Commit 03158519 authored by Wei Yang's avatar Wei Yang Committed by Juan Quintela
Browse files

migratioin/ram: leave RAMBlock->bmap blank on allocating 



During migration, we would sync bitmap from ram_list.dirty_memory to
RAMBlock.bmap in cpu_physical_memory_sync_dirty_bitmap().

Since we set RAMBlock.bmap and ram_list.dirty_memory both to all 1, this
means at the first round this sync is meaningless and is a duplicated
work.

Leaving RAMBlock->bmap blank on allocating would have a side effect on
migration_dirty_pages, since it is calculated from the result of
cpu_physical_memory_sync_dirty_bitmap(). To keep it right, we need to
set migration_dirty_pages to 0 in ram_state_init().

Signed-off-by: default avatarWei Yang <richardw.yang@linux.intel.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent 24d5588c

migration/ram.c

+13 −5
Original line number Diff line number Diff line
@@ -3173,11 +3173,11 @@ static int ram_state_init(RAMState **rsp) 
    QSIMPLEQ_INIT(&(*rsp)->src_page_requests);



    /*

     * Count the total number of pages used by ram blocks not including any

     * gaps due to alignment or unplugs.

     * This must match with the initial values of dirty bitmap.

     * Currently we initialize the dirty bitmap to all zeros so

     * here the total dirty page count is zero.

     */

    (*rsp)->migration_dirty_pages = ram_bytes_total() >> TARGET_PAGE_BITS;



    (*rsp)->migration_dirty_pages = 0;

    ram_state_reset(*rsp);



    return 0;
@@ -3192,8 +3192,16 @@ static void ram_list_init_bitmaps(void) 
    if (ram_bytes_total()) {

        RAMBLOCK_FOREACH_NOT_IGNORED(block) {

            pages = block->max_length >> TARGET_PAGE_BITS;

            /*

             * The initial dirty bitmap for migration must be set with all

             * ones to make sure we'll migrate every guest RAM page to

             * destination.

             * Here we didn't set RAMBlock.bmap simply because it is already

             * set in ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] in

             * ram_block_add, and that's where we'll sync the dirty bitmaps.

             * Here setting RAMBlock.bmap would be fine too but not necessary.

             */

            block->bmap = bitmap_new(pages);

            bitmap_set(block->bmap, 0, pages);

            if (migrate_postcopy_ram()) {

                block->unsentmap = bitmap_new(pages);

                bitmap_set(block->unsentmap, 0, pages);