tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18#include <xfs.h>
19
20static kmem_zone_t *ktrace_hdr_zone;
21static kmem_zone_t *ktrace_ent_zone;
22static int ktrace_zentries;
23
24void __init
25ktrace_init(int zentries)
26{
27 ktrace_zentries = roundup_pow_of_two(zentries);
28
29 ktrace_hdr_zone = kmem_zone_init(sizeof(ktrace_t),
30 "ktrace_hdr");
31 ASSERT(ktrace_hdr_zone);
32
33 ktrace_ent_zone = kmem_zone_init(ktrace_zentries
34 * sizeof(ktrace_entry_t),
35 "ktrace_ent");
36 ASSERT(ktrace_ent_zone);
37}
38
39void __exit
40ktrace_uninit(void)
41{
42 kmem_zone_destroy(ktrace_hdr_zone);
43 kmem_zone_destroy(ktrace_ent_zone);
44}
45
46/*
47 * ktrace_alloc()
48 *
49 * Allocate a ktrace header and enough buffering for the given
50 * number of entries. Round the number of entries up to a
51 * power of 2 so we can do fast masking to get the index from
52 * the atomic index counter.
53 */
54ktrace_t *
55ktrace_alloc(int nentries, unsigned int __nocast sleep)
56{
57 ktrace_t *ktp;
58 ktrace_entry_t *ktep;
59 int entries;
60
61 ktp = (ktrace_t*)kmem_zone_alloc(ktrace_hdr_zone, sleep);
62
63 if (ktp == (ktrace_t*)NULL) {
64 /*
65 * KM_SLEEP callers don't expect failure.
66 */
67 if (sleep & KM_SLEEP)
68 panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
69
70 return NULL;
71 }
72
73 /*
74 * Special treatment for buffers with the ktrace_zentries entries
75 */
76 entries = roundup_pow_of_two(nentries);
77 if (entries == ktrace_zentries) {
78 ktep = (ktrace_entry_t*)kmem_zone_zalloc(ktrace_ent_zone,
79 sleep);
80 } else {
81 ktep = (ktrace_entry_t*)kmem_zalloc((entries * sizeof(*ktep)),
82 sleep | KM_LARGE);
83 }
84
85 if (ktep == NULL) {
86 /*
87 * KM_SLEEP callers don't expect failure.
88 */
89 if (sleep & KM_SLEEP)
90 panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
91
92 kmem_free(ktp);
93
94 return NULL;
95 }
96
97 ktp->kt_entries = ktep;
98 ktp->kt_nentries = entries;
99 ASSERT(is_power_of_2(entries));
100 ktp->kt_index_mask = entries - 1;
101 atomic_set(&ktp->kt_index, 0);
102 ktp->kt_rollover = 0;
103 return ktp;
104}
105
106
107/*
108 * ktrace_free()
109 *
110 * Free up the ktrace header and buffer. It is up to the caller
111 * to ensure that no-one is referencing it.
112 */
113void
114ktrace_free(ktrace_t *ktp)
115{
116 if (ktp == (ktrace_t *)NULL)
117 return;
118
119 /*
120 * Special treatment for the Vnode trace buffer.
121 */
122 if (ktp->kt_nentries == ktrace_zentries)
123 kmem_zone_free(ktrace_ent_zone, ktp->kt_entries);
124 else
125 kmem_free(ktp->kt_entries);
126
127 kmem_zone_free(ktrace_hdr_zone, ktp);
128}
129
130
131/*
132 * Enter the given values into the "next" entry in the trace buffer.
133 * kt_index is always the index of the next entry to be filled.
134 */
135void
136ktrace_enter(
137 ktrace_t *ktp,
138 void *val0,
139 void *val1,
140 void *val2,
141 void *val3,
142 void *val4,
143 void *val5,
144 void *val6,
145 void *val7,
146 void *val8,
147 void *val9,
148 void *val10,
149 void *val11,
150 void *val12,
151 void *val13,
152 void *val14,
153 void *val15)
154{
155 int index;
156 ktrace_entry_t *ktep;
157
158 ASSERT(ktp != NULL);
159
160 /*
161 * Grab an entry by pushing the index up to the next one.
162 */
163 index = atomic_add_return(1, &ktp->kt_index);
164 index = (index - 1) & ktp->kt_index_mask;
165 if (!ktp->kt_rollover && index == ktp->kt_nentries - 1)
166 ktp->kt_rollover = 1;
167
168 ASSERT((index >= 0) && (index < ktp->kt_nentries));
169
170 ktep = &(ktp->kt_entries[index]);
171
172 ktep->val[0] = val0;
173 ktep->val[1] = val1;
174 ktep->val[2] = val2;
175 ktep->val[3] = val3;
176 ktep->val[4] = val4;
177 ktep->val[5] = val5;
178 ktep->val[6] = val6;
179 ktep->val[7] = val7;
180 ktep->val[8] = val8;
181 ktep->val[9] = val9;
182 ktep->val[10] = val10;
183 ktep->val[11] = val11;
184 ktep->val[12] = val12;
185 ktep->val[13] = val13;
186 ktep->val[14] = val14;
187 ktep->val[15] = val15;
188}
189
190/*
191 * Return the number of entries in the trace buffer.
192 */
193int
194ktrace_nentries(
195 ktrace_t *ktp)
196{
197 int index;
198 if (ktp == NULL)
199 return 0;
200
201 index = atomic_read(&ktp->kt_index) & ktp->kt_index_mask;
202 return (ktp->kt_rollover ? ktp->kt_nentries : index);
203}
204
205/*
206 * ktrace_first()
207 *
208 * This is used to find the start of the trace buffer.
209 * In conjunction with ktrace_next() it can be used to
210 * iterate through the entire trace buffer. This code does
211 * not do any locking because it is assumed that it is called
212 * from the debugger.
213 *
214 * The caller must pass in a pointer to a ktrace_snap
215 * structure in which we will keep some state used to
216 * iterate through the buffer. This state must not touched
217 * by any code outside of this module.
218 */
219ktrace_entry_t *
220ktrace_first(ktrace_t *ktp, ktrace_snap_t *ktsp)
221{
222 ktrace_entry_t *ktep;
223 int index;
224 int nentries;
225
226 if (ktp->kt_rollover)
227 index = atomic_read(&ktp->kt_index) & ktp->kt_index_mask;
228 else
229 index = 0;
230
231 ktsp->ks_start = index;
232 ktep = &(ktp->kt_entries[index]);
233
234 nentries = ktrace_nentries(ktp);
235 index++;
236 if (index < nentries) {
237 ktsp->ks_index = index;
238 } else {
239 ktsp->ks_index = 0;
240 if (index > nentries)
241 ktep = NULL;
242 }
243 return ktep;
244}
245
246/*
247 * ktrace_next()
248 *
249 * This is used to iterate through the entries of the given
250 * trace buffer. The caller must pass in the ktrace_snap_t
251 * structure initialized by ktrace_first(). The return value
252 * will be either a pointer to the next ktrace_entry or NULL
253 * if all of the entries have been traversed.
254 */
255ktrace_entry_t *
256ktrace_next(
257 ktrace_t *ktp,
258 ktrace_snap_t *ktsp)
259{
260 int index;
261 ktrace_entry_t *ktep;
262
263 index = ktsp->ks_index;
264 if (index == ktsp->ks_start) {
265 ktep = NULL;
266 } else {
267 ktep = &ktp->kt_entries[index];
268 }
269
270 index++;
271 if (index == ktrace_nentries(ktp)) {
272 ktsp->ks_index = 0;
273 } else {
274 ktsp->ks_index = index;
275 }
276
277 return ktep;
278}
279
280/*
281 * ktrace_skip()
282 *
283 * Skip the next "count" entries and return the entry after that.
284 * Return NULL if this causes us to iterate past the beginning again.
285 */
286ktrace_entry_t *
287ktrace_skip(
288 ktrace_t *ktp,
289 int count,
290 ktrace_snap_t *ktsp)
291{
292 int index;
293 int new_index;
294 ktrace_entry_t *ktep;
295 int nentries = ktrace_nentries(ktp);
296
297 index = ktsp->ks_index;
298 new_index = index + count;
299 while (new_index >= nentries) {
300 new_index -= nentries;
301 }
302 if (index == ktsp->ks_start) {
303 /*
304 * We've iterated around to the start, so we're done.
305 */
306 ktep = NULL;
307 } else if ((new_index < index) && (index < ktsp->ks_index)) {
308 /*
309 * We've skipped past the start again, so we're done.
310 */
311 ktep = NULL;
312 ktsp->ks_index = ktsp->ks_start;
313 } else {
314 ktep = &(ktp->kt_entries[new_index]);
315 new_index++;
316 if (new_index == nentries) {
317 ktsp->ks_index = 0;
318 } else {
319 ktsp->ks_index = new_index;
320 }
321 }
322 return ktep;
323}