On 08/21/2013 06:48 PM, Paolo Bonzini wrote:
Il 21/08/2013 09:18, Lei Li ha scritto:
Send all the ram blocks hooked by save_page, which will copy
ram page and MADV_DONTNEED the page just copied.
You should implement this entirely in the hook.
It will be a little less efficient because of the dirty bitmap overhead,
but you should aim at having *zero* changes in arch_init.c and migration.c.
Yes, the reason I modify the migration_thread() to have new process that send
all
the ram pages in adjusted qemu_savevm_state_begin stage and send device states
in
qemu_savevm_device_state stage for localhost migration is to avoid the bitmap
thing,
which is a little less efficient just like you mentioned above.
The performance assurance is very important to this feature, our goal is 100ms
of downtime for a 1TB guest.
Paolo
Signed-off-by: Lei Li <li...@linux.vnet.ibm.com>
---
arch_init.c | 19 +++++++++++++------
1 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/arch_init.c b/arch_init.c
index 434a4ca..cbbb4db 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -474,7 +474,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
/* In doubt sent page as normal */
bytes_sent = -1;
ret = ram_control_save_page(f, block->offset,
- offset, TARGET_PAGE_SIZE, &bytes_sent);
+ offset, TARGET_PAGE_SIZE, &bytes_sent);
if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
if (ret != RAM_SAVE_CONTROL_DELAYED) {
@@ -613,11 +613,13 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
RAMBlock *block;
int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
- migration_bitmap = bitmap_new(ram_pages);
- bitmap_set(migration_bitmap, 0, ram_pages);
- migration_dirty_pages = ram_pages;
- mig_throttle_on = false;
- dirty_rate_high_cnt = 0;
+ if (!migrate_is_localhost()) {
+ migration_bitmap = bitmap_new(ram_pages);
+ bitmap_set(migration_bitmap, 0, ram_pages);
+ migration_dirty_pages = ram_pages;
+ mig_throttle_on = false;
+ dirty_rate_high_cnt = 0;
+ }
if (migrate_use_xbzrle()) {
XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
@@ -641,6 +643,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
migration_bitmap_sync();
qemu_mutex_unlock_iothread();
+ if (migrate_is_localhost()) {
+ ram_save_blocks(f);
+ return 0;
+ }
+
qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
--
Lei
