1*4882a593SmuzhiyunWhat: /sys/module/xen_blkback/parameters/max_buffer_pages 2*4882a593SmuzhiyunDate: March 2013 3*4882a593SmuzhiyunKernelVersion: 3.11 4*4882a593SmuzhiyunContact: Roger Pau Monné <roger.pau@citrix.com> 5*4882a593SmuzhiyunDescription: 6*4882a593Smuzhiyun Maximum number of free pages to keep in each block 7*4882a593Smuzhiyun backend buffer. 8*4882a593Smuzhiyun 9*4882a593SmuzhiyunWhat: /sys/module/xen_blkback/parameters/max_persistent_grants 10*4882a593SmuzhiyunDate: March 2013 11*4882a593SmuzhiyunKernelVersion: 3.11 12*4882a593SmuzhiyunContact: Roger Pau Monné <roger.pau@citrix.com> 13*4882a593SmuzhiyunDescription: 14*4882a593Smuzhiyun Maximum number of grants to map persistently in 15*4882a593Smuzhiyun blkback. If the frontend tries to use more than 16*4882a593Smuzhiyun max_persistent_grants, the LRU kicks in and starts 17*4882a593Smuzhiyun removing 5% of max_persistent_grants every 100ms. 18*4882a593Smuzhiyun 19*4882a593SmuzhiyunWhat: /sys/module/xen_blkback/parameters/persistent_grant_unused_seconds 20*4882a593SmuzhiyunDate: August 2018 21*4882a593SmuzhiyunKernelVersion: 4.19 22*4882a593SmuzhiyunContact: Roger Pau Monné <roger.pau@citrix.com> 23*4882a593SmuzhiyunDescription: 24*4882a593Smuzhiyun How long a persistent grant is allowed to remain 25*4882a593Smuzhiyun allocated without being in use. The time is in 26*4882a593Smuzhiyun seconds, 0 means indefinitely long. 27*4882a593Smuzhiyun The default is 60 seconds. 28*4882a593Smuzhiyun 29*4882a593SmuzhiyunWhat: /sys/module/xen_blkback/parameters/buffer_squeeze_duration_ms 30*4882a593SmuzhiyunDate: December 2019 31*4882a593SmuzhiyunKernelVersion: 5.6 32*4882a593SmuzhiyunContact: SeongJae Park <sjpark@amazon.de> 33*4882a593SmuzhiyunDescription: 34*4882a593Smuzhiyun When memory pressure is reported to blkback this option 35*4882a593Smuzhiyun controls the duration in milliseconds that blkback will not 36*4882a593Smuzhiyun cache any page not backed by a grant mapping. 37*4882a593Smuzhiyun The default is 10ms. 38*4882a593Smuzhiyun 39*4882a593SmuzhiyunWhat: /sys/module/xen_blkback/parameters/feature_persistent 40*4882a593SmuzhiyunDate: September 2020 41*4882a593SmuzhiyunKernelVersion: 5.10 42*4882a593SmuzhiyunContact: SeongJae Park <sjpark@amazon.de> 43*4882a593SmuzhiyunDescription: 44*4882a593Smuzhiyun Whether to enable the persistent grants feature or not. Note 45*4882a593Smuzhiyun that this option only takes effect on newly connected backends. 46*4882a593Smuzhiyun The default is Y (enable). 47