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 } 68 69 /* 70 * Return TRUE if we are under our minimum low-free-pages threshold. 71 * This activates the pageout demon. The pageout demon tries to 72 * reach the target but may stop once it satisfies the minimum. 73 * 74 * reserved < severe < minimum < target < paging_target 75 */ 76 static __inline 77 int 78 vm_page_count_min(int donotcount) 79 { 80 return (vmstats.v_free_min + donotcount > 81 (vmstats.v_free_count + vmstats.v_cache_count) || 82 vmstats.v_free_reserved > vmstats.v_free_count); 83 } 84 85 /* 86 * Return TRUE if we are under our free page target. The pageout demon 87 * tries to reach the target but may stop once it gets past the min. 88 */ 89 static __inline 90 int 91 vm_page_count_target(void) 92 { 93 return (vmstats.v_free_target > 94 (vmstats.v_free_count + vmstats.v_cache_count)); 95 } 96 97 /* 98 * Return the number of pages the pageout daemon needs to move into the 99 * cache or free lists. A negative number means we have sufficient free 100 * pages. 101 */ 102 static __inline 103 int 104 vm_paging_target(void) 105 { 106 return ( 107 (vmstats.v_free_target + vmstats.v_cache_min) - 108 (vmstats.v_free_count + vmstats.v_cache_count) 109 ); 110 } 111 112 /* 113 * Return TRUE if we need to start paging. This routine should not be 114 * used to determine when to block on the VM system. It supplies hysteresis 115 * to the pageout code. 116 * 117 * XXX this triggers a wakeup of the pagedaemon. As part of its work 118 * the pagedaemon tries to maintain v_free_reserved worth of truely 119 * free pages. Set the trigger point a bit lower so we have some hystereis. 120 */ 121 static __inline 122 int 123 vm_paging_needed(void) 124 { 125 int trigger; 126 127 trigger = vmstats.v_interrupt_free_min + 128 (vmstats.v_free_reserved - vmstats.v_interrupt_free_min) / 2; 129 if (trigger < 10) /* safety */ 130 trigger = 10; 131 132 return ( 133 (vmstats.v_free_min + vmstats.v_cache_min) > 134 (vmstats.v_free_count + vmstats.v_cache_count) || 135 trigger > vmstats.v_free_count 136 ); 137 } 138 139 static __inline 140 void 141 vm_page_event(vm_page_t m, vm_page_event_t event) 142 { 143 if (LIST_FIRST(&m->action_list)) 144 vm_page_event_internal(m, event); 145 } 146 147 static __inline 148 void 149 vm_page_init_action(vm_page_action_t action, 150 void (*func)(vm_page_t, vm_page_action_t), void *data) 151 { 152 action->func = func; 153 action->data = data; 154 } 155 156 static __inline 157 void 158 vm_page_register_action(vm_page_t m, vm_page_action_t action, 159 vm_page_event_t event) 160 { 161 action->event = event; 162 LIST_INSERT_HEAD(&m->action_list, action, entry); 163 } 164 165 static __inline 166 void 167 vm_page_unregister_action(vm_page_t m, vm_page_action_t action) 168 { 169 if (action->event != VMEVENT_NONE) { 170 action->event = VMEVENT_NONE; 171 LIST_REMOVE(action, entry); 172 } 173 } 174 175 #endif /* _KERNEL */ 176 #endif /* _VM_VM_PAGE2_H_ */ 177 178