11d199650SKonrad Rzeszutek WilkWhat: /sys/module/xen_blkback/parameters/max_buffer_pages 21d199650SKonrad Rzeszutek WilkDate: March 2013 31d199650SKonrad Rzeszutek WilkKernelVersion: 3.11 41d199650SKonrad Rzeszutek WilkContact: Roger Pau Monné <roger.pau@citrix.com> 51d199650SKonrad Rzeszutek WilkDescription: 61d199650SKonrad Rzeszutek Wilk Maximum number of free pages to keep in each block 71d199650SKonrad Rzeszutek Wilk backend buffer. 81d199650SKonrad Rzeszutek Wilk 91d199650SKonrad Rzeszutek WilkWhat: /sys/module/xen_blkback/parameters/max_persistent_grants 101d199650SKonrad Rzeszutek WilkDate: March 2013 111d199650SKonrad Rzeszutek WilkKernelVersion: 3.11 121d199650SKonrad Rzeszutek WilkContact: Roger Pau Monné <roger.pau@citrix.com> 131d199650SKonrad Rzeszutek WilkDescription: 141d199650SKonrad Rzeszutek Wilk Maximum number of grants to map persistently in 151d199650SKonrad Rzeszutek Wilk blkback. If the frontend tries to use more than 161d199650SKonrad Rzeszutek Wilk max_persistent_grants, the LRU kicks in and starts 171d199650SKonrad Rzeszutek Wilk removing 5% of max_persistent_grants every 100ms. 18973e5405SJuergen Gross 19973e5405SJuergen GrossWhat: /sys/module/xen_blkback/parameters/persistent_grant_unused_seconds 20973e5405SJuergen GrossDate: August 2018 21973e5405SJuergen GrossKernelVersion: 4.19 22973e5405SJuergen GrossContact: Roger Pau Monné <roger.pau@citrix.com> 23973e5405SJuergen GrossDescription: 24973e5405SJuergen Gross How long a persistent grant is allowed to remain 25973e5405SJuergen Gross allocated without being in use. The time is in 26973e5405SJuergen Gross seconds, 0 means indefinitely long. 27973e5405SJuergen Gross The default is 60 seconds. 28cb9369bdSSeongJae Park 29cb9369bdSSeongJae ParkWhat: /sys/module/xen_blkback/parameters/buffer_squeeze_duration_ms 30cb9369bdSSeongJae ParkDate: December 2019 31cb9369bdSSeongJae ParkKernelVersion: 5.6 3212f112c3SSeongJae ParkContact: Maximilian Heyne <mheyne@amazon.de> 33cb9369bdSSeongJae ParkDescription: 34cb9369bdSSeongJae Park When memory pressure is reported to blkback this option 35cb9369bdSSeongJae Park controls the duration in milliseconds that blkback will not 36cb9369bdSSeongJae Park cache any page not backed by a grant mapping. 37cb9369bdSSeongJae Park The default is 10ms. 38aac8a70dSSeongJae Park 39aac8a70dSSeongJae ParkWhat: /sys/module/xen_blkback/parameters/feature_persistent 40aac8a70dSSeongJae ParkDate: September 2020 41aac8a70dSSeongJae ParkKernelVersion: 5.10 4212f112c3SSeongJae ParkContact: Maximilian Heyne <mheyne@amazon.de> 43aac8a70dSSeongJae ParkDescription: 44aac8a70dSSeongJae Park Whether to enable the persistent grants feature or not. Note 45*e94c6101SMaximilian Heyne that this option only takes effect on newly connected backends. 46aac8a70dSSeongJae Park The default is Y (enable). 47