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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 | /* Slow work debugging * * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public Licence * as published by the Free Software Foundation; either version * 2 of the Licence, or (at your option) any later version. */ #include <linux/module.h> #include <linux/slow-work.h> #include <linux/fs.h> #include <linux/time.h> #include <linux/seq_file.h> #include "slow-work.h" #define ITERATOR_SHIFT (BITS_PER_LONG - 4) #define ITERATOR_SELECTOR (0xfUL << ITERATOR_SHIFT) #define ITERATOR_COUNTER (~ITERATOR_SELECTOR) void slow_work_new_thread_desc(struct slow_work *work, struct seq_file *m) { seq_puts(m, "Slow-work: New thread"); } /* * Render the time mark field on a work item into a 5-char time with units plus * a space */ static void slow_work_print_mark(struct seq_file *m, struct slow_work *work) { struct timespec now, diff; now = CURRENT_TIME; diff = timespec_sub(now, work->mark); if (diff.tv_sec < 0) seq_puts(m, " -ve "); else if (diff.tv_sec == 0 && diff.tv_nsec < 1000) seq_printf(m, "%3luns ", diff.tv_nsec); else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000) seq_printf(m, "%3luus ", diff.tv_nsec / 1000); else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000000) seq_printf(m, "%3lums ", diff.tv_nsec / 1000000); else if (diff.tv_sec <= 1) seq_puts(m, " 1s "); else if (diff.tv_sec < 60) seq_printf(m, "%4lus ", diff.tv_sec); else if (diff.tv_sec < 60 * 60) seq_printf(m, "%4lum ", diff.tv_sec / 60); else if (diff.tv_sec < 60 * 60 * 24) seq_printf(m, "%4luh ", diff.tv_sec / 3600); else seq_puts(m, "exces "); } /* * Describe a slow work item for debugfs */ static int slow_work_runqueue_show(struct seq_file *m, void *v) { struct slow_work *work; struct list_head *p = v; unsigned long id; switch ((unsigned long) v) { case 1: seq_puts(m, "THR PID ITEM ADDR FL MARK DESC\n"); return 0; case 2: seq_puts(m, "=== ===== ================ == ===== ==========\n"); return 0; case 3 ... 3 + SLOW_WORK_THREAD_LIMIT - 1: id = (unsigned long) v - 3; read_lock(&slow_work_execs_lock); work = slow_work_execs[id]; if (work) { smp_read_barrier_depends(); seq_printf(m, "%3lu %5d %16p %2lx ", id, slow_work_pids[id], work, work->flags); slow_work_print_mark(m, work); if (work->ops->desc) work->ops->desc(work, m); seq_putc(m, '\n'); } read_unlock(&slow_work_execs_lock); return 0; default: work = list_entry(p, struct slow_work, link); seq_printf(m, "%3s - %16p %2lx ", work->flags & SLOW_WORK_VERY_SLOW ? "vsq" : "sq", work, work->flags); slow_work_print_mark(m, work); if (work->ops->desc) work->ops->desc(work, m); seq_putc(m, '\n'); return 0; } } /* * map the iterator to a work item */ static void *slow_work_runqueue_index(struct seq_file *m, loff_t *_pos) { struct list_head *p; unsigned long count, id; switch (*_pos >> ITERATOR_SHIFT) { case 0x0: if (*_pos == 0) *_pos = 1; if (*_pos < 3) return (void *)(unsigned long) *_pos; if (*_pos < 3 + SLOW_WORK_THREAD_LIMIT) for (id = *_pos - 3; id < SLOW_WORK_THREAD_LIMIT; id++, (*_pos)++) if (slow_work_execs[id]) return (void *)(unsigned long) *_pos; *_pos = 0x1UL << ITERATOR_SHIFT; case 0x1: count = *_pos & ITERATOR_COUNTER; list_for_each(p, &slow_work_queue) { if (count == 0) return p; count--; } *_pos = 0x2UL << ITERATOR_SHIFT; case 0x2: count = *_pos & ITERATOR_COUNTER; list_for_each(p, &vslow_work_queue) { if (count == 0) return p; count--; } *_pos = 0x3UL << ITERATOR_SHIFT; default: return NULL; } } /* * set up the iterator to start reading from the first line */ static void *slow_work_runqueue_start(struct seq_file *m, loff_t *_pos) { spin_lock_irq(&slow_work_queue_lock); return slow_work_runqueue_index(m, _pos); } /* * move to the next line */ static void *slow_work_runqueue_next(struct seq_file *m, void *v, loff_t *_pos) { struct list_head *p = v; unsigned long selector = *_pos >> ITERATOR_SHIFT; (*_pos)++; switch (selector) { case 0x0: return slow_work_runqueue_index(m, _pos); case 0x1: if (*_pos >> ITERATOR_SHIFT == 0x1) { p = p->next; if (p != &slow_work_queue) return p; } *_pos = 0x2UL << ITERATOR_SHIFT; p = &vslow_work_queue; case 0x2: if (*_pos >> ITERATOR_SHIFT == 0x2) { p = p->next; if (p != &vslow_work_queue) return p; } *_pos = 0x3UL << ITERATOR_SHIFT; default: return NULL; } } /* * clean up after reading */ static void slow_work_runqueue_stop(struct seq_file *m, void *v) { spin_unlock_irq(&slow_work_queue_lock); } static const struct seq_operations slow_work_runqueue_ops = { .start = slow_work_runqueue_start, .stop = slow_work_runqueue_stop, .next = slow_work_runqueue_next, .show = slow_work_runqueue_show, }; /* * open "/sys/kernel/debug/slow_work/runqueue" to list queue contents */ static int slow_work_runqueue_open(struct inode *inode, struct file *file) { return seq_open(file, &slow_work_runqueue_ops); } const struct file_operations slow_work_runqueue_fops = { .owner = THIS_MODULE, .open = slow_work_runqueue_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; |