Unverified Commit a824b373 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
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!763 DAMON features: Support for process-level hot and cold data recognition and adjustment. 

Merge Pull Request from: @gesefudiao 
 
The higher version community DAMON features in rounds:

Removed the debugfs interface and enabled the sysfs interface.
Added the lru_sort module to achieve proactive adjustment of the system-level LRU list for physical address monitoring.
Support for online automation adjustment of DAMON strategies. 
 
Link:https://gitee.com/openeuler/kernel/pulls/763

 

Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents 8614faa4 2dc30548

Documentation/ABI/testing/sysfs-kernel-mm-damon

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what:		/sys/kernel/mm/damon/

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Interface for Data Access MONitoring (DAMON).  Contains files

		for controlling DAMON.  For more details on DAMON itself,

		please refer to Documentation/admin-guide/mm/damon/index.rst.



What:		/sys/kernel/mm/damon/admin/

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Interface for privileged users of DAMON.  Contains files for

		controlling DAMON that aimed to be used by privileged users.



What:		/sys/kernel/mm/damon/admin/kdamonds/nr_kdamonds

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a number 'N' to this file creates the number of

		directories for controlling each DAMON worker thread (kdamond)

		named '0' to 'N-1' under the kdamonds/ directory.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/state

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing 'on' or 'off' to this file makes the kdamond starts or

		stops, respectively.  Reading the file returns the keywords

		based on the current status.  Writing 'commit' to this file

		makes the kdamond reads the user inputs in the sysfs files

		except 'state' again.  Writing 'update_schemes_stats' to the

		file updates contents of schemes stats files of the kdamond.

		Writing 'update_schemes_tried_regions' to the file updates

		contents of 'tried_regions' directory of every scheme directory

		of this kdamond.  Writing 'clear_schemes_tried_regions' to the

		file removes contents of the 'tried_regions' directory.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/pid

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the pid of the kdamond if it is

		running.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/nr_contexts

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a number 'N' to this file creates the number of

		directories for controlling each DAMON context named '0' to

		'N-1' under the contexts/ directory.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/avail_operations

Date:		Apr 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the available monitoring operations

		sets on the currently running kernel.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/operations

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a keyword for a monitoring operations set ('vaddr' for

		virtual address spaces monitoring, 'fvaddr' for fixed virtual

		address ranges monitoring, and 'paddr' for the physical address

		space monitoring) to this file makes the context to use the

		operations set.  Reading the file returns the keyword for the

		operations set the context is set to use.



		Note that only the operations sets that listed in

		'avail_operations' file are valid inputs.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/monitoring_attrs/intervals/sample_us

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a value to this file sets the sampling interval of the

		DAMON context in microseconds as the value.  Reading this file

		returns the value.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/monitoring_attrs/intervals/aggr_us

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a value to this file sets the aggregation interval of

		the DAMON context in microseconds as the value.  Reading this

		file returns the value.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/monitoring_attrs/intervals/update_us

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a value to this file sets the update interval of the

		DAMON context in microseconds as the value.  Reading this file

		returns the value.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/monitoring_attrs/nr_regions/min



WDate:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a value to this file sets the minimum number of

		monitoring regions of the DAMON context as the value.  Reading

		this file returns the value.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/monitoring_attrs/nr_regions/max

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a value to this file sets the maximum number of

		monitoring regions of the DAMON context as the value.  Reading

		this file returns the value.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/targets/nr_targets

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a number 'N' to this file creates the number of

		directories for controlling each DAMON target of the context

		named '0' to 'N-1' under the contexts/ directory.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/targets/<T>/pid_target

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the pid of

		the target process if the context is for virtual address spaces

		monitoring, respectively.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/targets/<T>/regions/nr_regions

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a number 'N' to this file creates the number of

		directories for setting each DAMON target memory region of the

		context named '0' to 'N-1' under the regions/ directory.  In

		case of the virtual address space monitoring, DAMON

		automatically sets the target memory region based on the target

		processes' mappings.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/targets/<T>/regions/<R>/start

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the start

		address of the monitoring region.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/targets/<T>/regions/<R>/end

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the end

		address of the monitoring region.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/nr_schemes

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing a number 'N' to this file creates the number of

		directories for controlling each DAMON-based operation scheme

		of the context named '0' to 'N-1' under the schemes/ directory.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/action

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the action

		of the scheme.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/sz/min

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the mimimum

		size of the scheme's target regions in bytes.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/sz/max

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the maximum

		size of the scheme's target regions in bytes.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/nr_accesses/min

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the manimum

		'nr_accesses' of the scheme's target regions.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/nr_accesses/max

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the maximum

		'nr_accesses' of the scheme's target regions.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/age/min

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the minimum

		'age' of the scheme's target regions.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/access_pattern/age/max

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the maximum

		'age' of the scheme's target regions.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/quotas/ms

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the time

		quota of the scheme in milliseconds.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/quotas/bytes

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the size

		quota of the scheme in bytes.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/quotas/reset_interval_ms

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the quotas

		charge reset interval of the scheme in milliseconds.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/quotas/weights/sz_permil

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the

		under-quota limit regions prioritization weight for 'size' in

		permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/quotas/weights/nr_accesses_permil

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the

		under-quota limit regions prioritization weight for

		'nr_accesses' in permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/quotas/weights/age_permil

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the

		under-quota limit regions prioritization weight for 'age' in

		permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/watermarks/metric

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the metric

		of the watermarks for the scheme.  The writable/readable

		keywords for this file are 'none' for disabling the watermarks

		feature, or 'free_mem_rate' for the system's global free memory

		rate in permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/watermarks/interval_us

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the metric

		check interval of the watermarks for the scheme in

		microseconds.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/watermarks/high

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the high

		watermark of the scheme in permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/watermarks/mid

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the mid

		watermark of the scheme in permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/watermarks/low

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Writing to and reading from this file sets and gets the low

		watermark of the scheme in permil.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/stats/nr_tried

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the number of regions that the action

		of the scheme has tried to be applied.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/stats/sz_tried

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the total size of regions that the

		action of the scheme has tried to be applied in bytes.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/stats/nr_applied

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the number of regions that the action

		of the scheme has successfully applied.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/stats/sz_applied

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the total size of regions that the

		action of the scheme has successfully applied in bytes.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/stats/qt_exceeds

Date:		Mar 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the number of the exceed events of

		the scheme's quotas.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/start

Date:		Oct 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the start address of a memory region

		that corresponding DAMON-based Operation Scheme's action has

		tried to be applied.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/end

Date:		Oct 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the end address of a memory region

		that corresponding DAMON-based Operation Scheme's action has

		tried to be applied.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/nr_accesses

Date:		Oct 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the 'nr_accesses' of a memory region

		that corresponding DAMON-based Operation Scheme's action has

		tried to be applied.



What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/age

Date:		Oct 2022

Contact:	SeongJae Park <sj@kernel.org>

Description:	Reading this file returns the 'age' of a memory region that

		corresponding DAMON-based Operation Scheme's action has tried

		to be applied.

Documentation/admin-guide/mm/damon/index.rst

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@@ -14,3 +14,4 @@ optimize those. 
   start

   usage

   reclaim

   lru_sort

Documentation/admin-guide/mm/damon/lru_sort.rst

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.. SPDX-License-Identifier: GPL-2.0



=============================

DAMON-based LRU-lists Sorting

=============================



DAMON-based LRU-lists Sorting (DAMON_LRU_SORT) is a static kernel module that

aimed to be used for proactive and lightweight data access pattern based

(de)prioritization of pages on their LRU-lists for making LRU-lists a more

trusworthy data access pattern source.



Where Proactive LRU-lists Sorting is Required?

==============================================



As page-granularity access checking overhead could be significant on huge

systems, LRU lists are normally not proactively sorted but partially and

reactively sorted for special events including specific user requests, system

calls and memory pressure.  As a result, LRU lists are sometimes not so

perfectly prepared to be used as a trustworthy access pattern source for some

situations including reclamation target pages selection under sudden memory

pressure.



Because DAMON can identify access patterns of best-effort accuracy while

inducing only user-specified range of overhead, proactively running

DAMON_LRU_SORT could be helpful for making LRU lists more trustworthy access

pattern source with low and controlled overhead.



How It Works?

=============



DAMON_LRU_SORT finds hot pages (pages of memory regions that showing access

rates that higher than a user-specified threshold) and cold pages (pages of

memory regions that showing no access for a time that longer than a

user-specified threshold) using DAMON, and prioritizes hot pages while

deprioritizing cold pages on their LRU-lists.  To avoid it consuming too much

CPU for the prioritizations, a CPU time usage limit can be configured.  Under

the limit, it prioritizes and deprioritizes more hot and cold pages first,

respectively.  System administrators can also configure under what situation

this scheme should automatically activated and deactivated with three memory

pressure watermarks.



Its default parameters for hotness/coldness thresholds and CPU quota limit are

conservatively chosen.  That is, the module under its default parameters could

be widely used without harm for common situations while providing a level of

benefits for systems having clear hot/cold access patterns under memory

pressure while consuming only a limited small portion of CPU time.



Interface: Module Parameters

============================



To use this feature, you should first ensure your system is running on a kernel

that is built with ``CONFIG_DAMON_LRU_SORT=y``.



To let sysadmins enable or disable it and tune for the given system,

DAMON_LRU_SORT utilizes module parameters.  That is, you can put

``damon_lru_sort.<parameter>=<value>`` on the kernel boot command line or write

proper values to ``/sys/modules/damon_lru_sort/parameters/<parameter>`` files.



Below are the description of each parameter.



enabled

-------



Enable or disable DAMON_LRU_SORT.



You can enable DAMON_LRU_SORT by setting the value of this parameter as ``Y``.

Setting it as ``N`` disables DAMON_LRU_SORT.  Note that DAMON_LRU_SORT could do

no real monitoring and LRU-lists sorting due to the watermarks-based activation

condition.  Refer to below descriptions for the watermarks parameter for this.



commit_inputs

-------------



Make DAMON_LRU_SORT reads the input parameters again, except ``enabled``.



Input parameters that updated while DAMON_LRU_SORT is running are not applied

by default.  Once this parameter is set as ``Y``, DAMON_LRU_SORT reads values

of parametrs except ``enabled`` again.  Once the re-reading is done, this

parameter is set as ``N``.  If invalid parameters are found while the

re-reading, DAMON_LRU_SORT will be disabled.



hot_thres_access_freq

---------------------



Access frequency threshold for hot memory regions identification in permil.



If a memory region is accessed in frequency of this or higher, DAMON_LRU_SORT

identifies the region as hot, and mark it as accessed on the LRU list, so that

it could not be reclaimed under memory pressure.  50% by default.



cold_min_age

------------



Time threshold for cold memory regions identification in microseconds.



If a memory region is not accessed for this or longer time, DAMON_LRU_SORT

identifies the region as cold, and mark it as unaccessed on the LRU list, so

that it could be reclaimed first under memory pressure.  120 seconds by

default.



quota_ms

--------



Limit of time for trying the LRU lists sorting in milliseconds.



DAMON_LRU_SORT tries to use only up to this time within a time window

(quota_reset_interval_ms) for trying LRU lists sorting.  This can be used

for limiting CPU consumption of DAMON_LRU_SORT.  If the value is zero, the

limit is disabled.



10 ms by default.



quota_reset_interval_ms

-----------------------



The time quota charge reset interval in milliseconds.



The charge reset interval for the quota of time (quota_ms).  That is,

DAMON_LRU_SORT does not try LRU-lists sorting for more than quota_ms

milliseconds or quota_sz bytes within quota_reset_interval_ms milliseconds.



1 second by default.



wmarks_interval

---------------



The watermarks check time interval in microseconds.



Minimal time to wait before checking the watermarks, when DAMON_LRU_SORT is

enabled but inactive due to its watermarks rule.  5 seconds by default.



wmarks_high

-----------



Free memory rate (per thousand) for the high watermark.



If free memory of the system in bytes per thousand bytes is higher than this,

DAMON_LRU_SORT becomes inactive, so it does nothing but periodically checks the

watermarks.  200 (20%) by default.



wmarks_mid

----------



Free memory rate (per thousand) for the middle watermark.



If free memory of the system in bytes per thousand bytes is between this and

the low watermark, DAMON_LRU_SORT becomes active, so starts the monitoring and

the LRU-lists sorting.  150 (15%) by default.



wmarks_low

----------



Free memory rate (per thousand) for the low watermark.



If free memory of the system in bytes per thousand bytes is lower than this,

DAMON_LRU_SORT becomes inactive, so it does nothing but periodically checks the

watermarks.  50 (5%) by default.



sample_interval

---------------



Sampling interval for the monitoring in microseconds.



The sampling interval of DAMON for the cold memory monitoring.  Please refer to

the DAMON documentation (:doc:`usage`) for more detail.  5ms by default.



aggr_interval

-------------



Aggregation interval for the monitoring in microseconds.



The aggregation interval of DAMON for the cold memory monitoring.  Please

refer to the DAMON documentation (:doc:`usage`) for more detail.  100ms by

default.



min_nr_regions

--------------



Minimum number of monitoring regions.



The minimal number of monitoring regions of DAMON for the cold memory

monitoring.  This can be used to set lower-bound of the monitoring quality.

But, setting this too high could result in increased monitoring overhead.

Please refer to the DAMON documentation (:doc:`usage`) for more detail.  10 by

default.



max_nr_regions

--------------



Maximum number of monitoring regions.



The maximum number of monitoring regions of DAMON for the cold memory

monitoring.  This can be used to set upper-bound of the monitoring overhead.

However, setting this too low could result in bad monitoring quality.  Please

refer to the DAMON documentation (:doc:`usage`) for more detail.  1000 by

defaults.



monitor_region_start

--------------------



Start of target memory region in physical address.



The start physical address of memory region that DAMON_LRU_SORT will do work

against.  By default, biggest System RAM is used as the region.



monitor_region_end

------------------



End of target memory region in physical address.



The end physical address of memory region that DAMON_LRU_SORT will do work

against.  By default, biggest System RAM is used as the region.



kdamond_pid

-----------



PID of the DAMON thread.



If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread.  Else,

-1.



nr_lru_sort_tried_hot_regions

-----------------------------



Number of hot memory regions that tried to be LRU-sorted.



bytes_lru_sort_tried_hot_regions

--------------------------------



Total bytes of hot memory regions that tried to be LRU-sorted.



nr_lru_sorted_hot_regions

-------------------------



Number of hot memory regions that successfully be LRU-sorted.



bytes_lru_sorted_hot_regions

----------------------------



Total bytes of hot memory regions that successfully be LRU-sorted.



nr_hot_quota_exceeds

--------------------



Number of times that the time quota limit for hot regions have exceeded.



nr_lru_sort_tried_cold_regions

------------------------------



Number of cold memory regions that tried to be LRU-sorted.



bytes_lru_sort_tried_cold_regions

---------------------------------



Total bytes of cold memory regions that tried to be LRU-sorted.



nr_lru_sorted_cold_regions

--------------------------



Number of cold memory regions that successfully be LRU-sorted.



bytes_lru_sorted_cold_regions

-----------------------------



Total bytes of cold memory regions that successfully be LRU-sorted.



nr_cold_quota_exceeds

---------------------



Number of times that the time quota limit for cold regions have exceeded.



Example

=======



Below runtime example commands make DAMON_LRU_SORT to find memory regions

having >=50% access frequency and LRU-prioritize while LRU-deprioritizing

memory regions that not accessed for 120 seconds.  The prioritization and

deprioritization is limited to be done using only up to 1% CPU time to avoid

DAMON_LRU_SORT consuming too much CPU time for the (de)prioritization.  It also

asks DAMON_LRU_SORT to do nothing if the system's free memory rate is more than

50%, but start the real works if it becomes lower than 40%.  If DAMON_RECLAIM

doesn't make progress and therefore the free memory rate becomes lower than

20%, it asks DAMON_LRU_SORT to do nothing again, so that we can fall back to

the LRU-list based page granularity reclamation. ::



    # cd /sys/modules/damon_lru_sort/parameters

    # echo 500 > hot_thres_access_freq

    # echo 120000000 > cold_min_age

    # echo 10 > quota_ms

    # echo 1000 > quota_reset_interval_ms

    # echo 500 > wmarks_high

    # echo 400 > wmarks_mid

    # echo 200 > wmarks_low

    # echo Y > enabled

Documentation/admin-guide/mm/damon/reclaim.rst

+11 −0
Original line number Diff line number Diff line
@@ -66,6 +66,17 @@ Setting it as ``N`` disables DAMON_RECLAIM. Note that DAMON_RECLAIM could do 
no real monitoring and reclamation due to the watermarks-based activation

condition.  Refer to below descriptions for the watermarks parameter for this.



commit_inputs

-------------



Make DAMON_RECLAIM reads the input parameters again, except ``enabled``.



Input parameters that updated while DAMON_RECLAIM is running are not applied

by default.  Once this parameter is set as ``Y``, DAMON_RECLAIM reads values

of parametrs except ``enabled`` again.  Once the re-reading is done, this

parameter is set as ``N``.  If invalid parameters are found while the

re-reading, DAMON_RECLAIM will be disabled.



min_age

-------

Documentation/admin-guide/mm/damon/usage.rst

+400 −6

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