326 lines
8.5 KiB
C
326 lines
8.5 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 <zlib.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 zlib_data {
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/* stream for compression */
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z_stream zs;
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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 zlib compression */
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/**
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* zlib_send_setup: setup send side
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*
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* Setup each channel with zlib 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 zlib_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 zlib_data *z = g_malloc0(sizeof(struct zlib_data));
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z_stream *zs = &z->zs;
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zs->zalloc = Z_NULL;
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zs->zfree = Z_NULL;
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zs->opaque = Z_NULL;
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if (deflateInit(zs, migrate_multifd_zlib_level()) != Z_OK) {
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g_free(z);
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error_setg(errp, "multifd %d: deflate init failed", p->id);
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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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deflateEnd(&z->zs);
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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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p->data = z;
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return 0;
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}
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/**
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* zlib_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 zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
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{
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struct zlib_data *z = p->data;
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deflateEnd(&z->zs);
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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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* zlib_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 zlib_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 zlib_data *z = p->data;
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z_stream *zs = &z->zs;
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uint32_t out_size = 0;
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int ret;
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uint32_t i;
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for (i = 0; i < used; i++) {
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uint32_t available = z->zbuff_len - out_size;
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int flush = Z_NO_FLUSH;
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if (i == used - 1) {
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flush = Z_SYNC_FLUSH;
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}
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zs->avail_in = iov[i].iov_len;
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zs->next_in = iov[i].iov_base;
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zs->avail_out = available;
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zs->next_out = z->zbuff + out_size;
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/*
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* Welcome to deflate semantics
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*
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* We need to loop while:
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* - return is Z_OK
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* - there are stuff to be compressed
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* - there are output space free
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*/
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do {
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ret = deflate(zs, flush);
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} while (ret == Z_OK && zs->avail_in && zs->avail_out);
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if (ret == Z_OK && zs->avail_in) {
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error_setg(errp, "multifd %d: deflate failed to compress all input",
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p->id);
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return -1;
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}
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if (ret != Z_OK) {
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error_setg(errp, "multifd %d: deflate returned %d instead of Z_OK",
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p->id, ret);
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return -1;
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}
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out_size += available - zs->avail_out;
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}
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p->next_packet_size = out_size;
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p->flags |= MULTIFD_FLAG_ZLIB;
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return 0;
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}
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/**
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* zlib_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 zlib_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
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{
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struct zlib_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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* zlib_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 zlib_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 zlib_data *z = g_malloc0(sizeof(struct zlib_data));
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z_stream *zs = &z->zs;
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p->data = z;
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zs->zalloc = Z_NULL;
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zs->zfree = Z_NULL;
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zs->opaque = Z_NULL;
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zs->avail_in = 0;
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zs->next_in = Z_NULL;
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if (inflateInit(zs) != Z_OK) {
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error_setg(errp, "multifd %d: inflate init failed", p->id);
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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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inflateEnd(zs);
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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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* zlib_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 zlib_recv_cleanup(MultiFDRecvParams *p)
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{
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struct zlib_data *z = p->data;
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inflateEnd(&z->zs);
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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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* zlib_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 zlib_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp)
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{
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struct zlib_data *z = p->data;
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z_stream *zs = &z->zs;
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uint32_t in_size = p->next_packet_size;
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/* we measure the change of total_out */
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uint32_t out_size = zs->total_out;
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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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int ret;
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int i;
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if (flags != MULTIFD_FLAG_ZLIB) {
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error_setg(errp, "multifd %d: flags received %x flags expected %x",
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p->id, flags, MULTIFD_FLAG_ZLIB);
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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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zs->avail_in = in_size;
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zs->next_in = z->zbuff;
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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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int flush = Z_NO_FLUSH;
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unsigned long start = zs->total_out;
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if (i == used - 1) {
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flush = Z_SYNC_FLUSH;
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}
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zs->avail_out = iov->iov_len;
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zs->next_out = iov->iov_base;
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/*
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* Welcome to inflate semantics
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*
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* We need to loop while:
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* - return is Z_OK
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* - there are input available
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* - we haven't completed a full page
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*/
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do {
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ret = inflate(zs, flush);
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} while (ret == Z_OK && zs->avail_in
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&& (zs->total_out - start) < iov->iov_len);
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if (ret == Z_OK && (zs->total_out - start) < iov->iov_len) {
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error_setg(errp, "multifd %d: inflate generated too few output",
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p->id);
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return -1;
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}
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if (ret != Z_OK) {
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error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
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p->id, ret);
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return -1;
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}
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}
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out_size = zs->total_out - out_size;
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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_zlib_ops = {
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.send_setup = zlib_send_setup,
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.send_cleanup = zlib_send_cleanup,
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.send_prepare = zlib_send_prepare,
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.send_write = zlib_send_write,
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.recv_setup = zlib_recv_setup,
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.recv_cleanup = zlib_recv_cleanup,
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.recv_pages = zlib_recv_pages
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};
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static void multifd_zlib_register(void)
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{
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multifd_register_ops(MULTIFD_COMPRESSION_ZLIB, &multifd_zlib_ops);
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}
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migration_init(multifd_zlib_register);
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