[Devel] [PATCH vz10] selftests/damon: wait for the merge to apply the new max_nr_regions

[Eva Kurchatova (Virtuozzo)]

On 8/21/26 18:13, Eva Kurchatova wrote:
> damon_nr_regions sleeps 0.3s after committing max_nr_regions and then
> reads the number of regions back, which assumes the merge has happened
> by then.  On a machine that is not idle it has not, and the test fails
> on a region count that is still the old one.
>
> Poll until the count settles instead of sleeping for a fixed time.
>
> https://virtuozzo.atlassian.net/browse/VSTOR-132453
> Feature: fix selftests
> Signed-off-by: Eva Kurchatova <eva.kurchatova at virtuozzo.com>
> ---
>   .../selftests/damon/damon_nr_regions.py       | 35 +++++++++++--------
>   1 file changed, 20 insertions(+), 15 deletions(-)
>
> diff --git a/tools/testing/selftests/damon/damon_nr_regions.py b/tools/testing/selftests/damon/damon_nr_regions.py
> index cb31cd140d22..39063ce5b27d 100755
> --- a/tools/testing/selftests/damon/damon_nr_regions.py
> +++ b/tools/testing/selftests/damon/damon_nr_regions.py
> @@ -4,6 +4,7 @@
>   import subprocess
>   import time
>   
> +
>   import _damon_sysfs
>   
>   def test_nr_regions(real_nr_regions, min_nr_regions, max_nr_regions):
> @@ -114,27 +115,31 @@ def main():
>           proc.terminate()
>           print('commit failed: %s' % err)
>           exit(1)
> -    # wait for next merge operation is executed
> -    time.sleep(0.3)
> +    # wait for the merge operations to apply the new max_nr_regions
> +    nr_tried_regions = 0
> +    for _ in range(50):
> +        time.sleep(0.1)
>   
> -    err = kdamonds.kdamonds[0].update_schemes_tried_regions()
> -    if err is not None:
> -        proc.terminate()
> -        print('tried regions update failed: %s' % err)
> -        exit(1)
> +        err = kdamonds.kdamonds[0].update_schemes_tried_regions()
> +        if err is not None:
> +            proc.terminate()
> +            print('tried regions update failed: %s' % err)
> +            exit(1)
>   
> -    scheme = kdamonds.kdamonds[0].contexts[0].schemes[0]
> -    if scheme.tried_regions is None:
> -        proc.terminate()
> -        print('tried regions is not collected')
> -        exit(1)
> +        scheme = kdamonds.kdamonds[0].contexts[0].schemes[0]
> +        if scheme.tried_regions is None:
> +            proc.terminate()
> +            print('tried regions is not collected')
> +            exit(1)
> +
> +        nr_tried_regions = len(scheme.tried_regions)
> +        if 0 < nr_tried_regions <= 7:
> +            break
> +    proc.terminate()
>   
> -    nr_tried_regions = len(scheme.tried_regions)
>       if nr_tried_regions <= 0:
> -        proc.terminate()
>           print('tried regions is not created')
>           exit(1)
> -    proc.terminate()
>   
>       if nr_tried_regions > 7:
>           print('fail online-tuned max_nr_regions: %d > 7' % nr_tried_regions)

Sent v2, replacing this commit with two upstream backports: 
https://lists.openvz.org/pipermail/devel/2026-September/084959.html

Verification: 
https://bitbucket.org/virtuozzocore/vzkernel.vzspecs/pipelines/results/609