1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/kern/kern_iosched.c,v 1.1 2008/06/28 17:59:49 dillon Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/kernel.h> 40 #include <sys/proc.h> 41 #include <sys/rtprio.h> 42 #include <sys/queue.h> 43 #include <machine/cpu.h> 44 #include <sys/spinlock.h> 45 #include <sys/iosched.h> 46 #include <sys/sysctl.h> 47 #include <sys/buf.h> 48 #include <sys/limits.h> 49 50 #include <sys/thread2.h> 51 #include <sys/spinlock2.h> 52 53 #include <vm/vm.h> 54 #include <vm/vm_param.h> 55 #include <vm/vm_kern.h> 56 #include <vm/vm_extern.h> 57 58 SYSCTL_NODE(, OID_AUTO, iosched, CTLFLAG_RW, 0, "I/O Scheduler"); 59 60 static int iosched_debug = 0; 61 SYSCTL_INT(_iosched, OID_AUTO, debug, CTLFLAG_RW, &iosched_debug, 0, ""); 62 63 static struct iosched_data ioscpu[SMP_MAXCPU]; 64 65 /* 66 * MPSAFE 67 */ 68 static int 69 badjiosched(thread_t td, size_t bytes) 70 { 71 globaldata_t gd = mycpu; 72 size_t iostotal; 73 int factor; 74 int i; 75 int delta; 76 77 iostotal = 0; 78 for (i = 0; i < ncpus; ++i) 79 iostotal += ioscpu[i].iowbytes; 80 if (SIZE_T_MAX / SMP_MAXCPU - td->td_iosdata.iowbytes < bytes) 81 bytes = SIZE_T_MAX / SMP_MAXCPU - td->td_iosdata.iowbytes; 82 td->td_iosdata.iowbytes += bytes; 83 ioscpu[gd->gd_cpuid].iowbytes += bytes; 84 iostotal += bytes; 85 delta = ticks - td->td_iosdata.lastticks; 86 if (delta) { 87 td->td_iosdata.lastticks = ticks; 88 if (delta < 0 || delta > hz * 10) 89 delta = hz * 10; 90 /* be careful of interger overflows */ 91 bytes = (int64_t)td->td_iosdata.iowbytes * delta / (hz * 10); 92 td->td_iosdata.iowbytes -= bytes; 93 ioscpu[gd->gd_cpuid].iowbytes -= bytes; 94 iostotal -= bytes; 95 } 96 97 /* be careful of interger overflows */ 98 if (iostotal > 0) 99 factor = (int64_t)td->td_iosdata.iowbytes * 100 / iostotal; 100 else 101 factor = 50; 102 103 if (delta && (iosched_debug & 1)) { 104 kprintf("proc %12s (%-5d) factor %3d (%zd/%zd)\n", 105 td->td_comm, 106 (td->td_lwp ? (int)td->td_lwp->lwp_proc->p_pid : -1), 107 factor, td->td_iosdata.iowbytes, iostotal); 108 } 109 return (factor); 110 } 111 112 void 113 biosched_done(thread_t td) 114 { 115 globaldata_t gd = mycpu; 116 size_t bytes; 117 118 if ((bytes = td->td_iosdata.iowbytes) != 0) { 119 td->td_iosdata.iowbytes = 0; 120 ioscpu[gd->gd_cpuid].iowbytes -= bytes; 121 } 122 } 123 124 /* 125 * Caller intends to write (bytes) 126 * 127 * MPSAFE 128 */ 129 void 130 bwillwrite(int bytes) 131 { 132 long count; 133 long factor; 134 135 count = bd_heatup(); 136 if (count > 0) { 137 /* be careful of interger overflows */ 138 factor = badjiosched(curthread, (size_t)bytes); 139 count = hidirtybufspace / 100 * factor; 140 bd_wait(count); 141 } 142 } 143 144 /* 145 * Caller intends to read (bytes) 146 * 147 * MPSAFE 148 */ 149 void 150 bwillread(int bytes) 151 { 152 } 153 154 /* 155 * Call intends to do an inode-modifying operation of some sort. 156 * 157 * MPSAFE 158 */ 159 void 160 bwillinode(int n) 161 { 162 long count; 163 long factor; 164 165 count = bd_heatup(); 166 if (count > 0) { 167 factor = badjiosched(curthread, PAGE_SIZE); 168 count = count * factor / 100; 169 bd_wait(count); 170 } 171 } 172 173