On Fri, Aug 24, 2018 at 03:52:23PM +0200, Juergen Gross wrote: > On 17/08/18 17:59, Roger Pau Monné wrote: > > On Mon, Aug 13, 2018 at 04:01:09PM +0200, Juergen Gross wrote: > >> Persistent grants are used in the Xen's blkfront/blkback drivers to > >> avoid mapping/unmapping of I/O buffers in the backend for each I/O. > >> > >> While this speeds up processing quite a bit there are problems related > >> to persistent grants in some configurations: domains with multiple > >> block devices making use of persistent grants might suffer from a lack > >> of grants if each of the block devices experienced a high I/O load at > >> some time. This is due to the number of persistent grants per device > >> only to be limited by a rather high maximum value, but never being > >> released even in case of longer times without any I/O. > >> > >> This series modifies xen-blkback to unmap any domU page mapped via a > >> persistent grant after a timeout (default: 60 seconds). The timeout > >> is set to its default value again when a persistent grant has been > >> used for an I/O. > >> > >> xen-blkfront is modified to scan every 10 seconds for persistent grants > >> not in use by blkback any more and to remove such grants. > >> > >> The last 3 patches are small cleanups of blkfront and blkback drivers. > >> > >> V3: > >> - patch 1: make timeout parameter static > > > > Konrad if you are OK with this series, could you please send a pull > > request to Jens? > > Ping? Yes, let me do that now. > > > Juergen
