[Qemu-devel] [PATCH v4 6/6] migration: Add zlib compression multifd support

[Juan Quintela]

Signed-off-by: Juan Quintela <address@hidden>
---
 hw/core/qdev-properties.c |   2 +-
 migration/ram.c           | 262 ++++++++++++++++++++++++++++++++++++++
 qapi/migration.json       |   2 +-
 tests/migration-test.c    |   6 +
 4 files changed, 270 insertions(+), 2 deletions(-)

diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index ebeeb5c88d..e40aa806e2 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -651,7 +651,7 @@ const PropertyInfo qdev_prop_fdc_drive_type = {
 const PropertyInfo qdev_prop_multifd_compress = {
     .name = "MultifdCompress",
     .description = "multifd_compress values, "
-                   "none",
+                   "none/zlib",
     .enum_table = &MultifdCompress_lookup,
     .get = get_enum,
     .set = set_enum,
diff --git a/migration/ram.c b/migration/ram.c
index 3b0002ddba..691ebd9108 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -583,6 +583,7 @@ exit:
 #define MULTIFD_VERSION 1
 
 #define MULTIFD_FLAG_SYNC (1 << 0)
+#define MULTIFD_FLAG_ZLIB (1 << 1)
 
 /* This value needs to be a multiple of qemu_target_page_size() */
 #define MULTIFD_PACKET_SIZE (512 * 1024)
@@ -625,6 +626,15 @@ typedef struct {
     RAMBlock *block;
 } MultiFDPages_t;
 
+struct zlib_data {
+    /* stream for compression */
+    z_stream zs;
+    /* compressed buffer */
+    uint8_t *zbuff;
+    /* size of compressed buffer */
+    uint32_t zbuff_len;
+};
+
 typedef struct {
     /* this fields are not changed once the thread is created */
     /* channel number */
@@ -841,8 +851,260 @@ static MultiFDMethods multifd_nocomp_ops = {
     .recv_pages = nocomp_recv_pages
 };
 
+/* 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;
+
+    p->data = z;
+    zs->zalloc = Z_NULL;
+    zs->zfree = Z_NULL;
+    zs->opaque = Z_NULL;
+    if (deflateInit(zs, migrate_compress_level()) != Z_OK) {
+        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) {
+        error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+        return -1;
+    }
+    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)
+{
+    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;
+
+        ret = deflate(zs, flush);
+        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) {
+        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)
+{
+    uint32_t in_size = p->next_packet_size;
+    uint32_t out_size = 0;
+    uint32_t expected_size = used * qemu_target_page_size();
+    struct zlib_data *z = p->data;
+    z_stream *zs = &z->zs;
+    int ret;
+    int i;
+
+    if (p->flags != MULTIFD_FLAG_ZLIB) {
+        error_setg(errp, "multifd %d: flags received %x flags expected %x",
+                   p->id, MULTIFD_FLAG_ZLIB, p->flags);
+        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;
+
+        if (i == used  - 1) {
+            flush = Z_SYNC_FLUSH;
+        }
+
+        zs->avail_out = iov->iov_len;
+        zs->next_out = iov->iov_base;
+
+        ret = inflate(zs, flush);
+        if (ret != Z_OK) {
+            error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
+                       p->id, ret);
+            return ret;
+        }
+        out_size += iov->iov_len;
+    }
+    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 MultiFDMethods *multifd_ops[MULTIFD_COMPRESS__MAX] = {
     [MULTIFD_COMPRESS_NONE] = &multifd_nocomp_ops,
+    [MULTIFD_COMPRESS_ZLIB] = &multifd_zlib_ops,
 };
 
 static int multifd_send_initial_packet(MultiFDSendParams *p, Error **errp)
diff --git a/qapi/migration.json b/qapi/migration.json
index 153527e120..085eba8f07 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -493,7 +493,7 @@
 #
 ##
 { 'enum': 'MultifdCompress',
-  'data': [ 'none' ] }
+  'data': [ 'none', 'zlib' ] }
 
 ##
 # @MigrationParameter:
diff --git a/tests/migration-test.c b/tests/migration-test.c
index e5b8125e1c..e6995ae4e7 100644
--- a/tests/migration-test.c
+++ b/tests/migration-test.c
@@ -1219,6 +1219,11 @@ static void test_multifd_tcp_none(void)
     test_multifd_tcp("none");
 }
 
+static void test_multifd_tcp_zlib(void)
+{
+    test_multifd_tcp("zlib");
+}
+
 int main(int argc, char **argv)
 {
     char template[] = "/tmp/migration-test-XXXXXX";
@@ -1275,6 +1280,7 @@ int main(int argc, char **argv)
     qtest_add_func("/migration/xbzrle/unix", test_xbzrle_unix);
     qtest_add_func("/migration/fd_proto", test_migrate_fd_proto);
     qtest_add_func("/migration/multifd/tcp/none", test_multifd_tcp_none);
+    qtest_add_func("/migration/multifd/tcp/zlib", test_multifd_tcp_zlib);
 
     ret = g_test_run();
 
-- 
2.21.0