migration: Add the framework of multi-thread compression

Add the code to create and destroy the multiple threads those will
be used to do data compression. Left some functions empty to keep
clearness, and the code will be added later.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Reviewed-by: Dr.David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 92 insertions, 2 deletions

diff --git a/arch_init.c b/arch_init.c
index 4c8fceed95..179c58c852 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -316,6 +316,69 @@ static uint64_t migration_dirty_pages;
 static uint32_t last_version;
 static bool ram_bulk_stage;
 
+struct CompressParam {
+    /* To be done */
+};
+typedef struct CompressParam CompressParam;
+
+static CompressParam *comp_param;
+static QemuThread *compress_threads;
+static bool quit_comp_thread;
+
+static void *do_data_compress(void *opaque)
+{
+    while (!quit_comp_thread) {
+
+    /* To be done */
+
+    }
+
+    return NULL;
+}
+
+static inline void terminate_compression_threads(void)
+{
+    quit_comp_thread = true;
+
+    /* To be done */
+}
+
+void migrate_compress_threads_join(void)
+{
+    int i, thread_count;
+
+    if (!migrate_use_compression()) {
+        return;
+    }
+    terminate_compression_threads();
+    thread_count = migrate_compress_threads();
+    for (i = 0; i < thread_count; i++) {
+        qemu_thread_join(compress_threads + i);
+    }
+    g_free(compress_threads);
+    g_free(comp_param);
+    compress_threads = NULL;
+    comp_param = NULL;
+}
+
+void migrate_compress_threads_create(void)
+{
+    int i, thread_count;
+
+    if (!migrate_use_compression()) {
+        return;
+    }
+    quit_comp_thread = false;
+    thread_count = migrate_compress_threads();
+    compress_threads = g_new0(QemuThread, thread_count);
+    comp_param = g_new0(CompressParam, thread_count);
+    for (i = 0; i < thread_count; i++) {
+        qemu_thread_create(compress_threads + i, "compress",
+                           do_data_compress, comp_param + i,
+                           QEMU_THREAD_JOINABLE);
+    }
+}
+
 /**
  * save_page_header: Write page header to wire
  *
@@ -693,6 +756,28 @@ static int ram_save_page(QEMUFile *f, RAMBlock* block, ram_addr_t offset,
 }
 
 /**
+ * ram_save_compressed_page: compress the given page and send it to the stream
+ *
+ * Returns: Number of pages written.
+ *
+ * @f: QEMUFile where to send the data
+ * @block: block that contains the page we want to send
+ * @offset: offset inside the block for the page
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ */
+static int ram_save_compressed_page(QEMUFile *f, RAMBlock *block,
+                                    ram_addr_t offset, bool last_stage,
+                                    uint64_t *bytes_transferred)
+{
+    int pages = -1;
+
+    /* To be done*/
+
+    return pages;
+}
+
+/**
  * ram_find_and_save_block: Finds a dirty page and sends it to f
  *
  * Called within an RCU critical section.
@@ -733,8 +818,13 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
                 ram_bulk_stage = false;
             }
         } else {
-            pages = ram_save_page(f, block, offset, last_stage,
-                                  bytes_transferred);
+            if (migrate_use_compression()) {
+                pages = ram_save_compressed_page(f, block, offset, last_stage,
+                                                 bytes_transferred);
+            } else {
+                pages = ram_save_page(f, block, offset, last_stage,
+                                      bytes_transferred);
+            }
 
             /* if page is unmodified, continue to the next */
             if (pages > 0) {