aboutsummaryrefslogtreecommitdiff
path: root/lib/sqfs/comp/block_processor_parallel.c
blob: a4e0f6e81dd6d3614a66894aaeb57cf95f565af3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * block_processor.c
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#include "config.h"

#include "sqfs/block_processor.h"
#include "util.h"

#include <pthread.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#define MAX_BACKLOG_FACTOR (10)

typedef struct {
	block_processor_t *shared;
	compressor_t *cmp;
	pthread_t thread;
	uint8_t scratch[];
} compress_worker_t;

struct block_processor_t {
	pthread_mutex_t mtx;
	pthread_cond_t queue_cond;
	pthread_cond_t done_cond;

	/* needs rw access by worker and main thread */
	block_t *queue;
	block_t *queue_last;

	block_t *done;
	bool terminate;
	size_t backlog;

	/* used by main thread only */
	uint32_t enqueue_id;
	uint32_t dequeue_id;

	unsigned int num_workers;
	block_cb cb;
	void *user;
	int status;

	/* used only by workers */
	size_t max_block_size;

	compress_worker_t *workers[];
};

static void store_completed_block(block_processor_t *shared, block_t *blk)
{
	block_t *it = shared->done, *prev = NULL;

	while (it != NULL) {
		if (it->sequence_number >= blk->sequence_number)
			break;
		prev = it;
		it = it->next;
	}

	if (prev == NULL) {
		blk->next = shared->done;
		shared->done = blk;
	} else {
		blk->next = prev->next;
		prev->next = blk;
	}
}

static void *worker_proc(void *arg)
{
	compress_worker_t *worker = arg;
	block_processor_t *shared = worker->shared;
	block_t *blk = NULL;

	for (;;) {
		pthread_mutex_lock(&shared->mtx);
		if (blk != NULL) {
			store_completed_block(shared, blk);
			shared->backlog -= 1;
			pthread_cond_broadcast(&shared->done_cond);
		}

		while (shared->queue == NULL && !shared->terminate) {
			pthread_cond_wait(&shared->queue_cond,
					  &shared->mtx);
		}

		if (shared->terminate) {
			pthread_mutex_unlock(&shared->mtx);
			break;
		}

		blk = shared->queue;
		shared->queue = blk->next;
		blk->next = NULL;

		if (shared->queue == NULL)
			shared->queue_last = NULL;
		pthread_mutex_unlock(&shared->mtx);

		if (process_block(blk, worker->cmp, worker->scratch,
				  shared->max_block_size)) {
			blk->flags |= BLK_COMPRESS_ERROR;
		}
	}
	return NULL;
}

block_processor_t *block_processor_create(size_t max_block_size,
					  compressor_t *cmp,
					  unsigned int num_workers,
					  void *user,
					  block_cb callback)
{
	block_processor_t *proc;
	unsigned int i;
	int ret;

	if (num_workers < 1)
		num_workers = 1;

	proc = alloc_flex(sizeof(*proc),
			  sizeof(proc->workers[0]), num_workers);
	if (proc == NULL) {
		perror("Creating block processor");
		return NULL;
	}

	proc->max_block_size = max_block_size;
	proc->cb = callback;
	proc->user = user;
	proc->num_workers = num_workers;

	if (pthread_mutex_init(&proc->mtx, NULL)) {
		perror("Creating block processor mutex");
		goto fail_free;
	}

	if (pthread_cond_init(&proc->queue_cond, NULL)) {
		perror("Creating block processor conditional");
		goto fail_mtx;
	}

	if (pthread_cond_init(&proc->done_cond, NULL)) {
		perror("Creating block processor completion conditional");
		goto fail_cond;
	}

	for (i = 0; i < num_workers; ++i) {
		proc->workers[i] = alloc_flex(sizeof(compress_worker_t),
					      1, max_block_size);

		if (proc->workers[i] == NULL) {
			perror("Creating block worker data");
			goto fail_init;
		}

		proc->workers[i]->shared = proc;
		proc->workers[i]->cmp = cmp->create_copy(cmp);

		if (proc->workers[i]->cmp == NULL)
			goto fail_init;
	}

	for (i = 0; i < num_workers; ++i) {
		ret = pthread_create(&proc->workers[i]->thread, NULL,
				     worker_proc, proc->workers[i]);

		if (ret != 0) {
			perror("Creating block processor thread");
			goto fail_thread;
		}
	}

	return proc;
fail_thread:
	pthread_mutex_lock(&proc->mtx);
	proc->terminate = true;
	pthread_cond_broadcast(&proc->queue_cond);
	pthread_mutex_unlock(&proc->mtx);

	for (i = 0; i < num_workers; ++i) {
		if (proc->workers[i]->thread > 0) {
			pthread_join(proc->workers[i]->thread, NULL);
		}
	}
fail_init:
	for (i = 0; i < num_workers; ++i) {
		if (proc->workers[i] != NULL) {
			if (proc->workers[i]->cmp != NULL) {
				proc->workers[i]->cmp->
					destroy(proc->workers[i]->cmp);
			}

			free(proc->workers[i]);
		}
	}
	pthread_cond_destroy(&proc->done_cond);
fail_cond:
	pthread_cond_destroy(&proc->queue_cond);
fail_mtx:
	pthread_mutex_destroy(&proc->mtx);
fail_free:
	free(proc);
	return NULL;
}

void block_processor_destroy(block_processor_t *proc)
{
	unsigned int i;
	block_t *blk;

	pthread_mutex_lock(&proc->mtx);
	proc->terminate = true;
	pthread_cond_broadcast(&proc->queue_cond);
	pthread_mutex_unlock(&proc->mtx);

	for (i = 0; i < proc->num_workers; ++i) {
		pthread_join(proc->workers[i]->thread, NULL);

		proc->workers[i]->cmp->destroy(proc->workers[i]->cmp);
		free(proc->workers[i]);
	}

	pthread_cond_destroy(&proc->done_cond);
	pthread_cond_destroy(&proc->queue_cond);
	pthread_mutex_destroy(&proc->mtx);

	while (proc->queue != NULL) {
		blk = proc->queue;
		proc->queue = blk->next;
		free(blk);
	}

	while (proc->done != NULL) {
		blk = proc->done;
		proc->done = blk->next;
		free(blk);
	}

	free(proc);
}

static int process_completed_blocks(block_processor_t *proc, block_t *queue)
{
	block_t *it;

	while (queue != NULL) {
		it = queue;
		queue = queue->next;

		if (it->flags & BLK_COMPRESS_ERROR) {
			proc->status = -1;
		} else {
			if (proc->cb(proc->user, it))
				proc->status = -1;
		}

		free(it);
	}

	return proc->status;
}

int block_processor_enqueue(block_processor_t *proc, block_t *block)
{
	block_t *queue = NULL, *it, *prev;

	block->sequence_number = proc->enqueue_id++;
	block->next = NULL;

	pthread_mutex_lock(&proc->mtx);
	if ((block->flags & BLK_DONT_COMPRESS) &&
	    (block->flags & BLK_DONT_CHECKSUM)) {
		store_completed_block(proc, block);
	} else {
		while (proc->backlog > proc->num_workers * MAX_BACKLOG_FACTOR)
			pthread_cond_wait(&proc->done_cond, &proc->mtx);

		if (proc->queue_last == NULL) {
			proc->queue = proc->queue_last = block;
		} else {
			proc->queue_last->next = block;
			proc->queue_last = block;
		}

		proc->backlog += 1;
	}

	it = proc->done;
	prev = NULL;

	while (it != NULL && it->sequence_number == proc->dequeue_id) {
		prev = it;
		it = it->next;
		proc->dequeue_id += 1;
	}

	if (prev != NULL) {
		queue = proc->done;
		prev->next = NULL;
		proc->done = it;
	}

	pthread_cond_broadcast(&proc->queue_cond);
	pthread_mutex_unlock(&proc->mtx);

	return process_completed_blocks(proc, queue);
}

int block_processor_finish(block_processor_t *proc)
{
	block_t *queue, *it;

	pthread_mutex_lock(&proc->mtx);
	while (proc->backlog > 0)
		pthread_cond_wait(&proc->done_cond, &proc->mtx);

	for (it = proc->done; it != NULL; it = it->next) {
		if (it->sequence_number != proc->dequeue_id++) {
			pthread_mutex_unlock(&proc->mtx);
			goto bug_seqnum;
		}
	}

	queue = proc->done;
	proc->done = NULL;
	pthread_mutex_unlock(&proc->mtx);

	return process_completed_blocks(proc, queue);
bug_seqnum:
	fputs("[BUG][parallel block processor] "
	      "gap in sequence numbers!\n", stderr);
	return -1;
}