|  | What:           /sys/module/xen_blkback/parameters/max_buffer_pages | 
|  | Date:           March 2013 | 
|  | KernelVersion:  3.11 | 
|  | Contact:        Roger Pau Monné <roger.pau@citrix.com> | 
|  | Description: | 
|  | Maximum number of free pages to keep in each block | 
|  | backend buffer. | 
|  |  | 
|  | What:           /sys/module/xen_blkback/parameters/max_persistent_grants | 
|  | Date:           March 2013 | 
|  | KernelVersion:  3.11 | 
|  | Contact:        Roger Pau Monné <roger.pau@citrix.com> | 
|  | Description: | 
|  | Maximum number of grants to map persistently in | 
|  | blkback. If the frontend tries to use more than | 
|  | max_persistent_grants, the LRU kicks in and starts | 
|  | removing 5% of max_persistent_grants every 100ms. | 
|  |  | 
|  | What:           /sys/module/xen_blkback/parameters/persistent_grant_unused_seconds | 
|  | Date:           August 2018 | 
|  | KernelVersion:  4.19 | 
|  | Contact:        Roger Pau Monné <roger.pau@citrix.com> | 
|  | Description: | 
|  | How long a persistent grant is allowed to remain | 
|  | allocated without being in use. The time is in | 
|  | seconds, 0 means indefinitely long. | 
|  | The default is 60 seconds. |