mm/damon/reclaim.rst

1 .. SPDX-License-Identifier: GPL-2.0
4 DAMON-based Reclamation
7 DAMON-based Reclamation (DAMON_RECLAIM) is a static kernel module that aimed to
9 It doesn't aim to replace the LRU-list based page_granularity reclamation, but
15 On general memory over-committed systems, proactively reclaiming cold pages
20 Free Pages Reporting [3]_ based memory over-commit virtualization systems are
24 guests could be not so memory-frugal, mainly because some kernel subsystems and
25 user-space applications are designed to use as much memory as available.  Then,
40 Interface: Module Parameters
47 DAMON_RECLAIM utilizes module parameters.  That is, you can put
49 proper values to ``/sys/module/damon_reclaim/parameters/<parameter>`` files.
54 -------
60 no real monitoring and reclamation due to the watermarks-based activation
64 -------------
70 of parametrs except ``enabled`` again.  Once the re-reading is done, this
72 re-reading, DAMON_RECLAIM will be disabled.
75 -------
85 --------
97 --------
109 -----------------------
121 ---------------
127 -----------
129 Free memory rate (per thousand) for the high watermark.
131 If free memory of the system in bytes per thousand bytes is higher than this,
136 ----------
138 Free memory rate (per thousand) for the middle watermark.
140 If free memory of the system in bytes per thousand bytes is between this and
145 ----------
147 Free memory rate (per thousand) for the low watermark.
149 If free memory of the system in bytes per thousand bytes is lower than this,
151 watermarks.  In the case, the system falls back to the LRU-list based page
155 ---------------
163 -------------
171 --------------
176 monitoring.  This can be used to set lower-bound of the monitoring quality.
181 --------------
186 monitoring.  This can be used to set upper-bound of the monitoring overhead.
191 --------------------
200 ------------------
209 ---------
218 -----------
223 -1.
226 ------------------------
231 ---------------------------
236 --------------------
241 -----------------------
246 ----------------
255 to be done only up to 1 GiB per second to avoid DAMON_RECLAIM consuming too
260 do nothing again, so that we can fall back to the LRU-list based page
263     # cd /sys/module/damon_reclaim/parameters