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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)vmmeter.h 8.2 (Berkeley) 7/10/94 34 * $FreeBSD: src/sys/sys/vmmeter.h,v 1.21.2.2 2002/10/10 19:28:21 dillon Exp $ 35 * $DragonFly: src/sys/vm/vm_page2.h,v 1.3 2008/04/14 20:00:29 dillon Exp $ 36 */ 37 38 #ifndef _VM_VM_PAGE2_H_ 39 #define _VM_VM_PAGE2_H_ 40 41 #ifndef _SYS_VMMETER_H_ 42 #include <sys/vmmeter.h> 43 #endif 44 #ifndef _SYS_QUEUE_H_ 45 #include <sys/queue.h> 46 #endif 47 #ifndef _VM_PAGE_H_ 48 #include <vm/vm_page.h> 49 #endif 50 51 #ifdef _KERNEL 52 53 /* 54 * Return TRUE if we are under our severe low-free-pages threshold 55 * 56 * This causes user processes to stall to avoid exhausting memory that 57 * the kernel might need. 58 * 59 * reserved < severe < minimum < target < paging_target 60 */ 61 static __inline 62 int 63 vm_page_count_severe(void) 64 { 65 return (vmstats.v_free_severe > 66 vmstats.v_free_count + vmstats.v_cache_count || 67 vmstats.v_free_reserved > vmstats.v_free_count); 68 } 69 70 /* 71 * Return TRUE if we are under our minimum low-free-pages threshold. 72 * This activates the pageout demon. The pageout demon tries to 73 * reach the target but may stop once it satisfies the minimum. 74 * 75 * reserved < severe < minimum < target < paging_target 76 */ 77 static __inline 78 int 79 vm_page_count_min(int donotcount) 80 { 81 return (vmstats.v_free_min + donotcount > 82 (vmstats.v_free_count + vmstats.v_cache_count) || 83 vmstats.v_free_reserved > vmstats.v_free_count); 84 } 85 86 /* 87 * Return TRUE if we are under our free page target. The pageout demon 88 * tries to reach the target but may stop once it gets past the min. 89 */ 90 static __inline 91 int 92 vm_page_count_target(void) 93 { 94 return (vmstats.v_free_target > 95 (vmstats.v_free_count + vmstats.v_cache_count) || 96 vmstats.v_free_reserved > vmstats.v_free_count); 97 } 98 99 /* 100 * Return the number of pages the pageout daemon needs to move into the 101 * cache or free lists. A negative number means we have sufficient free 102 * pages. 103 * 104 * The target free+cache is greater than vm_page_count_target(). The 105 * frontend uses vm_page_count_target() while the backend continue freeing 106 * based on vm_paging_target(). 107 * 108 * This function DOES NOT return TRUE or FALSE. 109 */ 110 static __inline 111 int 112 vm_paging_target(void) 113 { 114 return ( 115 (vmstats.v_free_target + vmstats.v_cache_min) - 116 (vmstats.v_free_count + vmstats.v_cache_count) 117 ); 118 } 119 120 /* 121 * Return TRUE if hysteresis dictates we should nominally wakeup the 122 * pageout daemon to start working on freeing up some memory. This 123 * routine should NOT be used to determine when to block on the VM system. 124 * We want to wakeup the pageout daemon before we might otherwise block. 125 * 126 * Paging begins when cache+free drops below cache_min + free_min. 127 */ 128 static __inline 129 int 130 vm_paging_needed(void) 131 { 132 if (vmstats.v_free_min + vmstats.v_cache_min > 133 vmstats.v_free_count + vmstats.v_cache_count) { 134 return 1; 135 } 136 if (vmstats.v_free_min > vmstats.v_free_count) 137 return 1; 138 return 0; 139 } 140 141 static __inline 142 void 143 vm_page_event(vm_page_t m, vm_page_event_t event) 144 { 145 if (m->flags & PG_ACTIONLIST) 146 vm_page_event_internal(m, event); 147 } 148 149 static __inline 150 void 151 vm_page_init_action(vm_page_t m, vm_page_action_t action, 152 void (*func)(vm_page_t, vm_page_action_t), void *data) 153 { 154 action->m = m; 155 action->func = func; 156 action->data = data; 157 } 158 159 /* 160 * Clear dirty bits in the VM page but truncate the 161 * end to a DEV_BSIZE'd boundary. 162 * 163 * Used when reading data in, typically via getpages. 164 * The partial device block at the end of the truncation 165 * range should not lose its dirty bit. 166 * 167 * NOTE: This function does not clear the pmap modified bit. 168 */ 169 static __inline 170 void 171 vm_page_clear_dirty_end_nonincl(vm_page_t m, int base, int size) 172 { 173 size = (base + size) & ~DEV_BMASK; 174 if (base < size) 175 vm_page_clear_dirty(m, base, size - base); 176 } 177 178 /* 179 * Clear dirty bits in the VM page but truncate the 180 * beginning to a DEV_BSIZE'd boundary. 181 * 182 * Used when truncating a buffer. The partial device 183 * block at the beginning of the truncation range 184 * should not lose its dirty bit. 185 * 186 * NOTE: This function does not clear the pmap modified bit. 187 */ 188 static __inline 189 void 190 vm_page_clear_dirty_beg_nonincl(vm_page_t m, int base, int size) 191 { 192 size += base; 193 base = (base + DEV_BMASK) & ~DEV_BMASK; 194 if (base < size) 195 vm_page_clear_dirty(m, base, size - base); 196 } 197 198 #endif /* _KERNEL */ 199 #endif /* _VM_VM_PAGE2_H_ */ 200 201