projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 7394daa8 DH |
1 | /* FS-Cache latency histogram |
| 2 | * | |
| 3 | * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. | |
| 4 | * Written by David Howells ([email protected]) | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or | |
| 7 | * modify it under the terms of the GNU General Public Licence | |
| 8 | * as published by the Free Software Foundation; either version | |
| 9 | * 2 of the Licence, or (at your option) any later version. | |
| 10 | */ | |
| 11 | ||
| 12 | #define FSCACHE_DEBUG_LEVEL THREAD | |
| 13 | #include <linux/module.h> | |
| 14 | #include <linux/proc_fs.h> | |
| 15 | #include <linux/seq_file.h> | |
| 16 | #include "internal.h" | |
| 17 | ||
| 18 | atomic_t fscache_obj_instantiate_histogram[HZ]; | |
| 19 | atomic_t fscache_objs_histogram[HZ]; | |
| 20 | atomic_t fscache_ops_histogram[HZ]; | |
| 21 | atomic_t fscache_retrieval_delay_histogram[HZ]; | |
| 22 | atomic_t fscache_retrieval_histogram[HZ]; | |
| 23 | ||
| 24 | /* | |
| 25 | * display the time-taken histogram | |
| 26 | */ | |
| 27 | static int fscache_histogram_show(struct seq_file *m, void *v) | |
| 28 | { | |
| 29 | unsigned long index; | |
| 30 | unsigned n[5], t; | |
| 31 | ||
| 32 | switch ((unsigned long) v) { | |
| 33 | case 1: | |
| 34 | seq_puts(m, "JIFS SECS OBJ INST OP RUNS OBJ RUNS " | |
| 35 | " RETRV DLY RETRIEVLS\n"); | |
| 36 | return 0; | |
| 37 | case 2: | |
| 38 | seq_puts(m, "===== ===== ========= ========= =========" | |
| 39 | " ========= =========\n"); | |
| 40 | return 0; | |
| 41 | default: | |
| 42 | index = (unsigned long) v - 3; | |
| 43 | n[0] = atomic_read(&fscache_obj_instantiate_histogram[index]); | |
| 44 | n[1] = atomic_read(&fscache_ops_histogram[index]); | |
| 45 | n[2] = atomic_read(&fscache_objs_histogram[index]); | |
| 46 | n[3] = atomic_read(&fscache_retrieval_delay_histogram[index]); | |
| 47 | n[4] = atomic_read(&fscache_retrieval_histogram[index]); | |
| 48 | if (!(n[0] | n[1] | n[2] | n[3] | n[4])) | |
| 49 | return 0; | |
| 50 | ||
| 51 | t = (index * 1000) / HZ; | |
| 52 | ||
| 53 | seq_printf(m, "%4lu 0.%03u %9u %9u %9u %9u %9u\n", | |
| 54 | index, t, n[0], n[1], n[2], n[3], n[4]); | |
| 55 | return 0; | |
| 56 | } | |
| 57 | } | |
| 58 | ||
| 59 | /* | |
| 60 | * set up the iterator to start reading from the first line | |
| 61 | */ | |
| 62 | static void *fscache_histogram_start(struct seq_file *m, loff_t *_pos) | |
| 63 | { | |
| 64 | if ((unsigned long long)*_pos >= HZ + 2) | |
| 65 | return NULL; | |
| 66 | if (*_pos == 0) | |
| 67 | *_pos = 1; | |
| 68 | return (void *)(unsigned long) *_pos; | |
| 69 | } | |
| 70 | ||
| 71 | /* | |
| 72 | * move to the next line | |
| 73 | */ | |
| 74 | static void *fscache_histogram_next(struct seq_file *m, void *v, loff_t *pos) | |
| 75 | { | |
| 76 | (*pos)++; | |
| 77 | return (unsigned long long)*pos > HZ + 2 ? | |
| 78 | NULL : (void *)(unsigned long) *pos; | |
| 79 | } | |
| 80 | ||
| 81 | /* | |
| 82 | * clean up after reading | |
| 83 | */ | |
| 84 | static void fscache_histogram_stop(struct seq_file *m, void *v) | |
| 85 | { | |
| 86 | } | |
| 87 | ||
| 88 | static const struct seq_operations fscache_histogram_ops = { | |
| 89 | .start = fscache_histogram_start, | |
| 90 | .stop = fscache_histogram_stop, | |
| 91 | .next = fscache_histogram_next, | |
| 92 | .show = fscache_histogram_show, | |
| 93 | }; | |
| 94 | ||
| 95 | /* | |
| 96 | * open "/proc/fs/fscache/histogram" to provide latency data | |
| 97 | */ | |
| 98 | static int fscache_histogram_open(struct inode *inode, struct file *file) | |
| 99 | { | |
| 100 | return seq_open(file, &fscache_histogram_ops); | |
| 101 | } | |
| 102 | ||
| 103 | const struct file_operations fscache_histogram_fops = { | |
| 104 | .owner = THIS_MODULE, | |
| 105 | .open = fscache_histogram_open, | |
| 106 | .read = seq_read, | |
| 107 | .llseek = seq_lseek, | |
| 108 | .release = seq_release, | |
| 109 | }; |