1 | /* $NetBSD: rf_engine.c,v 1.51 2016/01/03 08:17:24 mlelstv Exp $ */ |
2 | /* |
3 | * Copyright (c) 1995 Carnegie-Mellon University. |
4 | * All rights reserved. |
5 | * |
6 | * Author: William V. Courtright II, Mark Holland, Rachad Youssef |
7 | * |
8 | * Permission to use, copy, modify and distribute this software and |
9 | * its documentation is hereby granted, provided that both the copyright |
10 | * notice and this permission notice appear in all copies of the |
11 | * software, derivative works or modified versions, and any portions |
12 | * thereof, and that both notices appear in supporting documentation. |
13 | * |
14 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
15 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND |
16 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
17 | * |
18 | * Carnegie Mellon requests users of this software to return to |
19 | * |
20 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
21 | * School of Computer Science |
22 | * Carnegie Mellon University |
23 | * Pittsburgh PA 15213-3890 |
24 | * |
25 | * any improvements or extensions that they make and grant Carnegie the |
26 | * rights to redistribute these changes. |
27 | */ |
28 | |
29 | /**************************************************************************** |
30 | * * |
31 | * engine.c -- code for DAG execution engine * |
32 | * * |
33 | * Modified to work as follows (holland): * |
34 | * A user-thread calls into DispatchDAG, which fires off the nodes that * |
35 | * are direct successors to the header node. DispatchDAG then returns, * |
36 | * and the rest of the I/O continues asynchronously. As each node * |
37 | * completes, the node execution function calls FinishNode(). FinishNode * |
38 | * scans the list of successors to the node and increments the antecedent * |
39 | * counts. Each node that becomes enabled is placed on a central node * |
40 | * queue. A dedicated dag-execution thread grabs nodes off of this * |
41 | * queue and fires them. * |
42 | * * |
43 | * NULL nodes are never fired. * |
44 | * * |
45 | * Terminator nodes are never fired, but rather cause the callback * |
46 | * associated with the DAG to be invoked. * |
47 | * * |
48 | * If a node fails, the dag either rolls forward to the completion or * |
49 | * rolls back, undoing previously-completed nodes and fails atomically. * |
50 | * The direction of recovery is determined by the location of the failed * |
51 | * node in the graph. If the failure occurred before the commit node in * |
52 | * the graph, backward recovery is used. Otherwise, forward recovery is * |
53 | * used. * |
54 | * * |
55 | ****************************************************************************/ |
56 | |
57 | #include <sys/cdefs.h> |
58 | __KERNEL_RCSID(0, "$NetBSD: rf_engine.c,v 1.51 2016/01/03 08:17:24 mlelstv Exp $" ); |
59 | |
60 | #include <sys/errno.h> |
61 | |
62 | #include "rf_threadstuff.h" |
63 | #include "rf_dag.h" |
64 | #include "rf_engine.h" |
65 | #include "rf_etimer.h" |
66 | #include "rf_general.h" |
67 | #include "rf_dagutils.h" |
68 | #include "rf_shutdown.h" |
69 | #include "rf_raid.h" |
70 | #include "rf_kintf.h" |
71 | #include "rf_paritymap.h" |
72 | |
73 | static void rf_ShutdownEngine(void *); |
74 | static void DAGExecutionThread(RF_ThreadArg_t arg); |
75 | static void rf_RaidIOThread(RF_ThreadArg_t arg); |
76 | |
77 | /* synchronization primitives for this file. DO_WAIT should be enclosed in a while loop. */ |
78 | |
79 | #define DO_LOCK(_r_) \ |
80 | rf_lock_mutex2((_r_)->node_queue_mutex) |
81 | |
82 | #define DO_UNLOCK(_r_) \ |
83 | rf_unlock_mutex2((_r_)->node_queue_mutex) |
84 | |
85 | #define DO_WAIT(_r_) \ |
86 | rf_wait_cond2((_r_)->node_queue_cv, (_r_)->node_queue_mutex) |
87 | |
88 | #define DO_SIGNAL(_r_) \ |
89 | rf_broadcast_cond2((_r_)->node_queue_cv) /* XXX rf_signal_cond2? */ |
90 | |
91 | static void |
92 | rf_ShutdownEngine(void *arg) |
93 | { |
94 | RF_Raid_t *raidPtr; |
95 | |
96 | raidPtr = (RF_Raid_t *) arg; |
97 | |
98 | /* Tell the rf_RaidIOThread to shutdown */ |
99 | rf_lock_mutex2(raidPtr->iodone_lock); |
100 | |
101 | raidPtr->shutdown_raidio = 1; |
102 | rf_signal_cond2(raidPtr->iodone_cv); |
103 | |
104 | /* ...and wait for it to tell us it has finished */ |
105 | while (raidPtr->shutdown_raidio) |
106 | rf_wait_cond2(raidPtr->iodone_cv, raidPtr->iodone_lock); |
107 | |
108 | rf_unlock_mutex2(raidPtr->iodone_lock); |
109 | |
110 | /* Now shut down the DAG execution engine. */ |
111 | DO_LOCK(raidPtr); |
112 | raidPtr->shutdown_engine = 1; |
113 | DO_SIGNAL(raidPtr); |
114 | |
115 | /* ...and wait for it to tell us it has finished */ |
116 | while (raidPtr->shutdown_engine) |
117 | DO_WAIT(raidPtr); |
118 | |
119 | DO_UNLOCK(raidPtr); |
120 | |
121 | rf_destroy_mutex2(raidPtr->node_queue_mutex); |
122 | rf_destroy_cond2(raidPtr->node_queue_cv); |
123 | |
124 | rf_destroy_mutex2(raidPtr->iodone_lock); |
125 | rf_destroy_cond2(raidPtr->iodone_cv); |
126 | } |
127 | |
128 | int |
129 | rf_ConfigureEngine(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr, |
130 | RF_Config_t *cfgPtr) |
131 | { |
132 | |
133 | /* |
134 | * Initialise iodone for the IO thread. |
135 | */ |
136 | TAILQ_INIT(&(raidPtr->iodone)); |
137 | rf_init_mutex2(raidPtr->iodone_lock, IPL_VM); |
138 | rf_init_cond2(raidPtr->iodone_cv, "raidiow" ); |
139 | |
140 | rf_init_mutex2(raidPtr->node_queue_mutex, IPL_VM); |
141 | rf_init_cond2(raidPtr->node_queue_cv, "rfnodeq" ); |
142 | raidPtr->node_queue = NULL; |
143 | raidPtr->dags_in_flight = 0; |
144 | |
145 | /* we create the execution thread only once per system boot. no need |
146 | * to check return code b/c the kernel panics if it can't create the |
147 | * thread. */ |
148 | #if RF_DEBUG_ENGINE |
149 | if (rf_engineDebug) { |
150 | printf("raid%d: Creating engine thread\n" , raidPtr->raidid); |
151 | } |
152 | #endif |
153 | if (RF_CREATE_ENGINE_THREAD(raidPtr->engine_thread, |
154 | DAGExecutionThread, raidPtr, |
155 | "raid%d" , raidPtr->raidid)) { |
156 | printf("raid%d: Unable to create engine thread\n" , |
157 | raidPtr->raidid); |
158 | return (ENOMEM); |
159 | } |
160 | if (RF_CREATE_ENGINE_THREAD(raidPtr->engine_helper_thread, |
161 | rf_RaidIOThread, raidPtr, |
162 | "raidio%d" , raidPtr->raidid)) { |
163 | printf("raid%d: Unable to create raidio thread\n" , |
164 | raidPtr->raidid); |
165 | return (ENOMEM); |
166 | } |
167 | #if RF_DEBUG_ENGINE |
168 | if (rf_engineDebug) { |
169 | printf("raid%d: Created engine thread\n" , raidPtr->raidid); |
170 | } |
171 | #endif |
172 | |
173 | /* engine thread is now running and waiting for work */ |
174 | #if RF_DEBUG_ENGINE |
175 | if (rf_engineDebug) { |
176 | printf("raid%d: Engine thread running and waiting for events\n" , raidPtr->raidid); |
177 | } |
178 | #endif |
179 | rf_ShutdownCreate(listp, rf_ShutdownEngine, raidPtr); |
180 | |
181 | return (0); |
182 | } |
183 | |
184 | #if 0 |
185 | static int |
186 | BranchDone(RF_DagNode_t *node) |
187 | { |
188 | int i; |
189 | |
190 | /* return true if forward execution is completed for a node and its |
191 | * succedents */ |
192 | switch (node->status) { |
193 | case rf_wait: |
194 | /* should never be called in this state */ |
195 | RF_PANIC(); |
196 | break; |
197 | case rf_fired: |
198 | /* node is currently executing, so we're not done */ |
199 | return (RF_FALSE); |
200 | case rf_good: |
201 | /* for each succedent recursively check branch */ |
202 | for (i = 0; i < node->numSuccedents; i++) |
203 | if (!BranchDone(node->succedents[i])) |
204 | return RF_FALSE; |
205 | return RF_TRUE; /* node and all succedent branches aren't in |
206 | * fired state */ |
207 | case rf_bad: |
208 | /* succedents can't fire */ |
209 | return (RF_TRUE); |
210 | case rf_recover: |
211 | /* should never be called in this state */ |
212 | RF_PANIC(); |
213 | break; |
214 | case rf_undone: |
215 | case rf_panic: |
216 | /* XXX need to fix this case */ |
217 | /* for now, assume that we're done */ |
218 | return (RF_TRUE); |
219 | default: |
220 | /* illegal node status */ |
221 | RF_PANIC(); |
222 | break; |
223 | } |
224 | } |
225 | #endif |
226 | |
227 | static int |
228 | NodeReady(RF_DagNode_t *node) |
229 | { |
230 | int ready; |
231 | |
232 | switch (node->dagHdr->status) { |
233 | case rf_enable: |
234 | case rf_rollForward: |
235 | if ((node->status == rf_wait) && |
236 | (node->numAntecedents == node->numAntDone)) |
237 | ready = RF_TRUE; |
238 | else |
239 | ready = RF_FALSE; |
240 | break; |
241 | case rf_rollBackward: |
242 | RF_ASSERT(node->numSuccDone <= node->numSuccedents); |
243 | RF_ASSERT(node->numSuccFired <= node->numSuccedents); |
244 | RF_ASSERT(node->numSuccFired <= node->numSuccDone); |
245 | if ((node->status == rf_good) && |
246 | (node->numSuccDone == node->numSuccedents)) |
247 | ready = RF_TRUE; |
248 | else |
249 | ready = RF_FALSE; |
250 | break; |
251 | default: |
252 | printf("Execution engine found illegal DAG status in NodeReady\n" ); |
253 | RF_PANIC(); |
254 | break; |
255 | } |
256 | |
257 | return (ready); |
258 | } |
259 | |
260 | |
261 | |
262 | /* user context and dag-exec-thread context: Fire a node. The node's |
263 | * status field determines which function, do or undo, to be fired. |
264 | * This routine assumes that the node's status field has alread been |
265 | * set to "fired" or "recover" to indicate the direction of execution. |
266 | */ |
267 | static void |
268 | FireNode(RF_DagNode_t *node) |
269 | { |
270 | switch (node->status) { |
271 | case rf_fired: |
272 | /* fire the do function of a node */ |
273 | #if RF_DEBUG_ENGINE |
274 | if (rf_engineDebug) { |
275 | printf("raid%d: Firing node 0x%lx (%s)\n" , |
276 | node->dagHdr->raidPtr->raidid, |
277 | (unsigned long) node, node->name); |
278 | } |
279 | #endif |
280 | if (node->flags & RF_DAGNODE_FLAG_YIELD) { |
281 | #if defined(__NetBSD__) && defined(_KERNEL) |
282 | /* thread_block(); */ |
283 | /* printf("Need to block the thread here...\n"); */ |
284 | /* XXX thread_block is actually mentioned in |
285 | * /usr/include/vm/vm_extern.h */ |
286 | #else |
287 | thread_block(); |
288 | #endif |
289 | } |
290 | (*(node->doFunc)) (node); |
291 | break; |
292 | case rf_recover: |
293 | /* fire the undo function of a node */ |
294 | #if RF_DEBUG_ENGINE |
295 | if (rf_engineDebug) { |
296 | printf("raid%d: Firing (undo) node 0x%lx (%s)\n" , |
297 | node->dagHdr->raidPtr->raidid, |
298 | (unsigned long) node, node->name); |
299 | } |
300 | #endif |
301 | if (node->flags & RF_DAGNODE_FLAG_YIELD) |
302 | #if defined(__NetBSD__) && defined(_KERNEL) |
303 | /* thread_block(); */ |
304 | /* printf("Need to block the thread here...\n"); */ |
305 | /* XXX thread_block is actually mentioned in |
306 | * /usr/include/vm/vm_extern.h */ |
307 | #else |
308 | thread_block(); |
309 | #endif |
310 | (*(node->undoFunc)) (node); |
311 | break; |
312 | default: |
313 | RF_PANIC(); |
314 | break; |
315 | } |
316 | } |
317 | |
318 | |
319 | |
320 | /* user context: |
321 | * Attempt to fire each node in a linear array. |
322 | * The entire list is fired atomically. |
323 | */ |
324 | static void |
325 | FireNodeArray(int numNodes, RF_DagNode_t **nodeList) |
326 | { |
327 | RF_DagStatus_t dstat; |
328 | RF_DagNode_t *node; |
329 | int i, j; |
330 | |
331 | /* first, mark all nodes which are ready to be fired */ |
332 | for (i = 0; i < numNodes; i++) { |
333 | node = nodeList[i]; |
334 | dstat = node->dagHdr->status; |
335 | RF_ASSERT((node->status == rf_wait) || |
336 | (node->status == rf_good)); |
337 | if (NodeReady(node)) { |
338 | if ((dstat == rf_enable) || |
339 | (dstat == rf_rollForward)) { |
340 | RF_ASSERT(node->status == rf_wait); |
341 | if (node->commitNode) |
342 | node->dagHdr->numCommits++; |
343 | node->status = rf_fired; |
344 | for (j = 0; j < node->numAntecedents; j++) |
345 | node->antecedents[j]->numSuccFired++; |
346 | } else { |
347 | RF_ASSERT(dstat == rf_rollBackward); |
348 | RF_ASSERT(node->status == rf_good); |
349 | /* only one commit node per graph */ |
350 | RF_ASSERT(node->commitNode == RF_FALSE); |
351 | node->status = rf_recover; |
352 | } |
353 | } |
354 | } |
355 | /* now, fire the nodes */ |
356 | for (i = 0; i < numNodes; i++) { |
357 | if ((nodeList[i]->status == rf_fired) || |
358 | (nodeList[i]->status == rf_recover)) |
359 | FireNode(nodeList[i]); |
360 | } |
361 | } |
362 | |
363 | |
364 | /* user context: |
365 | * Attempt to fire each node in a linked list. |
366 | * The entire list is fired atomically. |
367 | */ |
368 | static void |
369 | FireNodeList(RF_DagNode_t *nodeList) |
370 | { |
371 | RF_DagNode_t *node, *next; |
372 | RF_DagStatus_t dstat; |
373 | int j; |
374 | |
375 | if (nodeList) { |
376 | /* first, mark all nodes which are ready to be fired */ |
377 | for (node = nodeList; node; node = next) { |
378 | next = node->next; |
379 | dstat = node->dagHdr->status; |
380 | RF_ASSERT((node->status == rf_wait) || |
381 | (node->status == rf_good)); |
382 | if (NodeReady(node)) { |
383 | if ((dstat == rf_enable) || |
384 | (dstat == rf_rollForward)) { |
385 | RF_ASSERT(node->status == rf_wait); |
386 | if (node->commitNode) |
387 | node->dagHdr->numCommits++; |
388 | node->status = rf_fired; |
389 | for (j = 0; j < node->numAntecedents; j++) |
390 | node->antecedents[j]->numSuccFired++; |
391 | } else { |
392 | RF_ASSERT(dstat == rf_rollBackward); |
393 | RF_ASSERT(node->status == rf_good); |
394 | /* only one commit node per graph */ |
395 | RF_ASSERT(node->commitNode == RF_FALSE); |
396 | node->status = rf_recover; |
397 | } |
398 | } |
399 | } |
400 | /* now, fire the nodes */ |
401 | for (node = nodeList; node; node = next) { |
402 | next = node->next; |
403 | if ((node->status == rf_fired) || |
404 | (node->status == rf_recover)) |
405 | FireNode(node); |
406 | } |
407 | } |
408 | } |
409 | /* interrupt context: |
410 | * for each succedent |
411 | * propagate required results from node to succedent |
412 | * increment succedent's numAntDone |
413 | * place newly-enable nodes on node queue for firing |
414 | * |
415 | * To save context switches, we don't place NIL nodes on the node queue, |
416 | * but rather just process them as if they had fired. Note that NIL nodes |
417 | * that are the direct successors of the header will actually get fired by |
418 | * DispatchDAG, which is fine because no context switches are involved. |
419 | * |
420 | * Important: when running at user level, this can be called by any |
421 | * disk thread, and so the increment and check of the antecedent count |
422 | * must be locked. I used the node queue mutex and locked down the |
423 | * entire function, but this is certainly overkill. |
424 | */ |
425 | static void |
426 | PropagateResults(RF_DagNode_t *node, int context) |
427 | { |
428 | RF_DagNode_t *s, *a; |
429 | RF_Raid_t *raidPtr; |
430 | int i; |
431 | RF_DagNode_t *finishlist = NULL; /* a list of NIL nodes to be |
432 | * finished */ |
433 | RF_DagNode_t *skiplist = NULL; /* list of nodes with failed truedata |
434 | * antecedents */ |
435 | RF_DagNode_t *firelist = NULL; /* a list of nodes to be fired */ |
436 | RF_DagNode_t *q = NULL, *qh = NULL, *next; |
437 | int j, skipNode; |
438 | |
439 | raidPtr = node->dagHdr->raidPtr; |
440 | |
441 | DO_LOCK(raidPtr); |
442 | |
443 | /* debug - validate fire counts */ |
444 | for (i = 0; i < node->numAntecedents; i++) { |
445 | a = *(node->antecedents + i); |
446 | RF_ASSERT(a->numSuccFired >= a->numSuccDone); |
447 | RF_ASSERT(a->numSuccFired <= a->numSuccedents); |
448 | a->numSuccDone++; |
449 | } |
450 | |
451 | switch (node->dagHdr->status) { |
452 | case rf_enable: |
453 | case rf_rollForward: |
454 | for (i = 0; i < node->numSuccedents; i++) { |
455 | s = *(node->succedents + i); |
456 | RF_ASSERT(s->status == rf_wait); |
457 | (s->numAntDone)++; |
458 | if (s->numAntDone == s->numAntecedents) { |
459 | /* look for NIL nodes */ |
460 | if (s->doFunc == rf_NullNodeFunc) { |
461 | /* don't fire NIL nodes, just process |
462 | * them */ |
463 | s->next = finishlist; |
464 | finishlist = s; |
465 | } else { |
466 | /* look to see if the node is to be |
467 | * skipped */ |
468 | skipNode = RF_FALSE; |
469 | for (j = 0; j < s->numAntecedents; j++) |
470 | if ((s->antType[j] == rf_trueData) && (s->antecedents[j]->status == rf_bad)) |
471 | skipNode = RF_TRUE; |
472 | if (skipNode) { |
473 | /* this node has one or more |
474 | * failed true data |
475 | * dependencies, so skip it */ |
476 | s->next = skiplist; |
477 | skiplist = s; |
478 | } else |
479 | /* add s to list of nodes (q) |
480 | * to execute */ |
481 | if (context != RF_INTR_CONTEXT) { |
482 | /* we only have to |
483 | * enqueue if we're at |
484 | * intr context */ |
485 | /* put node on |
486 | a list to |
487 | be fired |
488 | after we |
489 | unlock */ |
490 | s->next = firelist; |
491 | firelist = s; |
492 | } else { |
493 | /* enqueue the |
494 | node for |
495 | the dag |
496 | exec thread |
497 | to fire */ |
498 | RF_ASSERT(NodeReady(s)); |
499 | if (q) { |
500 | q->next = s; |
501 | q = s; |
502 | } else { |
503 | qh = q = s; |
504 | qh->next = NULL; |
505 | } |
506 | } |
507 | } |
508 | } |
509 | } |
510 | |
511 | if (q) { |
512 | /* xfer our local list of nodes to the node queue */ |
513 | q->next = raidPtr->node_queue; |
514 | raidPtr->node_queue = qh; |
515 | DO_SIGNAL(raidPtr); |
516 | } |
517 | DO_UNLOCK(raidPtr); |
518 | |
519 | for (; skiplist; skiplist = next) { |
520 | next = skiplist->next; |
521 | skiplist->status = rf_skipped; |
522 | for (i = 0; i < skiplist->numAntecedents; i++) { |
523 | skiplist->antecedents[i]->numSuccFired++; |
524 | } |
525 | if (skiplist->commitNode) { |
526 | skiplist->dagHdr->numCommits++; |
527 | } |
528 | rf_FinishNode(skiplist, context); |
529 | } |
530 | for (; finishlist; finishlist = next) { |
531 | /* NIL nodes: no need to fire them */ |
532 | next = finishlist->next; |
533 | finishlist->status = rf_good; |
534 | for (i = 0; i < finishlist->numAntecedents; i++) { |
535 | finishlist->antecedents[i]->numSuccFired++; |
536 | } |
537 | if (finishlist->commitNode) |
538 | finishlist->dagHdr->numCommits++; |
539 | /* |
540 | * Okay, here we're calling rf_FinishNode() on |
541 | * nodes that have the null function as their |
542 | * work proc. Such a node could be the |
543 | * terminal node in a DAG. If so, it will |
544 | * cause the DAG to complete, which will in |
545 | * turn free memory used by the DAG, which |
546 | * includes the node in question. Thus, we |
547 | * must avoid referencing the node at all |
548 | * after calling rf_FinishNode() on it. */ |
549 | rf_FinishNode(finishlist, context); /* recursive call */ |
550 | } |
551 | /* fire all nodes in firelist */ |
552 | FireNodeList(firelist); |
553 | break; |
554 | |
555 | case rf_rollBackward: |
556 | for (i = 0; i < node->numAntecedents; i++) { |
557 | a = *(node->antecedents + i); |
558 | RF_ASSERT(a->status == rf_good); |
559 | RF_ASSERT(a->numSuccDone <= a->numSuccedents); |
560 | RF_ASSERT(a->numSuccDone <= a->numSuccFired); |
561 | |
562 | if (a->numSuccDone == a->numSuccFired) { |
563 | if (a->undoFunc == rf_NullNodeFunc) { |
564 | /* don't fire NIL nodes, just process |
565 | * them */ |
566 | a->next = finishlist; |
567 | finishlist = a; |
568 | } else { |
569 | if (context != RF_INTR_CONTEXT) { |
570 | /* we only have to enqueue if |
571 | * we're at intr context */ |
572 | /* put node on a list to be |
573 | fired after we unlock */ |
574 | a->next = firelist; |
575 | |
576 | firelist = a; |
577 | } else { |
578 | /* enqueue the node for the |
579 | dag exec thread to fire */ |
580 | RF_ASSERT(NodeReady(a)); |
581 | if (q) { |
582 | q->next = a; |
583 | q = a; |
584 | } else { |
585 | qh = q = a; |
586 | qh->next = NULL; |
587 | } |
588 | } |
589 | } |
590 | } |
591 | } |
592 | if (q) { |
593 | /* xfer our local list of nodes to the node queue */ |
594 | q->next = raidPtr->node_queue; |
595 | raidPtr->node_queue = qh; |
596 | DO_SIGNAL(raidPtr); |
597 | } |
598 | DO_UNLOCK(raidPtr); |
599 | for (; finishlist; finishlist = next) { |
600 | /* NIL nodes: no need to fire them */ |
601 | next = finishlist->next; |
602 | finishlist->status = rf_good; |
603 | /* |
604 | * Okay, here we're calling rf_FinishNode() on |
605 | * nodes that have the null function as their |
606 | * work proc. Such a node could be the first |
607 | * node in a DAG. If so, it will cause the DAG |
608 | * to complete, which will in turn free memory |
609 | * used by the DAG, which includes the node in |
610 | * question. Thus, we must avoid referencing |
611 | * the node at all after calling |
612 | * rf_FinishNode() on it. */ |
613 | rf_FinishNode(finishlist, context); /* recursive call */ |
614 | } |
615 | /* fire all nodes in firelist */ |
616 | FireNodeList(firelist); |
617 | |
618 | break; |
619 | default: |
620 | printf("Engine found illegal DAG status in PropagateResults()\n" ); |
621 | RF_PANIC(); |
622 | break; |
623 | } |
624 | } |
625 | |
626 | |
627 | |
628 | /* |
629 | * Process a fired node which has completed |
630 | */ |
631 | static void |
632 | ProcessNode(RF_DagNode_t *node, int context) |
633 | { |
634 | #if RF_DEBUG_ENGINE |
635 | RF_Raid_t *raidPtr; |
636 | |
637 | raidPtr = node->dagHdr->raidPtr; |
638 | #endif |
639 | |
640 | switch (node->status) { |
641 | case rf_good: |
642 | /* normal case, don't need to do anything */ |
643 | break; |
644 | case rf_bad: |
645 | if ((node->dagHdr->numCommits > 0) || |
646 | (node->dagHdr->numCommitNodes == 0)) { |
647 | /* crossed commit barrier */ |
648 | node->dagHdr->status = rf_rollForward; |
649 | #if RF_DEBUG_ENGINE |
650 | if (rf_engineDebug) { |
651 | printf("raid%d: node (%s) returned fail, rolling forward\n" , raidPtr->raidid, node->name); |
652 | } |
653 | #endif |
654 | } else { |
655 | /* never reached commit barrier */ |
656 | node->dagHdr->status = rf_rollBackward; |
657 | #if RF_DEBUG_ENGINE |
658 | if (rf_engineDebug) { |
659 | printf("raid%d: node (%s) returned fail, rolling backward\n" , raidPtr->raidid, node->name); |
660 | } |
661 | #endif |
662 | } |
663 | break; |
664 | case rf_undone: |
665 | /* normal rollBackward case, don't need to do anything */ |
666 | break; |
667 | case rf_panic: |
668 | /* an undo node failed!!! */ |
669 | printf("UNDO of a node failed!!!\n" ); |
670 | break; |
671 | default: |
672 | printf("node finished execution with an illegal status!!!\n" ); |
673 | RF_PANIC(); |
674 | break; |
675 | } |
676 | |
677 | /* enqueue node's succedents (antecedents if rollBackward) for |
678 | * execution */ |
679 | PropagateResults(node, context); |
680 | } |
681 | |
682 | |
683 | |
684 | /* user context or dag-exec-thread context: |
685 | * This is the first step in post-processing a newly-completed node. |
686 | * This routine is called by each node execution function to mark the node |
687 | * as complete and fire off any successors that have been enabled. |
688 | */ |
689 | int |
690 | rf_FinishNode(RF_DagNode_t *node, int context) |
691 | { |
692 | int retcode = RF_FALSE; |
693 | node->dagHdr->numNodesCompleted++; |
694 | ProcessNode(node, context); |
695 | |
696 | return (retcode); |
697 | } |
698 | |
699 | |
700 | /* user context: submit dag for execution, return non-zero if we have |
701 | * to wait for completion. if and only if we return non-zero, we'll |
702 | * cause cbFunc to get invoked with cbArg when the DAG has completed. |
703 | * |
704 | * for now we always return 1. If the DAG does not cause any I/O, |
705 | * then the callback may get invoked before DispatchDAG returns. |
706 | * There's code in state 5 of ContinueRaidAccess to handle this. |
707 | * |
708 | * All we do here is fire the direct successors of the header node. |
709 | * The DAG execution thread does the rest of the dag processing. */ |
710 | int |
711 | rf_DispatchDAG(RF_DagHeader_t *dag, void (*cbFunc) (void *), |
712 | void *cbArg) |
713 | { |
714 | RF_Raid_t *raidPtr; |
715 | |
716 | raidPtr = dag->raidPtr; |
717 | #if RF_ACC_TRACE > 0 |
718 | if (dag->tracerec) { |
719 | RF_ETIMER_START(dag->tracerec->timer); |
720 | } |
721 | #endif |
722 | #if DEBUG |
723 | #if RF_DEBUG_VALIDATE_DAG |
724 | if (rf_engineDebug || rf_validateDAGDebug) { |
725 | if (rf_ValidateDAG(dag)) |
726 | RF_PANIC(); |
727 | } |
728 | #endif |
729 | #endif |
730 | #if RF_DEBUG_ENGINE |
731 | if (rf_engineDebug) { |
732 | printf("raid%d: Entering DispatchDAG\n" , raidPtr->raidid); |
733 | } |
734 | #endif |
735 | raidPtr->dags_in_flight++; /* debug only: blow off proper |
736 | * locking */ |
737 | dag->cbFunc = cbFunc; |
738 | dag->cbArg = cbArg; |
739 | dag->numNodesCompleted = 0; |
740 | dag->status = rf_enable; |
741 | FireNodeArray(dag->numSuccedents, dag->succedents); |
742 | return (1); |
743 | } |
744 | /* dedicated kernel thread: the thread that handles all DAG node |
745 | * firing. To minimize locking and unlocking, we grab a copy of the |
746 | * entire node queue and then set the node queue to NULL before doing |
747 | * any firing of nodes. This way we only have to release the lock |
748 | * once. Of course, it's probably rare that there's more than one |
749 | * node in the queue at any one time, but it sometimes happens. |
750 | */ |
751 | |
752 | static void |
753 | DAGExecutionThread(RF_ThreadArg_t arg) |
754 | { |
755 | RF_DagNode_t *nd, *local_nq, *term_nq, *fire_nq; |
756 | RF_Raid_t *raidPtr; |
757 | |
758 | raidPtr = (RF_Raid_t *) arg; |
759 | |
760 | #if RF_DEBUG_ENGINE |
761 | if (rf_engineDebug) { |
762 | printf("raid%d: Engine thread is running\n" , raidPtr->raidid); |
763 | } |
764 | #endif |
765 | |
766 | DO_LOCK(raidPtr); |
767 | while (!raidPtr->shutdown_engine) { |
768 | |
769 | while (raidPtr->node_queue != NULL) { |
770 | local_nq = raidPtr->node_queue; |
771 | fire_nq = NULL; |
772 | term_nq = NULL; |
773 | raidPtr->node_queue = NULL; |
774 | DO_UNLOCK(raidPtr); |
775 | |
776 | /* first, strip out the terminal nodes */ |
777 | while (local_nq) { |
778 | nd = local_nq; |
779 | local_nq = local_nq->next; |
780 | switch (nd->dagHdr->status) { |
781 | case rf_enable: |
782 | case rf_rollForward: |
783 | if (nd->numSuccedents == 0) { |
784 | /* end of the dag, add to |
785 | * callback list */ |
786 | nd->next = term_nq; |
787 | term_nq = nd; |
788 | } else { |
789 | /* not the end, add to the |
790 | * fire queue */ |
791 | nd->next = fire_nq; |
792 | fire_nq = nd; |
793 | } |
794 | break; |
795 | case rf_rollBackward: |
796 | if (nd->numAntecedents == 0) { |
797 | /* end of the dag, add to the |
798 | * callback list */ |
799 | nd->next = term_nq; |
800 | term_nq = nd; |
801 | } else { |
802 | /* not the end, add to the |
803 | * fire queue */ |
804 | nd->next = fire_nq; |
805 | fire_nq = nd; |
806 | } |
807 | break; |
808 | default: |
809 | RF_PANIC(); |
810 | break; |
811 | } |
812 | } |
813 | |
814 | /* execute callback of dags which have reached the |
815 | * terminal node */ |
816 | while (term_nq) { |
817 | nd = term_nq; |
818 | term_nq = term_nq->next; |
819 | nd->next = NULL; |
820 | (nd->dagHdr->cbFunc) (nd->dagHdr->cbArg); |
821 | raidPtr->dags_in_flight--; /* debug only */ |
822 | } |
823 | |
824 | /* fire remaining nodes */ |
825 | FireNodeList(fire_nq); |
826 | |
827 | DO_LOCK(raidPtr); |
828 | } |
829 | while (!raidPtr->shutdown_engine && |
830 | raidPtr->node_queue == NULL) { |
831 | DO_WAIT(raidPtr); |
832 | } |
833 | } |
834 | |
835 | /* Let rf_ShutdownEngine know that we're done... */ |
836 | raidPtr->shutdown_engine = 0; |
837 | DO_SIGNAL(raidPtr); |
838 | |
839 | DO_UNLOCK(raidPtr); |
840 | |
841 | kthread_exit(0); |
842 | } |
843 | |
844 | /* |
845 | * rf_RaidIOThread() -- When I/O to a component begins, raidstrategy() |
846 | * puts the I/O on a buffer queue, and then signals raidPtr->iodone. If |
847 | * necessary, this function calls raidstart() to initiate the I/O. |
848 | * When I/O to a component completes, KernelWakeupFunc() puts the |
849 | * completed request onto raidPtr->iodone TAILQ. This function looks |
850 | * after requests on that queue by calling rf_DiskIOComplete() for the |
851 | * request, and by calling any required CompleteFunc for the request. |
852 | */ |
853 | |
854 | static void |
855 | rf_RaidIOThread(RF_ThreadArg_t arg) |
856 | { |
857 | RF_Raid_t *raidPtr; |
858 | RF_DiskQueueData_t *req; |
859 | |
860 | raidPtr = (RF_Raid_t *) arg; |
861 | |
862 | rf_lock_mutex2(raidPtr->iodone_lock); |
863 | |
864 | while (!raidPtr->shutdown_raidio) { |
865 | /* if there is nothing to do, then snooze. */ |
866 | if (TAILQ_EMPTY(&(raidPtr->iodone)) && |
867 | rf_buf_queue_check(raidPtr)) { |
868 | rf_wait_cond2(raidPtr->iodone_cv, raidPtr->iodone_lock); |
869 | } |
870 | |
871 | /* Check for deferred parity-map-related work. */ |
872 | if (raidPtr->parity_map != NULL) { |
873 | rf_unlock_mutex2(raidPtr->iodone_lock); |
874 | rf_paritymap_checkwork(raidPtr->parity_map); |
875 | rf_lock_mutex2(raidPtr->iodone_lock); |
876 | } |
877 | |
878 | /* See what I/Os, if any, have arrived */ |
879 | while ((req = TAILQ_FIRST(&(raidPtr->iodone))) != NULL) { |
880 | TAILQ_REMOVE(&(raidPtr->iodone), req, iodone_entries); |
881 | rf_unlock_mutex2(raidPtr->iodone_lock); |
882 | rf_DiskIOComplete(req->queue, req, req->error); |
883 | (req->CompleteFunc) (req->argument, req->error); |
884 | rf_lock_mutex2(raidPtr->iodone_lock); |
885 | } |
886 | |
887 | /* process any pending outgoing IO */ |
888 | rf_unlock_mutex2(raidPtr->iodone_lock); |
889 | raidstart(raidPtr); |
890 | rf_lock_mutex2(raidPtr->iodone_lock); |
891 | |
892 | } |
893 | |
894 | /* Let rf_ShutdownEngine know that we're done... */ |
895 | raidPtr->shutdown_raidio = 0; |
896 | rf_signal_cond2(raidPtr->iodone_cv); |
897 | |
898 | rf_unlock_mutex2(raidPtr->iodone_lock); |
899 | |
900 | kthread_exit(0); |
901 | } |
902 | |