mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

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

Browse Source 
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: Wei Yang <richardw.yang@linux.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>
This commit is contained in:
Wei Yang 2019-06-04 14:17:27 +08:00 committed by Juan Quintela
parent 24d5588c86
commit 0315851938
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
migration/ram.c
View File

@ -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);