sys/kern/kern_iosched.c

   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