367cfa4946
Simple textbook Not Recently Used eviction algorithm. Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
41 lines
1.3 KiB
Plaintext
41 lines
1.3 KiB
Plaintext
# Copyright (c) 2020 Intel Corporation
|
|
# SPDX-License-Identifier: Apache-2.0
|
|
#
|
|
# Demand paging sample eviction algorithms
|
|
|
|
choice EVICTION_CHOICE
|
|
prompt "Page frame eviction algorithms"
|
|
default EVICTION_NRU
|
|
depends on DEMAND_PAGING
|
|
|
|
config EVICTION_CUSTOM
|
|
bool "Custom eviction algorithm"
|
|
help
|
|
This option is chosen when the eviction algorithm will be implemented
|
|
by the application, instead of using one included in Zephyr.
|
|
|
|
config EVICTION_NRU
|
|
bool "Not Recently Used (NRU) page eviction algorithm"
|
|
help
|
|
This implements a Not Recently Used page eviction algorithm.
|
|
A periodic timer will clear the accessed state of all virtual pages.
|
|
When a page frame needs to be evicted, the algorithm will prefer to
|
|
evict page frames using an ascending order of priority:
|
|
|
|
- recently accessed, dirty
|
|
- recently accessed, clean
|
|
- not recently accessed, dirty
|
|
- not recently accessed, clean
|
|
|
|
endchoice
|
|
|
|
if EVICTION_NRU
|
|
config EVICTION_NRU_PERIOD
|
|
int "Recently accessed period, in milliseconds"
|
|
default 100
|
|
help
|
|
A periodic timer will fire that clears the accessed state of all virtual
|
|
pages that are capable of being paged out. At eviction time, if a page
|
|
still has the accessed property, it will be considered as recently used.
|
|
endif # EVICTION_NRU
|