Re: [PATCH v2 06/15] migration: Yield bitmap_mutex properly when sending/sleeping

[Peter Xu]

On Wed, Oct 12, 2022 at 05:43:53PM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (peterx@redhat.com) wrote:
> > Don't take the bitmap mutex when sending pages, or when being throttled by
> > migration_rate_limit() (which is a bit tricky to call it here in ram code,
> > but seems still helpful).
> > 
> > It prepares for the possibility of concurrently sending pages in >1 threads
> > using the function ram_save_host_page() because all threads may need the
> > bitmap_mutex to operate on bitmaps, so that either sendmsg() or any kind of
> > qemu_sem_wait() blocking for one thread will not block the other from
> > progressing.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> 
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> 
> although a comment above the reclaration of ram_save_host_pages saying
> it can drop the lock would be veyr good.

Let me add that.  Thanks,

-- 
Peter Xu