1 /*- 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)vmmeter.h 8.2 (Berkeley) 7/10/94 30 * $FreeBSD: src/sys/sys/vmmeter.h,v 1.21.2.2 2002/10/10 19:28:21 dillon Exp $ 31 */ 32 33 #ifndef _VM_VM_PAGE2_H_ 34 #define _VM_VM_PAGE2_H_ 35 36 #ifdef _KERNEL 37 38 #ifndef _SYS_VMMETER_H_ 39 #include <sys/vmmeter.h> 40 #endif 41 #ifndef _SYS_QUEUE_H_ 42 #include <sys/queue.h> 43 #endif 44 #ifndef _VM_VM_PAGE_H_ 45 #include <vm/vm_page.h> 46 #endif 47 #ifndef _SYS_SPINLOCK_H_ 48 #include <sys/spinlock.h> 49 #endif 50 #ifndef _SYS_SPINLOCK2_H_ 51 #include <sys/spinlock2.h> 52 #endif 53 54 /* 55 * Return TRUE if we are under our severe low-free-pages threshold 56 * 57 * This causes user processes to stall to avoid exhausting memory that 58 * the kernel might need. 59 * 60 * reserved < severe < minimum < target < paging_target 61 */ 62 static __inline 63 int 64 vm_page_count_severe(void) 65 { 66 return (vmstats.v_free_severe > 67 vmstats.v_free_count + vmstats.v_cache_count || 68 vmstats.v_free_reserved > vmstats.v_free_count); 69 } 70 71 /* 72 * Return TRUE if we are under our minimum low-free-pages threshold. 73 * This activates the pageout demon. The pageout demon tries to 74 * reach the target but may stop once it satisfies the minimum. 75 * 76 * reserved < severe < minimum < target < paging_target 77 */ 78 static __inline 79 int 80 vm_page_count_min(int donotcount) 81 { 82 return (vmstats.v_free_min + donotcount > 83 (vmstats.v_free_count + vmstats.v_cache_count) || 84 vmstats.v_free_reserved > vmstats.v_free_count); 85 } 86 87 /* 88 * Return TRUE if we are under our free page target. The pageout demon 89 * tries to reach the target but may stop once it gets past the min. 90 * 91 * User threads doing normal allocations might wait based on this 92 * function but MUST NOT wait in a loop based on this function as the 93 * VM load may prevent the target from being reached. 94 */ 95 static __inline 96 int 97 vm_page_count_target(void) 98 { 99 return (vmstats.v_free_target > 100 (vmstats.v_free_count + vmstats.v_cache_count) || 101 vmstats.v_free_reserved > vmstats.v_free_count); 102 } 103 104 /* 105 * Return the number of pages the pageout daemon needs to move into the 106 * cache or free lists. A negative number means we have sufficient free 107 * pages. 108 * 109 * The target free+cache is greater than vm_page_count_target(). The 110 * frontend uses vm_page_count_target() while the backend continue freeing 111 * based on vm_paging_target(). 112 * 113 * This function DOES NOT return TRUE or FALSE. 114 */ 115 static __inline 116 int 117 vm_paging_target(void) 118 { 119 return ( 120 (vmstats.v_free_target + vmstats.v_cache_min) - 121 (vmstats.v_free_count + vmstats.v_cache_count) 122 ); 123 } 124 125 /* 126 * Return TRUE if hysteresis dictates we should nominally wakeup the 127 * pageout daemon to start working on freeing up some memory. This 128 * routine should NOT be used to determine when to block on the VM system. 129 * We want to wakeup the pageout daemon before we might otherwise block. 130 * 131 * Paging begins when cache+free drops below cache_min + free_min. 132 */ 133 static __inline 134 int 135 vm_paging_needed(void) 136 { 137 if (vmstats.v_free_min + vmstats.v_cache_min > 138 vmstats.v_free_count + vmstats.v_cache_count) { 139 return 1; 140 } 141 if (vmstats.v_free_min > vmstats.v_free_count) 142 return 1; 143 return 0; 144 } 145 146 static __inline 147 void 148 vm_page_event(vm_page_t m, vm_page_event_t event) 149 { 150 if (m->flags & PG_ACTIONLIST) 151 vm_page_event_internal(m, event); 152 } 153 154 static __inline 155 void 156 vm_page_init_action(vm_page_t m, vm_page_action_t action, 157 void (*func)(vm_page_t, vm_page_action_t), void *data) 158 { 159 action->m = m; 160 action->func = func; 161 action->data = data; 162 } 163 164 /* 165 * Clear dirty bits in the VM page but truncate the 166 * end to a DEV_BSIZE'd boundary. 167 * 168 * Used when reading data in, typically via getpages. 169 * The partial device block at the end of the truncation 170 * range should not lose its dirty bit. 171 * 172 * NOTE: This function does not clear the pmap modified bit. 173 */ 174 static __inline 175 void 176 vm_page_clear_dirty_end_nonincl(vm_page_t m, int base, int size) 177 { 178 size = (base + size) & ~DEV_BMASK; 179 if (base < size) 180 vm_page_clear_dirty(m, base, size - base); 181 } 182 183 /* 184 * Clear dirty bits in the VM page but truncate the 185 * beginning to a DEV_BSIZE'd boundary. 186 * 187 * Used when truncating a buffer. The partial device 188 * block at the beginning of the truncation range 189 * should not lose its dirty bit. 190 * 191 * NOTE: This function does not clear the pmap modified bit. 192 */ 193 static __inline 194 void 195 vm_page_clear_dirty_beg_nonincl(vm_page_t m, int base, int size) 196 { 197 size += base; 198 base = (base + DEV_BMASK) & ~DEV_BMASK; 199 if (base < size) 200 vm_page_clear_dirty(m, base, size - base); 201 } 202 203 static __inline 204 void 205 vm_page_spin_lock(vm_page_t m) 206 { 207 spin_pool_lock(m); 208 } 209 210 static __inline 211 void 212 vm_page_spin_unlock(vm_page_t m) 213 { 214 spin_pool_unlock(m); 215 } 216 217 /* 218 * Wire a vm_page that is already wired. Does not require a busied 219 * page. 220 */ 221 static __inline 222 void 223 vm_page_wire_quick(vm_page_t m) 224 { 225 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) 226 panic("vm_page_wire_quick: wire_count was 0"); 227 } 228 229 /* 230 * Unwire a vm_page quickly, does not require a busied page. 231 * 232 * This routine refuses to drop the wire_count to 0 and will return 233 * TRUE if it would have had to (instead of decrementing it to 0). 234 * The caller can then busy the page and deal with it. 235 */ 236 static __inline 237 int 238 vm_page_unwire_quick(vm_page_t m) 239 { 240 KKASSERT(m->wire_count > 0); 241 for (;;) { 242 u_int wire_count = m->wire_count; 243 244 cpu_ccfence(); 245 if (wire_count == 1) 246 return TRUE; 247 if (atomic_cmpset_int(&m->wire_count, wire_count, wire_count - 1)) 248 return FALSE; 249 } 250 } 251 252 /* 253 * Functions implemented as macros 254 */ 255 256 static __inline void 257 vm_page_flag_set(vm_page_t m, unsigned int bits) 258 { 259 atomic_set_int(&(m)->flags, bits); 260 } 261 262 static __inline void 263 vm_page_flag_clear(vm_page_t m, unsigned int bits) 264 { 265 atomic_clear_int(&(m)->flags, bits); 266 } 267 268 /* 269 * Wakeup anyone waiting for the page after potentially unbusying 270 * (hard or soft) or doing other work on a page that might make a 271 * waiter ready. The setting of PG_WANTED is integrated into the 272 * related flags and it can't be set once the flags are already 273 * clear, so there should be no races here. 274 */ 275 276 static __inline void 277 vm_page_flash(vm_page_t m) 278 { 279 if (m->flags & PG_WANTED) { 280 vm_page_flag_clear(m, PG_WANTED); 281 wakeup(m); 282 } 283 } 284 285 /* 286 * Reduce the protection of a page. This routine never raises the 287 * protection and therefore can be safely called if the page is already 288 * at VM_PROT_NONE (it will be a NOP effectively ). 289 * 290 * VM_PROT_NONE will remove all user mappings of a page. This is often 291 * necessary when a page changes state (for example, turns into a copy-on-write 292 * page or needs to be frozen for write I/O) in order to force a fault, or 293 * to force a page's dirty bits to be synchronized and avoid hardware 294 * (modified/accessed) bit update races with pmap changes. 295 * 296 * Since 'prot' is usually a constant, this inline usually winds up optimizing 297 * out the primary conditional. 298 * 299 * WARNING: VM_PROT_NONE can block, but will loop until all mappings have 300 * been cleared. Callers should be aware that other page related elements 301 * might have changed, however. 302 */ 303 static __inline void 304 vm_page_protect(vm_page_t m, int prot) 305 { 306 KKASSERT(m->flags & PG_BUSY); 307 if (prot == VM_PROT_NONE) { 308 if (m->flags & (PG_WRITEABLE|PG_MAPPED)) { 309 pmap_page_protect(m, VM_PROT_NONE); 310 /* PG_WRITEABLE & PG_MAPPED cleared by call */ 311 } 312 } else if ((prot == VM_PROT_READ) && (m->flags & PG_WRITEABLE)) { 313 pmap_page_protect(m, VM_PROT_READ); 314 /* PG_WRITEABLE cleared by call */ 315 } 316 } 317 318 /* 319 * Zero-fill the specified page. The entire contents of the page will be 320 * zero'd out. 321 */ 322 static __inline boolean_t 323 vm_page_zero_fill(vm_page_t m) 324 { 325 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 326 return (TRUE); 327 } 328 329 /* 330 * Copy the contents of src_m to dest_m. The pages must be stable but spl 331 * and other protections depend on context. 332 */ 333 static __inline void 334 vm_page_copy(vm_page_t src_m, vm_page_t dest_m) 335 { 336 pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m)); 337 dest_m->valid = VM_PAGE_BITS_ALL; 338 dest_m->dirty = VM_PAGE_BITS_ALL; 339 } 340 341 /* 342 * Free a page. The page must be marked BUSY. 343 */ 344 static __inline void 345 vm_page_free(vm_page_t m) 346 { 347 vm_page_free_toq(m); 348 } 349 350 /* 351 * Free a page to the zerod-pages queue. The caller must ensure that the 352 * page has been zerod. 353 */ 354 static __inline void 355 vm_page_free_zero(vm_page_t m) 356 { 357 #ifdef PMAP_DEBUG 358 #ifdef PHYS_TO_DMAP 359 char *p = (char *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)); 360 int i; 361 362 for (i = 0; i < PAGE_SIZE; i++) { 363 if (p[i] != 0) { 364 panic("non-zero page in vm_page_free_zero()"); 365 } 366 } 367 #endif 368 #endif 369 vm_page_free_toq(m); 370 } 371 372 /* 373 * Set page to not be dirty. Note: does not clear pmap modify bits . 374 */ 375 static __inline void 376 vm_page_undirty(vm_page_t m) 377 { 378 m->dirty = 0; 379 } 380 381 #endif /* _KERNEL */ 382 #endif /* _VM_VM_PAGE2_H_ */ 383 384