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 bytes = (int64_t)td->td_iosdata.iowbytes * delta / (hz * 10); 91 td->td_iosdata.iowbytes -= bytes; 92 ioscpu[gd->gd_cpuid].iowbytes -= bytes; 93 iostotal -= bytes; 94 } 95 if (iostotal > 0) 96 factor = td->td_iosdata.iowbytes * 100 / iostotal; 97 else 98 factor = 50; 99 if (delta && (iosched_debug & 1)) { 100 kprintf("proc %12s (%-5d) factor %3d (%zd/%zd)\n", 101 td->td_comm, 102 (td->td_lwp ? (int)td->td_lwp->lwp_proc->p_pid : -1), 103 factor, td->td_iosdata.iowbytes, iostotal); 104 } 105 return (factor); 106 } 107 108 void 109 biosched_done(thread_t td) 110 { 111 globaldata_t gd = mycpu; 112 size_t bytes; 113 114 if ((bytes = td->td_iosdata.iowbytes) != 0) { 115 td->td_iosdata.iowbytes = 0; 116 ioscpu[gd->gd_cpuid].iowbytes -= bytes; 117 } 118 } 119 120 /* 121 * Caller intends to write (bytes) 122 * 123 * MPSAFE 124 */ 125 void 126 bwillwrite(int bytes) 127 { 128 int count; 129 int factor; 130 131 count = bd_heatup(); 132 if (count > 0) { 133 factor = badjiosched(curthread, (size_t)bytes); 134 count = hidirtybufspace * factor / 100; 135 bd_wait(count); 136 } 137 } 138 139 /* 140 * Caller intends to read (bytes) 141 * 142 * MPSAFE 143 */ 144 void 145 bwillread(int bytes) 146 { 147 } 148 149 /* 150 * Call intends to do an inode-modifying operation of some sort. 151 * 152 * MPSAFE 153 */ 154 void 155 bwillinode(int n) 156 { 157 int count; 158 int factor; 159 160 count = bd_heatup(); 161 if (count > 0) { 162 factor = badjiosched(curthread, PAGE_SIZE); 163 count = count * factor / 100; 164 bd_wait(count); 165 } 166 } 167 168