"Dr. David Alan Gilbert" <dgilb...@redhat.com> wrote:
> * Juan Quintela (quint...@redhat.com) wrote:
>> Yang Hongyang <yanghongy...@huawei.com> wrote:
>> > On 2017/3/24 4:45, Juan Quintela wrote:
>> >> We change the meaning of start to be the offset from the beggining of
>> >> the block.
>> >>
>> >> @@ -701,7 +701,7 @@ static void migration_bitmap_sync(RAMState *rs)
>> >> qemu_mutex_lock(&rs->bitmap_mutex);
>> >> rcu_read_lock();
>> >> QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
>> >> - migration_bitmap_sync_range(rs, block->offset,
>> >> block->used_length);
>> >> + migration_bitmap_sync_range(rs, block, 0, block->used_length);
>> If you have several terabytes of RAM that is too ineficient, because
>> when we arrive to the page_send(page), it is possible that it is already
>> dirty again, and we have to send it twice. So, the idea is to change to
>> something like:
>>
>> while(true) {
>> foreach(block)
>> bitmap_sync(block)
>> foreach(block)
>> foreach(64pages)
>> bitmap_sync(64pages)
>> foreach(page of the 64)
>> if (dirty)
>> page_send(page)
>
> Yes, although it might be best to actually do the sync in a separate thread
> so that the sync is always a bit ahead of the thread doing the writing.
Doing it synchronously shouldn't be a problem. But we should be able to
in smaller chucks.
Thanks, Juan.
