diff options
Diffstat (limited to 'migration/multifd-zstd.c')
| -rw-r--r-- | migration/multifd-zstd.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c new file mode 100644 index 0000000000..693bddf8c9 --- /dev/null +++ b/migration/multifd-zstd.c @@ -0,0 +1,339 @@ +/* + * Multifd zlib compression implementation + * + * Copyright (c) 2020 Red Hat Inc + * + * Authors: + * Juan Quintela <quintela@redhat.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include <zstd.h> +#include "qemu/rcu.h" +#include "exec/target_page.h" +#include "qapi/error.h" +#include "migration.h" +#include "trace.h" +#include "multifd.h" + +struct zstd_data { + /* stream for compression */ + ZSTD_CStream *zcs; + /* stream for decompression */ + ZSTD_DStream *zds; + /* buffers */ + ZSTD_inBuffer in; + ZSTD_outBuffer out; + /* compressed buffer */ + uint8_t *zbuff; + /* size of compressed buffer */ + uint32_t zbuff_len; +}; + +/* Multifd zstd compression */ + +/** + * zstd_send_setup: setup send side + * + * Setup each channel with zstd compression. + * + * Returns 0 for success or -1 for error + * + * @p: Params for the channel that we are using + * @errp: pointer to an error + */ +static int zstd_send_setup(MultiFDSendParams *p, Error **errp) +{ + uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size(); + struct zstd_data *z = g_new0(struct zstd_data, 1); + int res; + + p->data = z; + z->zcs = ZSTD_createCStream(); + if (!z->zcs) { + g_free(z); + error_setg(errp, "multifd %d: zstd createCStream failed", p->id); + return -1; + } + + res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level()); + if (ZSTD_isError(res)) { + ZSTD_freeCStream(z->zcs); + g_free(z); + error_setg(errp, "multifd %d: initCStream failed with error %s", + p->id, ZSTD_getErrorName(res)); + return -1; + } + /* We will never have more than page_count pages */ + z->zbuff_len = page_count * qemu_target_page_size(); + z->zbuff_len *= 2; + z->zbuff = g_try_malloc(z->zbuff_len); + if (!z->zbuff) { + ZSTD_freeCStream(z->zcs); + g_free(z); + error_setg(errp, "multifd %d: out of memory for zbuff", p->id); + return -1; + } + return 0; +} + +/** + * zstd_send_cleanup: cleanup send side + * + * Close the channel and return memory. + * + * @p: Params for the channel that we are using + */ +static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp) +{ + struct zstd_data *z = p->data; + + ZSTD_freeCStream(z->zcs); + z->zcs = NULL; + g_free(z->zbuff); + z->zbuff = NULL; + g_free(p->data); + p->data = NULL; +} + +/** + * zstd_send_prepare: prepare date to be able to send + * + * Create a compressed buffer with all the pages that we are going to + * send. + * + * Returns 0 for success or -1 for error + * + * @p: Params for the channel that we are using + * @used: number of pages used + */ +static int zstd_send_prepare(MultiFDSendParams *p, uint32_t used, Error **errp) +{ + struct iovec *iov = p->pages->iov; + struct zstd_data *z = p->data; + int ret; + uint32_t i; + + z->out.dst = z->zbuff; + z->out.size = z->zbuff_len; + z->out.pos = 0; + + for (i = 0; i < used; i++) { + ZSTD_EndDirective flush = ZSTD_e_continue; + + if (i == used - 1) { + flush = ZSTD_e_flush; + } + z->in.src = iov[i].iov_base; + z->in.size = iov[i].iov_len; + z->in.pos = 0; + + /* + * Welcome to compressStream2 semantics + * + * We need to loop while: + * - return is > 0 + * - there is input available + * - there is output space free + */ + do { + ret = ZSTD_compressStream2(z->zcs, &z->out, &z->in, flush); + } while (ret > 0 && (z->in.size - z->in.pos > 0) + && (z->out.size - z->out.pos > 0)); + if (ret > 0 && (z->in.size - z->in.pos > 0)) { + error_setg(errp, "multifd %d: compressStream buffer too small", + p->id); + return -1; + } + if (ZSTD_isError(ret)) { + error_setg(errp, "multifd %d: compressStream error %s", + p->id, ZSTD_getErrorName(ret)); + return -1; + } + } + p->next_packet_size = z->out.pos; + p->flags |= MULTIFD_FLAG_ZSTD; + + return 0; +} + +/** + * zstd_send_write: do the actual write of the data + * + * Do the actual write of the comprresed buffer. + * + * Returns 0 for success or -1 for error + * + * @p: Params for the channel that we are using + * @used: number of pages used + * @errp: pointer to an error + */ +static int zstd_send_write(MultiFDSendParams *p, uint32_t used, Error **errp) +{ + struct zstd_data *z = p->data; + + return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size, + errp); +} + +/** + * zstd_recv_setup: setup receive side + * + * Create the compressed channel and buffer. + * + * Returns 0 for success or -1 for error + * + * @p: Params for the channel that we are using + * @errp: pointer to an error + */ +static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp) +{ + uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size(); + struct zstd_data *z = g_new0(struct zstd_data, 1); + int ret; + + p->data = z; + z->zds = ZSTD_createDStream(); + if (!z->zds) { + g_free(z); + error_setg(errp, "multifd %d: zstd createDStream failed", p->id); + return -1; + } + + ret = ZSTD_initDStream(z->zds); + if (ZSTD_isError(ret)) { + ZSTD_freeDStream(z->zds); + g_free(z); + error_setg(errp, "multifd %d: initDStream failed with error %s", + p->id, ZSTD_getErrorName(ret)); + return -1; + } + + /* We will never have more than page_count pages */ + z->zbuff_len = page_count * qemu_target_page_size(); + /* We know compression "could" use more space */ + z->zbuff_len *= 2; + z->zbuff = g_try_malloc(z->zbuff_len); + if (!z->zbuff) { + ZSTD_freeDStream(z->zds); + g_free(z); + error_setg(errp, "multifd %d: out of memory for zbuff", p->id); + return -1; + } + return 0; +} + +/** + * zstd_recv_cleanup: setup receive side + * + * For no compression this function does nothing. + * + * @p: Params for the channel that we are using + */ +static void zstd_recv_cleanup(MultiFDRecvParams *p) +{ + struct zstd_data *z = p->data; + + ZSTD_freeDStream(z->zds); + z->zds = NULL; + g_free(z->zbuff); + z->zbuff = NULL; + g_free(p->data); + p->data = NULL; +} + +/** + * zstd_recv_pages: read the data from the channel into actual pages + * + * Read the compressed buffer, and uncompress it into the actual + * pages. + * + * Returns 0 for success or -1 for error + * + * @p: Params for the channel that we are using + * @used: number of pages used + * @errp: pointer to an error + */ +static int zstd_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp) +{ + uint32_t in_size = p->next_packet_size; + uint32_t out_size = 0; + uint32_t expected_size = used * qemu_target_page_size(); + uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK; + struct zstd_data *z = p->data; + int ret; + int i; + + if (flags != MULTIFD_FLAG_ZSTD) { + error_setg(errp, "multifd %d: flags received %x flags expected %x", + p->id, flags, MULTIFD_FLAG_ZSTD); + return -1; + } + ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp); + + if (ret != 0) { + return ret; + } + + z->in.src = z->zbuff; + z->in.size = in_size; + z->in.pos = 0; + + for (i = 0; i < used; i++) { + struct iovec *iov = &p->pages->iov[i]; + + z->out.dst = iov->iov_base; + z->out.size = iov->iov_len; + z->out.pos = 0; + + /* + * Welcome to decompressStream semantics + * + * We need to loop while: + * - return is > 0 + * - there is input available + * - we haven't put out a full page + */ + do { + ret = ZSTD_decompressStream(z->zds, &z->out, &z->in); + } while (ret > 0 && (z->in.size - z->in.pos > 0) + && (z->out.pos < iov->iov_len)); + if (ret > 0 && (z->out.pos < iov->iov_len)) { + error_setg(errp, "multifd %d: decompressStream buffer too small", + p->id); + return -1; + } + if (ZSTD_isError(ret)) { + error_setg(errp, "multifd %d: decompressStream returned %s", + p->id, ZSTD_getErrorName(ret)); + return ret; + } + out_size += z->out.pos; + } + if (out_size != expected_size) { + error_setg(errp, "multifd %d: packet size received %d size expected %d", + p->id, out_size, expected_size); + return -1; + } + return 0; +} + +static MultiFDMethods multifd_zstd_ops = { + .send_setup = zstd_send_setup, + .send_cleanup = zstd_send_cleanup, + .send_prepare = zstd_send_prepare, + .send_write = zstd_send_write, + .recv_setup = zstd_recv_setup, + .recv_cleanup = zstd_recv_cleanup, + .recv_pages = zstd_recv_pages +}; + +static void multifd_zstd_register(void) +{ + multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops); +} + +migration_init(multifd_zstd_register); |