2 * Multifd zlib compression implementation
4 * Copyright (c) 2020 Red Hat Inc
7 * Juan Quintela <quintela@redhat.com>
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
13 #include "qemu/osdep.h"
16 #include "exec/ramblock.h"
17 #include "exec/target_page.h"
18 #include "qapi/error.h"
19 #include "migration.h"
24 /* stream for compression */
26 /* stream for decompression */
31 /* compressed buffer */
33 /* size of compressed buffer */
37 /* Multifd zstd compression */
40 * zstd_send_setup: setup send side
42 * Setup each channel with zstd compression.
44 * Returns 0 for success or -1 for error
46 * @p: Params for the channel that we are using
47 * @errp: pointer to an error
49 static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
51 struct zstd_data *z = g_new0(struct zstd_data, 1);
55 z->zcs = ZSTD_createCStream();
58 error_setg(errp, "multifd %u: zstd createCStream failed", p->id);
62 res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level());
63 if (ZSTD_isError(res)) {
64 ZSTD_freeCStream(z->zcs);
66 error_setg(errp, "multifd %u: initCStream failed with error %s",
67 p->id, ZSTD_getErrorName(res));
70 /* This is the maxium size of the compressed buffer */
71 z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE);
72 z->zbuff = g_try_malloc(z->zbuff_len);
74 ZSTD_freeCStream(z->zcs);
76 error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
83 * zstd_send_cleanup: cleanup send side
85 * Close the channel and return memory.
87 * @p: Params for the channel that we are using
88 * @errp: pointer to an error
90 static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
92 struct zstd_data *z = p->data;
94 ZSTD_freeCStream(z->zcs);
103 * zstd_send_prepare: prepare date to be able to send
105 * Create a compressed buffer with all the pages that we are going to
108 * Returns 0 for success or -1 for error
110 * @p: Params for the channel that we are using
111 * @errp: pointer to an error
113 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
115 struct zstd_data *z = p->data;
116 size_t page_size = qemu_target_page_size();
120 z->out.dst = z->zbuff;
121 z->out.size = z->zbuff_len;
124 for (i = 0; i < p->normal_num; i++) {
125 ZSTD_EndDirective flush = ZSTD_e_continue;
127 if (i == p->normal_num - 1) {
128 flush = ZSTD_e_flush;
130 z->in.src = p->pages->block->host + p->normal[i];
131 z->in.size = page_size;
135 * Welcome to compressStream2 semantics
137 * We need to loop while:
139 * - there is input available
140 * - there is output space free
143 ret = ZSTD_compressStream2(z->zcs, &z->out, &z->in, flush);
144 } while (ret > 0 && (z->in.size - z->in.pos > 0)
145 && (z->out.size - z->out.pos > 0));
146 if (ret > 0 && (z->in.size - z->in.pos > 0)) {
147 error_setg(errp, "multifd %u: compressStream buffer too small",
151 if (ZSTD_isError(ret)) {
152 error_setg(errp, "multifd %u: compressStream error %s",
153 p->id, ZSTD_getErrorName(ret));
157 p->iov[p->iovs_num].iov_base = z->zbuff;
158 p->iov[p->iovs_num].iov_len = z->out.pos;
160 p->next_packet_size = z->out.pos;
161 p->flags |= MULTIFD_FLAG_ZSTD;
167 * zstd_recv_setup: setup receive side
169 * Create the compressed channel and buffer.
171 * Returns 0 for success or -1 for error
173 * @p: Params for the channel that we are using
174 * @errp: pointer to an error
176 static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
178 struct zstd_data *z = g_new0(struct zstd_data, 1);
182 z->zds = ZSTD_createDStream();
185 error_setg(errp, "multifd %u: zstd createDStream failed", p->id);
189 ret = ZSTD_initDStream(z->zds);
190 if (ZSTD_isError(ret)) {
191 ZSTD_freeDStream(z->zds);
193 error_setg(errp, "multifd %u: initDStream failed with error %s",
194 p->id, ZSTD_getErrorName(ret));
198 /* To be safe, we reserve twice the size of the packet */
199 z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
200 z->zbuff = g_try_malloc(z->zbuff_len);
202 ZSTD_freeDStream(z->zds);
204 error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
211 * zstd_recv_cleanup: setup receive side
213 * For no compression this function does nothing.
215 * @p: Params for the channel that we are using
217 static void zstd_recv_cleanup(MultiFDRecvParams *p)
219 struct zstd_data *z = p->data;
221 ZSTD_freeDStream(z->zds);
230 * zstd_recv_pages: read the data from the channel into actual pages
232 * Read the compressed buffer, and uncompress it into the actual
235 * Returns 0 for success or -1 for error
237 * @p: Params for the channel that we are using
238 * @errp: pointer to an error
240 static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
242 uint32_t in_size = p->next_packet_size;
243 uint32_t out_size = 0;
244 size_t page_size = qemu_target_page_size();
245 uint32_t expected_size = p->normal_num * page_size;
246 uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
247 struct zstd_data *z = p->data;
251 if (flags != MULTIFD_FLAG_ZSTD) {
252 error_setg(errp, "multifd %u: flags received %x flags expected %x",
253 p->id, flags, MULTIFD_FLAG_ZSTD);
256 ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
262 z->in.src = z->zbuff;
263 z->in.size = in_size;
266 for (i = 0; i < p->normal_num; i++) {
267 z->out.dst = p->host + p->normal[i];
268 z->out.size = page_size;
272 * Welcome to decompressStream semantics
274 * We need to loop while:
276 * - there is input available
277 * - we haven't put out a full page
280 ret = ZSTD_decompressStream(z->zds, &z->out, &z->in);
281 } while (ret > 0 && (z->in.size - z->in.pos > 0)
282 && (z->out.pos < page_size));
283 if (ret > 0 && (z->out.pos < page_size)) {
284 error_setg(errp, "multifd %u: decompressStream buffer too small",
288 if (ZSTD_isError(ret)) {
289 error_setg(errp, "multifd %u: decompressStream returned %s",
290 p->id, ZSTD_getErrorName(ret));
293 out_size += z->out.pos;
295 if (out_size != expected_size) {
296 error_setg(errp, "multifd %u: packet size received %u size expected %u",
297 p->id, out_size, expected_size);
303 static MultiFDMethods multifd_zstd_ops = {
304 .send_setup = zstd_send_setup,
305 .send_cleanup = zstd_send_cleanup,
306 .send_prepare = zstd_send_prepare,
307 .recv_setup = zstd_recv_setup,
308 .recv_cleanup = zstd_recv_cleanup,
309 .recv_pages = zstd_recv_pages
312 static void multifd_zstd_register(void)
314 multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops);
317 migration_init(multifd_zstd_register);