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99cea7eb52
Writing a non-zero value to a kdamond's 'refresh_ms' sysfs file should make DAMON periodically update the read-only sysfs files on its own, without the user writing update keywords such as 'update_schemes_stats' to the 'state' file. This behavior has no test coverage. Add a test that starts a kdamond with refresh_ms set and a 'stat' scheme whose default access pattern matches every monitored region, then polls the scheme's 'nr_tried' stats file directly, without requesting an update. The value can become non-zero only via the periodic refresh, so the test confirms refresh_ms works; with refresh_ms disabled the stat stays zero and the test fails. Link: https://lore.kernel.org/20260602131217.2210912-3-linuxoid@gmail.com Link: https://lore.kernel.org/20260629144927.134237-3-sj@kernel.org Signed-off-by: Ruslan Valiyev <linuxoid@gmail.com> Reviewed-by: SJ Park <sj@kernel.org> Signed-off-by: SJ Park <sj@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
76 lines
2.6 KiB
Python
Executable File
76 lines
2.6 KiB
Python
Executable File
#!/usr/bin/env python3
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# SPDX-License-Identifier: GPL-2.0
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import os
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import subprocess
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import time
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import _damon_sysfs
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def main():
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# Continuously access a memory region for far longer than the test needs,
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# so the kdamond always has a live target to monitor while we poll.
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sz_region = 10 * 1024 * 1024
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proc = subprocess.Popen(
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['./access_memory', '1', '%d' % sz_region, '60000', 'repeat'])
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# A 'stat' scheme with the default (maximally wide) access pattern matches
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# every monitored region, so its 'nr_tried' stat increases as the kdamond
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# runs. refresh_ms should make DAMON update the schemes' stats files under
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# sysfs on its own, without a manual 'update_schemes_stats' request.
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kdamond = _damon_sysfs.Kdamond(
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refresh_ms=100,
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contexts=[_damon_sysfs.DamonCtx(
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ops='vaddr',
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targets=[_damon_sysfs.DamonTarget(pid=proc.pid)],
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schemes=[_damon_sysfs.Damos(action='stat')],
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)])
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kdamonds = _damon_sysfs.Kdamonds([kdamond])
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err = kdamonds.start()
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if err is not None:
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# Kernels older than the refresh_ms feature have no such file; treat
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# that as unsupported rather than a failure.
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if not os.path.exists(os.path.join(kdamond.sysfs_dir(), 'refresh_ms')):
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proc.terminate()
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proc.wait()
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print('kdamond has no refresh_ms file; skipping')
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exit(_damon_sysfs.ksft_skip)
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proc.terminate()
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proc.wait()
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print('kdamond start failed: %s' % err)
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exit(1)
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scheme = kdamond.contexts[0].schemes[0]
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nr_tried_path = os.path.join(scheme.sysfs_dir(), 'stats', 'nr_tried')
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try:
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# Poll the stat file directly. We never request an update (e.g.
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# 'update_schemes_stats'), so 'nr_tried' can become non-zero only
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# through the periodic refresh that refresh_ms enables.
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nr_tried = 0
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deadline = time.monotonic() + 10
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while time.monotonic() < deadline:
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if proc.poll() is not None:
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print('the access_memory target exited unexpectedly')
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exit(1)
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content, err = _damon_sysfs.read_file(nr_tried_path)
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if err is not None:
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print('reading %s failed: %s' % (nr_tried_path, err))
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exit(1)
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nr_tried = int(content)
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if nr_tried > 0:
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break
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time.sleep(0.1)
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finally:
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kdamonds.stop()
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proc.terminate()
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proc.wait()
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if nr_tried == 0:
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print('refresh_ms did not auto-update the schemes stats')
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exit(1)
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if __name__ == '__main__':
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main()
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