[Qemu-devel] [v3 03/13] migration: Add the framework of muti-thread decompression

[Liang Li]

Signed-off-by: Liang Li <address@hidden>
Signed-off-by: Yang Zhang <address@hidden>
---
 arch_init.c                   | 70 +++++++++++++++++++++++++++++++++++++++++++
 include/migration/migration.h |  4 +++
 migration.c                   | 15 ++++++++++
 3 files changed, 89 insertions(+)

diff --git a/arch_init.c b/arch_init.c
index a988ec2..2f1d0c4 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -126,6 +126,7 @@ static uint64_t bitmap_sync_count;
 #define RAM_SAVE_FLAG_CONTINUE 0x20
 #define RAM_SAVE_FLAG_XBZRLE   0x40
 /* 0x80 is reserved in migration.h start with 0x100 next */
+#define RAM_SAVE_FLAG_COMPRESS_PAGE    0x100
 
 static struct defconfig_file {
     const char *filename;
@@ -332,13 +333,26 @@ static uint64_t migration_dirty_pages;
 static uint32_t last_version;
 static bool ram_bulk_stage;
 
+/* using compressBound() to calculate the buffer size needed to save the
+ * compressed data, to support the maximun TARGET_PAGE_SIZE bytes of
+ * data, we need more 15 bytes, use 16 to align the data.
+ */
+#define COMPRESS_BUF_SIZE (TARGET_PAGE_SIZE + 16)
+
 struct compress_param {
     /* To be done */
 };
 typedef struct compress_param compress_param;
 
+struct decompress_param {
+    /* To be done */
+};
+typedef struct decompress_param decompress_param;
+
 static compress_param *comp_param;
 static bool quit_thread;
+static decompress_param *decomp_param;
+static QemuThread *decompress_threads;
 
 static void *do_data_compress(void *opaque)
 {
@@ -1124,10 +1138,54 @@ void ram_handle_compressed(void *host, uint8_t ch, 
uint64_t size)
     }
 }
 
+static void *do_data_decompress(void *opaque)
+{
+    while (!quit_thread) {
+        /* To be done */
+    }
+    return NULL;
+}
+
+void migrate_decompress_threads_create(int count)
+{
+    int i;
+
+    decompress_threads = g_malloc0(sizeof(QemuThread) * count);
+    decomp_param = g_malloc0(sizeof(decompress_param) * count);
+    quit_thread = false;
+    for (i = 0; i < count; i++) {
+        qemu_thread_create(decompress_threads + i, "decompress",
+            do_data_decompress, decomp_param + i, QEMU_THREAD_JOINABLE);
+    }
+}
+
+void migrate_decompress_threads_join(void)
+{
+    int i, thread_count;
+
+    quit_thread = true;
+    thread_count = migrate_decompress_threads();
+    for (i = 0; i < thread_count; i++) {
+        qemu_thread_join(decompress_threads + i);
+    }
+    g_free(decompress_threads);
+    g_free(decomp_param);
+    decompress_threads = NULL;
+    decomp_param = NULL;
+}
+
+static void decompress_data_with_multi_threads(uint8_t *compbuf,
+        void *host, int len)
+{
+    /* To be done */
+}
+
 static int ram_load(QEMUFile *f, void *opaque, int version_id)
 {
     int flags = 0, ret = 0;
     static uint64_t seq_iter;
+    int len = 0;
+    uint8_t compbuf[COMPRESS_BUF_SIZE];
 
     seq_iter++;
 
@@ -1201,6 +1259,18 @@ static int ram_load(QEMUFile *f, void *opaque, int 
version_id)
 
             qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
             break;
+        case RAM_SAVE_FLAG_COMPRESS_PAGE:
+            host = host_from_stream_offset(f, addr, flags);
+            if (!host) {
+                error_report("Illegal RAM offset " RAM_ADDR_FMT, addr);
+                ret = -EINVAL;
+                break;
+            }
+
+            len = qemu_get_be32(f);
+            qemu_get_buffer(f, compbuf, len);
+            decompress_data_with_multi_threads(compbuf, host, len);
+            break;
         case RAM_SAVE_FLAG_XBZRLE:
             host = host_from_stream_offset(f, addr, flags);
             if (!host) {
diff --git a/include/migration/migration.h b/include/migration/migration.h
index daf6c81..0c4f21c 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -51,6 +51,7 @@ struct MigrationState
     QEMUFile *file;
     QemuThread *compress_thread;
     int compress_thread_count;
+    int decompress_thread_count;
     int compress_level;
 
     int state;
@@ -112,6 +113,8 @@ MigrationState *migrate_get_current(void);
 
 void migrate_compress_threads_create(MigrationState *s);
 void migrate_compress_threads_join(MigrationState *s);
+void migrate_decompress_threads_create(int count);
+void migrate_decompress_threads_join(void);
 uint64_t ram_bytes_remaining(void);
 uint64_t ram_bytes_transferred(void);
 uint64_t ram_bytes_total(void);
@@ -164,6 +167,7 @@ int64_t xbzrle_cache_resize(int64_t new_size);
 bool migrate_use_compression(void);
 int migrate_compress_level(void);
 int migrate_compress_threads(void);
+int migrate_decompress_threads(void);
 
 void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
 void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
diff --git a/migration.c b/migration.c
index 402daae..082ddb7 100644
--- a/migration.c
+++ b/migration.c
@@ -45,6 +45,7 @@ enum {
 
 /* Default compression thread count */
 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
+#define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */
 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
 
@@ -66,6 +67,7 @@ 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,
     };
 
@@ -123,10 +125,13 @@ static void process_incoming_migration_co(void *opaque)
     } else {
         runstate_set(RUN_STATE_PAUSED);
     }
+    migrate_decompress_threads_join();
 }
 
 void process_incoming_migration(QEMUFile *f)
 {
+    int thread_count = migrate_decompress_threads();
+    migrate_decompress_threads_create(thread_count);
     Coroutine *co = qemu_coroutine_create(process_incoming_migration_co);
     int fd = qemu_get_fd(f);
 
@@ -383,6 +388,7 @@ 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));
@@ -395,6 +401,7 @@ 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 = MIG_STATE_SETUP;
     trace_migrate_set_state(MIG_STATE_SETUP);
@@ -591,6 +598,14 @@ 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)
 {
-- 
1.8.3.1