kernel - Fix intermediate value overflows in badjiosched() and bwillwrite()
[dragonfly.git] / sys / kern / kern_iosched.c
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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>
79eae878 46#include <sys/sysctl.h>
c4df9635 47#include <sys/buf.h>
79eae878 48#include <sys/limits.h>
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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
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58SYSCTL_NODE(, OID_AUTO, iosched, CTLFLAG_RW, 0, "I/O Scheduler");
59
60static int iosched_debug = 0;
61SYSCTL_INT(_iosched, OID_AUTO, debug, CTLFLAG_RW, &iosched_debug, 0, "");
62
63static struct iosched_data ioscpu[SMP_MAXCPU];
64
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65/*
66 * MPSAFE
67 */
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68static int
69badjiosched(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;
06f4f9eb 90 /* be careful of interger overflows */
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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 }
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96
97 /* be careful of interger overflows */
79eae878 98 if (iostotal > 0)
06f4f9eb 99 factor = (int64_t)td->td_iosdata.iowbytes * 100 / iostotal;
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100 else
101 factor = 50;
06f4f9eb 102
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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
112void
113biosched_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
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124/*
125 * Caller intends to write (bytes)
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126 *
127 * MPSAFE
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128 */
129void
130bwillwrite(int bytes)
131{
132 int count;
79eae878 133 int factor;
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134
135 count = bd_heatup();
79eae878 136 if (count > 0) {
06f4f9eb 137 /* be careful of interger overflows */
79eae878 138 factor = badjiosched(curthread, (size_t)bytes);
06f4f9eb 139 count = hidirtybufspace / 100 * factor;
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140 bd_wait(count);
141 }
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142}
143
144/*
145 * Caller intends to read (bytes)
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146 *
147 * MPSAFE
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148 */
149void
150bwillread(int bytes)
151{
152}
153
154/*
155 * Call intends to do an inode-modifying operation of some sort.
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156 *
157 * MPSAFE
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158 */
159void
160bwillinode(int n)
161{
162 int count;
79eae878 163 int factor;
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164
165 count = bd_heatup();
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166 if (count > 0) {
167 factor = badjiosched(curthread, PAGE_SIZE);
168 count = count * factor / 100;
169 bd_wait(count);
170 }
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171}
172