* David Hildenbrand (da...@redhat.com) wrote: > On 15.05.20 14:45, Dr. David Alan Gilbert wrote: > > * David Hildenbrand (da...@redhat.com) wrote: > >> RDMA will pin all guest memory (as documented in docs/rdma.txt). We want > >> to mark RAM block discards to be broken - however, to keep it simple > >> use ram_block_discard_is_required() instead of inhibiting. > > > > Should this be dependent on whether rdma->pin_all is set? > > Even with !pin_all some will be pinned at any given time > > (when it's registered with the rdma stack). > > Do you know how much memory this is? Is such memory only temporarily pinned?
With pin_all not set, only a subset of memory, I think multiple 1MB chunks, are pinned at any one time. > At least with special-cases of vfio, it's acceptable if some memory is > temporarily pinned - we assume it's only the working set of the driver, > which guests will not inflate as long as they don't want to shoot > themselves in the foot. > > This here sounds like the guest does not know the pinned memory is > special, right? Right - for RDMA it's all of memory that's being transferred, and the guest doesn't see when each part is transferred. Dave > -- > Thanks, > > David / dhildenb -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
