diff mbox series

[v6,2/2] tests/functional: add memlock tests

Message ID 20250417114008.169350-3-dtalexundeer@yandex-team.ru (mailing list archive)
State New
Headers show
Series tests/functional: add memlock tests | expand

Commit Message

Alexandr Moshkov April 17, 2025, 11:40 a.m. UTC
Add new tests to check the correctness of the `-overcommit memlock`
option (possible values: off, on, on-fault) by using
`/proc/{qemu_pid}/smaps` file to check in Size, Rss and Locked fields of
anonymous segments:

* if `memlock=off`, then Locked = 0 on every anonymous smaps;
* if `memlock=on`, then Size, Rss and Locked values must be equal for
every anon smaps where Rss is not 0;
* if `memlock=on-fault`, then Rss and Locked must be equal on every anon
smaps and anonymous segment with Rss < Size must exists.

Signed-off-by: Alexandr Moshkov <dtalexundeer@yandex-team.ru>
---
 tests/functional/meson.build     |   1 +
 tests/functional/test_memlock.py | 104 +++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100755 tests/functional/test_memlock.py
diff mbox series

Patch

diff --git a/tests/functional/meson.build b/tests/functional/meson.build
index 0f8be30fe2..339af7835f 100644
--- a/tests/functional/meson.build
+++ b/tests/functional/meson.build
@@ -61,6 +61,7 @@  tests_generic_system = [
   'empty_cpu_model',
   'info_usernet',
   'version',
+  'memlock',
 ]
 
 tests_generic_linuxuser = [
diff --git a/tests/functional/test_memlock.py b/tests/functional/test_memlock.py
new file mode 100755
index 0000000000..eaf3d46dec
--- /dev/null
+++ b/tests/functional/test_memlock.py
@@ -0,0 +1,104 @@ 
+#!/usr/bin/env python3
+#
+# Functional test that check overcommit memlock options
+#
+# Copyright (c) Yandex Technologies LLC, 2025
+#
+# Author:
+#  Alexandr Moshkov <dtalexundeer@yandex-team.ru>
+#
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+import re
+
+from typing import List, Dict
+
+from qemu_test import QemuSystemTest
+from qemu_test import skipLockedMemoryTest
+
+
+SMAPS_HEADER_PATTERN = re.compile(r'^\w+-\w+', re.MULTILINE)
+SMAPS_VALUE_PATTERN = re.compile(r'^(\w+):\s+(\d+) kB', re.MULTILINE)
+
+
+@skipLockedMemoryTest(2_097_152)  # 2GB
+class MemlockTest(QemuSystemTest):
+    """
+    Boots a Linux system with memlock options.
+    Then verify, that this options is working correctly
+    by checking the smaps of the QEMU proccess.
+    """
+
+    def common_vm_setup_with_memlock(self, memlock):
+        self.vm.add_args('-overcommit', f'mem-lock={memlock}')
+        self.vm.launch()
+
+    def get_anon_smaps_by_pid(self, pid):
+        smaps_raw = self._get_raw_smaps_by_pid(pid)
+        return self._parse_anonymous_smaps(smaps_raw)
+
+    def test_memlock_off(self):
+        self.common_vm_setup_with_memlock('off')
+
+        anon_smaps = self.get_anon_smaps_by_pid(self.vm.get_pid())
+
+        # locked = 0 on every smap
+        for smap in anon_smaps:
+            self.assertEqual(smap['Locked'], 0)
+
+    def test_memlock_on(self):
+        self.common_vm_setup_with_memlock('on')
+
+        anon_smaps = self.get_anon_smaps_by_pid(self.vm.get_pid())
+
+        # size = rss = locked on every smap where rss not 0
+        for smap in anon_smaps:
+            if smap['Rss'] == 0:
+                continue
+            self.assertTrue(smap['Size'] == smap['Rss'] == smap['Locked'])
+
+    def test_memlock_onfault(self):
+        self.common_vm_setup_with_memlock('on-fault')
+
+        anon_smaps = self.get_anon_smaps_by_pid(self.vm.get_pid())
+
+        # rss = locked on every smap and segment with rss < size exists
+        exists = False
+        for smap in anon_smaps:
+            self.assertTrue(smap['Rss'] == smap['Locked'])
+            if smap['Rss'] < smap['Size']:
+                exists = True
+        self.assertTrue(exists)
+
+    def _parse_anonymous_smaps(self, smaps_raw: str) -> List[Dict[str, int]]:
+        result_segments = []
+        current_segment = {}
+        is_anonymous = False
+
+        for line in smaps_raw.split('\n'):
+            if SMAPS_HEADER_PATTERN.match(line):
+                if current_segment and is_anonymous:
+                    result_segments.append(current_segment)
+                current_segment = {}
+                # anonymous segment header looks like this:
+                # 7f3b8d3f0000-7f3b8d3f3000 rw-s 00000000 00:0f 1052
+                # and non anonymous header looks like this:
+                # 7f3b8d3f0000-7f3b8d3f3000 rw-s 00000000 00:0f 1052   [stack]
+                is_anonymous = len(line.split()) == 5
+            elif m := SMAPS_VALUE_PATTERN.match(line):
+                current_segment[m.group(1)] = int(m.group(2))
+
+        if current_segment and is_anonymous:
+            result_segments.append(current_segment)
+
+        return result_segments
+
+    def _get_raw_smaps_by_pid(self, pid: int) -> str:
+        with open(f'/proc/{pid}/smaps', 'r') as f:
+            return f.read()
+
+
+if __name__ == '__main__':
+    MemlockTest.main()