On Thu, Jul 29, 2021 at 09:39:24PM +0200, David Hildenbrand wrote: > > > > In the meantime I adjusted the code but it does the clearing under the > > > iothread lock, which should not be what we want ... I'll have a look. > > > > Thanks; if it takes more changes than expected we can still start from > > simple, > > IMHO, by taking bql and timely yield it. > > > > At the meantime, I found two things in ram_init_bitmaps() that I'm not sure > > we > > need them of not: > > > > 1. Do we need WITH_RCU_READ_LOCK_GUARD() if with both bql and ramlist > > lock? > > (small question) > > Good question, I'm not sure if we need it. > > > > > 2. Do we need migration_bitmap_sync_precopy() even if dirty bmap is all > > 1's? > > (bigger question) > > IIRC, the bitmap sync will fetch the proper dirty bitmap from KVM and set > the proper bits in the clear_bitmap. So once we call > migration_clear_memory_region_dirty_bitmap_range() etc. later we will > actually clear dirty bits.
Good point, however.. then I'm wondering whether we should just init clear_bmap to all 1's too when init just like dirty bmap. :) Besides: let's not be affected with these details as they should be more suitable to be handled separately; maybe I'll follow this up. It could be a place to discuss things, but shouldn't be a burden to block this series. Thanks, -- Peter Xu
