multifd: Add zlib compression multifd support

Signed-off-by: Juan Quintela <quintela@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 325 insertions, 0 deletions

diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
new file mode 100644
index 0000000000..ab4ba75d75
--- /dev/null
+++ b/migration/multifd-zlib.c
@@ -0,0 +1,325 @@
+/*
+ * 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 <zlib.h>
+#include "qemu/rcu.h"
+#include "exec/target_page.h"
+#include "qapi/error.h"
+#include "migration.h"
+#include "trace.h"
+#include "multifd.h"
+
+struct zlib_data {
+    /* stream for compression */
+    z_stream zs;
+    /* compressed buffer */
+    uint8_t *zbuff;
+    /* size of compressed buffer */
+    uint32_t zbuff_len;
+};
+
+/* Multifd zlib compression */
+
+/**
+ * zlib_send_setup: setup send side
+ *
+ * Setup each channel with zlib 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 zlib_send_setup(MultiFDSendParams *p, Error **errp)
+{
+    uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
+    struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
+    z_stream *zs = &z->zs;
+
+    zs->zalloc = Z_NULL;
+    zs->zfree = Z_NULL;
+    zs->opaque = Z_NULL;
+    if (deflateInit(zs, migrate_multifd_zlib_level()) != Z_OK) {
+        g_free(z);
+        error_setg(errp, "multifd %d: deflate init failed", p->id);
+        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) {
+        deflateEnd(&z->zs);
+        g_free(z);
+        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        return -1;
+    }
+    p->data = z;
+    return 0;
+}
+
+/**
+ * zlib_send_cleanup: cleanup send side
+ *
+ * Close the channel and return memory.
+ *
+ * @p: Params for the channel that we are using
+ */
+static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
+{
+    struct zlib_data *z = p->data;
+
+    deflateEnd(&z->zs);
+    g_free(z->zbuff);
+    z->zbuff = NULL;
+    g_free(p->data);
+    p->data = NULL;
+}
+
+/**
+ * zlib_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 zlib_send_prepare(MultiFDSendParams *p, uint32_t used, Error **errp)
+{
+    struct iovec *iov = p->pages->iov;
+    struct zlib_data *z = p->data;
+    z_stream *zs = &z->zs;
+    uint32_t out_size = 0;
+    int ret;
+    uint32_t i;
+
+    for (i = 0; i < used; i++) {
+        uint32_t available = z->zbuff_len - out_size;
+        int flush = Z_NO_FLUSH;
+
+        if (i == used - 1) {
+            flush = Z_SYNC_FLUSH;
+        }
+
+        zs->avail_in = iov[i].iov_len;
+        zs->next_in = iov[i].iov_base;
+
+        zs->avail_out = available;
+        zs->next_out = z->zbuff + out_size;
+
+        /*
+         * Welcome to deflate semantics
+         *
+         * We need to loop while:
+         * - return is Z_OK
+         * - there are stuff to be compressed
+         * - there are output space free
+         */
+        do {
+            ret = deflate(zs, flush);
+        } while (ret == Z_OK && zs->avail_in && zs->avail_out);
+        if (ret == Z_OK && zs->avail_in) {
+            error_setg(errp, "multifd %d: deflate failed to compress all input",
+                       p->id);
+            return -1;
+        }
+        if (ret != Z_OK) {
+            error_setg(errp, "multifd %d: deflate returned %d instead of Z_OK",
+                       p->id, ret);
+            return -1;
+        }
+        out_size += available - zs->avail_out;
+    }
+    p->next_packet_size = out_size;
+    p->flags |= MULTIFD_FLAG_ZLIB;
+
+    return 0;
+}
+
+/**
+ * zlib_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 zlib_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
+{
+    struct zlib_data *z = p->data;
+
+    return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size,
+                                 errp);
+}
+
+/**
+ * zlib_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 zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
+{
+    uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
+    struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
+    z_stream *zs = &z->zs;
+
+    p->data = z;
+    zs->zalloc = Z_NULL;
+    zs->zfree = Z_NULL;
+    zs->opaque = Z_NULL;
+    zs->avail_in = 0;
+    zs->next_in = Z_NULL;
+    if (inflateInit(zs) != Z_OK) {
+        error_setg(errp, "multifd %d: inflate init failed", p->id);
+        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) {
+        inflateEnd(zs);
+        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        return -1;
+    }
+    return 0;
+}
+
+/**
+ * zlib_recv_cleanup: setup receive side
+ *
+ * For no compression this function does nothing.
+ *
+ * @p: Params for the channel that we are using
+ */
+static void zlib_recv_cleanup(MultiFDRecvParams *p)
+{
+    struct zlib_data *z = p->data;
+
+    inflateEnd(&z->zs);
+    g_free(z->zbuff);
+    z->zbuff = NULL;
+    g_free(p->data);
+    p->data = NULL;
+}
+
+/**
+ * zlib_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 zlib_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp)
+{
+    struct zlib_data *z = p->data;
+    z_stream *zs = &z->zs;
+    uint32_t in_size = p->next_packet_size;
+    /* we measure the change of total_out */
+    uint32_t out_size = zs->total_out;
+    uint32_t expected_size = used * qemu_target_page_size();
+    uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
+    int ret;
+    int i;
+
+    if (flags != MULTIFD_FLAG_ZLIB) {
+        error_setg(errp, "multifd %d: flags received %x flags expected %x",
+                   p->id, flags, MULTIFD_FLAG_ZLIB);
+        return -1;
+    }
+    ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
+
+    if (ret != 0) {
+        return ret;
+    }
+
+    zs->avail_in = in_size;
+    zs->next_in = z->zbuff;
+
+    for (i = 0; i < used; i++) {
+        struct iovec *iov = &p->pages->iov[i];
+        int flush = Z_NO_FLUSH;
+        unsigned long start = zs->total_out;
+
+        if (i == used - 1) {
+            flush = Z_SYNC_FLUSH;
+        }
+
+        zs->avail_out = iov->iov_len;
+        zs->next_out = iov->iov_base;
+
+        /*
+         * Welcome to inflate semantics
+         *
+         * We need to loop while:
+         * - return is Z_OK
+         * - there are input available
+         * - we haven't completed a full page
+         */
+        do {
+            ret = inflate(zs, flush);
+        } while (ret == Z_OK && zs->avail_in
+                             && (zs->total_out - start) < iov->iov_len);
+        if (ret == Z_OK && (zs->total_out - start) < iov->iov_len) {
+            error_setg(errp, "multifd %d: inflate generated too few output",
+                       p->id);
+            return -1;
+        }
+        if (ret != Z_OK) {
+            error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
+                       p->id, ret);
+            return -1;
+        }
+    }
+    out_size = zs->total_out - out_size;
+    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_zlib_ops = {
+    .send_setup = zlib_send_setup,
+    .send_cleanup = zlib_send_cleanup,
+    .send_prepare = zlib_send_prepare,
+    .send_write = zlib_send_write,
+    .recv_setup = zlib_recv_setup,
+    .recv_cleanup = zlib_recv_cleanup,
+    .recv_pages = zlib_recv_pages
+};
+
+static void multifd_zlib_register(void)
+{
+    multifd_register_ops(MULTIFD_COMPRESSION_ZLIB, &multifd_zlib_ops);
+}
+
+migration_init(multifd_zlib_register);