| 1139 | * fact that we moved it, and because we may be invalidating |
| 1140 | * swap. If the page is on the cache, we have to deactivate it |
| 1141 | * or vm_page_dirty() will panic. Dirty pages are not allowed |
| 1142 | * on the cache. |
| 1143 | */ |
| 1144 | void |
| 1145 | vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) |
| 1146 | { |
| 1147 | KKASSERT(m->flags & PG_BUSY); |
| 1148 | ASSERT_LWKT_TOKEN_HELD(vm_object_token(new_object)); |
| 1149 | if (m->object) { |
| 1150 | ASSERT_LWKT_TOKEN_HELD(vm_object_token(m->object)); |
| 1151 | vm_page_remove(m); |
| 1152 | } |
| 1153 | if (vm_page_insert(m, new_object, new_pindex) == FALSE) { |
| 1154 | panic("vm_page_rename: target exists (%p,%"PRIu64")", |
| 1155 | new_object, new_pindex); |
| 1156 | } |
| 1157 | if (m->queue - m->pc == PQ_CACHE) |
| 1158 | vm_page_deactivate(m); |
| 1159 | vm_page_dirty(m); |
| 1160 | } |
| 1161 | |
| 1162 | /* |
| 1163 | * vm_page_unqueue() without any wakeup. This routine is used when a page |
| 1164 | * is being moved between queues or otherwise is to remain BUSYied by the |
| 1165 | * caller. |
| 1166 | * |
| 1167 | * This routine may not block. |
| 1168 | */ |
| 1169 | void |
| 1170 | vm_page_unqueue_nowakeup(vm_page_t m) |
| 1171 | { |
| 1172 | vm_page_and_queue_spin_lock(m); |
| 1173 | (void)_vm_page_rem_queue_spinlocked(m); |
| 1174 | vm_page_spin_unlock(m); |
| 1175 | } |
| 1176 | |
| 1177 | /* |
| 1178 | * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon |
| 1179 | * if necessary. |
| 1180 | * |
| 1181 | * This routine may not block. |
| 1182 | */ |
| 1183 | void |
| 1184 | vm_page_unqueue(vm_page_t m) |
| 1185 | { |
| 1186 | u_short queue; |
| 1187 | |
| 1188 | vm_page_and_queue_spin_lock(m); |
| 1189 | queue = _vm_page_rem_queue_spinlocked(m); |
| 1190 | if (queue == PQ_FREE || queue == PQ_CACHE) { |
| 1191 | vm_page_spin_unlock(m); |
| 1192 | pagedaemon_wakeup(); |
| 1193 | } else { |
| 1194 | vm_page_spin_unlock(m); |
| 1195 | } |
| 1196 | } |
| 1197 | |
| 1198 | /* |
| 1199 | * vm_page_list_find() |
| 1200 | * |
| 1201 | * Find a page on the specified queue with color optimization. |
| 1202 | * |
| 1203 | * The page coloring optimization attempts to locate a page that does |
| 1204 | * not overload other nearby pages in the object in the cpu's L1 or L2 |
| 1205 | * caches. We need this optimization because cpu caches tend to be |
| 1206 | * physical caches, while object spaces tend to be virtual. |
| 1207 | * |
| 1208 | * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock |
| 1209 | * and the algorithm is adjusted to localize allocations on a per-core basis. |
| 1210 | * This is done by 'twisting' the colors. |
| 1211 | * |
| 1212 | * The page is returned spinlocked and removed from its queue (it will |
| 1213 | * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller |
| 1214 | * is responsible for dealing with the busy-page case (usually by |
| 1215 | * deactivating the page and looping). |
| 1216 | * |
| 1217 | * NOTE: This routine is carefully inlined. A non-inlined version |
| 1218 | * is available for outside callers but the only critical path is |
| 1219 | * from within this source file. |
| 1220 | * |
| 1221 | * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE |
| 1222 | * represent stable storage, allowing us to order our locks vm_page |
| 1223 | * first, then queue. |
| 1224 | */ |
| 1225 | static __inline |
| 1226 | vm_page_t |
| 1227 | _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) |
| 1228 | { |
| 1229 | vm_page_t m; |
| 1230 | |
| 1231 | for (;;) { |
| 1232 | if (prefer_zero) |
| 1233 | m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist); |
| 1234 | else |
| 1235 | m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl); |
| 1236 | if (m == NULL) { |
| 1237 | m = _vm_page_list_find2(basequeue, index); |
| 1238 | return(m); |
| 1239 | } |
| 1240 | vm_page_and_queue_spin_lock(m); |
| 1241 | if (m->queue == basequeue + index) { |
| 1242 | _vm_page_rem_queue_spinlocked(m); |
| 1243 | /* vm_page_t spin held, no queue spin */ |
| 1244 | break; |
| 1245 | } |
| 1246 | vm_page_and_queue_spin_unlock(m); |
| 1247 | } |
| 1248 | return(m); |
| 1249 | } |
| 1250 | |
| 1251 | static vm_page_t |
| 1252 | _vm_page_list_find2(int basequeue, int index) |
| 1253 | { |
| 1254 | int i; |
| 1255 | vm_page_t m = NULL; |
| 1256 | struct vpgqueues *pq; |
| 1257 | |
| 1258 | pq = &vm_page_queues[basequeue]; |
| 1259 | |
| 1260 | /* |
| 1261 | * Note that for the first loop, index+i and index-i wind up at the |
| 1262 | * same place. Even though this is not totally optimal, we've already |
| 1263 | * blown it by missing the cache case so we do not care. |
| 1264 | */ |
| 1265 | for (i = PQ_L2_SIZE / 2; i > 0; --i) { |
| 1266 | for (;;) { |
| 1267 | m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl); |
| 1268 | if (m) { |
| 1269 | _vm_page_and_queue_spin_lock(m); |
| 1270 | if (m->queue == |
| 1271 | basequeue + ((index + i) & PQ_L2_MASK)) { |
| 1272 | _vm_page_rem_queue_spinlocked(m); |
| 1273 | return(m); |
| 1274 | } |
| 1275 | _vm_page_and_queue_spin_unlock(m); |
| 1276 | continue; |
| 1277 | } |
| 1278 | m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl); |
| 1279 | if (m) { |
| 1280 | _vm_page_and_queue_spin_lock(m); |
| 1281 | if (m->queue == |
| 1282 | basequeue + ((index - i) & PQ_L2_MASK)) { |
| 1283 | _vm_page_rem_queue_spinlocked(m); |
| 1284 | return(m); |
| 1285 | } |
| 1286 | _vm_page_and_queue_spin_unlock(m); |
| 1287 | continue; |
| 1288 | } |
| 1289 | break; /* next i */ |
| 1290 | } |
| 1291 | } |
| 1292 | return(m); |
| 1293 | } |
| 1294 | |
| 1295 | /* |
| 1296 | * Returns a vm_page candidate for allocation. The page is not busied so |
| 1297 | * it can move around. The caller must busy the page (and typically |
| 1298 | * deactivate it if it cannot be busied!) |
| 1299 | * |
| 1300 | * Returns a spinlocked vm_page that has been removed from its queue. |
| 1301 | */ |
| 1302 | vm_page_t |
| 1303 | vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) |
| 1304 | { |
| 1305 | return(_vm_page_list_find(basequeue, index, prefer_zero)); |
| 1306 | } |
| 1307 | |
| 1308 | /* |
| 1309 | * Find a page on the cache queue with color optimization, remove it |
| 1310 | * from the queue, and busy it. The returned page will not be spinlocked. |
| 1311 | * |
| 1312 | * A candidate failure will be deactivated. Candidates can fail due to |
| 1313 | * being busied by someone else, in which case they will be deactivated. |
| 1314 | * |
| 1315 | * This routine may not block. |
| 1316 | * |
| 1317 | */ |
| 1318 | static vm_page_t |
| 1319 | vm_page_select_cache(u_short pg_color) |
| 1320 | { |
| 1321 | vm_page_t m; |
| 1322 | |
| 1323 | for (;;) { |
| 1324 | m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK, FALSE); |
| 1325 | if (m == NULL) |
| 1326 | break; |
| 1327 | /* |
| 1328 | * (m) has been removed from its queue and spinlocked |
| 1329 | */ |
| 1330 | if (vm_page_busy_try(m, TRUE)) { |
| 1331 | _vm_page_deactivate_locked(m, 0); |
| 1332 | vm_page_spin_unlock(m); |
| 1333 | #ifdef INVARIANTS |
| 1334 | kprintf("Warning: busy page %p found in cache\n", m); |
| 1335 | #endif |
| 1336 | } else { |
| 1337 | /* |
| 1338 | * We successfully busied the page |
| 1339 | */ |
| 1340 | if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) == 0 && |
| 1341 | m->hold_count == 0 && |
| 1342 | m->wire_count == 0 && |
| 1343 | (m->dirty & m->valid) == 0) { |
| 1344 | vm_page_spin_unlock(m); |
| 1345 | pagedaemon_wakeup(); |
| 1346 | return(m); |
| 1347 | } |
| 1348 | |
| 1349 | /* |
| 1350 | * The page cannot be recycled, deactivate it. |
| 1351 | */ |
| 1352 | _vm_page_deactivate_locked(m, 0); |
| 1353 | if (_vm_page_wakeup(m)) { |
| 1354 | vm_page_spin_unlock(m); |
| 1355 | wakeup(m); |
| 1356 | } else { |
| 1357 | vm_page_spin_unlock(m); |
| 1358 | } |
| 1359 | } |
| 1360 | } |
| 1361 | return (m); |
| 1362 | } |
| 1363 | |
| 1364 | /* |
| 1365 | * Find a free or zero page, with specified preference. We attempt to |
| 1366 | * inline the nominal case and fall back to _vm_page_select_free() |
| 1367 | * otherwise. A busied page is removed from the queue and returned. |
| 1368 | * |
| 1369 | * This routine may not block. |
| 1370 | */ |
| 1371 | static __inline vm_page_t |
| 1372 | vm_page_select_free(u_short pg_color, boolean_t prefer_zero) |
| 1373 | { |
| 1374 | vm_page_t m; |
| 1375 | |
| 1376 | for (;;) { |
| 1377 | m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK, |
| 1378 | prefer_zero); |
| 1379 | if (m == NULL) |
| 1380 | break; |
| 1381 | if (vm_page_busy_try(m, TRUE)) { |
| 1382 | /* |
| 1383 | * Various mechanisms such as a pmap_collect can |
| 1384 | * result in a busy page on the free queue. We |
| 1385 | * have to move the page out of the way so we can |
| 1386 | * retry the allocation. If the other thread is not |
| 1387 | * allocating the page then m->valid will remain 0 and |
| 1388 | * the pageout daemon will free the page later on. |
| 1389 | * |
| 1390 | * Since we could not busy the page, however, we |
| 1391 | * cannot make assumptions as to whether the page |
| 1392 | * will be allocated by the other thread or not, |
| 1393 | * so all we can do is deactivate it to move it out |
| 1394 | * of the way. In particular, if the other thread |
| 1395 | * wires the page it may wind up on the inactive |
| 1396 | * queue and the pageout daemon will have to deal |
| 1397 | * with that case too. |
| 1398 | */ |
| 1399 | _vm_page_deactivate_locked(m, 0); |
| 1400 | vm_page_spin_unlock(m); |
| 1401 | #ifdef INVARIANTS |
| 1402 | kprintf("Warning: busy page %p found in cache\n", m); |
| 1403 | #endif |
| 1404 | } else { |
| 1405 | /* |
| 1406 | * Theoretically if we are able to busy the page |
| 1407 | * atomic with the queue removal (using the vm_page |
| 1408 | * lock) nobody else should be able to mess with the |
| 1409 | * page before us. |
| 1410 | */ |
| 1411 | KKASSERT((m->flags & (PG_UNMANAGED | |
| 1412 | PG_NEED_COMMIT)) == 0); |
| 1413 | KKASSERT(m->hold_count == 0); |
| 1414 | KKASSERT(m->wire_count == 0); |
| 1415 | vm_page_spin_unlock(m); |
| 1416 | pagedaemon_wakeup(); |
| 1417 | |
| 1418 | /* return busied and removed page */ |
| 1419 | return(m); |
| 1420 | } |
| 1421 | } |
| 1422 | return(m); |
| 1423 | } |
| 1424 | |
| 1425 | /* |
| 1426 | * This implements a per-cpu cache of free, zero'd, ready-to-go pages. |
| 1427 | * The idea is to populate this cache prior to acquiring any locks so |
| 1428 | * we don't wind up potentially zeroing VM pages (under heavy loads) while |
| 1429 | * holding potentialy contending locks. |
| 1430 | * |
| 1431 | * Note that we allocate the page uninserted into anything and use a pindex |
| 1432 | * of 0, the vm_page_alloc() will effectively add gd_cpuid so these |
| 1433 | * allocations should wind up being uncontended. However, we still want |
| 1434 | * to rove across PQ_L2_SIZE. |
| 1435 | */ |
| 1436 | void |
| 1437 | vm_page_pcpu_cache(void) |
| 1438 | { |
| 1439 | #if 0 |
| 1440 | globaldata_t gd = mycpu; |
| 1441 | vm_page_t m; |
| 1442 | |
| 1443 | if (gd->gd_vmpg_count < GD_MINVMPG) { |
| 1444 | crit_enter_gd(gd); |
| 1445 | while (gd->gd_vmpg_count < GD_MAXVMPG) { |
| 1446 | m = vm_page_alloc(NULL, ticks & ~ncpus2_mask, |
| 1447 | VM_ALLOC_NULL_OK | VM_ALLOC_NORMAL | |
| 1448 | VM_ALLOC_NULL_OK | VM_ALLOC_ZERO); |
| 1449 | if (gd->gd_vmpg_count < GD_MAXVMPG) { |
| 1450 | if ((m->flags & PG_ZERO) == 0) { |
| 1451 | pmap_zero_page(VM_PAGE_TO_PHYS(m)); |
| 1452 | vm_page_flag_set(m, PG_ZERO); |
| 1453 | } |
| 1454 | gd->gd_vmpg_array[gd->gd_vmpg_count++] = m; |
| 1455 | } else { |
| 1456 | vm_page_free(m); |
| 1457 | } |
| 1458 | } |
| 1459 | crit_exit_gd(gd); |
| 1460 | } |
| 1461 | #endif |
| 1462 | } |
| 1463 | |
| 1464 | /* |
| 1465 | * vm_page_alloc() |
| 1466 | * |
| 1467 | * Allocate and return a memory cell associated with this VM object/offset |
| 1468 | * pair. If object is NULL an unassociated page will be allocated. |
| 1469 | * |
| 1470 | * The returned page will be busied and removed from its queues. This |
| 1471 | * routine can block and may return NULL if a race occurs and the page |
| 1472 | * is found to already exist at the specified (object, pindex). |
| 1473 | * |
| 1474 | * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain |
| 1475 | * VM_ALLOC_QUICK like normal but cannot use cache |
| 1476 | * VM_ALLOC_SYSTEM greater free drain |
| 1477 | * VM_ALLOC_INTERRUPT allow free list to be completely drained |
| 1478 | * VM_ALLOC_ZERO advisory request for pre-zero'd page only |
| 1479 | * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only |
| 1480 | * VM_ALLOC_NULL_OK ok to return NULL on insertion collision |
| 1481 | * (see vm_page_grab()) |
| 1482 | * VM_ALLOC_USE_GD ok to use per-gd cache |
| 1483 | * |
| 1484 | * The object must be held if not NULL |
| 1485 | * This routine may not block |
| 1486 | * |
| 1487 | * Additional special handling is required when called from an interrupt |
| 1488 | * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache |
| 1489 | * in this case. |
| 1490 | */ |
| 1491 | vm_page_t |
| 1492 | vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req) |
| 1493 | { |
| 1494 | globaldata_t gd = mycpu; |
| 1495 | vm_object_t obj; |
| 1496 | vm_page_t m; |
| 1497 | u_short pg_color; |
| 1498 | |
| 1499 | #if 0 |
| 1500 | /* |
| 1501 | * Special per-cpu free VM page cache. The pages are pre-busied |
| 1502 | * and pre-zerod for us. |
| 1503 | */ |
| 1504 | if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) { |
| 1505 | crit_enter_gd(gd); |
| 1506 | if (gd->gd_vmpg_count) { |
| 1507 | m = gd->gd_vmpg_array[--gd->gd_vmpg_count]; |
| 1508 | crit_exit_gd(gd); |
| 1509 | goto done; |
| 1510 | } |
| 1511 | crit_exit_gd(gd); |
| 1512 | } |
| 1513 | #endif |
| 1514 | m = NULL; |
| 1515 | |
| 1516 | /* |
| 1517 | * Cpu twist - cpu localization algorithm |
| 1518 | */ |
| 1519 | if (object) { |
| 1520 | pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask) + |
| 1521 | (object->pg_color & ~ncpus_fit_mask); |
| 1522 | } else { |
| 1523 | pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask); |
| 1524 | } |
| 1525 | KKASSERT(page_req & |
| 1526 | (VM_ALLOC_NORMAL|VM_ALLOC_QUICK| |
| 1527 | VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); |
| 1528 | |
| 1529 | /* |
| 1530 | * Certain system threads (pageout daemon, buf_daemon's) are |
| 1531 | * allowed to eat deeper into the free page list. |
| 1532 | */ |
| 1533 | if (curthread->td_flags & TDF_SYSTHREAD) |
| 1534 | page_req |= VM_ALLOC_SYSTEM; |
| 1535 | |
| 1536 | loop: |
| 1537 | if (vmstats.v_free_count > vmstats.v_free_reserved || |
| 1538 | ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) || |
| 1539 | ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 && |
| 1540 | vmstats.v_free_count > vmstats.v_interrupt_free_min) |
| 1541 | ) { |
| 1542 | /* |
| 1543 | * The free queue has sufficient free pages to take one out. |
| 1544 | */ |
| 1545 | if (page_req & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) |
| 1546 | m = vm_page_select_free(pg_color, TRUE); |
| 1547 | else |
| 1548 | m = vm_page_select_free(pg_color, FALSE); |
| 1549 | } else if (page_req & VM_ALLOC_NORMAL) { |
| 1550 | /* |
| 1551 | * Allocatable from the cache (non-interrupt only). On |
| 1552 | * success, we must free the page and try again, thus |
| 1553 | * ensuring that vmstats.v_*_free_min counters are replenished. |
| 1554 | */ |
| 1555 | #ifdef INVARIANTS |
| 1556 | if (curthread->td_preempted) { |
| 1557 | kprintf("vm_page_alloc(): warning, attempt to allocate" |
| 1558 | " cache page from preempting interrupt\n"); |
| 1559 | m = NULL; |
| 1560 | } else { |
| 1561 | m = vm_page_select_cache(pg_color); |
| 1562 | } |
| 1563 | #else |
| 1564 | m = vm_page_select_cache(pg_color); |
| 1565 | #endif |
| 1566 | /* |
| 1567 | * On success move the page into the free queue and loop. |
| 1568 | * |
| 1569 | * Only do this if we can safely acquire the vm_object lock, |
| 1570 | * because this is effectively a random page and the caller |
| 1571 | * might be holding the lock shared, we don't want to |
| 1572 | * deadlock. |
| 1573 | */ |
| 1574 | if (m != NULL) { |
| 1575 | KASSERT(m->dirty == 0, |
| 1576 | ("Found dirty cache page %p", m)); |
| 1577 | if ((obj = m->object) != NULL) { |
| 1578 | if (vm_object_hold_try(obj)) { |
| 1579 | vm_page_protect(m, VM_PROT_NONE); |
| 1580 | vm_page_free(m); |
| 1581 | /* m->object NULL here */ |
| 1582 | vm_object_drop(obj); |
| 1583 | } else { |
| 1584 | vm_page_deactivate(m); |
| 1585 | vm_page_wakeup(m); |
| 1586 | } |
| 1587 | } else { |
| 1588 | vm_page_protect(m, VM_PROT_NONE); |
| 1589 | vm_page_free(m); |
| 1590 | } |
| 1591 | goto loop; |
| 1592 | } |
| 1593 | |
| 1594 | /* |
| 1595 | * On failure return NULL |
| 1596 | */ |
| 1597 | #if defined(DIAGNOSTIC) |
| 1598 | if (vmstats.v_cache_count > 0) |
| 1599 | kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count); |
| 1600 | #endif |
| 1601 | vm_pageout_deficit++; |
| 1602 | pagedaemon_wakeup(); |
| 1603 | return (NULL); |
| 1604 | } else { |
| 1605 | /* |
| 1606 | * No pages available, wakeup the pageout daemon and give up. |
| 1607 | */ |
| 1608 | vm_pageout_deficit++; |
| 1609 | pagedaemon_wakeup(); |
| 1610 | return (NULL); |
| 1611 | } |
| 1612 | |
| 1613 | /* |
| 1614 | * v_free_count can race so loop if we don't find the expected |
| 1615 | * page. |
| 1616 | */ |
| 1617 | if (m == NULL) |
| 1618 | goto loop; |
| 1619 | |
| 1620 | /* |
| 1621 | * Good page found. The page has already been busied for us and |
| 1622 | * removed from its queues. |
| 1623 | */ |
| 1624 | KASSERT(m->dirty == 0, |
| 1625 | ("vm_page_alloc: free/cache page %p was dirty", m)); |
| 1626 | KKASSERT(m->queue == PQ_NONE); |
| 1627 | |
| 1628 | #if 0 |
| 1629 | done: |
| 1630 | #endif |
| 1631 | /* |
| 1632 | * Initialize the structure, inheriting some flags but clearing |
| 1633 | * all the rest. The page has already been busied for us. |
| 1634 | */ |
| 1635 | vm_page_flag_clear(m, ~(PG_ZERO | PG_BUSY | PG_SBUSY)); |
| 1636 | KKASSERT(m->wire_count == 0); |
| 1637 | KKASSERT(m->busy == 0); |
| 1638 | m->act_count = 0; |
| 1639 | m->valid = 0; |
| 1640 | |
| 1641 | /* |
| 1642 | * Caller must be holding the object lock (asserted by |
| 1643 | * vm_page_insert()). |
| 1644 | * |
| 1645 | * NOTE: Inserting a page here does not insert it into any pmaps |
| 1646 | * (which could cause us to block allocating memory). |
| 1647 | * |
| 1648 | * NOTE: If no object an unassociated page is allocated, m->pindex |
| 1649 | * can be used by the caller for any purpose. |
| 1650 | */ |
| 1651 | if (object) { |
| 1652 | if (vm_page_insert(m, object, pindex) == FALSE) { |
| 1653 | kprintf("PAGE RACE (%p:%d,%"PRIu64")\n", |
| 1654 | object, object->type, pindex); |
| 1655 | vm_page_free(m); |
| 1656 | m = NULL; |
| 1657 | if ((page_req & VM_ALLOC_NULL_OK) == 0) |
| 1658 | panic("PAGE RACE"); |
| 1659 | } |
| 1660 | } else { |
| 1661 | m->pindex = pindex; |
| 1662 | } |
| 1663 | |
| 1664 | /* |
| 1665 | * Don't wakeup too often - wakeup the pageout daemon when |
| 1666 | * we would be nearly out of memory. |
| 1667 | */ |
| 1668 | pagedaemon_wakeup(); |
| 1669 | |
| 1670 | /* |
| 1671 | * A PG_BUSY page is returned. |
| 1672 | */ |
| 1673 | return (m); |
| 1674 | } |
| 1675 | |
| 1676 | /* |
| 1677 | * Attempt to allocate contiguous physical memory with the specified |
| 1678 | * requirements. |
| 1679 | */ |
| 1680 | vm_page_t |
| 1681 | vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high, |
| 1682 | unsigned long alignment, unsigned long boundary, |
| 1683 | unsigned long size) |
| 1684 | { |
| 1685 | alist_blk_t blk; |
| 1686 | |
| 1687 | alignment >>= PAGE_SHIFT; |
| 1688 | if (alignment == 0) |
| 1689 | alignment = 1; |
| 1690 | boundary >>= PAGE_SHIFT; |
| 1691 | if (boundary == 0) |
| 1692 | boundary = 1; |
| 1693 | size = (size + PAGE_MASK) >> PAGE_SHIFT; |
| 1694 | |
| 1695 | spin_lock(&vm_contig_spin); |
| 1696 | blk = alist_alloc(&vm_contig_alist, 0, size); |
| 1697 | if (blk == ALIST_BLOCK_NONE) { |
| 1698 | spin_unlock(&vm_contig_spin); |
| 1699 | if (bootverbose) { |
| 1700 | kprintf("vm_page_alloc_contig: %ldk nospace\n", |
| 1701 | (size + PAGE_MASK) * (PAGE_SIZE / 1024)); |
| 1702 | } |
| 1703 | return(NULL); |
| 1704 | } |
| 1705 | if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) { |
| 1706 | alist_free(&vm_contig_alist, blk, size); |
| 1707 | spin_unlock(&vm_contig_spin); |
| 1708 | if (bootverbose) { |
| 1709 | kprintf("vm_page_alloc_contig: %ldk high " |
| 1710 | "%016jx failed\n", |
| 1711 | (size + PAGE_MASK) * (PAGE_SIZE / 1024), |
| 1712 | (intmax_t)high); |
| 1713 | } |
| 1714 | return(NULL); |
| 1715 | } |
| 1716 | spin_unlock(&vm_contig_spin); |
| 1717 | if (vm_contig_verbose) { |
| 1718 | kprintf("vm_page_alloc_contig: %016jx/%ldk\n", |
| 1719 | (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT, |
| 1720 | (size + PAGE_MASK) * (PAGE_SIZE / 1024)); |
| 1721 | } |
| 1722 | return (PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT)); |
| 1723 | } |
| 1724 | |
| 1725 | /* |
| 1726 | * Free contiguously allocated pages. The pages will be wired but not busy. |
| 1727 | * When freeing to the alist we leave them wired and not busy. |
| 1728 | */ |
| 1729 | void |
| 1730 | vm_page_free_contig(vm_page_t m, unsigned long size) |
| 1731 | { |
| 1732 | vm_paddr_t pa = VM_PAGE_TO_PHYS(m); |
| 1733 | vm_pindex_t start = pa >> PAGE_SHIFT; |
| 1734 | vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT; |
| 1735 | |
| 1736 | if (vm_contig_verbose) { |
| 1737 | kprintf("vm_page_free_contig: %016jx/%ldk\n", |
| 1738 | (intmax_t)pa, size / 1024); |
| 1739 | } |
| 1740 | if (pa < vm_low_phys_reserved) { |
| 1741 | KKASSERT(pa + size <= vm_low_phys_reserved); |
| 1742 | spin_lock(&vm_contig_spin); |
| 1743 | alist_free(&vm_contig_alist, start, pages); |
| 1744 | spin_unlock(&vm_contig_spin); |
| 1745 | } else { |
| 1746 | while (pages) { |
| 1747 | vm_page_busy_wait(m, FALSE, "cpgfr"); |
| 1748 | vm_page_unwire(m, 0); |
| 1749 | vm_page_free(m); |
| 1750 | --pages; |
| 1751 | ++m; |
| 1752 | } |
| 1753 | |
| 1754 | } |
| 1755 | } |
| 1756 | |
| 1757 | |
| 1758 | /* |
| 1759 | * Wait for sufficient free memory for nominal heavy memory use kernel |
| 1760 | * operations. |
| 1761 | * |
| 1762 | * WARNING! Be sure never to call this in any vm_pageout code path, which |
| 1763 | * will trivially deadlock the system. |
| 1764 | */ |
| 1765 | void |
| 1766 | vm_wait_nominal(void) |
| 1767 | { |
| 1768 | while (vm_page_count_min(0)) |
| 1769 | vm_wait(0); |
| 1770 | } |
| 1771 | |
| 1772 | /* |
| 1773 | * Test if vm_wait_nominal() would block. |
| 1774 | */ |
| 1775 | int |
| 1776 | vm_test_nominal(void) |
| 1777 | { |
| 1778 | if (vm_page_count_min(0)) |
| 1779 | return(1); |
| 1780 | return(0); |
| 1781 | } |
| 1782 | |
| 1783 | /* |
| 1784 | * Block until free pages are available for allocation, called in various |
| 1785 | * places before memory allocations. |
| 1786 | * |
| 1787 | * The caller may loop if vm_page_count_min() == FALSE so we cannot be |
| 1788 | * more generous then that. |
| 1789 | */ |
| 1790 | void |
| 1791 | vm_wait(int timo) |
| 1792 | { |
| 1793 | /* |
| 1794 | * never wait forever |
| 1795 | */ |
| 1796 | if (timo == 0) |
| 1797 | timo = hz; |
| 1798 | lwkt_gettoken(&vm_token); |
| 1799 | |
| 1800 | if (curthread == pagethread) { |
| 1801 | /* |
| 1802 | * The pageout daemon itself needs pages, this is bad. |
| 1803 | */ |
| 1804 | if (vm_page_count_min(0)) { |
| 1805 | vm_pageout_pages_needed = 1; |
| 1806 | tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo); |
| 1807 | } |
| 1808 | } else { |
| 1809 | /* |
| 1810 | * Wakeup the pageout daemon if necessary and wait. |
| 1811 | */ |
| 1812 | if (vm_page_count_target()) { |
| 1813 | if (vm_pages_needed == 0) { |
| 1814 | vm_pages_needed = 1; |
| 1815 | wakeup(&vm_pages_needed); |
| 1816 | } |
| 1817 | ++vm_pages_waiting; /* SMP race ok */ |
| 1818 | tsleep(&vmstats.v_free_count, 0, "vmwait", timo); |
| 1819 | } |
| 1820 | } |
| 1821 | lwkt_reltoken(&vm_token); |
| 1822 | } |
| 1823 | |
| 1824 | /* |
| 1825 | * Block until free pages are available for allocation |
| 1826 | * |
| 1827 | * Called only from vm_fault so that processes page faulting can be |
| 1828 | * easily tracked. |
| 1829 | */ |
| 1830 | void |
| 1831 | vm_waitpfault(void) |
| 1832 | { |
| 1833 | /* |
| 1834 | * Wakeup the pageout daemon if necessary and wait. |
| 1835 | */ |
| 1836 | if (vm_page_count_target()) { |
| 1837 | lwkt_gettoken(&vm_token); |
| 1838 | if (vm_page_count_target()) { |
| 1839 | if (vm_pages_needed == 0) { |
| 1840 | vm_pages_needed = 1; |
| 1841 | wakeup(&vm_pages_needed); |
| 1842 | } |
| 1843 | ++vm_pages_waiting; /* SMP race ok */ |
| 1844 | tsleep(&vmstats.v_free_count, 0, "pfault", hz); |
| 1845 | } |
| 1846 | lwkt_reltoken(&vm_token); |
| 1847 | } |
| 1848 | } |
| 1849 | |
| 1850 | /* |
| 1851 | * Put the specified page on the active list (if appropriate). Ensure |
| 1852 | * that act_count is at least ACT_INIT but do not otherwise mess with it. |
| 1853 | * |
| 1854 | * The caller should be holding the page busied ? XXX |
| 1855 | * This routine may not block. |
| 1856 | */ |
| 1857 | void |
| 1858 | vm_page_activate(vm_page_t m) |
| 1859 | { |
| 1860 | u_short oqueue; |
| 1861 | |
| 1862 | vm_page_spin_lock(m); |
| 1863 | if (m->queue - m->pc != PQ_ACTIVE) { |
| 1864 | _vm_page_queue_spin_lock(m); |
| 1865 | oqueue = _vm_page_rem_queue_spinlocked(m); |
| 1866 | /* page is left spinlocked, queue is unlocked */ |
| 1867 | |
| 1868 | if (oqueue == PQ_CACHE) |
| 1869 | mycpu->gd_cnt.v_reactivated++; |
| 1870 | if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { |
| 1871 | if (m->act_count < ACT_INIT) |
| 1872 | m->act_count = ACT_INIT; |
| 1873 | _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); |
| 1874 | } |
| 1875 | _vm_page_and_queue_spin_unlock(m); |
| 1876 | if (oqueue == PQ_CACHE || oqueue == PQ_FREE) |
| 1877 | pagedaemon_wakeup(); |
| 1878 | } else { |
| 1879 | if (m->act_count < ACT_INIT) |
| 1880 | m->act_count = ACT_INIT; |
| 1881 | vm_page_spin_unlock(m); |
| 1882 | } |
| 1883 | } |
| 1884 | |
| 1885 | /* |
| 1886 | * Helper routine for vm_page_free_toq() and vm_page_cache(). This |
| 1887 | * routine is called when a page has been added to the cache or free |
| 1888 | * queues. |
| 1889 | * |
| 1890 | * This routine may not block. |
| 1891 | */ |
| 1892 | static __inline void |
| 1893 | vm_page_free_wakeup(void) |
| 1894 | { |
| 1895 | /* |
| 1896 | * If the pageout daemon itself needs pages, then tell it that |
| 1897 | * there are some free. |
| 1898 | */ |
| 1899 | if (vm_pageout_pages_needed && |
| 1900 | vmstats.v_cache_count + vmstats.v_free_count >= |
| 1901 | vmstats.v_pageout_free_min |
| 1902 | ) { |
| 1903 | wakeup(&vm_pageout_pages_needed); |
| 1904 | vm_pageout_pages_needed = 0; |
| 1905 | } |
| 1906 | |
| 1907 | /* |
| 1908 | * Wakeup processes that are waiting on memory. |
| 1909 | * |
| 1910 | * NOTE: vm_paging_target() is the pageout daemon's target, while |
| 1911 | * vm_page_count_target() is somewhere inbetween. We want |
| 1912 | * to wake processes up prior to the pageout daemon reaching |
| 1913 | * its target to provide some hysteresis. |
| 1914 | */ |
| 1915 | if (vm_pages_waiting) { |
| 1916 | if (!vm_page_count_target()) { |
| 1917 | /* |
| 1918 | * Plenty of pages are free, wakeup everyone. |
| 1919 | */ |
| 1920 | vm_pages_waiting = 0; |
| 1921 | wakeup(&vmstats.v_free_count); |
| 1922 | ++mycpu->gd_cnt.v_ppwakeups; |
| 1923 | } else if (!vm_page_count_min(0)) { |
| 1924 | /* |
| 1925 | * Some pages are free, wakeup someone. |
| 1926 | */ |
| 1927 | int wcount = vm_pages_waiting; |
| 1928 | if (wcount > 0) |
| 1929 | --wcount; |
| 1930 | vm_pages_waiting = wcount; |
| 1931 | wakeup_one(&vmstats.v_free_count); |
| 1932 | ++mycpu->gd_cnt.v_ppwakeups; |
| 1933 | } |
| 1934 | } |
| 1935 | } |
| 1936 | |
| 1937 | /* |
| 1938 | * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates |
| 1939 | * it from its VM object. |
| 1940 | * |
| 1941 | * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on |
| 1942 | * return (the page will have been freed). |
| 1943 | */ |
| 1944 | void |
| 1945 | vm_page_free_toq(vm_page_t m) |
| 1946 | { |
| 1947 | mycpu->gd_cnt.v_tfree++; |
| 1948 | KKASSERT((m->flags & PG_MAPPED) == 0); |
| 1949 | KKASSERT(m->flags & PG_BUSY); |
| 1950 | |
| 1951 | if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { |
| 1952 | kprintf("vm_page_free: pindex(%lu), busy(%d), " |
| 1953 | "PG_BUSY(%d), hold(%d)\n", |
| 1954 | (u_long)m->pindex, m->busy, |
| 1955 | ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count); |
| 1956 | if ((m->queue - m->pc) == PQ_FREE) |
| 1957 | panic("vm_page_free: freeing free page"); |
| 1958 | else |
| 1959 | panic("vm_page_free: freeing busy page"); |
| 1960 | } |
| 1961 | |
| 1962 | /* |
| 1963 | * Remove from object, spinlock the page and its queues and |
| 1964 | * remove from any queue. No queue spinlock will be held |
| 1965 | * after this section (because the page was removed from any |
| 1966 | * queue). |
| 1967 | */ |
| 1968 | vm_page_remove(m); |
| 1969 | vm_page_and_queue_spin_lock(m); |
| 1970 | _vm_page_rem_queue_spinlocked(m); |
| 1971 | |
| 1972 | /* |
| 1973 | * No further management of fictitious pages occurs beyond object |
| 1974 | * and queue removal. |
| 1975 | */ |
| 1976 | if ((m->flags & PG_FICTITIOUS) != 0) { |
| 1977 | vm_page_spin_unlock(m); |
| 1978 | vm_page_wakeup(m); |
| 1979 | return; |
| 1980 | } |
| 1981 | |
| 1982 | m->valid = 0; |
| 1983 | vm_page_undirty(m); |
| 1984 | |
| 1985 | if (m->wire_count != 0) { |
| 1986 | if (m->wire_count > 1) { |
| 1987 | panic( |
| 1988 | "vm_page_free: invalid wire count (%d), pindex: 0x%lx", |
| 1989 | m->wire_count, (long)m->pindex); |
| 1990 | } |
| 1991 | panic("vm_page_free: freeing wired page"); |
| 1992 | } |
| 1993 | |
| 1994 | /* |
| 1995 | * Clear the UNMANAGED flag when freeing an unmanaged page. |
| 1996 | * Clear the NEED_COMMIT flag |
| 1997 | */ |
| 1998 | if (m->flags & PG_UNMANAGED) |
| 1999 | vm_page_flag_clear(m, PG_UNMANAGED); |
| 2000 | if (m->flags & PG_NEED_COMMIT) |
| 2001 | vm_page_flag_clear(m, PG_NEED_COMMIT); |
| 2002 | |
| 2003 | if (m->hold_count != 0) { |
| 2004 | vm_page_flag_clear(m, PG_ZERO); |
| 2005 | _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); |
| 2006 | } else { |
| 2007 | _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); |
| 2008 | } |
| 2009 | |
| 2010 | /* |
| 2011 | * This sequence allows us to clear PG_BUSY while still holding |
| 2012 | * its spin lock, which reduces contention vs allocators. We |
| 2013 | * must not leave the queue locked or _vm_page_wakeup() may |
| 2014 | * deadlock. |
| 2015 | */ |
| 2016 | _vm_page_queue_spin_unlock(m); |
| 2017 | if (_vm_page_wakeup(m)) { |
| 2018 | vm_page_spin_unlock(m); |
| 2019 | wakeup(m); |
| 2020 | } else { |
| 2021 | vm_page_spin_unlock(m); |
| 2022 | } |
| 2023 | vm_page_free_wakeup(); |
| 2024 | } |
| 2025 | |
| 2026 | /* |
| 2027 | * vm_page_free_fromq_fast() |
| 2028 | * |
| 2029 | * Remove a non-zero page from one of the free queues; the page is removed for |
| 2030 | * zeroing, so do not issue a wakeup. |
| 2031 | */ |
| 2032 | vm_page_t |
| 2033 | vm_page_free_fromq_fast(void) |
| 2034 | { |
| 2035 | static int qi; |
| 2036 | vm_page_t m; |
| 2037 | int i; |
| 2038 | |
| 2039 | for (i = 0; i < PQ_L2_SIZE; ++i) { |
| 2040 | m = vm_page_list_find(PQ_FREE, qi, FALSE); |
| 2041 | /* page is returned spinlocked and removed from its queue */ |
| 2042 | if (m) { |
| 2043 | if (vm_page_busy_try(m, TRUE)) { |
| 2044 | /* |
| 2045 | * We were unable to busy the page, deactivate |
| 2046 | * it and loop. |
| 2047 | */ |
| 2048 | _vm_page_deactivate_locked(m, 0); |
| 2049 | vm_page_spin_unlock(m); |
| 2050 | } else if (m->flags & PG_ZERO) { |
| 2051 | /* |
| 2052 | * The page is PG_ZERO, requeue it and loop |
| 2053 | */ |
| 2054 | _vm_page_add_queue_spinlocked(m, |
| 2055 | PQ_FREE + m->pc, |
| 2056 | 0); |
| 2057 | vm_page_queue_spin_unlock(m); |
| 2058 | if (_vm_page_wakeup(m)) { |
| 2059 | vm_page_spin_unlock(m); |
| 2060 | wakeup(m); |
| 2061 | } else { |
| 2062 | vm_page_spin_unlock(m); |
| 2063 | } |
| 2064 | } else { |
| 2065 | /* |
| 2066 | * The page is not PG_ZERO'd so return it. |
| 2067 | */ |
| 2068 | vm_page_spin_unlock(m); |
| 2069 | KKASSERT((m->flags & (PG_UNMANAGED | |
| 2070 | PG_NEED_COMMIT)) == 0); |
| 2071 | KKASSERT(m->hold_count == 0); |
| 2072 | KKASSERT(m->wire_count == 0); |
| 2073 | break; |
| 2074 | } |
| 2075 | m = NULL; |
| 2076 | } |
| 2077 | qi = (qi + PQ_PRIME2) & PQ_L2_MASK; |
| 2078 | } |
| 2079 | return (m); |
| 2080 | } |
| 2081 | |
| 2082 | /* |
| 2083 | * vm_page_unmanage() |
| 2084 | * |
| 2085 | * Prevent PV management from being done on the page. The page is |
| 2086 | * removed from the paging queues as if it were wired, and as a |
| 2087 | * consequence of no longer being managed the pageout daemon will not |
| 2088 | * touch it (since there is no way to locate the pte mappings for the |
| 2089 | * page). madvise() calls that mess with the pmap will also no longer |
| 2090 | * operate on the page. |
| 2091 | * |
| 2092 | * Beyond that the page is still reasonably 'normal'. Freeing the page |
| 2093 | * will clear the flag. |
| 2094 | * |
| 2095 | * This routine is used by OBJT_PHYS objects - objects using unswappable |
| 2096 | * physical memory as backing store rather then swap-backed memory and |
| 2097 | * will eventually be extended to support 4MB unmanaged physical |
| 2098 | * mappings. |
| 2099 | * |
| 2100 | * Caller must be holding the page busy. |
| 2101 | */ |
| 2102 | void |
| 2103 | vm_page_unmanage(vm_page_t m) |
| 2104 | { |
| 2105 | KKASSERT(m->flags & PG_BUSY); |
| 2106 | if ((m->flags & PG_UNMANAGED) == 0) { |
| 2107 | if (m->wire_count == 0) |
| 2108 | vm_page_unqueue(m); |
| 2109 | } |
| 2110 | vm_page_flag_set(m, PG_UNMANAGED); |
| 2111 | } |
| 2112 | |
| 2113 | /* |
| 2114 | * Mark this page as wired down by yet another map, removing it from |
| 2115 | * paging queues as necessary. |
| 2116 | * |
| 2117 | * Caller must be holding the page busy. |
| 2118 | */ |
| 2119 | void |
| 2120 | vm_page_wire(vm_page_t m) |
| 2121 | { |
| 2122 | /* |
| 2123 | * Only bump the wire statistics if the page is not already wired, |
| 2124 | * and only unqueue the page if it is on some queue (if it is unmanaged |
| 2125 | * it is already off the queues). Don't do anything with fictitious |
| 2126 | * pages because they are always wired. |
| 2127 | */ |
| 2128 | KKASSERT(m->flags & PG_BUSY); |
| 2129 | if ((m->flags & PG_FICTITIOUS) == 0) { |
| 2130 | if (atomic_fetchadd_int(&m->wire_count, 1) == 0) { |
| 2131 | if ((m->flags & PG_UNMANAGED) == 0) |
| 2132 | vm_page_unqueue(m); |
| 2133 | atomic_add_int(&vmstats.v_wire_count, 1); |
| 2134 | } |
| 2135 | KASSERT(m->wire_count != 0, |
| 2136 | ("vm_page_wire: wire_count overflow m=%p", m)); |
| 2137 | } |
| 2138 | } |
| 2139 | |
| 2140 | /* |
| 2141 | * Release one wiring of this page, potentially enabling it to be paged again. |
| 2142 | * |
| 2143 | * Many pages placed on the inactive queue should actually go |
| 2144 | * into the cache, but it is difficult to figure out which. What |
| 2145 | * we do instead, if the inactive target is well met, is to put |
| 2146 | * clean pages at the head of the inactive queue instead of the tail. |
| 2147 | * This will cause them to be moved to the cache more quickly and |
| 2148 | * if not actively re-referenced, freed more quickly. If we just |
| 2149 | * stick these pages at the end of the inactive queue, heavy filesystem |
| 2150 | * meta-data accesses can cause an unnecessary paging load on memory bound |
| 2151 | * processes. This optimization causes one-time-use metadata to be |
| 2152 | * reused more quickly. |
| 2153 | * |
| 2154 | * Pages marked PG_NEED_COMMIT are always activated and never placed on |
| 2155 | * the inactive queue. This helps the pageout daemon determine memory |
| 2156 | * pressure and act on out-of-memory situations more quickly. |
| 2157 | * |
| 2158 | * BUT, if we are in a low-memory situation we have no choice but to |
| 2159 | * put clean pages on the cache queue. |
| 2160 | * |
| 2161 | * A number of routines use vm_page_unwire() to guarantee that the page |
| 2162 | * will go into either the inactive or active queues, and will NEVER |
| 2163 | * be placed in the cache - for example, just after dirtying a page. |
| 2164 | * dirty pages in the cache are not allowed. |
| 2165 | * |
| 2166 | * The page queues must be locked. |
| 2167 | * This routine may not block. |
| 2168 | */ |
| 2169 | void |
| 2170 | vm_page_unwire(vm_page_t m, int activate) |
| 2171 | { |
| 2172 | KKASSERT(m->flags & PG_BUSY); |
| 2173 | if (m->flags & PG_FICTITIOUS) { |
| 2174 | /* do nothing */ |
| 2175 | } else if (m->wire_count <= 0) { |
| 2176 | panic("vm_page_unwire: invalid wire count: %d", m->wire_count); |
| 2177 | } else { |
| 2178 | if (atomic_fetchadd_int(&m->wire_count, -1) == 1) { |
| 2179 | atomic_add_int(&vmstats.v_wire_count, -1); |
| 2180 | if (m->flags & PG_UNMANAGED) { |
| 2181 | ; |
| 2182 | } else if (activate || (m->flags & PG_NEED_COMMIT)) { |
| 2183 | vm_page_spin_lock(m); |
| 2184 | _vm_page_add_queue_spinlocked(m, |
| 2185 | PQ_ACTIVE + m->pc, 0); |
| 2186 | _vm_page_and_queue_spin_unlock(m); |
| 2187 | } else { |
| 2188 | vm_page_spin_lock(m); |
| 2189 | vm_page_flag_clear(m, PG_WINATCFLS); |
| 2190 | _vm_page_add_queue_spinlocked(m, |
| 2191 | PQ_INACTIVE + m->pc, 0); |
| 2192 | ++vm_swapcache_inactive_heuristic; |
| 2193 | _vm_page_and_queue_spin_unlock(m); |
| 2194 | } |
| 2195 | } |
| 2196 | } |
| 2197 | } |
| 2198 | |
| 2199 | /* |
| 2200 | * Move the specified page to the inactive queue. If the page has |
| 2201 | * any associated swap, the swap is deallocated. |
| 2202 | * |
| 2203 | * Normally athead is 0 resulting in LRU operation. athead is set |
| 2204 | * to 1 if we want this page to be 'as if it were placed in the cache', |
| 2205 | * except without unmapping it from the process address space. |
| 2206 | * |
| 2207 | * vm_page's spinlock must be held on entry and will remain held on return. |
| 2208 | * This routine may not block. |
| 2209 | */ |
| 2210 | static void |
| 2211 | _vm_page_deactivate_locked(vm_page_t m, int athead) |
| 2212 | { |
| 2213 | u_short oqueue; |
| 2214 | |
| 2215 | /* |
| 2216 | * Ignore if already inactive. |
| 2217 | */ |
| 2218 | if (m->queue - m->pc == PQ_INACTIVE) |
| 2219 | return; |
| 2220 | _vm_page_queue_spin_lock(m); |
| 2221 | oqueue = _vm_page_rem_queue_spinlocked(m); |
| 2222 | |
| 2223 | if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { |
| 2224 | if (oqueue == PQ_CACHE) |
| 2225 | mycpu->gd_cnt.v_reactivated++; |
| 2226 | vm_page_flag_clear(m, PG_WINATCFLS); |
| 2227 | _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead); |
| 2228 | if (athead == 0) |
| 2229 | ++vm_swapcache_inactive_heuristic; |
| 2230 | } |
| 2231 | _vm_page_queue_spin_unlock(m); |
| 2232 | /* leaves vm_page spinlocked */ |
| 2233 | } |
| 2234 | |
| 2235 | /* |
| 2236 | * Attempt to deactivate a page. |
| 2237 | * |
| 2238 | * No requirements. |
| 2239 | */ |
| 2240 | void |
| 2241 | vm_page_deactivate(vm_page_t m) |
| 2242 | { |
| 2243 | vm_page_spin_lock(m); |
| 2244 | _vm_page_deactivate_locked(m, 0); |
| 2245 | vm_page_spin_unlock(m); |
| 2246 | } |
| 2247 | |
| 2248 | void |
| 2249 | vm_page_deactivate_locked(vm_page_t m) |
| 2250 | { |
| 2251 | _vm_page_deactivate_locked(m, 0); |
| 2252 | } |
| 2253 | |
| 2254 | /* |
| 2255 | * Attempt to move a page to PQ_CACHE. |
| 2256 | * |
| 2257 | * Returns 0 on failure, 1 on success |
| 2258 | * |
| 2259 | * The page should NOT be busied by the caller. This function will validate |
| 2260 | * whether the page can be safely moved to the cache. |
| 2261 | */ |
| 2262 | int |
| 2263 | vm_page_try_to_cache(vm_page_t m) |
| 2264 | { |
| 2265 | vm_page_spin_lock(m); |
| 2266 | if (vm_page_busy_try(m, TRUE)) { |
| 2267 | vm_page_spin_unlock(m); |
| 2268 | return(0); |
| 2269 | } |
| 2270 | if (m->dirty || m->hold_count || m->wire_count || |
| 2271 | (m->flags & (PG_UNMANAGED | PG_NEED_COMMIT))) { |
| 2272 | if (_vm_page_wakeup(m)) { |
| 2273 | vm_page_spin_unlock(m); |
| 2274 | wakeup(m); |
| 2275 | } else { |
| 2276 | vm_page_spin_unlock(m); |
| 2277 | } |
| 2278 | return(0); |
| 2279 | } |
| 2280 | vm_page_spin_unlock(m); |
| 2281 | |
| 2282 | /* |
| 2283 | * Page busied by us and no longer spinlocked. Dirty pages cannot |
| 2284 | * be moved to the cache. |
| 2285 | */ |
| 2286 | vm_page_test_dirty(m); |
| 2287 | if (m->dirty) { |
| 2288 | vm_page_wakeup(m); |
| 2289 | return(0); |
| 2290 | } |
| 2291 | vm_page_cache(m); |
| 2292 | return(1); |
| 2293 | } |
| 2294 | |
| 2295 | /* |
| 2296 | * Attempt to free the page. If we cannot free it, we do nothing. |
| 2297 | * 1 is returned on success, 0 on failure. |
| 2298 | * |
| 2299 | * No requirements. |
| 2300 | */ |
| 2301 | int |
| 2302 | vm_page_try_to_free(vm_page_t m) |
| 2303 | { |
| 2304 | vm_page_spin_lock(m); |
| 2305 | if (vm_page_busy_try(m, TRUE)) { |
| 2306 | vm_page_spin_unlock(m); |
| 2307 | return(0); |
| 2308 | } |
| 2309 | |
| 2310 | /* |
| 2311 | * The page can be in any state, including already being on the free |
| 2312 | * queue. Check to see if it really can be freed. |
| 2313 | */ |
| 2314 | if (m->dirty || /* can't free if it is dirty */ |
| 2315 | m->hold_count || /* or held (XXX may be wrong) */ |
| 2316 | m->wire_count || /* or wired */ |
| 2317 | (m->flags & (PG_UNMANAGED | /* or unmanaged */ |
| 2318 | PG_NEED_COMMIT)) || /* or needs a commit */ |
| 2319 | m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */ |
| 2320 | m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */ |
| 2321 | if (_vm_page_wakeup(m)) { |
| 2322 | vm_page_spin_unlock(m); |
| 2323 | wakeup(m); |
| 2324 | } else { |
| 2325 | vm_page_spin_unlock(m); |
| 2326 | } |
| 2327 | return(0); |
| 2328 | } |
| 2329 | vm_page_spin_unlock(m); |
| 2330 | |
| 2331 | /* |
| 2332 | * We can probably free the page. |
| 2333 | * |
| 2334 | * Page busied by us and no longer spinlocked. Dirty pages will |
| 2335 | * not be freed by this function. We have to re-test the |
| 2336 | * dirty bit after cleaning out the pmaps. |
| 2337 | */ |
| 2338 | vm_page_test_dirty(m); |
| 2339 | if (m->dirty) { |
| 2340 | vm_page_wakeup(m); |
| 2341 | return(0); |
| 2342 | } |
| 2343 | vm_page_protect(m, VM_PROT_NONE); |
| 2344 | if (m->dirty) { |
| 2345 | vm_page_wakeup(m); |
| 2346 | return(0); |
| 2347 | } |
| 2348 | vm_page_free(m); |
| 2349 | return(1); |
| 2350 | } |
| 2351 | |
| 2352 | /* |
| 2353 | * vm_page_cache |
| 2354 | * |
| 2355 | * Put the specified page onto the page cache queue (if appropriate). |
| 2356 | * |
| 2357 | * The page must be busy, and this routine will release the busy and |
| 2358 | * possibly even free the page. |
| 2359 | */ |
| 2360 | void |
| 2361 | vm_page_cache(vm_page_t m) |
| 2362 | { |
| 2363 | if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) || |
| 2364 | m->busy || m->wire_count || m->hold_count) { |
| 2365 | kprintf("vm_page_cache: attempting to cache busy/held page\n"); |
| 2366 | vm_page_wakeup(m); |
| 2367 | return; |
| 2368 | } |
| 2369 | |
| 2370 | /* |
| 2371 | * Already in the cache (and thus not mapped) |
| 2372 | */ |
| 2373 | if ((m->queue - m->pc) == PQ_CACHE) { |
| 2374 | KKASSERT((m->flags & PG_MAPPED) == 0); |
| 2375 | vm_page_wakeup(m); |
| 2376 | return; |
| 2377 | } |
| 2378 | |
| 2379 | /* |
| 2380 | * Caller is required to test m->dirty, but note that the act of |
| 2381 | * removing the page from its maps can cause it to become dirty |
| 2382 | * on an SMP system due to another cpu running in usermode. |
| 2383 | */ |
| 2384 | if (m->dirty) { |
| 2385 | panic("vm_page_cache: caching a dirty page, pindex: %ld", |
| 2386 | (long)m->pindex); |
| 2387 | } |
| 2388 | |
| 2389 | /* |
| 2390 | * Remove all pmaps and indicate that the page is not |
| 2391 | * writeable or mapped. Our vm_page_protect() call may |
| 2392 | * have blocked (especially w/ VM_PROT_NONE), so recheck |
| 2393 | * everything. |
| 2394 | */ |
| 2395 | vm_page_protect(m, VM_PROT_NONE); |
| 2396 | if ((m->flags & (PG_UNMANAGED | PG_MAPPED)) || |
| 2397 | m->busy || m->wire_count || m->hold_count) { |
| 2398 | vm_page_wakeup(m); |
| 2399 | } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) { |
| 2400 | vm_page_deactivate(m); |
| 2401 | vm_page_wakeup(m); |
| 2402 | } else { |
| 2403 | _vm_page_and_queue_spin_lock(m); |
| 2404 | _vm_page_rem_queue_spinlocked(m); |
| 2405 | _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0); |
| 2406 | _vm_page_queue_spin_unlock(m); |
| 2407 | if (_vm_page_wakeup(m)) { |
| 2408 | vm_page_spin_unlock(m); |
| 2409 | wakeup(m); |
| 2410 | } else { |
| 2411 | vm_page_spin_unlock(m); |
| 2412 | } |
| 2413 | vm_page_free_wakeup(); |
| 2414 | } |
| 2415 | } |
| 2416 | |
| 2417 | /* |
| 2418 | * vm_page_dontneed() |
| 2419 | * |
| 2420 | * Cache, deactivate, or do nothing as appropriate. This routine |
| 2421 | * is typically used by madvise() MADV_DONTNEED. |
| 2422 | * |
| 2423 | * Generally speaking we want to move the page into the cache so |
| 2424 | * it gets reused quickly. However, this can result in a silly syndrome |
| 2425 | * due to the page recycling too quickly. Small objects will not be |
| 2426 | * fully cached. On the otherhand, if we move the page to the inactive |
| 2427 | * queue we wind up with a problem whereby very large objects |
| 2428 | * unnecessarily blow away our inactive and cache queues. |
| 2429 | * |
| 2430 | * The solution is to move the pages based on a fixed weighting. We |
| 2431 | * either leave them alone, deactivate them, or move them to the cache, |
| 2432 | * where moving them to the cache has the highest weighting. |
| 2433 | * By forcing some pages into other queues we eventually force the |
| 2434 | * system to balance the queues, potentially recovering other unrelated |
| 2435 | * space from active. The idea is to not force this to happen too |
| 2436 | * often. |
| 2437 | * |
| 2438 | * The page must be busied. |
| 2439 | */ |
| 2440 | void |
| 2441 | vm_page_dontneed(vm_page_t m) |
| 2442 | { |
| 2443 | static int dnweight; |
| 2444 | int dnw; |
| 2445 | int head; |
| 2446 | |
| 2447 | dnw = ++dnweight; |
| 2448 | |
| 2449 | /* |
| 2450 | * occassionally leave the page alone |
| 2451 | */ |
| 2452 | if ((dnw & 0x01F0) == 0 || |
| 2453 | m->queue - m->pc == PQ_INACTIVE || |
| 2454 | m->queue - m->pc == PQ_CACHE |
| 2455 | ) { |
| 2456 | if (m->act_count >= ACT_INIT) |
| 2457 | --m->act_count; |
| 2458 | return; |
| 2459 | } |
| 2460 | |
| 2461 | /* |
| 2462 | * If vm_page_dontneed() is inactivating a page, it must clear |
| 2463 | * the referenced flag; otherwise the pagedaemon will see references |
| 2464 | * on the page in the inactive queue and reactivate it. Until the |
| 2465 | * page can move to the cache queue, madvise's job is not done. |
| 2466 | */ |
| 2467 | vm_page_flag_clear(m, PG_REFERENCED); |
| 2468 | pmap_clear_reference(m); |
| 2469 | |
| 2470 | if (m->dirty == 0) |
| 2471 | vm_page_test_dirty(m); |
| 2472 | |
| 2473 | if (m->dirty || (dnw & 0x0070) == 0) { |
| 2474 | /* |
| 2475 | * Deactivate the page 3 times out of 32. |
| 2476 | */ |
| 2477 | head = 0; |
| 2478 | } else { |
| 2479 | /* |
| 2480 | * Cache the page 28 times out of every 32. Note that |
| 2481 | * the page is deactivated instead of cached, but placed |
| 2482 | * at the head of the queue instead of the tail. |
| 2483 | */ |
| 2484 | head = 1; |
| 2485 | } |
| 2486 | vm_page_spin_lock(m); |
| 2487 | _vm_page_deactivate_locked(m, head); |
| 2488 | vm_page_spin_unlock(m); |
| 2489 | } |
| 2490 | |
| 2491 | /* |
| 2492 | * These routines manipulate the 'soft busy' count for a page. A soft busy |
| 2493 | * is almost like PG_BUSY except that it allows certain compatible operations |
| 2494 | * to occur on the page while it is busy. For example, a page undergoing a |
| 2495 | * write can still be mapped read-only. |
| 2496 | * |
| 2497 | * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only |
| 2498 | * adjusted while the vm_page is PG_BUSY so the flash will occur when the |
| 2499 | * busy bit is cleared. |
| 2500 | */ |
| 2501 | void |
| 2502 | vm_page_io_start(vm_page_t m) |
| 2503 | { |
| 2504 | KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!")); |
| 2505 | atomic_add_char(&m->busy, 1); |
| 2506 | vm_page_flag_set(m, PG_SBUSY); |
| 2507 | } |
| 2508 | |
| 2509 | void |
| 2510 | vm_page_io_finish(vm_page_t m) |
| 2511 | { |
| 2512 | KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!")); |
| 2513 | atomic_subtract_char(&m->busy, 1); |
| 2514 | if (m->busy == 0) |
| 2515 | vm_page_flag_clear(m, PG_SBUSY); |
| 2516 | } |
| 2517 | |
| 2518 | /* |
| 2519 | * Indicate that a clean VM page requires a filesystem commit and cannot |
| 2520 | * be reused. Used by tmpfs. |
| 2521 | */ |
| 2522 | void |
| 2523 | vm_page_need_commit(vm_page_t m) |
| 2524 | { |
| 2525 | vm_page_flag_set(m, PG_NEED_COMMIT); |
| 2526 | } |
| 2527 | |
| 2528 | void |
| 2529 | vm_page_clear_commit(vm_page_t m) |
| 2530 | { |
| 2531 | vm_page_flag_clear(m, PG_NEED_COMMIT); |
| 2532 | } |
| 2533 | |
| 2534 | /* |
| 2535 | * Grab a page, blocking if it is busy and allocating a page if necessary. |
| 2536 | * A busy page is returned or NULL. The page may or may not be valid and |
| 2537 | * might not be on a queue (the caller is responsible for the disposition of |
| 2538 | * the page). |
| 2539 | * |
| 2540 | * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the |
| 2541 | * page will be zero'd and marked valid. |
| 2542 | * |
| 2543 | * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked |
| 2544 | * valid even if it already exists. |
| 2545 | * |
| 2546 | * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also |
| 2547 | * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified. |
| 2548 | * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified. |
| 2549 | * |
| 2550 | * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is |
| 2551 | * always returned if we had blocked. |
| 2552 | * |
| 2553 | * This routine may not be called from an interrupt. |
| 2554 | * |
| 2555 | * PG_ZERO is *ALWAYS* cleared by this routine. |
| 2556 | * |
| 2557 | * No other requirements. |
| 2558 | */ |
| 2559 | vm_page_t |
| 2560 | vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) |
| 2561 | { |
| 2562 | vm_page_t m; |
| 2563 | int error; |
| 2564 | |
| 2565 | KKASSERT(allocflags & |
| 2566 | (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); |
| 2567 | vm_object_hold(object); |
| 2568 | for (;;) { |
| 2569 | m = vm_page_lookup_busy_try(object, pindex, TRUE, &error); |
| 2570 | if (error) { |
| 2571 | vm_page_sleep_busy(m, TRUE, "pgrbwt"); |
| 2572 | if ((allocflags & VM_ALLOC_RETRY) == 0) { |
| 2573 | m = NULL; |
| 2574 | break; |
| 2575 | } |
| 2576 | /* retry */ |
| 2577 | } else if (m == NULL) { |
| 2578 | if (allocflags & VM_ALLOC_RETRY) |
| 2579 | allocflags |= VM_ALLOC_NULL_OK; |
| 2580 | m = vm_page_alloc(object, pindex, |
| 2581 | allocflags & ~VM_ALLOC_RETRY); |
| 2582 | if (m) |
| 2583 | break; |
| 2584 | vm_wait(0); |
| 2585 | if ((allocflags & VM_ALLOC_RETRY) == 0) |
| 2586 | goto failed; |
| 2587 | } else { |
| 2588 | /* m found */ |
| 2589 | break; |
| 2590 | } |
| 2591 | } |
| 2592 | |
| 2593 | /* |
| 2594 | * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid. |
| 2595 | * |
| 2596 | * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set |
| 2597 | * valid even if already valid. |
| 2598 | */ |
| 2599 | if (m->valid == 0) { |
| 2600 | if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) { |
| 2601 | if ((m->flags & PG_ZERO) == 0) |
| 2602 | pmap_zero_page(VM_PAGE_TO_PHYS(m)); |
| 2603 | m->valid = VM_PAGE_BITS_ALL; |
| 2604 | } |
| 2605 | } else if (allocflags & VM_ALLOC_FORCE_ZERO) { |
| 2606 | pmap_zero_page(VM_PAGE_TO_PHYS(m)); |
| 2607 | m->valid = VM_PAGE_BITS_ALL; |
| 2608 | } |
| 2609 | vm_page_flag_clear(m, PG_ZERO); |
| 2610 | failed: |
| 2611 | vm_object_drop(object); |
| 2612 | return(m); |
| 2613 | } |
| 2614 | |
| 2615 | /* |
| 2616 | * Mapping function for valid bits or for dirty bits in |
| 2617 | * a page. May not block. |
| 2618 | * |
| 2619 | * Inputs are required to range within a page. |
| 2620 | * |
| 2621 | * No requirements. |
| 2622 | * Non blocking. |
| 2623 | */ |
| 2624 | int |
| 2625 | vm_page_bits(int base, int size) |
| 2626 | { |
| 2627 | int first_bit; |
| 2628 | int last_bit; |
| 2629 | |
| 2630 | KASSERT( |
| 2631 | base + size <= PAGE_SIZE, |
| 2632 | ("vm_page_bits: illegal base/size %d/%d", base, size) |
| 2633 | ); |
| 2634 | |
| 2635 | if (size == 0) /* handle degenerate case */ |
| 2636 | return(0); |
| 2637 | |
| 2638 | first_bit = base >> DEV_BSHIFT; |
| 2639 | last_bit = (base + size - 1) >> DEV_BSHIFT; |
| 2640 | |
| 2641 | return ((2 << last_bit) - (1 << first_bit)); |
| 2642 | } |
| 2643 | |
| 2644 | /* |
| 2645 | * Sets portions of a page valid and clean. The arguments are expected |
| 2646 | * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive |
| 2647 | * of any partial chunks touched by the range. The invalid portion of |
| 2648 | * such chunks will be zero'd. |
| 2649 | * |
| 2650 | * NOTE: When truncating a buffer vnode_pager_setsize() will automatically |
| 2651 | * align base to DEV_BSIZE so as not to mark clean a partially |
| 2652 | * truncated device block. Otherwise the dirty page status might be |
| 2653 | * lost. |
| 2654 | * |
| 2655 | * This routine may not block. |
| 2656 | * |
| 2657 | * (base + size) must be less then or equal to PAGE_SIZE. |
| 2658 | */ |
| 2659 | static void |
| 2660 | _vm_page_zero_valid(vm_page_t m, int base, int size) |
| 2661 | { |
| 2662 | int frag; |
| 2663 | int endoff; |
| 2664 | |
| 2665 | if (size == 0) /* handle degenerate case */ |
| 2666 | return; |
| 2667 | |
| 2668 | /* |
| 2669 | * If the base is not DEV_BSIZE aligned and the valid |
| 2670 | * bit is clear, we have to zero out a portion of the |
| 2671 | * first block. |
| 2672 | */ |
| 2673 | |
| 2674 | if ((frag = base & ~(DEV_BSIZE - 1)) != base && |
| 2675 | (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 |
| 2676 | ) { |
| 2677 | pmap_zero_page_area( |
| 2678 | VM_PAGE_TO_PHYS(m), |
| 2679 | frag, |
| 2680 | base - frag |
| 2681 | ); |
| 2682 | } |
| 2683 | |
| 2684 | /* |
| 2685 | * If the ending offset is not DEV_BSIZE aligned and the |
| 2686 | * valid bit is clear, we have to zero out a portion of |
| 2687 | * the last block. |
| 2688 | */ |
| 2689 | |
| 2690 | endoff = base + size; |
| 2691 | |
| 2692 | if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && |
| 2693 | (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 |
| 2694 | ) { |
| 2695 | pmap_zero_page_area( |
| 2696 | VM_PAGE_TO_PHYS(m), |
| 2697 | endoff, |
| 2698 | DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) |
| 2699 | ); |
| 2700 | } |
| 2701 | } |
| 2702 | |
| 2703 | /* |
| 2704 | * Set valid, clear dirty bits. If validating the entire |
| 2705 | * page we can safely clear the pmap modify bit. We also |
| 2706 | * use this opportunity to clear the PG_NOSYNC flag. If a process |
| 2707 | * takes a write fault on a MAP_NOSYNC memory area the flag will |
| 2708 | * be set again. |
| 2709 | * |
| 2710 | * We set valid bits inclusive of any overlap, but we can only |
| 2711 | * clear dirty bits for DEV_BSIZE chunks that are fully within |
| 2712 | * the range. |
| 2713 | * |
| 2714 | * Page must be busied? |
| 2715 | * No other requirements. |
| 2716 | */ |
| 2717 | void |
| 2718 | vm_page_set_valid(vm_page_t m, int base, int size) |
| 2719 | { |
| 2720 | _vm_page_zero_valid(m, base, size); |
| 2721 | m->valid |= vm_page_bits(base, size); |
| 2722 | } |
| 2723 | |
| 2724 | |
| 2725 | /* |
| 2726 | * Set valid bits and clear dirty bits. |
| 2727 | * |
| 2728 | * NOTE: This function does not clear the pmap modified bit. |
| 2729 | * Also note that e.g. NFS may use a byte-granular base |
| 2730 | * and size. |
| 2731 | * |
| 2732 | * WARNING: Page must be busied? But vfs_clean_one_page() will call |
| 2733 | * this without necessarily busying the page (via bdwrite()). |
| 2734 | * So for now vm_token must also be held. |
| 2735 | * |
| 2736 | * No other requirements. |
| 2737 | */ |
| 2738 | void |
| 2739 | vm_page_set_validclean(vm_page_t m, int base, int size) |
| 2740 | { |
| 2741 | int pagebits; |
| 2742 | |
| 2743 | _vm_page_zero_valid(m, base, size); |
| 2744 | pagebits = vm_page_bits(base, size); |
| 2745 | m->valid |= pagebits; |
| 2746 | m->dirty &= ~pagebits; |
| 2747 | if (base == 0 && size == PAGE_SIZE) { |
| 2748 | /*pmap_clear_modify(m);*/ |
| 2749 | vm_page_flag_clear(m, PG_NOSYNC); |
| 2750 | } |
| 2751 | } |
| 2752 | |
| 2753 | /* |
| 2754 | * Set valid & dirty. Used by buwrite() |
| 2755 | * |
| 2756 | * WARNING: Page must be busied? But vfs_dirty_one_page() will |
| 2757 | * call this function in buwrite() so for now vm_token must |
| 2758 | * be held. |
| 2759 | * |
| 2760 | * No other requirements. |
| 2761 | */ |
| 2762 | void |
| 2763 | vm_page_set_validdirty(vm_page_t m, int base, int size) |
| 2764 | { |
| 2765 | int pagebits; |
| 2766 | |
| 2767 | pagebits = vm_page_bits(base, size); |
| 2768 | m->valid |= pagebits; |
| 2769 | m->dirty |= pagebits; |
| 2770 | if (m->object) |
| 2771 | vm_object_set_writeable_dirty(m->object); |
| 2772 | } |
| 2773 | |
| 2774 | /* |
| 2775 | * Clear dirty bits. |
| 2776 | * |
| 2777 | * NOTE: This function does not clear the pmap modified bit. |
| 2778 | * Also note that e.g. NFS may use a byte-granular base |
| 2779 | * and size. |
| 2780 | * |
| 2781 | * Page must be busied? |
| 2782 | * No other requirements. |
| 2783 | */ |
| 2784 | void |
| 2785 | vm_page_clear_dirty(vm_page_t m, int base, int size) |
| 2786 | { |
| 2787 | m->dirty &= ~vm_page_bits(base, size); |
| 2788 | if (base == 0 && size == PAGE_SIZE) { |
| 2789 | /*pmap_clear_modify(m);*/ |
| 2790 | vm_page_flag_clear(m, PG_NOSYNC); |
| 2791 | } |
| 2792 | } |
| 2793 | |
| 2794 | /* |
| 2795 | * Make the page all-dirty. |
| 2796 | * |
| 2797 | * Also make sure the related object and vnode reflect the fact that the |
| 2798 | * object may now contain a dirty page. |
| 2799 | * |
| 2800 | * Page must be busied? |
| 2801 | * No other requirements. |
| 2802 | */ |
| 2803 | void |
| 2804 | vm_page_dirty(vm_page_t m) |
| 2805 | { |
| 2806 | #ifdef INVARIANTS |
| 2807 | int pqtype = m->queue - m->pc; |
| 2808 | #endif |
| 2809 | KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE, |
| 2810 | ("vm_page_dirty: page in free/cache queue!")); |
| 2811 | if (m->dirty != VM_PAGE_BITS_ALL) { |
| 2812 | m->dirty = VM_PAGE_BITS_ALL; |
| 2813 | if (m->object) |
| 2814 | vm_object_set_writeable_dirty(m->object); |
| 2815 | } |
| 2816 | } |
| 2817 | |
| 2818 | /* |
| 2819 | * Invalidates DEV_BSIZE'd chunks within a page. Both the |
| 2820 | * valid and dirty bits for the effected areas are cleared. |
| 2821 | * |
| 2822 | * Page must be busied? |
| 2823 | * Does not block. |
| 2824 | * No other requirements. |
| 2825 | */ |
| 2826 | void |
| 2827 | vm_page_set_invalid(vm_page_t m, int base, int size) |
| 2828 | { |
| 2829 | int bits; |
| 2830 | |
| 2831 | bits = vm_page_bits(base, size); |
| 2832 | m->valid &= ~bits; |
| 2833 | m->dirty &= ~bits; |
| 2834 | m->object->generation++; |
| 2835 | } |
| 2836 | |
| 2837 | /* |
| 2838 | * The kernel assumes that the invalid portions of a page contain |
| 2839 | * garbage, but such pages can be mapped into memory by user code. |
| 2840 | * When this occurs, we must zero out the non-valid portions of the |
| 2841 | * page so user code sees what it expects. |
| 2842 | * |
| 2843 | * Pages are most often semi-valid when the end of a file is mapped |
| 2844 | * into memory and the file's size is not page aligned. |
| 2845 | * |
| 2846 | * Page must be busied? |
| 2847 | * No other requirements. |
| 2848 | */ |
| 2849 | void |
| 2850 | vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) |
| 2851 | { |
| 2852 | int b; |
| 2853 | int i; |
| 2854 | |
| 2855 | /* |
| 2856 | * Scan the valid bits looking for invalid sections that |
| 2857 | * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the |
| 2858 | * valid bit may be set ) have already been zerod by |
| 2859 | * vm_page_set_validclean(). |
| 2860 | */ |
| 2861 | for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { |
| 2862 | if (i == (PAGE_SIZE / DEV_BSIZE) || |
| 2863 | (m->valid & (1 << i)) |
| 2864 | ) { |
| 2865 | if (i > b) { |
| 2866 | pmap_zero_page_area( |
| 2867 | VM_PAGE_TO_PHYS(m), |
| 2868 | b << DEV_BSHIFT, |
| 2869 | (i - b) << DEV_BSHIFT |
| 2870 | ); |
| 2871 | } |
| 2872 | b = i + 1; |
| 2873 | } |
| 2874 | } |
| 2875 | |
| 2876 | /* |
| 2877 | * setvalid is TRUE when we can safely set the zero'd areas |
| 2878 | * as being valid. We can do this if there are no cache consistency |
| 2879 | * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. |
| 2880 | */ |
| 2881 | if (setvalid) |
| 2882 | m->valid = VM_PAGE_BITS_ALL; |
| 2883 | } |
| 2884 | |
| 2885 | /* |
| 2886 | * Is a (partial) page valid? Note that the case where size == 0 |
| 2887 | * will return FALSE in the degenerate case where the page is entirely |
| 2888 | * invalid, and TRUE otherwise. |
| 2889 | * |
| 2890 | * Does not block. |
| 2891 | * No other requirements. |
| 2892 | */ |
| 2893 | int |
| 2894 | vm_page_is_valid(vm_page_t m, int base, int size) |
| 2895 | { |
| 2896 | int bits = vm_page_bits(base, size); |
| 2897 | |
| 2898 | if (m->valid && ((m->valid & bits) == bits)) |
| 2899 | return 1; |
| 2900 | else |
| 2901 | return 0; |
| 2902 | } |
| 2903 | |
| 2904 | /* |
| 2905 | * update dirty bits from pmap/mmu. May not block. |
| 2906 | * |
| 2907 | * Caller must hold the page busy |
| 2908 | */ |
| 2909 | void |
| 2910 | vm_page_test_dirty(vm_page_t m) |
| 2911 | { |
| 2912 | if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { |
| 2913 | vm_page_dirty(m); |
| 2914 | } |
| 2915 | } |
| 2916 | |
| 2917 | /* |
| 2918 | * Register an action, associating it with its vm_page |
| 2919 | */ |
| 2920 | void |
| 2921 | vm_page_register_action(vm_page_action_t action, vm_page_event_t event) |
| 2922 | { |
| 2923 | struct vm_page_action_list *list; |
| 2924 | int hv; |
| 2925 | |
| 2926 | hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; |
| 2927 | list = &action_list[hv]; |
| 2928 | |
| 2929 | lwkt_gettoken(&vm_token); |
| 2930 | vm_page_flag_set(action->m, PG_ACTIONLIST); |
| 2931 | action->event = event; |
| 2932 | LIST_INSERT_HEAD(list, action, entry); |
| 2933 | lwkt_reltoken(&vm_token); |
| 2934 | } |
| 2935 | |
| 2936 | /* |
| 2937 | * Unregister an action, disassociating it from its related vm_page |
| 2938 | */ |
| 2939 | void |
| 2940 | vm_page_unregister_action(vm_page_action_t action) |
| 2941 | { |
| 2942 | struct vm_page_action_list *list; |
| 2943 | int hv; |
| 2944 | |
| 2945 | lwkt_gettoken(&vm_token); |
| 2946 | if (action->event != VMEVENT_NONE) { |
| 2947 | action->event = VMEVENT_NONE; |
| 2948 | LIST_REMOVE(action, entry); |
| 2949 | |
| 2950 | hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; |
| 2951 | list = &action_list[hv]; |
| 2952 | if (LIST_EMPTY(list)) |
| 2953 | vm_page_flag_clear(action->m, PG_ACTIONLIST); |
| 2954 | } |
| 2955 | lwkt_reltoken(&vm_token); |
| 2956 | } |
| 2957 | |
| 2958 | /* |
| 2959 | * Issue an event on a VM page. Corresponding action structures are |
| 2960 | * removed from the page's list and called. |
| 2961 | * |
| 2962 | * If the vm_page has no more pending action events we clear its |
| 2963 | * PG_ACTIONLIST flag. |
| 2964 | */ |
| 2965 | void |
| 2966 | vm_page_event_internal(vm_page_t m, vm_page_event_t event) |
| 2967 | { |
| 2968 | struct vm_page_action_list *list; |
| 2969 | struct vm_page_action *scan; |
| 2970 | struct vm_page_action *next; |
| 2971 | int hv; |
| 2972 | int all; |
| 2973 | |
| 2974 | hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK; |
| 2975 | list = &action_list[hv]; |
| 2976 | all = 1; |
| 2977 | |
| 2978 | lwkt_gettoken(&vm_token); |
| 2979 | LIST_FOREACH_MUTABLE(scan, list, entry, next) { |
| 2980 | if (scan->m == m) { |
| 2981 | if (scan->event == event) { |
| 2982 | scan->event = VMEVENT_NONE; |
| 2983 | LIST_REMOVE(scan, entry); |
| 2984 | scan->func(m, scan); |
| 2985 | /* XXX */ |
| 2986 | } else { |
| 2987 | all = 0; |
| 2988 | } |
| 2989 | } |
| 2990 | } |
| 2991 | if (all) |
| 2992 | vm_page_flag_clear(m, PG_ACTIONLIST); |
| 2993 | lwkt_reltoken(&vm_token); |
| 2994 | } |
| 2995 | |
| 2996 | #include "opt_ddb.h" |
| 2997 | #ifdef DDB |
| 2998 | #include <sys/kernel.h> |
| 2999 | |
| 3000 | #include <ddb/ddb.h> |
| 3001 | |
| 3002 | DB_SHOW_COMMAND(page, vm_page_print_page_info) |
| 3003 | { |
| 3004 | db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count); |
| 3005 | db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count); |
| 3006 | db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count); |
| 3007 | db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count); |
| 3008 | db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count); |
| 3009 | db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved); |
| 3010 | db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min); |
| 3011 | db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target); |
| 3012 | db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min); |
| 3013 | db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target); |
| 3014 | } |
| 3015 | |
| 3016 | DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) |
| 3017 | { |
| 3018 | int i; |
| 3019 | db_printf("PQ_FREE:"); |
| 3020 | for(i=0;i<PQ_L2_SIZE;i++) { |
| 3021 | db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt); |
| 3022 | } |
| 3023 | db_printf("\n"); |
| 3024 | |
| 3025 | db_printf("PQ_CACHE:"); |
| 3026 | for(i=0;i<PQ_L2_SIZE;i++) { |
| 3027 | db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt); |
| 3028 | } |
| 3029 | db_printf("\n"); |
| 3030 | |
| 3031 | db_printf("PQ_ACTIVE:"); |
| 3032 | for(i=0;i<PQ_L2_SIZE;i++) { |
| 3033 | db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt); |
| 3034 | } |
| 3035 | db_printf("\n"); |
| 3036 | |
| 3037 | db_printf("PQ_INACTIVE:"); |
| 3038 | for(i=0;i<PQ_L2_SIZE;i++) { |
| 3039 | db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt); |
| 3040 | } |
| 3041 | db_printf("\n"); |
| 3042 | } |
| 3043 | #endif /* DDB */ |