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,
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60 no real monitoring and reclamation due to the watermarks-based activation
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70 of parametrs except ``enabled`` again.  Once the re-reading is done, this
72 re-reading, DAMON_RECLAIM will be disabled.
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94 10 ms by default.
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123 Desired level of memory pressure-stall time in microseconds.
127 memory pressure is incurred.  System-wide ``some`` memory PSI in microseconds
130 disabling this auto-tuning feature.
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137 User-specifiable feedback for auto-tuning of the effective quota.
143 this auto-tuning feature.
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168 the low watermark, DAMON_RECLAIM becomes active, so starts the monitoring and
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178 watermarks.  In the case, the system falls back to the LRU-list based page
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203 monitoring.  This can be used to set lower-bound of the monitoring quality.
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213 monitoring.  This can be used to set upper-bound of the monitoring overhead.
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250 -1.
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287 do nothing again, so that we can fall back to the LRU-list based page
291     # echo 30000000 > min_age
292     # echo $((1 * 1024 * 1024 * 1024)) > quota_sz
293     # echo 1000 > quota_reset_interval_ms
294     # echo 500 > wmarks_high
295     # echo 400 > wmarks_mid
296     # echo 200 > wmarks_low
297     # echo Y > enabled