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34dc7c2f BB |
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 | /* | |
428870ff | 22 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
29809a6c | 23 | * Portions Copyright 2011 Martin Matuska |
89103a26 | 24 | * Copyright (c) 2013 by Delphix. All rights reserved. |
34dc7c2f BB |
25 | */ |
26 | ||
34dc7c2f BB |
27 | #include <sys/zfs_context.h> |
28 | #include <sys/txg_impl.h> | |
29 | #include <sys/dmu_impl.h> | |
428870ff | 30 | #include <sys/dmu_tx.h> |
34dc7c2f | 31 | #include <sys/dsl_pool.h> |
428870ff | 32 | #include <sys/dsl_scan.h> |
34dc7c2f BB |
33 | #include <sys/callb.h> |
34 | ||
35 | /* | |
89103a26 AL |
36 | * ZFS Transaction Groups |
37 | * ---------------------- | |
38 | * | |
39 | * ZFS transaction groups are, as the name implies, groups of transactions | |
40 | * that act on persistent state. ZFS asserts consistency at the granularity of | |
41 | * these transaction groups. Each successive transaction group (txg) is | |
42 | * assigned a 64-bit consecutive identifier. There are three active | |
43 | * transaction group states: open, quiescing, or syncing. At any given time, | |
44 | * there may be an active txg associated with each state; each active txg may | |
45 | * either be processing, or blocked waiting to enter the next state. There may | |
46 | * be up to three active txgs, and there is always a txg in the open state | |
47 | * (though it may be blocked waiting to enter the quiescing state). In broad | |
48 | * strokes, transactions — operations that change in-memory structures — are | |
49 | * accepted into the txg in the open state, and are completed while the txg is | |
50 | * in the open or quiescing states. The accumulated changes are written to | |
51 | * disk in the syncing state. | |
52 | * | |
53 | * Open | |
54 | * | |
55 | * When a new txg becomes active, it first enters the open state. New | |
56 | * transactions — updates to in-memory structures — are assigned to the | |
57 | * currently open txg. There is always a txg in the open state so that ZFS can | |
58 | * accept new changes (though the txg may refuse new changes if it has hit | |
59 | * some limit). ZFS advances the open txg to the next state for a variety of | |
60 | * reasons such as it hitting a time or size threshold, or the execution of an | |
61 | * administrative action that must be completed in the syncing state. | |
62 | * | |
63 | * Quiescing | |
64 | * | |
65 | * After a txg exits the open state, it enters the quiescing state. The | |
66 | * quiescing state is intended to provide a buffer between accepting new | |
67 | * transactions in the open state and writing them out to stable storage in | |
68 | * the syncing state. While quiescing, transactions can continue their | |
69 | * operation without delaying either of the other states. Typically, a txg is | |
70 | * in the quiescing state very briefly since the operations are bounded by | |
71 | * software latencies rather than, say, slower I/O latencies. After all | |
72 | * transactions complete, the txg is ready to enter the next state. | |
73 | * | |
74 | * Syncing | |
75 | * | |
76 | * In the syncing state, the in-memory state built up during the open and (to | |
77 | * a lesser degree) the quiescing states is written to stable storage. The | |
78 | * process of writing out modified data can, in turn modify more data. For | |
79 | * example when we write new blocks, we need to allocate space for them; those | |
80 | * allocations modify metadata (space maps)... which themselves must be | |
81 | * written to stable storage. During the sync state, ZFS iterates, writing out | |
82 | * data until it converges and all in-memory changes have been written out. | |
83 | * The first such pass is the largest as it encompasses all the modified user | |
84 | * data (as opposed to filesystem metadata). Subsequent passes typically have | |
85 | * far less data to write as they consist exclusively of filesystem metadata. | |
86 | * | |
87 | * To ensure convergence, after a certain number of passes ZFS begins | |
88 | * overwriting locations on stable storage that had been allocated earlier in | |
89 | * the syncing state (and subsequently freed). ZFS usually allocates new | |
90 | * blocks to optimize for large, continuous, writes. For the syncing state to | |
91 | * converge however it must complete a pass where no new blocks are allocated | |
92 | * since each allocation requires a modification of persistent metadata. | |
93 | * Further, to hasten convergence, after a prescribed number of passes, ZFS | |
94 | * also defers frees, and stops compressing. | |
95 | * | |
96 | * In addition to writing out user data, we must also execute synctasks during | |
97 | * the syncing context. A synctask is the mechanism by which some | |
98 | * administrative activities work such as creating and destroying snapshots or | |
99 | * datasets. Note that when a synctask is initiated it enters the open txg, | |
100 | * and ZFS then pushes that txg as quickly as possible to completion of the | |
101 | * syncing state in order to reduce the latency of the administrative | |
102 | * activity. To complete the syncing state, ZFS writes out a new uberblock, | |
103 | * the root of the tree of blocks that comprise all state stored on the ZFS | |
104 | * pool. Finally, if there is a quiesced txg waiting, we signal that it can | |
105 | * now transition to the syncing state. | |
34dc7c2f BB |
106 | */ |
107 | ||
108 | static void txg_sync_thread(dsl_pool_t *dp); | |
109 | static void txg_quiesce_thread(dsl_pool_t *dp); | |
110 | ||
572e2857 | 111 | int zfs_txg_timeout = 5; /* max seconds worth of delta per txg */ |
34dc7c2f BB |
112 | |
113 | /* | |
114 | * Prepare the txg subsystem. | |
115 | */ | |
116 | void | |
117 | txg_init(dsl_pool_t *dp, uint64_t txg) | |
118 | { | |
119 | tx_state_t *tx = &dp->dp_tx; | |
120 | int c; | |
121 | bzero(tx, sizeof (tx_state_t)); | |
122 | ||
00b46022 | 123 | tx->tx_cpu = vmem_zalloc(max_ncpus * sizeof (tx_cpu_t), KM_SLEEP); |
34dc7c2f BB |
124 | |
125 | for (c = 0; c < max_ncpus; c++) { | |
126 | int i; | |
127 | ||
128 | mutex_init(&tx->tx_cpu[c].tc_lock, NULL, MUTEX_DEFAULT, NULL); | |
129 | for (i = 0; i < TXG_SIZE; i++) { | |
130 | cv_init(&tx->tx_cpu[c].tc_cv[i], NULL, CV_DEFAULT, | |
131 | NULL); | |
428870ff BB |
132 | list_create(&tx->tx_cpu[c].tc_callbacks[i], |
133 | sizeof (dmu_tx_callback_t), | |
134 | offsetof(dmu_tx_callback_t, dcb_node)); | |
34dc7c2f BB |
135 | } |
136 | } | |
137 | ||
34dc7c2f BB |
138 | mutex_init(&tx->tx_sync_lock, NULL, MUTEX_DEFAULT, NULL); |
139 | ||
fb5f0bc8 BB |
140 | cv_init(&tx->tx_sync_more_cv, NULL, CV_DEFAULT, NULL); |
141 | cv_init(&tx->tx_sync_done_cv, NULL, CV_DEFAULT, NULL); | |
142 | cv_init(&tx->tx_quiesce_more_cv, NULL, CV_DEFAULT, NULL); | |
143 | cv_init(&tx->tx_quiesce_done_cv, NULL, CV_DEFAULT, NULL); | |
144 | cv_init(&tx->tx_exit_cv, NULL, CV_DEFAULT, NULL); | |
145 | ||
34dc7c2f BB |
146 | tx->tx_open_txg = txg; |
147 | } | |
148 | ||
149 | /* | |
150 | * Close down the txg subsystem. | |
151 | */ | |
152 | void | |
153 | txg_fini(dsl_pool_t *dp) | |
154 | { | |
155 | tx_state_t *tx = &dp->dp_tx; | |
156 | int c; | |
157 | ||
158 | ASSERT(tx->tx_threads == 0); | |
159 | ||
34dc7c2f BB |
160 | mutex_destroy(&tx->tx_sync_lock); |
161 | ||
fb5f0bc8 BB |
162 | cv_destroy(&tx->tx_sync_more_cv); |
163 | cv_destroy(&tx->tx_sync_done_cv); | |
164 | cv_destroy(&tx->tx_quiesce_more_cv); | |
165 | cv_destroy(&tx->tx_quiesce_done_cv); | |
166 | cv_destroy(&tx->tx_exit_cv); | |
167 | ||
34dc7c2f BB |
168 | for (c = 0; c < max_ncpus; c++) { |
169 | int i; | |
170 | ||
171 | mutex_destroy(&tx->tx_cpu[c].tc_lock); | |
428870ff | 172 | for (i = 0; i < TXG_SIZE; i++) { |
34dc7c2f | 173 | cv_destroy(&tx->tx_cpu[c].tc_cv[i]); |
428870ff BB |
174 | list_destroy(&tx->tx_cpu[c].tc_callbacks[i]); |
175 | } | |
34dc7c2f BB |
176 | } |
177 | ||
428870ff BB |
178 | if (tx->tx_commit_cb_taskq != NULL) |
179 | taskq_destroy(tx->tx_commit_cb_taskq); | |
180 | ||
00b46022 | 181 | vmem_free(tx->tx_cpu, max_ncpus * sizeof (tx_cpu_t)); |
34dc7c2f BB |
182 | |
183 | bzero(tx, sizeof (tx_state_t)); | |
184 | } | |
185 | ||
186 | /* | |
187 | * Start syncing transaction groups. | |
188 | */ | |
189 | void | |
190 | txg_sync_start(dsl_pool_t *dp) | |
191 | { | |
192 | tx_state_t *tx = &dp->dp_tx; | |
193 | ||
194 | mutex_enter(&tx->tx_sync_lock); | |
195 | ||
196 | dprintf("pool %p\n", dp); | |
197 | ||
198 | ASSERT(tx->tx_threads == 0); | |
199 | ||
200 | tx->tx_threads = 2; | |
201 | ||
202 | tx->tx_quiesce_thread = thread_create(NULL, 0, txg_quiesce_thread, | |
203 | dp, 0, &p0, TS_RUN, minclsyspri); | |
204 | ||
b128c09f BB |
205 | /* |
206 | * The sync thread can need a larger-than-default stack size on | |
207 | * 32-bit x86. This is due in part to nested pools and | |
208 | * scrub_visitbp() recursion. | |
209 | */ | |
428870ff | 210 | tx->tx_sync_thread = thread_create(NULL, 32<<10, txg_sync_thread, |
34dc7c2f BB |
211 | dp, 0, &p0, TS_RUN, minclsyspri); |
212 | ||
213 | mutex_exit(&tx->tx_sync_lock); | |
214 | } | |
215 | ||
216 | static void | |
217 | txg_thread_enter(tx_state_t *tx, callb_cpr_t *cpr) | |
218 | { | |
219 | CALLB_CPR_INIT(cpr, &tx->tx_sync_lock, callb_generic_cpr, FTAG); | |
220 | mutex_enter(&tx->tx_sync_lock); | |
221 | } | |
222 | ||
223 | static void | |
224 | txg_thread_exit(tx_state_t *tx, callb_cpr_t *cpr, kthread_t **tpp) | |
225 | { | |
226 | ASSERT(*tpp != NULL); | |
227 | *tpp = NULL; | |
228 | tx->tx_threads--; | |
229 | cv_broadcast(&tx->tx_exit_cv); | |
230 | CALLB_CPR_EXIT(cpr); /* drops &tx->tx_sync_lock */ | |
231 | thread_exit(); | |
232 | } | |
233 | ||
234 | static void | |
235 | txg_thread_wait(tx_state_t *tx, callb_cpr_t *cpr, kcondvar_t *cv, uint64_t time) | |
236 | { | |
237 | CALLB_CPR_SAFE_BEGIN(cpr); | |
238 | ||
239 | if (time) | |
bfd214af | 240 | (void) cv_timedwait_interruptible(cv, &tx->tx_sync_lock, |
428870ff | 241 | ddi_get_lbolt() + time); |
34dc7c2f | 242 | else |
bfd214af | 243 | cv_wait_interruptible(cv, &tx->tx_sync_lock); |
34dc7c2f BB |
244 | |
245 | CALLB_CPR_SAFE_END(cpr, &tx->tx_sync_lock); | |
246 | } | |
247 | ||
248 | /* | |
249 | * Stop syncing transaction groups. | |
250 | */ | |
251 | void | |
252 | txg_sync_stop(dsl_pool_t *dp) | |
253 | { | |
254 | tx_state_t *tx = &dp->dp_tx; | |
255 | ||
256 | dprintf("pool %p\n", dp); | |
257 | /* | |
258 | * Finish off any work in progress. | |
259 | */ | |
260 | ASSERT(tx->tx_threads == 2); | |
428870ff BB |
261 | |
262 | /* | |
263 | * We need to ensure that we've vacated the deferred space_maps. | |
264 | */ | |
265 | txg_wait_synced(dp, tx->tx_open_txg + TXG_DEFER_SIZE); | |
34dc7c2f BB |
266 | |
267 | /* | |
268 | * Wake all sync threads and wait for them to die. | |
269 | */ | |
270 | mutex_enter(&tx->tx_sync_lock); | |
271 | ||
272 | ASSERT(tx->tx_threads == 2); | |
273 | ||
274 | tx->tx_exiting = 1; | |
275 | ||
276 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
277 | cv_broadcast(&tx->tx_quiesce_done_cv); | |
278 | cv_broadcast(&tx->tx_sync_more_cv); | |
279 | ||
280 | while (tx->tx_threads != 0) | |
281 | cv_wait(&tx->tx_exit_cv, &tx->tx_sync_lock); | |
282 | ||
283 | tx->tx_exiting = 0; | |
284 | ||
285 | mutex_exit(&tx->tx_sync_lock); | |
286 | } | |
287 | ||
288 | uint64_t | |
289 | txg_hold_open(dsl_pool_t *dp, txg_handle_t *th) | |
290 | { | |
291 | tx_state_t *tx = &dp->dp_tx; | |
15a9e033 | 292 | tx_cpu_t *tc; |
34dc7c2f BB |
293 | uint64_t txg; |
294 | ||
15a9e033 PS |
295 | /* |
296 | * It appears the processor id is simply used as a "random" | |
297 | * number to index into the array, and there isn't any other | |
298 | * significance to the chosen tx_cpu. Because.. Why not use | |
299 | * the current cpu to index into the array? | |
300 | */ | |
301 | kpreempt_disable(); | |
302 | tc = &tx->tx_cpu[CPU_SEQID]; | |
303 | kpreempt_enable(); | |
304 | ||
34dc7c2f BB |
305 | mutex_enter(&tc->tc_lock); |
306 | ||
307 | txg = tx->tx_open_txg; | |
308 | tc->tc_count[txg & TXG_MASK]++; | |
309 | ||
310 | th->th_cpu = tc; | |
311 | th->th_txg = txg; | |
312 | ||
313 | return (txg); | |
314 | } | |
315 | ||
316 | void | |
317 | txg_rele_to_quiesce(txg_handle_t *th) | |
318 | { | |
319 | tx_cpu_t *tc = th->th_cpu; | |
320 | ||
321 | mutex_exit(&tc->tc_lock); | |
322 | } | |
323 | ||
428870ff BB |
324 | void |
325 | txg_register_callbacks(txg_handle_t *th, list_t *tx_callbacks) | |
326 | { | |
327 | tx_cpu_t *tc = th->th_cpu; | |
328 | int g = th->th_txg & TXG_MASK; | |
329 | ||
330 | mutex_enter(&tc->tc_lock); | |
331 | list_move_tail(&tc->tc_callbacks[g], tx_callbacks); | |
332 | mutex_exit(&tc->tc_lock); | |
333 | } | |
334 | ||
34dc7c2f BB |
335 | void |
336 | txg_rele_to_sync(txg_handle_t *th) | |
337 | { | |
338 | tx_cpu_t *tc = th->th_cpu; | |
339 | int g = th->th_txg & TXG_MASK; | |
340 | ||
341 | mutex_enter(&tc->tc_lock); | |
342 | ASSERT(tc->tc_count[g] != 0); | |
343 | if (--tc->tc_count[g] == 0) | |
344 | cv_broadcast(&tc->tc_cv[g]); | |
345 | mutex_exit(&tc->tc_lock); | |
346 | ||
347 | th->th_cpu = NULL; /* defensive */ | |
348 | } | |
349 | ||
350 | static void | |
351 | txg_quiesce(dsl_pool_t *dp, uint64_t txg) | |
352 | { | |
353 | tx_state_t *tx = &dp->dp_tx; | |
354 | int g = txg & TXG_MASK; | |
355 | int c; | |
356 | ||
357 | /* | |
358 | * Grab all tx_cpu locks so nobody else can get into this txg. | |
359 | */ | |
360 | for (c = 0; c < max_ncpus; c++) | |
361 | mutex_enter(&tx->tx_cpu[c].tc_lock); | |
362 | ||
363 | ASSERT(txg == tx->tx_open_txg); | |
364 | tx->tx_open_txg++; | |
365 | ||
57f5a200 BB |
366 | /* |
367 | * Now that we've incremented tx_open_txg, we can let threads | |
368 | * enter the next transaction group. | |
369 | */ | |
370 | for (c = 0; c < max_ncpus; c++) | |
371 | mutex_exit(&tx->tx_cpu[c].tc_lock); | |
372 | ||
34dc7c2f BB |
373 | /* |
374 | * Quiesce the transaction group by waiting for everyone to txg_exit(). | |
375 | */ | |
376 | for (c = 0; c < max_ncpus; c++) { | |
377 | tx_cpu_t *tc = &tx->tx_cpu[c]; | |
378 | mutex_enter(&tc->tc_lock); | |
379 | while (tc->tc_count[g] != 0) | |
380 | cv_wait(&tc->tc_cv[g], &tc->tc_lock); | |
381 | mutex_exit(&tc->tc_lock); | |
382 | } | |
383 | } | |
384 | ||
428870ff BB |
385 | static void |
386 | txg_do_callbacks(list_t *cb_list) | |
387 | { | |
388 | dmu_tx_do_callbacks(cb_list, 0); | |
389 | ||
390 | list_destroy(cb_list); | |
391 | ||
392 | kmem_free(cb_list, sizeof (list_t)); | |
393 | } | |
394 | ||
395 | /* | |
396 | * Dispatch the commit callbacks registered on this txg to worker threads. | |
397 | */ | |
398 | static void | |
399 | txg_dispatch_callbacks(dsl_pool_t *dp, uint64_t txg) | |
400 | { | |
401 | int c; | |
402 | tx_state_t *tx = &dp->dp_tx; | |
403 | list_t *cb_list; | |
404 | ||
405 | for (c = 0; c < max_ncpus; c++) { | |
406 | tx_cpu_t *tc = &tx->tx_cpu[c]; | |
407 | /* No need to lock tx_cpu_t at this point */ | |
408 | ||
409 | int g = txg & TXG_MASK; | |
410 | ||
411 | if (list_is_empty(&tc->tc_callbacks[g])) | |
412 | continue; | |
413 | ||
414 | if (tx->tx_commit_cb_taskq == NULL) { | |
415 | /* | |
416 | * Commit callback taskq hasn't been created yet. | |
417 | */ | |
418 | tx->tx_commit_cb_taskq = taskq_create("tx_commit_cb", | |
090ff092 RC |
419 | 100, minclsyspri, max_ncpus, INT_MAX, |
420 | TASKQ_THREADS_CPU_PCT | TASKQ_PREPOPULATE); | |
428870ff BB |
421 | } |
422 | ||
b8d06fca | 423 | cb_list = kmem_alloc(sizeof (list_t), KM_PUSHPAGE); |
428870ff BB |
424 | list_create(cb_list, sizeof (dmu_tx_callback_t), |
425 | offsetof(dmu_tx_callback_t, dcb_node)); | |
426 | ||
090ff092 | 427 | list_move_tail(cb_list, &tc->tc_callbacks[g]); |
428870ff BB |
428 | |
429 | (void) taskq_dispatch(tx->tx_commit_cb_taskq, (task_func_t *) | |
430 | txg_do_callbacks, cb_list, TQ_SLEEP); | |
431 | } | |
432 | } | |
433 | ||
54a179e7 RC |
434 | /* |
435 | * Wait for pending commit callbacks of already-synced transactions to finish | |
436 | * processing. | |
437 | * Calling this function from within a commit callback will deadlock. | |
438 | */ | |
439 | void | |
440 | txg_wait_callbacks(dsl_pool_t *dp) | |
441 | { | |
442 | tx_state_t *tx = &dp->dp_tx; | |
443 | ||
444 | if (tx->tx_commit_cb_taskq != NULL) | |
445 | taskq_wait(tx->tx_commit_cb_taskq); | |
446 | } | |
447 | ||
34dc7c2f BB |
448 | static void |
449 | txg_sync_thread(dsl_pool_t *dp) | |
450 | { | |
428870ff | 451 | spa_t *spa = dp->dp_spa; |
34dc7c2f BB |
452 | tx_state_t *tx = &dp->dp_tx; |
453 | callb_cpr_t cpr; | |
b128c09f | 454 | uint64_t start, delta; |
34dc7c2f | 455 | |
8630650a BB |
456 | #ifdef _KERNEL |
457 | /* | |
458 | * Annotate this process with a flag that indicates that it is | |
459 | * unsafe to use KM_SLEEP during memory allocations due to the | |
460 | * potential for a deadlock. KM_PUSHPAGE should be used instead. | |
461 | */ | |
462 | current->flags |= PF_NOFS; | |
463 | #endif /* _KERNEL */ | |
464 | ||
34dc7c2f BB |
465 | txg_thread_enter(tx, &cpr); |
466 | ||
467 | start = delta = 0; | |
34dc7c2f | 468 | for (;;) { |
87d98efe | 469 | uint64_t timer, timeout; |
b128c09f | 470 | uint64_t txg; |
34dc7c2f | 471 | |
87d98efe BB |
472 | timeout = zfs_txg_timeout * hz; |
473 | ||
34dc7c2f | 474 | /* |
428870ff | 475 | * We sync when we're scanning, there's someone waiting |
b128c09f BB |
476 | * on us, or the quiesce thread has handed off a txg to |
477 | * us, or we have reached our timeout. | |
34dc7c2f BB |
478 | */ |
479 | timer = (delta >= timeout ? 0 : timeout - delta); | |
428870ff | 480 | while (!dsl_scan_active(dp->dp_scan) && |
b128c09f | 481 | !tx->tx_exiting && timer > 0 && |
34dc7c2f BB |
482 | tx->tx_synced_txg >= tx->tx_sync_txg_waiting && |
483 | tx->tx_quiesced_txg == 0) { | |
484 | dprintf("waiting; tx_synced=%llu waiting=%llu dp=%p\n", | |
485 | tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp); | |
486 | txg_thread_wait(tx, &cpr, &tx->tx_sync_more_cv, timer); | |
428870ff | 487 | delta = ddi_get_lbolt() - start; |
34dc7c2f BB |
488 | timer = (delta > timeout ? 0 : timeout - delta); |
489 | } | |
490 | ||
491 | /* | |
492 | * Wait until the quiesce thread hands off a txg to us, | |
493 | * prompting it to do so if necessary. | |
494 | */ | |
495 | while (!tx->tx_exiting && tx->tx_quiesced_txg == 0) { | |
496 | if (tx->tx_quiesce_txg_waiting < tx->tx_open_txg+1) | |
497 | tx->tx_quiesce_txg_waiting = tx->tx_open_txg+1; | |
498 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
499 | txg_thread_wait(tx, &cpr, &tx->tx_quiesce_done_cv, 0); | |
500 | } | |
501 | ||
502 | if (tx->tx_exiting) | |
503 | txg_thread_exit(tx, &cpr, &tx->tx_sync_thread); | |
504 | ||
34dc7c2f BB |
505 | /* |
506 | * Consume the quiesced txg which has been handed off to | |
507 | * us. This may cause the quiescing thread to now be | |
508 | * able to quiesce another txg, so we must signal it. | |
509 | */ | |
510 | txg = tx->tx_quiesced_txg; | |
511 | tx->tx_quiesced_txg = 0; | |
512 | tx->tx_syncing_txg = txg; | |
513 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
34dc7c2f BB |
514 | |
515 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
516 | txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); | |
517 | mutex_exit(&tx->tx_sync_lock); | |
b128c09f | 518 | |
428870ff BB |
519 | start = ddi_get_lbolt(); |
520 | spa_sync(spa, txg); | |
521 | delta = ddi_get_lbolt() - start; | |
34dc7c2f | 522 | |
34dc7c2f | 523 | mutex_enter(&tx->tx_sync_lock); |
34dc7c2f BB |
524 | tx->tx_synced_txg = txg; |
525 | tx->tx_syncing_txg = 0; | |
34dc7c2f | 526 | cv_broadcast(&tx->tx_sync_done_cv); |
428870ff BB |
527 | |
528 | /* | |
529 | * Dispatch commit callbacks to worker threads. | |
530 | */ | |
531 | txg_dispatch_callbacks(dp, txg); | |
34dc7c2f BB |
532 | } |
533 | } | |
534 | ||
535 | static void | |
536 | txg_quiesce_thread(dsl_pool_t *dp) | |
537 | { | |
538 | tx_state_t *tx = &dp->dp_tx; | |
539 | callb_cpr_t cpr; | |
540 | ||
541 | txg_thread_enter(tx, &cpr); | |
542 | ||
543 | for (;;) { | |
544 | uint64_t txg; | |
545 | ||
546 | /* | |
547 | * We quiesce when there's someone waiting on us. | |
548 | * However, we can only have one txg in "quiescing" or | |
549 | * "quiesced, waiting to sync" state. So we wait until | |
550 | * the "quiesced, waiting to sync" txg has been consumed | |
551 | * by the sync thread. | |
552 | */ | |
553 | while (!tx->tx_exiting && | |
554 | (tx->tx_open_txg >= tx->tx_quiesce_txg_waiting || | |
555 | tx->tx_quiesced_txg != 0)) | |
556 | txg_thread_wait(tx, &cpr, &tx->tx_quiesce_more_cv, 0); | |
557 | ||
558 | if (tx->tx_exiting) | |
559 | txg_thread_exit(tx, &cpr, &tx->tx_quiesce_thread); | |
560 | ||
561 | txg = tx->tx_open_txg; | |
562 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
563 | txg, tx->tx_quiesce_txg_waiting, | |
564 | tx->tx_sync_txg_waiting); | |
565 | mutex_exit(&tx->tx_sync_lock); | |
566 | txg_quiesce(dp, txg); | |
567 | mutex_enter(&tx->tx_sync_lock); | |
568 | ||
569 | /* | |
570 | * Hand this txg off to the sync thread. | |
571 | */ | |
572 | dprintf("quiesce done, handing off txg %llu\n", txg); | |
573 | tx->tx_quiesced_txg = txg; | |
574 | cv_broadcast(&tx->tx_sync_more_cv); | |
575 | cv_broadcast(&tx->tx_quiesce_done_cv); | |
576 | } | |
577 | } | |
578 | ||
579 | /* | |
580 | * Delay this thread by 'ticks' if we are still in the open transaction | |
581 | * group and there is already a waiting txg quiesing or quiesced. Abort | |
582 | * the delay if this txg stalls or enters the quiesing state. | |
583 | */ | |
584 | void | |
585 | txg_delay(dsl_pool_t *dp, uint64_t txg, int ticks) | |
586 | { | |
587 | tx_state_t *tx = &dp->dp_tx; | |
cddafdcb | 588 | clock_t timeout = ddi_get_lbolt() + ticks; |
34dc7c2f BB |
589 | |
590 | /* don't delay if this txg could transition to quiesing immediately */ | |
591 | if (tx->tx_open_txg > txg || | |
592 | tx->tx_syncing_txg == txg-1 || tx->tx_synced_txg == txg-1) | |
593 | return; | |
594 | ||
595 | mutex_enter(&tx->tx_sync_lock); | |
596 | if (tx->tx_open_txg > txg || tx->tx_synced_txg == txg-1) { | |
597 | mutex_exit(&tx->tx_sync_lock); | |
598 | return; | |
599 | } | |
600 | ||
428870ff | 601 | while (ddi_get_lbolt() < timeout && |
34dc7c2f BB |
602 | tx->tx_syncing_txg < txg-1 && !txg_stalled(dp)) |
603 | (void) cv_timedwait(&tx->tx_quiesce_more_cv, &tx->tx_sync_lock, | |
604 | timeout); | |
605 | ||
570827e1 BB |
606 | DMU_TX_STAT_BUMP(dmu_tx_delay); |
607 | ||
34dc7c2f BB |
608 | mutex_exit(&tx->tx_sync_lock); |
609 | } | |
610 | ||
611 | void | |
612 | txg_wait_synced(dsl_pool_t *dp, uint64_t txg) | |
613 | { | |
614 | tx_state_t *tx = &dp->dp_tx; | |
615 | ||
13fe0198 MA |
616 | ASSERT(!dsl_pool_config_held(dp)); |
617 | ||
34dc7c2f BB |
618 | mutex_enter(&tx->tx_sync_lock); |
619 | ASSERT(tx->tx_threads == 2); | |
620 | if (txg == 0) | |
428870ff | 621 | txg = tx->tx_open_txg + TXG_DEFER_SIZE; |
34dc7c2f BB |
622 | if (tx->tx_sync_txg_waiting < txg) |
623 | tx->tx_sync_txg_waiting = txg; | |
624 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
625 | txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); | |
626 | while (tx->tx_synced_txg < txg) { | |
627 | dprintf("broadcasting sync more " | |
628 | "tx_synced=%llu waiting=%llu dp=%p\n", | |
629 | tx->tx_synced_txg, tx->tx_sync_txg_waiting, dp); | |
630 | cv_broadcast(&tx->tx_sync_more_cv); | |
631 | cv_wait(&tx->tx_sync_done_cv, &tx->tx_sync_lock); | |
632 | } | |
633 | mutex_exit(&tx->tx_sync_lock); | |
634 | } | |
635 | ||
636 | void | |
637 | txg_wait_open(dsl_pool_t *dp, uint64_t txg) | |
638 | { | |
639 | tx_state_t *tx = &dp->dp_tx; | |
640 | ||
13fe0198 MA |
641 | ASSERT(!dsl_pool_config_held(dp)); |
642 | ||
34dc7c2f BB |
643 | mutex_enter(&tx->tx_sync_lock); |
644 | ASSERT(tx->tx_threads == 2); | |
645 | if (txg == 0) | |
646 | txg = tx->tx_open_txg + 1; | |
647 | if (tx->tx_quiesce_txg_waiting < txg) | |
648 | tx->tx_quiesce_txg_waiting = txg; | |
649 | dprintf("txg=%llu quiesce_txg=%llu sync_txg=%llu\n", | |
650 | txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); | |
651 | while (tx->tx_open_txg < txg) { | |
652 | cv_broadcast(&tx->tx_quiesce_more_cv); | |
653 | cv_wait(&tx->tx_quiesce_done_cv, &tx->tx_sync_lock); | |
654 | } | |
655 | mutex_exit(&tx->tx_sync_lock); | |
656 | } | |
657 | ||
b128c09f | 658 | boolean_t |
34dc7c2f BB |
659 | txg_stalled(dsl_pool_t *dp) |
660 | { | |
661 | tx_state_t *tx = &dp->dp_tx; | |
662 | return (tx->tx_quiesce_txg_waiting > tx->tx_open_txg); | |
663 | } | |
664 | ||
b128c09f BB |
665 | boolean_t |
666 | txg_sync_waiting(dsl_pool_t *dp) | |
667 | { | |
668 | tx_state_t *tx = &dp->dp_tx; | |
669 | ||
670 | return (tx->tx_syncing_txg <= tx->tx_sync_txg_waiting || | |
671 | tx->tx_quiesced_txg != 0); | |
672 | } | |
673 | ||
34dc7c2f BB |
674 | /* |
675 | * Per-txg object lists. | |
676 | */ | |
677 | void | |
678 | txg_list_create(txg_list_t *tl, size_t offset) | |
679 | { | |
680 | int t; | |
681 | ||
682 | mutex_init(&tl->tl_lock, NULL, MUTEX_DEFAULT, NULL); | |
683 | ||
684 | tl->tl_offset = offset; | |
685 | ||
686 | for (t = 0; t < TXG_SIZE; t++) | |
687 | tl->tl_head[t] = NULL; | |
688 | } | |
689 | ||
690 | void | |
691 | txg_list_destroy(txg_list_t *tl) | |
692 | { | |
693 | int t; | |
694 | ||
695 | for (t = 0; t < TXG_SIZE; t++) | |
696 | ASSERT(txg_list_empty(tl, t)); | |
697 | ||
698 | mutex_destroy(&tl->tl_lock); | |
699 | } | |
700 | ||
29809a6c | 701 | boolean_t |
34dc7c2f BB |
702 | txg_list_empty(txg_list_t *tl, uint64_t txg) |
703 | { | |
704 | return (tl->tl_head[txg & TXG_MASK] == NULL); | |
705 | } | |
706 | ||
707 | /* | |
13fe0198 MA |
708 | * Add an entry to the list (unless it's already on the list). |
709 | * Returns B_TRUE if it was actually added. | |
34dc7c2f | 710 | */ |
13fe0198 | 711 | boolean_t |
34dc7c2f BB |
712 | txg_list_add(txg_list_t *tl, void *p, uint64_t txg) |
713 | { | |
714 | int t = txg & TXG_MASK; | |
715 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
13fe0198 | 716 | boolean_t add; |
34dc7c2f BB |
717 | |
718 | mutex_enter(&tl->tl_lock); | |
13fe0198 MA |
719 | add = (tn->tn_member[t] == 0); |
720 | if (add) { | |
34dc7c2f BB |
721 | tn->tn_member[t] = 1; |
722 | tn->tn_next[t] = tl->tl_head[t]; | |
723 | tl->tl_head[t] = tn; | |
724 | } | |
725 | mutex_exit(&tl->tl_lock); | |
726 | ||
13fe0198 | 727 | return (add); |
34dc7c2f BB |
728 | } |
729 | ||
428870ff | 730 | /* |
13fe0198 MA |
731 | * Add an entry to the end of the list, unless it's already on the list. |
732 | * (walks list to find end) | |
733 | * Returns B_TRUE if it was actually added. | |
428870ff | 734 | */ |
13fe0198 | 735 | boolean_t |
428870ff BB |
736 | txg_list_add_tail(txg_list_t *tl, void *p, uint64_t txg) |
737 | { | |
738 | int t = txg & TXG_MASK; | |
739 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
13fe0198 | 740 | boolean_t add; |
428870ff BB |
741 | |
742 | mutex_enter(&tl->tl_lock); | |
13fe0198 MA |
743 | add = (tn->tn_member[t] == 0); |
744 | if (add) { | |
428870ff BB |
745 | txg_node_t **tp; |
746 | ||
747 | for (tp = &tl->tl_head[t]; *tp != NULL; tp = &(*tp)->tn_next[t]) | |
748 | continue; | |
749 | ||
750 | tn->tn_member[t] = 1; | |
751 | tn->tn_next[t] = NULL; | |
752 | *tp = tn; | |
753 | } | |
754 | mutex_exit(&tl->tl_lock); | |
755 | ||
13fe0198 | 756 | return (add); |
428870ff BB |
757 | } |
758 | ||
34dc7c2f BB |
759 | /* |
760 | * Remove the head of the list and return it. | |
761 | */ | |
762 | void * | |
763 | txg_list_remove(txg_list_t *tl, uint64_t txg) | |
764 | { | |
765 | int t = txg & TXG_MASK; | |
766 | txg_node_t *tn; | |
767 | void *p = NULL; | |
768 | ||
769 | mutex_enter(&tl->tl_lock); | |
770 | if ((tn = tl->tl_head[t]) != NULL) { | |
771 | p = (char *)tn - tl->tl_offset; | |
772 | tl->tl_head[t] = tn->tn_next[t]; | |
773 | tn->tn_next[t] = NULL; | |
774 | tn->tn_member[t] = 0; | |
775 | } | |
776 | mutex_exit(&tl->tl_lock); | |
777 | ||
778 | return (p); | |
779 | } | |
780 | ||
781 | /* | |
782 | * Remove a specific item from the list and return it. | |
783 | */ | |
784 | void * | |
785 | txg_list_remove_this(txg_list_t *tl, void *p, uint64_t txg) | |
786 | { | |
787 | int t = txg & TXG_MASK; | |
788 | txg_node_t *tn, **tp; | |
789 | ||
790 | mutex_enter(&tl->tl_lock); | |
791 | ||
792 | for (tp = &tl->tl_head[t]; (tn = *tp) != NULL; tp = &tn->tn_next[t]) { | |
793 | if ((char *)tn - tl->tl_offset == p) { | |
794 | *tp = tn->tn_next[t]; | |
795 | tn->tn_next[t] = NULL; | |
796 | tn->tn_member[t] = 0; | |
797 | mutex_exit(&tl->tl_lock); | |
798 | return (p); | |
799 | } | |
800 | } | |
801 | ||
802 | mutex_exit(&tl->tl_lock); | |
803 | ||
804 | return (NULL); | |
805 | } | |
806 | ||
13fe0198 | 807 | boolean_t |
34dc7c2f BB |
808 | txg_list_member(txg_list_t *tl, void *p, uint64_t txg) |
809 | { | |
810 | int t = txg & TXG_MASK; | |
811 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
812 | ||
13fe0198 | 813 | return (tn->tn_member[t] != 0); |
34dc7c2f BB |
814 | } |
815 | ||
816 | /* | |
817 | * Walk a txg list -- only safe if you know it's not changing. | |
818 | */ | |
819 | void * | |
820 | txg_list_head(txg_list_t *tl, uint64_t txg) | |
821 | { | |
822 | int t = txg & TXG_MASK; | |
823 | txg_node_t *tn = tl->tl_head[t]; | |
824 | ||
825 | return (tn == NULL ? NULL : (char *)tn - tl->tl_offset); | |
826 | } | |
827 | ||
828 | void * | |
829 | txg_list_next(txg_list_t *tl, void *p, uint64_t txg) | |
830 | { | |
831 | int t = txg & TXG_MASK; | |
832 | txg_node_t *tn = (txg_node_t *)((char *)p + tl->tl_offset); | |
833 | ||
834 | tn = tn->tn_next[t]; | |
835 | ||
836 | return (tn == NULL ? NULL : (char *)tn - tl->tl_offset); | |
837 | } | |
c28b2279 BB |
838 | |
839 | #if defined(_KERNEL) && defined(HAVE_SPL) | |
840 | EXPORT_SYMBOL(txg_init); | |
841 | EXPORT_SYMBOL(txg_fini); | |
842 | EXPORT_SYMBOL(txg_sync_start); | |
843 | EXPORT_SYMBOL(txg_sync_stop); | |
844 | EXPORT_SYMBOL(txg_hold_open); | |
845 | EXPORT_SYMBOL(txg_rele_to_quiesce); | |
846 | EXPORT_SYMBOL(txg_rele_to_sync); | |
847 | EXPORT_SYMBOL(txg_register_callbacks); | |
848 | EXPORT_SYMBOL(txg_delay); | |
849 | EXPORT_SYMBOL(txg_wait_synced); | |
850 | EXPORT_SYMBOL(txg_wait_open); | |
54a179e7 | 851 | EXPORT_SYMBOL(txg_wait_callbacks); |
c28b2279 BB |
852 | EXPORT_SYMBOL(txg_stalled); |
853 | EXPORT_SYMBOL(txg_sync_waiting); | |
87d98efe BB |
854 | |
855 | module_param(zfs_txg_timeout, int, 0644); | |
856 | MODULE_PARM_DESC(zfs_txg_timeout, "Max seconds worth of delta per txg"); | |
c28b2279 | 857 | #endif |