selftests/damon/wss_estimation: deduplicate failed samples output

When the test fails, it shows whole sampled working set size measurements.
The purpose is showing the distribution of the measured v

selftests/damon/wss_estimation: deduplicate failed samples output

When the test fails, it shows whole sampled working set size measurements.
The purpose is showing the distribution of the measured values, to let
the tester know if it was just intermittent failure. Multiple same values
on the output are therefore unnecessary. It was not a big deal since the
test was failing only once in the past. But the test can now fail
multiple times with increased working set size, until it passes or the
working set size reaches a limit. Hence the noisy output can be quite
long and annoying. Print only the deduplicated distribution information.

Link: https://lkml.kernel.org/r/20260117020731.226785-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

selftests/damon/wss_estimation: ensure number of collected wss

DAMON selftest for working set size estimation collects DAMON's working
set size measurements of the running artificial memory access g

selftests/damon/wss_estimation: ensure number of collected wss

DAMON selftest for working set size estimation collects DAMON's working
set size measurements of the running artificial memory access generator
program until the program is finished. Depending on how quickly the
program finishes, and how quickly DAMON starts, the number of collected
working set size measurements may vary, and make the test results
unreliable. Ensure it collects 40 measurements by using the repeat mode
of the artificial memory access generator program, and finish the
measurements only after the desired number of collections are made.

Link: https://lkml.kernel.org/r/20260117020731.226785-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

selftests/damon/access_memory: add repeat mode

'access_memory' is an artificial memory access generator program that is
used for a few DAMON selftests. It accesses a given number of regions one
by

selftests/damon/access_memory: add repeat mode

'access_memory' is an artificial memory access generator program that is
used for a few DAMON selftests. It accesses a given number of regions one
by one only once, and exits. Depending on systems, the test workload may
exit faster than expected, making the tests unreliable. For reliable
control of the artificial memory access pattern, add a mode to make it
repeat running.

Link: https://lkml.kernel.org/r/20260117020731.226785-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

selftests/damon/wss_estimation: test for up to 160 MiB working set size

DAMON reads and writes Accessed bits of page tables without manual TLB
flush for two reasons. First, it minimizes the overhea

selftests/damon/wss_estimation: test for up to 160 MiB working set size

DAMON reads and writes Accessed bits of page tables without manual TLB
flush for two reasons. First, it minimizes the overhead. Second, real
systems that need DAMON are expected to be memory intensive enough to
cause periodic TLB flushes. For test setups that use small test
workloads, however, the system's TLB could be big enough to cover whole or
most accesses of the test workload. In this case, no page table walk
happens and DAMON cannot show any access from the test workload.

The test workload for DAMON's working set size estimation selftest is such
a case. It accesses only 10 MiB working set, and it turned out there are
test setups that have TLBs large enough to cover the 10 MiB data accesses.
As a result, the test fails depending on the test machine.

Make it more reliable by trying larger working sets up to 160 MiB when it
fails.

Link: https://lkml.kernel.org/r/20260117020731.226785-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

selftests/damon/sysfs_memcg_path_leak.sh: use kmemleak

Patch series "selftests/damon: improve leak detection and wss estimation
reliability".

Two DAMON selftets, namely 'sysfs_memcg_leak' and
'sysf

selftests/damon/sysfs_memcg_path_leak.sh: use kmemleak

Patch series "selftests/damon: improve leak detection and wss estimation
reliability".

Two DAMON selftets, namely 'sysfs_memcg_leak' and
'sysfs_update_schemes_tried_regions_wss_estimation' frequently show
intermittent failures due to their unreliable leak detection and working
set size estimation. Make those more reliable.


This patch (of 5):

sysfs_memcg_path_leak.sh determines if the memory leak has happened by
seeing if Slab size on /proc/meminfo increases more than expected after an
action. Depending on the system and background workloads, the reasonable
expectation varies. For the reason, the test frequently shows
intermittent failures. Use kmemleak, which is much more reliable and
correct, instead.

Link: https://lkml.kernel.org/r/20260117020731.226785-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260117020731.226785-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...