[Qemu-devel] [PATCH 5/5] ram: Make RAMState dynamic

[Juan Quintela]

We create the variable while we are at migration and we remove it
after migration.

Signed-off-by: Juan Quintela <address@hidden>
---
 migration/ram.c | 52 ++++++++++++++++++++++++++++++++--------------------
 1 file changed, 32 insertions(+), 20 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 6c48219..1164f14 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -199,7 +199,7 @@ struct RAMState {
 };
 typedef struct RAMState RAMState;
 
-static RAMState ram_state;
+static RAMState *ram_state;
 
 MigrationStats ram_counters;
 
@@ -783,7 +783,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus 
*pss, bool last_stage)
 static int do_compress_ram_page(QEMUFile *f, RAMBlock *block,
                                 ram_addr_t offset)
 {
-    RAMState *rs = &ram_state;
+    RAMState *rs = ram_state;
     int bytes_sent, blen;
     uint8_t *p = block->host + (offset & TARGET_PAGE_MASK);
 
@@ -1130,7 +1130,7 @@ static void migration_page_queue_free(RAMState *rs)
 int ram_save_queue_pages(const char *rbname, ram_addr_t start, ram_addr_t len)
 {
     RAMBlock *ramblock;
-    RAMState *rs = &ram_state;
+    RAMState *rs = ram_state;
 
     ram_counters.postcopy_requests++;
     rcu_read_lock();
@@ -1351,7 +1351,7 @@ void free_xbzrle_decoded_buf(void)
 
 static void ram_migration_cleanup(void *opaque)
 {
-    RAMState *rs = opaque;
+    RAMState **rsp = opaque;
     RAMBlock *block;
 
     /* caller have hold iothread lock or is in a bh, so there is
@@ -1378,7 +1378,9 @@ static void ram_migration_cleanup(void *opaque)
         XBZRLE.zero_target_page = NULL;
     }
     XBZRLE_cache_unlock();
-    migration_page_queue_free(rs);
+    migration_page_queue_free(*rsp);
+    g_free(*rsp);
+    *rsp = NULL;
 }
 
 static void ram_state_reset(RAMState *rs)
@@ -1703,7 +1705,7 @@ static int postcopy_chunk_hostpages(MigrationState *ms, 
RAMBlock *block)
  */
 int ram_postcopy_send_discard_bitmap(MigrationState *ms)
 {
-    RAMState *rs = &ram_state;
+    RAMState *rs = ram_state;
     RAMBlock *block;
     int ret;
 
@@ -1786,12 +1788,13 @@ err:
     return ret;
 }
 
-static int ram_state_init(RAMState *rs)
+static int ram_state_init(RAMState **rsp)
 {
-    memset(rs, 0, sizeof(*rs));
-    qemu_mutex_init(&rs->bitmap_mutex);
-    qemu_mutex_init(&rs->src_page_req_mutex);
-    QSIMPLEQ_INIT(&rs->src_page_requests);
+    *rsp = g_new0(RAMState, 1);
+
+    qemu_mutex_init(&(*rsp)->bitmap_mutex);
+    qemu_mutex_init(&(*rsp)->src_page_req_mutex);
+    QSIMPLEQ_INIT(&(*rsp)->src_page_requests);
 
     if (migrate_use_xbzrle()) {
         XBZRLE_cache_lock();
@@ -1802,6 +1805,8 @@ static int ram_state_init(RAMState *rs)
         if (!XBZRLE.cache) {
             XBZRLE_cache_unlock();
             error_report("Error creating cache");
+            g_free(*rsp);
+            *rsp = NULL;
             return -1;
         }
         XBZRLE_cache_unlock();
@@ -1810,6 +1815,8 @@ static int ram_state_init(RAMState *rs)
         XBZRLE.encoded_buf = g_try_malloc0(TARGET_PAGE_SIZE);
         if (!XBZRLE.encoded_buf) {
             error_report("Error allocating encoded_buf");
+            g_free(*rsp);
+            *rsp = NULL;
             return -1;
         }
 
@@ -1818,6 +1825,8 @@ static int ram_state_init(RAMState *rs)
             error_report("Error allocating current_buf");
             g_free(XBZRLE.encoded_buf);
             XBZRLE.encoded_buf = NULL;
+            g_free(*rsp);
+            *rsp = NULL;
             return -1;
         }
     }
@@ -1827,7 +1836,7 @@ static int ram_state_init(RAMState *rs)
 
     qemu_mutex_lock_ramlist();
     rcu_read_lock();
-    ram_state_reset(rs);
+    ram_state_reset(*rsp);
 
     /* Skip setting bitmap if there is no RAM */
     if (ram_bytes_total()) {
@@ -1852,7 +1861,7 @@ static int ram_state_init(RAMState *rs)
     ram_counters.remaining_pages = ram_bytes_total() >> TARGET_PAGE_BITS;
 
     memory_global_dirty_log_start();
-    migration_bitmap_sync(rs);
+    migration_bitmap_sync(*rsp);
     qemu_mutex_unlock_ramlist();
     qemu_mutex_unlock_iothread();
     rcu_read_unlock();
@@ -1877,16 +1886,16 @@ static int ram_state_init(RAMState *rs)
  */
 static int ram_save_setup(QEMUFile *f, void *opaque)
 {
-    RAMState *rs = opaque;
+    RAMState **rsp = opaque;
     RAMBlock *block;
 
     /* migration has already setup the bitmap, reuse it. */
     if (!migration_in_colo_state()) {
-        if (ram_state_init(rs) < 0) {
+        if (ram_state_init(rsp) != 0) {
             return -1;
-         }
+        }
     }
-    rs->f = f;
+    (*rsp)->f = f;
 
     rcu_read_lock();
 
@@ -1921,7 +1930,8 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
  */
 static int ram_save_iterate(QEMUFile *f, void *opaque)
 {
-    RAMState *rs = opaque;
+    RAMState **temp = opaque;
+    RAMState *rs = *temp;
     int ret;
     int i;
     int64_t t0;
@@ -1996,7 +2006,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
  */
 static int ram_save_complete(QEMUFile *f, void *opaque)
 {
-    RAMState *rs = opaque;
+    RAMState **temp = opaque;
+    RAMState *rs = *temp;
 
     rcu_read_lock();
 
@@ -2033,7 +2044,8 @@ static void ram_save_pending(QEMUFile *f, void *opaque, 
uint64_t max_size,
                              uint64_t *non_postcopiable_pending,
                              uint64_t *postcopiable_pending)
 {
-    RAMState *rs = opaque;
+    RAMState **temp = opaque;
+    RAMState *rs = *temp;
     uint64_t remaining_size;
 
     remaining_size = ram_counters.remaining_pages * TARGET_PAGE_SIZE;
-- 
2.9.4