Documentation/ABI/testing/sysfs-driver-xen-blkback

   1 What:           /sys/module/xen_blkback/parameters/max_buffer_pages
   2 Date:           March 2013
   3 KernelVersion:  3.11
   4 Contact:        Roger Pau Monné <roger.pau@citrix.com>
   5 Description:
   6                 Maximum number of free pages to keep in each block
   7                 backend buffer.
   8
   9 What:           /sys/module/xen_blkback/parameters/max_persistent_grants
  10 Date:           March 2013
  11 KernelVersion:  3.11
  12 Contact:        Roger Pau Monné <roger.pau@citrix.com>
  13 Description:
  14                 Maximum number of grants to map persistently in
  15                 blkback. If the frontend tries to use more than
  16                 max_persistent_grants, the LRU kicks in and starts
  17                 removing 5% of max_persistent_grants every 100ms.
  18
  19 What:           /sys/module/xen_blkback/parameters/persistent_grant_unused_seconds
  20 Date:           August 2018
  21 KernelVersion:  4.19
  22 Contact:        Roger Pau Monné <roger.pau@citrix.com>
  23 Description:
  24                 How long a persistent grant is allowed to remain
  25                 allocated without being in use. The time is in
  26                 seconds, 0 means indefinitely long.
  27                 The default is 60 seconds.
  28
  29 What:           /sys/module/xen_blkback/parameters/buffer_squeeze_duration_ms
  30 Date:           December 2019
  31 KernelVersion:  5.6
  32 Contact:        SeongJae Park <sjpark@amazon.de>
  33 Description:
  34                 When memory pressure is reported to blkback this option
  35                 controls the duration in milliseconds that blkback will not
  36                 cache any page not backed by a grant mapping.
  37                 The default is 10ms.
  38
  39 What:           /sys/module/xen_blkback/parameters/feature_persistent
  40 Date:           September 2020
  41 KernelVersion:  5.10
  42 Contact:        SeongJae Park <sjpark@amazon.de>
  43 Description:
  44                 Whether to enable the persistent grants feature or not.  Note
  45                 that this option only takes effect on newly created backends.
  46                 The default is Y (enable).