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1 | /* |
2 | * CDDL HEADER START | |
3 | * | |
4 | * The contents of this file are subject to the terms of the | |
5 | * Common Development and Distribution License (the "License"). | |
6 | * You may not use this file except in compliance with the License. | |
7 | * | |
8 | * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE | |
9 | * or http://www.opensolaris.org/os/licensing. | |
10 | * See the License for the specific language governing permissions | |
11 | * and limitations under the License. | |
12 | * | |
13 | * When distributing Covered Code, include this CDDL HEADER in each | |
14 | * file and include the License file at usr/src/OPENSOLARIS.LICENSE. | |
15 | * If applicable, add the following below this CDDL HEADER, with the | |
16 | * fields enclosed by brackets "[]" replaced with your own identifying | |
17 | * information: Portions Copyright [yyyy] [name of copyright owner] | |
18 | * | |
19 | * CDDL HEADER END | |
20 | */ | |
21 | /* | |
22 | * Copyright 2008 Sun Microsystems, Inc. All rights reserved. | |
23 | * Use is subject to license terms. | |
24 | */ | |
25 | ||
26 | #pragma ident "@(#)txg.c 1.4 08/03/20 SMI" | |
27 | ||
28 | #include <sys/zfs_context.h> | |
29 | #include <sys/txg_impl.h> | |
30 | #include <sys/dmu_impl.h> | |
31 | #include <sys/dsl_pool.h> | |
32 | #include <sys/callb.h> | |
33 | ||
34 | /* | |
35 | * Pool-wide transaction groups. | |
36 | */ | |
37 | ||
38 | static void txg_sync_thread(dsl_pool_t *dp); | |
39 | static void txg_quiesce_thread(dsl_pool_t *dp); | |
40 | ||
41 | int zfs_txg_timeout = 30; /* max seconds worth of delta per txg */ | |
42 | int zfs_txg_synctime = 5; /* target seconds to sync a txg */ | |
43 | ||
44 | int zfs_write_limit_shift = 3; /* 1/8th of physical memory */ | |
45 | ||
46 | uint64_t zfs_write_limit_min = 32 << 20; /* min write limit is 32MB */ | |
47 | uint64_t zfs_write_limit_max = 0; /* max data payload per txg */ | |
48 | uint64_t zfs_write_limit_inflated = 0; | |
49 | ||
50 | /* | |
51 | * Prepare the txg subsystem. | |
52 | */ | |
53 | void | |
54 | txg_init(dsl_pool_t *dp, uint64_t txg) | |
55 | { | |
56 | tx_state_t *tx = &dp->dp_tx; | |
57 | int c; | |
58 | bzero(tx, sizeof (tx_state_t)); | |
59 | ||
60 | tx->tx_cpu = kmem_zalloc(max_ncpus * sizeof (tx_cpu_t), KM_SLEEP); | |
61 | ||
62 | for (c = 0; c < max_ncpus; c++) { | |
63 | int i; | |
64 | ||
65 | mutex_init(&tx->tx_cpu[c].tc_lock, NULL, MUTEX_DEFAULT, NULL); | |
66 | for (i = 0; i < TXG_SIZE; i++) { | |
67 | cv_init(&tx->tx_cpu[c].tc_cv[i], NULL, CV_DEFAULT, | |
68 | NULL); | |
69 | } | |
70 | } | |
71 | ||
72 | rw_init(&tx->tx_suspend, NULL, RW_DEFAULT, NULL); | |
73 | mutex_init(&tx->tx_sync_lock, NULL, MUTEX_DEFAULT, NULL); | |
74 | ||
75 | tx->tx_open_txg = txg; | |
76 | } | |
77 | ||
78 | /* | |
79 | * Close down the txg subsystem. | |
80 | */ | |
81 | void | |
82 | txg_fini(dsl_pool_t *dp) | |
83 | { | |
84 | tx_state_t *tx = &dp->dp_tx; | |
85 | int c; | |
86 | ||
87 | ASSERT(tx->tx_threads == 0); | |
88 | ||
89 | rw_destroy(&tx->tx_suspend); | |
90 | mutex_destroy(&tx->tx_sync_lock); | |
91 | ||
92 | for (c = 0; c < max_ncpus; c++) { | |
93 | int i; | |
94 | ||
95 | mutex_destroy(&tx->tx_cpu[c].tc_lock); | |
96 | for (i = 0; i < TXG_SIZE; i++) | |
97 | cv_destroy(&tx->tx_cpu[c].tc_cv[i]); | |
98 | } | |
99 | ||
100 | kmem_free(tx->tx_cpu, max_ncpus * sizeof (tx_cpu_t)); | |
101 | ||
102 | bzero(tx, sizeof (tx_state_t)); | |
103 | } | |
104 | ||
105 | /* | |
106 | * Start syncing transaction groups. | |
107 | */ | |
108 | void | |
109 | txg_sync_start(dsl_pool_t *dp) | |
110 | { | |
111 | tx_state_t *tx = &dp->dp_tx; | |
112 | ||
113 | mutex_enter(&tx->tx_sync_lock); | |
114 | ||
115 | dprintf("pool %p\n", dp); | |
116 | ||
117 | ASSERT(tx->tx_threads == 0); | |
118 | ||
119 | tx->tx_threads = 2; | |
120 | ||
121 | tx->tx_quiesce_thread = thread_create(NULL, 0, txg_quiesce_thread, | |
122 | dp, 0, &p0, TS_RUN, minclsyspri); | |
123 | ||
124 | tx->tx_sync_thread = thread_create(NULL, 0, txg_sync_thread, | |
125 | dp, 0, &p0, TS_RUN, minclsyspri); | |
126 | ||
127 | mutex_exit(&tx->tx_sync_lock); | |
128 | } | |
129 | ||
130 | static void | |
131 | txg_thread_enter(tx_state_t *tx, callb_cpr_t *cpr) | |
132 | { | |
133 | CALLB_CPR_INIT(cpr, &tx->tx_sync_lock, callb_generic_cpr, FTAG); | |
134 | mutex_enter(&tx->tx_sync_lock); | |
135 | } | |
136 | ||
137 | static void | |
138 | txg_thread_exit(tx_state_t *tx, callb_cpr_t *cpr, kthread_t **tpp) | |
139 | { | |
140 | ASSERT(*tpp != NULL); | |
141 | *tpp = NULL; | |
142 | tx->tx_threads--; | |
143 | cv_broadcast(&tx->tx_exit_cv); | |
144 | CALLB_CPR_EXIT(cpr); /* drops &tx->tx_sync_lock */ | |
145 | thread_exit(); | |
146 | } | |
147 | ||
148 | static void | |
149 | txg_thread_wait(tx_state_t *tx, callb_cpr_t *cpr, kcondvar_t *cv, uint64_t time) | |
150 | { | |
151 | CALLB_CPR_SAFE_BEGIN(cpr); | |
152 | ||
153 | if (time) | |
154 | (void) cv_timedwait(cv, &tx->tx_sync_lock, lbolt + time); | |
155 | else | |
156 | cv_wait(cv, &tx->tx_sync_lock); | |
157 | ||
158 | CALLB_CPR_SAFE_END(cpr, &tx->tx_sync_lock); | |
159 | } | |
160 | ||
161 | /* | |
162 | * Stop syncing transaction groups. | |
163 | */ | |
164 | void | |
165 | txg_sync_stop(dsl_pool_t *dp) | |
166 | { | |
167 | tx_state_t *tx = &dp->dp_tx; | |
168 | ||
169 | dprintf("pool %p\n", dp); | |
170 | /* | |
171 | * Finish off any work in progress. | |
172 | */ | |
173 | ASSERT(tx->tx_threads == 2); | |
174 | txg_wait_synced(dp, 0); | |
175 | ||
176 | /* | |
177 | * Wake all sync threads and wait for them to die. | |
178 | */ | |
179 | mutex_enter(&tx->tx_sync_lock); | |
180 | ||
181 | ASSERT(tx->tx_threads == 2); | |
182 | ||
183 | tx->tx_exiting = 1; | |
184 | ||
185 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
186 | cv_broadcast(&tx->tx_quiesce_done_cv); | |
187 | cv_broadcast(&tx->tx_sync_more_cv); | |
188 | ||
189 | while (tx->tx_threads != 0) | |
190 | cv_wait(&tx->tx_exit_cv, &tx->tx_sync_lock); | |
191 | ||
192 | tx->tx_exiting = 0; | |
193 | ||
194 | mutex_exit(&tx->tx_sync_lock); | |
195 | } | |
196 | ||
197 | uint64_t | |
198 | txg_hold_open(dsl_pool_t *dp, txg_handle_t *th) | |
199 | { | |
200 | tx_state_t *tx = &dp->dp_tx; | |
201 | tx_cpu_t *tc = &tx->tx_cpu[CPU_SEQID]; | |
202 | uint64_t txg; | |
203 | ||
204 | mutex_enter(&tc->tc_lock); | |
205 | ||
206 | txg = tx->tx_open_txg; | |
207 | tc->tc_count[txg & TXG_MASK]++; | |
208 | ||
209 | th->th_cpu = tc; | |
210 | th->th_txg = txg; | |
211 | ||
212 | return (txg); | |
213 | } | |
214 | ||
215 | void | |
216 | txg_rele_to_quiesce(txg_handle_t *th) | |
217 | { | |
218 | tx_cpu_t *tc = th->th_cpu; | |
219 | ||
220 | mutex_exit(&tc->tc_lock); | |
221 | } | |
222 | ||
223 | void | |
224 | txg_rele_to_sync(txg_handle_t *th) | |
225 | { | |
226 | tx_cpu_t *tc = th->th_cpu; | |
227 | int g = th->th_txg & TXG_MASK; | |
228 | ||
229 | mutex_enter(&tc->tc_lock); | |
230 | ASSERT(tc->tc_count[g] != 0); | |
231 | if (--tc->tc_count[g] == 0) | |
232 | cv_broadcast(&tc->tc_cv[g]); | |
233 | mutex_exit(&tc->tc_lock); | |
234 | ||
235 | th->th_cpu = NULL; /* defensive */ | |
236 | } | |
237 | ||
238 | static void | |
239 | txg_quiesce(dsl_pool_t *dp, uint64_t txg) | |
240 | { | |
241 | tx_state_t *tx = &dp->dp_tx; | |
242 | int g = txg & TXG_MASK; | |
243 | int c; | |
244 | ||
245 | /* | |
246 | * Grab all tx_cpu locks so nobody else can get into this txg. | |
247 | */ | |
248 | for (c = 0; c < max_ncpus; c++) | |
249 | mutex_enter(&tx->tx_cpu[c].tc_lock); | |
250 | ||
251 | ASSERT(txg == tx->tx_open_txg); | |
252 | tx->tx_open_txg++; | |
253 | ||
254 | /* | |
255 | * Now that we've incremented tx_open_txg, we can let threads | |
256 | * enter the next transaction group. | |
257 | */ | |
258 | for (c = 0; c < max_ncpus; c++) | |
259 | mutex_exit(&tx->tx_cpu[c].tc_lock); | |
260 | ||
261 | /* | |
262 | * Quiesce the transaction group by waiting for everyone to txg_exit(). | |
263 | */ | |
264 | for (c = 0; c < max_ncpus; c++) { | |
265 | tx_cpu_t *tc = &tx->tx_cpu[c]; | |
266 | mutex_enter(&tc->tc_lock); | |
267 | while (tc->tc_count[g] != 0) | |
268 | cv_wait(&tc->tc_cv[g], &tc->tc_lock); | |
269 | mutex_exit(&tc->tc_lock); | |
270 | } | |
271 | } | |
272 | ||
273 | static void | |
274 | txg_sync_thread(dsl_pool_t *dp) | |
275 | { | |
276 | tx_state_t *tx = &dp->dp_tx; | |
277 | callb_cpr_t cpr; | |
278 | uint64_t timeout, start, delta, timer; | |
279 | int target; | |
280 | ||
281 | txg_thread_enter(tx, &cpr); | |
282 | ||
283 | start = delta = 0; | |
284 | timeout = zfs_txg_timeout * hz; | |
285 | for (;;) { | |
286 | uint64_t txg, written; | |
287 | ||
288 | /* | |
289 | * We sync when there's someone waiting on us, or the | |
290 | * quiesce thread has handed off a txg to us, or we have | |
291 | * reached our timeout. | |
292 | */ | |
293 | timer = (delta >= timeout ? 0 : timeout - delta); | |
294 | while (!tx->tx_exiting && timer > 0 && | |
295 | tx->tx_synced_txg >= tx->tx_sync_txg_waiting && | |
296 | tx->tx_quiesced_txg == 0) { | |
297 | dprintf("waiting; tx_synced=%llu waiting=%llu dp=%p\n", | |
298 | tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp); | |
299 | txg_thread_wait(tx, &cpr, &tx->tx_sync_more_cv, timer); | |
300 | delta = lbolt - start; | |
301 | timer = (delta > timeout ? 0 : timeout - delta); | |
302 | } | |
303 | ||
304 | /* | |
305 | * Wait until the quiesce thread hands off a txg to us, | |
306 | * prompting it to do so if necessary. | |
307 | */ | |
308 | while (!tx->tx_exiting && tx->tx_quiesced_txg == 0) { | |
309 | if (tx->tx_quiesce_txg_waiting < tx->tx_open_txg+1) | |
310 | tx->tx_quiesce_txg_waiting = tx->tx_open_txg+1; | |
311 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
312 | txg_thread_wait(tx, &cpr, &tx->tx_quiesce_done_cv, 0); | |
313 | } | |
314 | ||
315 | if (tx->tx_exiting) | |
316 | txg_thread_exit(tx, &cpr, &tx->tx_sync_thread); | |
317 | ||
318 | rw_enter(&tx->tx_suspend, RW_WRITER); | |
319 | ||
320 | /* | |
321 | * Consume the quiesced txg which has been handed off to | |
322 | * us. This may cause the quiescing thread to now be | |
323 | * able to quiesce another txg, so we must signal it. | |
324 | */ | |
325 | txg = tx->tx_quiesced_txg; | |
326 | tx->tx_quiesced_txg = 0; | |
327 | tx->tx_syncing_txg = txg; | |
328 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
329 | rw_exit(&tx->tx_suspend); | |
330 | ||
331 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
332 | txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); | |
333 | mutex_exit(&tx->tx_sync_lock); | |
334 | start = lbolt; | |
335 | spa_sync(dp->dp_spa, txg); | |
336 | delta = lbolt - start; | |
337 | ||
338 | written = dp->dp_space_towrite[txg & TXG_MASK]; | |
339 | dp->dp_space_towrite[txg & TXG_MASK] = 0; | |
340 | ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0); | |
341 | ||
342 | /* | |
343 | * If the write limit max has not been explicitly set, set it | |
344 | * to a fraction of available phisical memory (default 1/8th). | |
345 | * Note that we must inflate the limit because the spa | |
346 | * inflates write sizes to account for data replication. | |
347 | * Check this each sync phase to catch changing memory size. | |
348 | */ | |
349 | if (zfs_write_limit_inflated == 0 || | |
350 | (zfs_write_limit_shift && zfs_write_limit_max != | |
351 | physmem * PAGESIZE >> zfs_write_limit_shift)) { | |
352 | zfs_write_limit_max = | |
353 | physmem * PAGESIZE >> zfs_write_limit_shift; | |
354 | zfs_write_limit_inflated = | |
355 | spa_get_asize(dp->dp_spa, zfs_write_limit_max); | |
356 | if (zfs_write_limit_min > zfs_write_limit_inflated) | |
357 | zfs_write_limit_inflated = zfs_write_limit_min; | |
358 | } | |
359 | ||
360 | /* | |
361 | * Attempt to keep the sync time consistant by adjusting the | |
362 | * amount of write traffic allowed into each transaction group. | |
363 | */ | |
364 | target = zfs_txg_synctime * hz; | |
365 | if (delta > target) { | |
366 | uint64_t old = MIN(dp->dp_write_limit, written); | |
367 | ||
368 | dp->dp_write_limit = MAX(zfs_write_limit_min, | |
369 | old * target / delta); | |
370 | } else if (written >= dp->dp_write_limit && | |
371 | delta >> 3 < target >> 3) { | |
372 | uint64_t rescale = | |
373 | MIN((100 * target) / delta, 200); | |
374 | ||
375 | dp->dp_write_limit = MIN(zfs_write_limit_inflated, | |
376 | written * rescale / 100); | |
377 | } | |
378 | ||
379 | mutex_enter(&tx->tx_sync_lock); | |
380 | rw_enter(&tx->tx_suspend, RW_WRITER); | |
381 | tx->tx_synced_txg = txg; | |
382 | tx->tx_syncing_txg = 0; | |
383 | rw_exit(&tx->tx_suspend); | |
384 | cv_broadcast(&tx->tx_sync_done_cv); | |
385 | } | |
386 | } | |
387 | ||
388 | static void | |
389 | txg_quiesce_thread(dsl_pool_t *dp) | |
390 | { | |
391 | tx_state_t *tx = &dp->dp_tx; | |
392 | callb_cpr_t cpr; | |
393 | ||
394 | txg_thread_enter(tx, &cpr); | |
395 | ||
396 | for (;;) { | |
397 | uint64_t txg; | |
398 | ||
399 | /* | |
400 | * We quiesce when there's someone waiting on us. | |
401 | * However, we can only have one txg in "quiescing" or | |
402 | * "quiesced, waiting to sync" state. So we wait until | |
403 | * the "quiesced, waiting to sync" txg has been consumed | |
404 | * by the sync thread. | |
405 | */ | |
406 | while (!tx->tx_exiting && | |
407 | (tx->tx_open_txg >= tx->tx_quiesce_txg_waiting || | |
408 | tx->tx_quiesced_txg != 0)) | |
409 | txg_thread_wait(tx, &cpr, &tx->tx_quiesce_more_cv, 0); | |
410 | ||
411 | if (tx->tx_exiting) | |
412 | txg_thread_exit(tx, &cpr, &tx->tx_quiesce_thread); | |
413 | ||
414 | txg = tx->tx_open_txg; | |
415 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
416 | txg, tx->tx_quiesce_txg_waiting, | |
417 | tx->tx_sync_txg_waiting); | |
418 | mutex_exit(&tx->tx_sync_lock); | |
419 | txg_quiesce(dp, txg); | |
420 | mutex_enter(&tx->tx_sync_lock); | |
421 | ||
422 | /* | |
423 | * Hand this txg off to the sync thread. | |
424 | */ | |
425 | dprintf("quiesce done, handing off txg %llu\n", txg); | |
426 | tx->tx_quiesced_txg = txg; | |
427 | cv_broadcast(&tx->tx_sync_more_cv); | |
428 | cv_broadcast(&tx->tx_quiesce_done_cv); | |
429 | } | |
430 | } | |
431 | ||
432 | /* | |
433 | * Delay this thread by 'ticks' if we are still in the open transaction | |
434 | * group and there is already a waiting txg quiesing or quiesced. Abort | |
435 | * the delay if this txg stalls or enters the quiesing state. | |
436 | */ | |
437 | void | |
438 | txg_delay(dsl_pool_t *dp, uint64_t txg, int ticks) | |
439 | { | |
440 | tx_state_t *tx = &dp->dp_tx; | |
441 | int timeout = lbolt + ticks; | |
442 | ||
443 | /* don't delay if this txg could transition to quiesing immediately */ | |
444 | if (tx->tx_open_txg > txg || | |
445 | tx->tx_syncing_txg == txg-1 || tx->tx_synced_txg == txg-1) | |
446 | return; | |
447 | ||
448 | mutex_enter(&tx->tx_sync_lock); | |
449 | if (tx->tx_open_txg > txg || tx->tx_synced_txg == txg-1) { | |
450 | mutex_exit(&tx->tx_sync_lock); | |
451 | return; | |
452 | } | |
453 | ||
454 | while (lbolt < timeout && | |
455 | tx->tx_syncing_txg < txg-1 && !txg_stalled(dp)) | |
456 | (void) cv_timedwait(&tx->tx_quiesce_more_cv, &tx->tx_sync_lock, | |
457 | timeout); | |
458 | ||
459 | mutex_exit(&tx->tx_sync_lock); | |
460 | } | |
461 | ||
462 | void | |
463 | txg_wait_synced(dsl_pool_t *dp, uint64_t txg) | |
464 | { | |
465 | tx_state_t *tx = &dp->dp_tx; | |
466 | ||
467 | mutex_enter(&tx->tx_sync_lock); | |
468 | ASSERT(tx->tx_threads == 2); | |
469 | if (txg == 0) | |
470 | txg = tx->tx_open_txg; | |
471 | if (tx->tx_sync_txg_waiting < txg) | |
472 | tx->tx_sync_txg_waiting = txg; | |
473 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
474 | txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); | |
475 | while (tx->tx_synced_txg < txg) { | |
476 | dprintf("broadcasting sync more " | |
477 | "tx_synced=%llu waiting=%llu dp=%p\n", | |
478 | tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp); | |
479 | cv_broadcast(&tx->tx_sync_more_cv); | |
480 | cv_wait(&tx->tx_sync_done_cv, &tx->tx_sync_lock); | |
481 | } | |
482 | mutex_exit(&tx->tx_sync_lock); | |
483 | } | |
484 | ||
485 | void | |
486 | txg_wait_open(dsl_pool_t *dp, uint64_t txg) | |
487 | { | |
488 | tx_state_t *tx = &dp->dp_tx; | |
489 | ||
490 | mutex_enter(&tx->tx_sync_lock); | |
491 | ASSERT(tx->tx_threads == 2); | |
492 | if (txg == 0) | |
493 | txg = tx->tx_open_txg + 1; | |
494 | if (tx->tx_quiesce_txg_waiting < txg) | |
495 | tx->tx_quiesce_txg_waiting = txg; | |
496 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
497 | txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); | |
498 | while (tx->tx_open_txg < txg) { | |
499 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
500 | cv_wait(&tx->tx_quiesce_done_cv, &tx->tx_sync_lock); | |
501 | } | |
502 | mutex_exit(&tx->tx_sync_lock); | |
503 | } | |
504 | ||
505 | int | |
506 | txg_stalled(dsl_pool_t *dp) | |
507 | { | |
508 | tx_state_t *tx = &dp->dp_tx; | |
509 | return (tx->tx_quiesce_txg_waiting > tx->tx_open_txg); | |
510 | } | |
511 | ||
512 | void | |
513 | txg_suspend(dsl_pool_t *dp) | |
514 | { | |
515 | tx_state_t *tx = &dp->dp_tx; | |
516 | /* XXX some code paths suspend when they are already suspended! */ | |
517 | rw_enter(&tx->tx_suspend, RW_READER); | |
518 | } | |
519 | ||
520 | void | |
521 | txg_resume(dsl_pool_t *dp) | |
522 | { | |
523 | tx_state_t *tx = &dp->dp_tx; | |
524 | rw_exit(&tx->tx_suspend); | |
525 | } | |
526 | ||
527 | /* | |
528 | * Per-txg object lists. | |
529 | */ | |
530 | void | |
531 | txg_list_create(txg_list_t *tl, size_t offset) | |
532 | { | |
533 | int t; | |
534 | ||
535 | mutex_init(&tl->tl_lock, NULL, MUTEX_DEFAULT, NULL); | |
536 | ||
537 | tl->tl_offset = offset; | |
538 | ||
539 | for (t = 0; t < TXG_SIZE; t++) | |
540 | tl->tl_head[t] = NULL; | |
541 | } | |
542 | ||
543 | void | |
544 | txg_list_destroy(txg_list_t *tl) | |
545 | { | |
546 | int t; | |
547 | ||
548 | for (t = 0; t < TXG_SIZE; t++) | |
549 | ASSERT(txg_list_empty(tl, t)); | |
550 | ||
551 | mutex_destroy(&tl->tl_lock); | |
552 | } | |
553 | ||
554 | int | |
555 | txg_list_empty(txg_list_t *tl, uint64_t txg) | |
556 | { | |
557 | return (tl->tl_head[txg & TXG_MASK] == NULL); | |
558 | } | |
559 | ||
560 | /* | |
561 | * Add an entry to the list. | |
562 | * Returns 0 if it's a new entry, 1 if it's already there. | |
563 | */ | |
564 | int | |
565 | txg_list_add(txg_list_t *tl, void *p, uint64_t txg) | |
566 | { | |
567 | int t = txg & TXG_MASK; | |
568 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
569 | int already_on_list; | |
570 | ||
571 | mutex_enter(&tl->tl_lock); | |
572 | already_on_list = tn->tn_member[t]; | |
573 | if (!already_on_list) { | |
574 | tn->tn_member[t] = 1; | |
575 | tn->tn_next[t] = tl->tl_head[t]; | |
576 | tl->tl_head[t] = tn; | |
577 | } | |
578 | mutex_exit(&tl->tl_lock); | |
579 | ||
580 | return (already_on_list); | |
581 | } | |
582 | ||
583 | /* | |
584 | * Remove the head of the list and return it. | |
585 | */ | |
586 | void * | |
587 | txg_list_remove(txg_list_t *tl, uint64_t txg) | |
588 | { | |
589 | int t = txg & TXG_MASK; | |
590 | txg_node_t *tn; | |
591 | void *p = NULL; | |
592 | ||
593 | mutex_enter(&tl->tl_lock); | |
594 | if ((tn = tl->tl_head[t]) != NULL) { | |
595 | p = (char *)tn - tl->tl_offset; | |
596 | tl->tl_head[t] = tn->tn_next[t]; | |
597 | tn->tn_next[t] = NULL; | |
598 | tn->tn_member[t] = 0; | |
599 | } | |
600 | mutex_exit(&tl->tl_lock); | |
601 | ||
602 | return (p); | |
603 | } | |
604 | ||
605 | /* | |
606 | * Remove a specific item from the list and return it. | |
607 | */ | |
608 | void * | |
609 | txg_list_remove_this(txg_list_t *tl, void *p, uint64_t txg) | |
610 | { | |
611 | int t = txg & TXG_MASK; | |
612 | txg_node_t *tn, **tp; | |
613 | ||
614 | mutex_enter(&tl->tl_lock); | |
615 | ||
616 | for (tp = &tl->tl_head[t]; (tn = *tp) != NULL; tp = &tn->tn_next[t]) { | |
617 | if ((char *)tn - tl->tl_offset == p) { | |
618 | *tp = tn->tn_next[t]; | |
619 | tn->tn_next[t] = NULL; | |
620 | tn->tn_member[t] = 0; | |
621 | mutex_exit(&tl->tl_lock); | |
622 | return (p); | |
623 | } | |
624 | } | |
625 | ||
626 | mutex_exit(&tl->tl_lock); | |
627 | ||
628 | return (NULL); | |
629 | } | |
630 | ||
631 | int | |
632 | txg_list_member(txg_list_t *tl, void *p, uint64_t txg) | |
633 | { | |
634 | int t = txg & TXG_MASK; | |
635 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
636 | ||
637 | return (tn->tn_member[t]); | |
638 | } | |
639 | ||
640 | /* | |
641 | * Walk a txg list -- only safe if you know it's not changing. | |
642 | */ | |
643 | void * | |
644 | txg_list_head(txg_list_t *tl, uint64_t txg) | |
645 | { | |
646 | int t = txg & TXG_MASK; | |
647 | txg_node_t *tn = tl->tl_head[t]; | |
648 | ||
649 | return (tn == NULL ? NULL : (char *)tn - tl->tl_offset); | |
650 | } | |
651 | ||
652 | void * | |
653 | txg_list_next(txg_list_t *tl, void *p, uint64_t txg) | |
654 | { | |
655 | int t = txg & TXG_MASK; | |
656 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
657 | ||
658 | tn = tn->tn_next[t]; | |
659 | ||
660 | return (tn == NULL ? NULL : (char *)tn - tl->tl_offset); | |
661 | } |