On 05.02.20 09:54, Wang, Wei W wrote: > On Wednesday, February 5, 2020 4:19 PM, David Hildenbrand wrote: >> Yes, I agree with you. Yet, I am thinking about one >> (unlikely?impossible?) scenario. Can you refresh my brain why that cannot >> happen (IOW, why we don't have to wait for the host to process the >> request)? >> >> 1. Guest allocates a page and sends it to the host. >> 2. Shrinker gets active and releases that page again. >> 3. Some user in the guest allocates and modifies that page. After that, it is >> done using that page for the next hour. >> 4. The host processes the request and clears the bit in the dirty bitmap. >> 5. The guest is being migrated by the host. The modified page is not being >> migrated. > > Whenever the guest modifies a page during migration, it will be captured by the > dirty logging and the hypervisor will send the dirtied the page in the following round. Please explain why the steps I outlined don't apply esp. in the last round. Your general statement does not explain why this race can't happen. -- Thanks, David / dhildenb
