linux-stable.git/mm/damon, branch linux-6.2.y

mm/damon/paddr: fix missing folio_put()

2023-03-10T08:29:41+00:00

commit 3f98c9a62c338bbe06a215c9491e6166ea39bf82 upstream.

damon_get_folio() would always increase folio _refcount and
folio_isolate_lru() would increase folio _refcount if the folio's lru flag
is set.

If an unevictable folio isolated successfully, there will be two more
_refcount.  The one from folio_isolate_lru() will be decreased in
folio_puback_lru(), but the other one from damon_get_folio() will be left
behind.  This causes a pin page.

Whatever the case, the _refcount from damon_get_folio() should be
decreased.

Link: https://lkml.kernel.org/r/20230222064223.6735-1-andrew.yang@mediatek.com
Fixes: 57223ac29584 ("mm/damon/paddr: support the pageout scheme")
Signed-off-by: andrew.yang 
Reviewed-by: SeongJae Park 
Cc: 	[5.16.x]
Signed-off-by: Andrew Morton 
Signed-off-by: SeongJae Park 
Signed-off-by: Greg Kroah-Hartman

mm/damon: use kstrtobool() instead of strtobool()

2022-11-30T23:58:45+00:00

strtobool() is the same as kstrtobool().  However, the latter is more used
within the kernel.

In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.

While at it, include the corresponding header file ()

Link: https://lkml.kernel.org/r/ed2b46489a513988688decb53850339cc228940c.1667336095.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET 
Reviewed-by: SeongJae Park 
Signed-off-by: Andrew Morton

mm/damon/sysfs-schemes: implement DAMOS-tried regions clear command

2022-11-30T23:58:44+00:00

When there are huge number of DAMON regions that specific scheme actions
are tried to be applied, directories and files under 'tried_regions'
scheme directory could waste some memory.  Add another special input
keyword ('clear_schemes_tried_regions') for 'state' file of each kdamond
sysfs directory that can be used for cleanup of the 'tried_regions'
sub-directories.

[sj@kernel.org: skip regions clearing if the scheme directory was removed]
  Link: https://lkml.kernel.org/r/20221114182954.4745-3-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-6-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/sysfs: implement DAMOS tried regions update command

2022-11-30T23:58:44+00:00

Implement the code for filling the data of 'tried_regions' DAMON sysfs
directory.  With this commit, DAMON sysfs interface users can write a
special keyword, 'update_schemes_tried_regions' to the corresponding
'state' file of the kdamond.  Then, DAMON sysfs interface will collect the
tried regions information using the 'before_damos_apply()' callback for
one aggregation interval and populate scheme region directories with the
values.

[sj@kernel.org: skip tried regions update if the scheme directory was removed]
  Link: https://lkml.kernel.org/r/20221114182954.4745-2-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-5-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/sysfs-schemes: implement scheme region directory

2022-11-30T23:58:44+00:00

Implement region directories under 'tried_regions' directory of each
scheme DAMON sysfs directory.  This directory will provide the address
range, the monitored access frequency ('nr_accesses'), and the age of each
DAMON region that corresponding DAMON-based operation scheme has tried to
be applied.  Note that this commit doesn't implement the code for filling
the data but only the sysfs directory.

Link: https://lkml.kernel.org/r/20221101220328.95765-4-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/sysfs-schemes: implement schemes/tried_regions directory

2022-11-30T23:58:44+00:00

For efficient and simple query-like DAMON monitoring results readings and
deep level investigations of DAMOS, DAMON kernel API
(include/linux/damon.h) users can use 'before_damos_apply' DAMON callback.
However, DAMON sysfs interface users don't have such option.

Add a directory, namely 'tried_regions', under each scheme directory to
use it as the interface for the purpose.  Note that this commit is
implementing only the directory but the data filling.

After the data filling change is made, users will be able to signal DAMON
to fill the directory with the regions that corresponding scheme has tried
to be applied.  By setting the access pattern of the scheme, users could
do the efficient query-like monitoring.

Link: https://lkml.kernel.org/r/20221101220328.95765-3-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/core: add a callback for scheme target regions check

2022-11-30T23:58:43+00:00

Patch series "efficiently expose damos action tried regions information".

DAMON users can retrieve the monitoring results via 'after_aggregation'
callbacks if the user is using the kernel API, or 'damon_aggregated'
tracepoint if the user is in the user space.  Those are useful if full
monitoring results are necessary.  However, if the user has interest in
only a snapshot of the results for some regions having specific access
pattern, the interfaces could be inefficient.  For example, some users
only want to know which memory regions are not accessed for more than a
specific time at the moment.

Also, some DAMOS users would want to know exactly to what memory regions
the schemes' actions tried to be applied, for a debugging or a tuning.  As
DAMOS has its internal mechanism for quota and regions prioritization, the
users would need to simulate DAMOS' mechanism against the monitoring
results.  That's unnecessarily complex.

This patchset implements DAMON kernel API callbacks and sysfs directory
for efficient exposure of the information for the use cases.  The new
callback will be called for each region when a DAMOS action is gonna tried
to be applied to it.  The sysfs directory will be called 'tried_regions'
and placed under each scheme sysfs directory.  Users can write a special
keyworkd, 'update_schemes_regions', to the 'state' file of a kdamond sysfs
directory.  Then, DAMON sysfs interface will fill the directory with the
information of regions that corresponding scheme action was tried to be
applied for next one aggregation interval.

Patches Sequence
----------------

The first one (patch 1) implements the callback for the kernel space
users.  Following two patches (patches 2 and 3) implements sysfs
directories for the information and its sub directories.  Two patches
(patches 4 and 5) for implementing the special keywords for filling the
data to and cleaning up the directories follow.  Patch 6 adds a selftest
for the new sysfs directory.  Finally, two patches (patches 7 and 8)
document the new feature in the administrator guide and the ABI document.


This patch (of 8):

Getting DAMON monitoring results of only specific access pattern (e.g.,
getting address ranges of memory that not accessed at all for two minutes)
can be useful for efficient monitoring of the system.  The information can
also be helpful for deep level investigation of DAMON-based operation
schemes.

For that, users need to record (in case of the user space users) or
iterate (in case of the kernel space users) full monitoring results and
filter it out for the specific access pattern.  In case of the DAMOS
investigation, users will even need to simulate DAMOS' quota and
prioritization mechanisms.  It's inefficient and complex.

Add a new DAMON callback that will be called before each scheme is applied
to each region.  DAMON kernel API users will be able to do the query-like
monitoring results collection, or DAMOS investigation in an efficient and
simple way using it.

Commits for providing the capability to the user space users will follow.

Link: https://lkml.kernel.org/r/20221101220328.95765-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221101220328.95765-2-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/lru_sort: enable and disable synchronously

2022-11-30T23:01:27+00:00

Writing a value to DAMON_RECLAIM's 'enabled' parameter turns on or off
DAMON in an ansychronous way.  This means the parameter cannot be used to
read the current status of DAMON_RECLAIM.  'kdamond_pid' parameter should
be used instead for the purpose.  The documentation is easy to be read as
it works in a synchronous way, so it is a little bit confusing.  It also
makes the user space tooling dirty.

There's no real reason to have the asynchronous behavior, though.  Simply
make the parameter works synchronously, rather than updating the document.

Link: https://lkml.kernel.org/r/20221025173650.90624-4-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/reclaim: enable and disable synchronously

2022-11-30T23:01:26+00:00

Patch series "mm/damon/reclaim,lru_sort: enable/disable synchronously".

Writing a value to DAMON_RECLAIM and DAMON_LRU_SORT's 'enabled' parameters
turns on or off DAMON in an ansychronous way.  This means the parameter
cannot be used to read the current status of them.  'kdamond_pid'
parameter should be used instead for the purpose.  The documentation is
easy to be read as it works in a synchronous way, so it is a little bit
confusing.  It also makes the user space tooling dirty.

There's no real reason to have the asynchronous behavior, though.  Simply
make the parameter works synchronously, rather than updating the document.

The first and second patches changes the behavior of the 'enabled'
parameter for DAMON_RECLAIM and adds a selftest for the changed behavior,
respectively.  Following two patches make the same changes for
DAMON_LRU_SORT.


This patch (of 4):

Writing a value to DAMON_RECLAIM's 'enabled' parameter turns on or off
DAMON in an ansychronous way.  This means the parameter cannot be used to
read the current status of DAMON_RECLAIM.  'kdamond_pid' parameter should
be used instead for the purpose.  The documentation is easy to be read as
it works in a synchronous way, so it is a little bit confusing.  It also
makes the user space tooling dirty.

There's no real reason to have the asynchronous behavior, though.  Simply
make the parameter works synchronously, rather than updating the document.

Link: https://lkml.kernel.org/r/20221025173650.90624-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20221025173650.90624-2-sj@kernel.org
Signed-off-by: SeongJae Park 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton

mm/damon/{reclaim,lru_sort}: remove unnecessarily included headers

2022-11-30T23:01:26+00:00

Some headers that 'reclaim.c' and 'lru_sort.c' are including are
unnecessary now owing to previous cleanups and refactorings.  Remove
those.

Link: https://lkml.kernel.org/r/20221026225943.100429-13-sj@kernel.org
Signed-off-by: SeongJae Park 
Signed-off-by: Andrew Morton