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 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/proc.h> 39 #include <sys/rtprio.h> 40 #include <sys/queue.h> 41 #include <machine/cpu.h> 42 #include <sys/spinlock.h> 43 #include <sys/iosched.h> 44 #include <sys/sysctl.h> 45 #include <sys/buf.h> 46 #include <sys/limits.h> 47 48 #include <sys/spinlock2.h> 49 50 #include <vm/vm.h> 51 #include <vm/vm_param.h> 52 #include <vm/vm_kern.h> 53 #include <vm/vm_extern.h> 54 55 SYSCTL_NODE(, OID_AUTO, iosched, CTLFLAG_RW, 0, "I/O Scheduler"); 56 57 static int iosched_debug = 0; 58 SYSCTL_INT(_iosched, OID_AUTO, debug, CTLFLAG_RW, &iosched_debug, 0, ""); 59 60 static struct iosched_data ioscpu[SMP_MAXCPU]; 61 62 /* 63 * MPSAFE 64 */ 65 static int 66 badjiosched(thread_t td, size_t bytes) 67 { 68 globaldata_t gd = mycpu; 69 size_t iostotal; 70 int factor; 71 int i; 72 int delta; 73 74 iostotal = 0; 75 for (i = 0; i < ncpus; ++i) 76 iostotal += ioscpu[i].iowbytes; 77 if (SIZE_T_MAX / SMP_MAXCPU - td->td_iosdata.iowbytes < bytes) 78 bytes = SIZE_T_MAX / SMP_MAXCPU - td->td_iosdata.iowbytes; 79 td->td_iosdata.iowbytes += bytes; 80 ioscpu[gd->gd_cpuid].iowbytes += bytes; 81 iostotal += bytes; 82 delta = ticks - td->td_iosdata.lastticks; 83 if (delta) { 84 td->td_iosdata.lastticks = ticks; 85 if (delta < 0 || delta > hz * 10) 86 delta = hz * 10; 87 /* be careful of interger overflows */ 88 bytes = (int64_t)td->td_iosdata.iowbytes * delta / (hz * 10); 89 td->td_iosdata.iowbytes -= bytes; 90 ioscpu[gd->gd_cpuid].iowbytes -= bytes; 91 iostotal -= bytes; 92 } 93 94 /* be careful of interger overflows */ 95 if (iostotal > 0) 96 factor = (int64_t)td->td_iosdata.iowbytes * 100 / iostotal; 97 else 98 factor = 50; 99 100 if (delta && (iosched_debug & 1)) { 101 kprintf("proc %12s (%-5d) factor %3d (%zd/%zd)\n", 102 td->td_comm, 103 (td->td_lwp ? (int)td->td_lwp->lwp_proc->p_pid : -1), 104 factor, td->td_iosdata.iowbytes, iostotal); 105 } 106 return (factor); 107 } 108 109 void 110 biosched_done(thread_t td) 111 { 112 globaldata_t gd = mycpu; 113 size_t bytes; 114 115 if ((bytes = td->td_iosdata.iowbytes) != 0) { 116 td->td_iosdata.iowbytes = 0; 117 ioscpu[gd->gd_cpuid].iowbytes -= bytes; 118 } 119 } 120 121 /* 122 * Caller intends to write (bytes) 123 * 124 * MPSAFE 125 */ 126 void 127 bwillwrite(int bytes) 128 { 129 long count; 130 long factor; 131 132 count = bd_heatup(); 133 if (count > 0) { 134 /* be careful of interger overflows */ 135 factor = badjiosched(curthread, (size_t)bytes); 136 count = hidirtybufspace / 100 * factor; 137 bd_wait(count); 138 } 139 } 140 141 /* 142 * Caller intends to read (bytes) 143 * 144 * MPSAFE 145 */ 146 void 147 bwillread(int bytes) 148 { 149 } 150 151 /* 152 * Call intends to do an inode-modifying operation of some sort. 153 * 154 * MPSAFE 155 */ 156 void 157 bwillinode(int n) 158 { 159 long count; 160 long factor; 161 162 count = bd_heatup(); 163 if (count > 0) { 164 factor = badjiosched(curthread, PAGE_SIZE); 165 count = count * factor / 100; 166 bd_wait(count); 167 } 168 } 169 170