linux.git/mm/damon, branch v6.16

mm/damon/core: commit damos_quota_goal->nid

2025-07-25T00:57:59+00:00

DAMOS quota goal uses 'nid' field when the metric is
DAMOS_QUOTA_NODE_MEM_{USED,FREE}_BP.  But the goal commit function is not
updating the goal's nid field.  Fix it.

Link: https://lkml.kernel.org/r/20250719181932.72944-1-sj@kernel.org
Fixes: 0e1c773b501f ("mm/damon/core: introduce damos quota goal metrics for memory node utilization")	[6.16.x]
Signed-off-by: SeongJae Park 
Cc: 
Signed-off-by: Andrew Morton

mm/damon: fix divide by zero in damon_get_intervals_score()

2025-07-10T04:07:55+00:00

The current implementation allows having zero size regions with no special
reasons, but damon_get_intervals_score() gets crashed by divide by zero
when the region size is zero.

  [   29.403950] Oops: divide error: 0000 [#1] SMP NOPTI

This patch fixes the bug, but does not disallow zero size regions to keep
the backward compatibility since disallowing zero size regions might be a
breaking change for some users.

In addition, the same crash can happen when intervals_goal.access_bp is
zero so this should be fixed in stable trees as well.

Link: https://lkml.kernel.org/r/20250702000205.1921-5-honggyu.kim@sk.com
Fixes: f04b0fedbe71 ("mm/damon/core: implement intervals auto-tuning")
Signed-off-by: Honggyu Kim 
Reviewed-by: SeongJae Park 
Cc: 
Signed-off-by: Andrew Morton

mm/damon/core: handle damon_call_control as normal under kdmond deactivation

2025-07-10T04:07:54+00:00

DAMON sysfs interface internally uses damon_call() to update DAMON
parameters as users requested, online.  However, DAMON core cancels any
damon_call() requests when it is deactivated by DAMOS watermarks.

As a result, users cannot change DAMON parameters online while DAMON is
deactivated.  Note that users can turn DAMON off and on with different
watermarks to work around.  Since deactivated DAMON is nearly same to
stopped DAMON, the work around should have no big problem.  Anyway, a bug
is a bug.

There is no real good reason to cancel the damon_call() request under
DAMOS deactivation.  Fix it by simply handling the request as normal,
rather than cancelling under the situation.

Link: https://lkml.kernel.org/r/20250629204914.54114-1-sj@kernel.org
Fixes: 42b7491af14c ("mm/damon/core: introduce damon_call()")
Signed-off-by: SeongJae Park 
Cc: 	[6.14+]
Signed-off-by: Andrew Morton

mm/damon/sysfs-schemes: free old damon_sysfs_scheme_filter->memcg_path on write

2025-06-25T22:55:03+00:00

memcg_path_store() assigns a newly allocated memory buffer to
filter->memcg_path, without deallocating the previously allocated and
assigned memory buffer.  As a result, users can leak kernel memory by
continuously writing a data to memcg_path DAMOS sysfs file.  Fix the leak
by deallocating the previously set memory buffer.

Link: https://lkml.kernel.org/r/20250619183608.6647-2-sj@kernel.org
Fixes: 7ee161f18b5d ("mm/damon/sysfs-schemes: implement filter directory")
Signed-off-by: SeongJae Park 
Cc: Shuah Khan 
Cc: 		[6.3.x]
Signed-off-by: Andrew Morton

Revert "mm/damon/Kconfig: enable CONFIG_DAMON by default"

2025-06-10T17:22:15+00:00

This reverts commit 28615e6eed152f2fda5486680090b74aeed7b554.

No, we don't make random features default to being on.

Reported-by: Geert Uytterhoeven 
Cc: Andrew Morton 
Cc: SeongJae Park 
Signed-off-by: Linus Torvalds

mm/damon: s/primitives/code/ on comments

2025-06-06T04:55:41+00:00

The word 'primitive' is not explicit.  To make the code more easily
understood, this commit renames 'primitives' to 'code' in header comments
of some source files.

Link: https://lkml.kernel.org/r/20250530053115.153238-1-lienze@kylinos.cn
Signed-off-by: Enze Li 
Reviewed-by: SeongJae Park 
Signed-off-by: Andrew Morton

mm/damon/Kconfig: enable CONFIG_DAMON by default

2025-06-01T05:46:12+00:00

As of this writing, multiple major distros including Alma, Amazon,
Android, CentOS, Debian, Fedora, and Oracle are build-enabling DAMON (set
CONFIG_DAMON[1]).  Enabling it by default will save configuration setup
time for the current and future DAMON users.

Build-enabling DAMON does not introduce a real risk since it makes no
behavioral change by default.  It requires explicit user requests to do
anything.  Only one potential risk is making the size of the kernel a
little bit larger.  On a production-purpose configuration, it increases
the resulting kernel package size by about 0.1 % of the final package
file.  I believe that's too small to be a real problem in common setups.

Hence, the benefit of enabling CONFIG_DAMON outweighs the potential risk. 
Set CONFIG_DAMON by default.

Link: https://oracle.github.io/kconfigs/?config=UTS_RELEASE&config=DAMON [1]
Link: https://lkml.kernel.org/r/20250521042755.39653-3-sj@kernel.org
Signed-off-by: SeongJae Park 
Acked-by: Honggyu Kim 
Signed-off-by: Andrew Morton

mm/damon/Kconfig: set DAMON_{VADDR,PADDR,SYSFS} default to DAMON

2025-06-01T05:46:11+00:00

Patch series "mm/damon: build-enable essential DAMON components by
default".

As of this writing, multiple major distros including Alma, Amazon,
Android, CentOS, Debian, Fedora, and Oracle are build-enabling DAMON (set
CONFIG_DAMON[1]).  Configuring DAMON is not very easy, since it is
disabled by default, and there are multiple essential options that need to
be manually turned on, one by one.  Make it easier, by grouping essential
configurations to be enabled with one selection, and enabling build of the
essential parts of DAMON by default.

Note that build-enabling DAMON does not introduce any real risk, since it
makes no behavioral change by default.  It requires explicit user requests
to do anything.  Only one potential risk is making the size of the kernel
a little bit larger.  On a production-purpose configuration, it increases
the resulting kernel package binary size by about 0.1 % of the final
package file.  I believe that's too small to be a real problem in common
setups.

DAMON_{VADDR,PADDR,SYSFS} are de-facto essential parts of DAMON for normal
usages.  Because those need to be enabled one by one, however, and there
are other test-purpose or non-essential configurations, it is easy to be
confused and make mistakes at setup.  Make the essential configurations
default to CONFIG_DAMON, so that those can be enabled by default with a
single change.

Link: https://oracle.github.io/kconfigs/?config=UTS_RELEASE&config=DAMON [1]
Link: https://lkml.kernel.org/r/20250521042755.39653-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250521042755.39653-2-sj@kernel.org
Signed-off-by: SeongJae Park 
Acked-by: Honggyu Kim 
Signed-off-by: Andrew Morton

mm/damon/core: avoid destroyed target reference from DAMOS quota

2025-06-01T05:46:09+00:00

When the number of the monitoring targets in running contexts is reduced,
there may be DAMOS quotas referencing the targets that will be destroyed.

Applying the scheme action for such DAMOS scheme will be skipped forever
looking for the starting part of the region for the destroyed monitoring
target.

To fix this issue, when the monitoring target is destroyed, reset the
starting part for all DAMOS quotas that reference the target.

Link: https://lkml.kernel.org/r/20250517141852.142802-1-akinobu.mita@gmail.com
Fixes: da87878010e5 ("mm/damon/sysfs: support online inputs update")
Signed-off-by: Akinobu Mita 
Reviewed-by: SeongJae Park 
Signed-off-by: Andrew Morton

mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()

2025-05-22T21:55:38+00:00

DAMOS filters' default reject behavior is not very simple.  Actually there
was a mistake[1] during the development.  Add a kunit test for validating
the behavior.

Link: https://lkml.kernel.org/r/20250513002715.40126-5-sj@kernel.org
Link: https://lore.kernel.org/20250227002913.19359-1-sj@kernel.org [1]
Signed-off-by: SeongJae Park 
Cc: Brendan Higgins 
Cc: David Gow 
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton