On 05/12/2016 12:53, Stefan Hajnoczi wrote: > Adding the BlockBackend *query_blk parameter is a reasonable short-term > workaround. I wonder if the polling stats APIs need to be rethought in > the longer term. > > Regarding the low-level details of block statistics inside QEMU, we can > probably collect statistics without requiring the AioContext lock. This > means guest I/O processing does not need to be interrupted. There > should be some RCU-style scheme that can be used to extract the stats.
The question is also what level of consistency you want. Perhaps as long as you can access it atomically (so no tearing of values) you don't need a lock at all, blk_ref/unref is enough. Paolo
