WIP FPC-III support
[linux/fpc-iii.git] / Documentation / ABI / testing / sysfs-driver-xen-blkback
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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.
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.
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.
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.
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).