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? Juergen
