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