migration: Add the framework of multi-thread decompression

Add the code to create and destroy the multiple threads those will be
used to do data decompression. Left some functions empty just 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, 19 insertions, 0 deletions

diff --git a/migration/migration.c b/migration/migration.c
index 5a8b5a7c74..19409e6790 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -35,6 +35,9 @@
 
 /* Default compression thread count */
 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
+/* Default decompression thread count, usually decompression is at
+ * least 4 times as fast as compression.*/
+#define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */
 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
 
@@ -58,6 +61,7 @@ MigrationState *migrate_get_current(void)
         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
         .mbps = -1,
         .compress_thread_count = DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
+        .decompress_thread_count = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
         .compress_level = DEFAULT_MIGRATE_COMPRESS_LEVEL,
     };
 
@@ -113,6 +117,7 @@ static void process_incoming_migration_co(void *opaque)
     free_xbzrle_decoded_buf();
     if (ret < 0) {
         error_report("load of migration failed: %s", strerror(-ret));
+        migrate_decompress_threads_join();
         exit(EXIT_FAILURE);
     }
     qemu_announce_self();
@@ -121,6 +126,7 @@ static void process_incoming_migration_co(void *opaque)
     bdrv_invalidate_cache_all(&local_err);
     if (local_err) {
         error_report_err(local_err);
+        migrate_decompress_threads_join();
         exit(EXIT_FAILURE);
     }
 
@@ -129,6 +135,7 @@ static void process_incoming_migration_co(void *opaque)
     } else {
         runstate_set(RUN_STATE_PAUSED);
     }
+    migrate_decompress_threads_join();
 }
 
 void process_incoming_migration(QEMUFile *f)
@@ -137,6 +144,7 @@ void process_incoming_migration(QEMUFile *f)
     int fd = qemu_get_fd(f);
 
     assert(fd != -1);
+    migrate_decompress_threads_create();
     qemu_set_nonblock(fd);
     qemu_coroutine_enter(co, f);
 }
@@ -400,6 +408,7 @@ static MigrationState *migrate_init(const MigrationParams *params)
     int64_t xbzrle_cache_size = s->xbzrle_cache_size;
     int compress_level = s->compress_level;
     int compress_thread_count = s->compress_thread_count;
+    int decompress_thread_count = s->decompress_thread_count;
 
     memcpy(enabled_capabilities, s->enabled_capabilities,
            sizeof(enabled_capabilities));
@@ -412,6 +421,7 @@ static MigrationState *migrate_init(const MigrationParams *params)
 
     s->compress_level = compress_level;
     s->compress_thread_count = compress_thread_count;
+    s->decompress_thread_count = decompress_thread_count;
     s->bandwidth_limit = bandwidth_limit;
     s->state = MIGRATION_STATUS_SETUP;
     trace_migrate_set_state(MIGRATION_STATUS_SETUP);
@@ -623,6 +633,15 @@ int migrate_compress_threads(void)
     return s->compress_thread_count;
 }
 
+int migrate_decompress_threads(void)
+{
+    MigrationState *s;
+
+    s = migrate_get_current();
+
+    return s->decompress_thread_count;
+}
+
 int migrate_use_xbzrle(void)
 {
     MigrationState *s;