6.12-stable review patch. If anyone has any objections, please let me know.
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From: SeongJae Park sj@kernel.org
commit 695469c07a65547acb6e229b3fdf6aaa881817e3 upstream.
damon_nr_regions.py updates max_nr_regions to a number smaller than expected number of real regions and confirms DAMON respect the harsh limit. To give time for DAMON to make changes for the regions, 3 aggregation intervals (300 milliseconds) are given.
The internal mechanism works with not only the max_nr_regions, but also sz_limit, though. It avoids merging region if that casn make region of size larger than sz_limit. In the test, sz_limit is set too small to achive the new max_nr_regions, unless it is updated for the new min_nr_regions. But the update is done only once per operations set update interval, which is one second by default.
Hence, the test randomly incurs false positive failures. Fix it by setting the ops interval same to aggregation interval, to make sure sz_limit is updated by the time of the check.
Link: https://lkml.kernel.org/r/20250225222333.505646-3-sj@kernel.org Fixes: 8bf890c81612 ("selftests/damon/damon_nr_regions: test online-tuned max_nr_regions") Signed-off-by: SeongJae Park sj@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/damon/damon_nr_regions.py | 1 + 1 file changed, 1 insertion(+)
--- a/tools/testing/selftests/damon/damon_nr_regions.py +++ b/tools/testing/selftests/damon/damon_nr_regions.py @@ -109,6 +109,7 @@ def main(): attrs = kdamonds.kdamonds[0].contexts[0].monitoring_attrs attrs.min_nr_regions = 3 attrs.max_nr_regions = 7 + attrs.update_us = 100000 err = kdamonds.kdamonds[0].commit() if err is not None: proc.terminate()