Test for loading CAS kernel module with insufficient memory

Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>

Author: Ostrokrzew

test/functional/tests/cli/test_cas_memory_usage.py

@@ -0,0 +1,79 @@
+#
+# Copyright(c) 2020 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+import pytest
+
+from api.cas.cas_module import CasModule
+from core.test_run import TestRun
+from test_utils.size import Unit
+from test_utils.os_utils import (allocate_memory,
+                                 defaultize_memory_affecting_functions,
+                                 disable_memory_affecting_functions,
+                                 drop_caches,
+                                 get_free_memory,
+                                 is_kernel_module_loaded,
+                                 load_kernel_module,
+                                 unload_kernel_module,
+                                 unmount_ramfs)
+
+
+@pytest.mark.os_dependent
+def test_insufficient_memory_for_cas_module():
+    """
+        title: Negative test of ability to load OpenCAS kernel module with insufficient memory.
+        description: |
+          Check that OpenCAS kernel module won’t be loaded in case not enough memory is available.
+        pass_criteria:
+          - Loading OpenCAS kernel module returns error.
+    """
+    with TestRun.step("Disable caching and memory over-committing."):
+        disable_memory_affecting_functions()
+        drop_caches()
+
+    with TestRun.step("Measure memory usage without OpenCAS module."):
+        if is_kernel_module_loaded(CasModule.cache.value):
+            unload_kernel_module(CasModule.cache.value)
+            unload_kernel_module(CasModule.disk.value)
+        available_mem_before_cas = get_free_memory()
+
+    with TestRun.step("Load OpenCAS module"):
+        output = load_kernel_module(CasModule.cache.value)
+        if output.exit_code != 0:
+            TestRun.fail("Cannot load OpenCAS module!")
+
+    with TestRun.step("Measure memory usage with OpenCAS module."):
+        available_mem_with_cas = get_free_memory()
+        memory_used_by_cas = available_mem_before_cas - available_mem_with_cas
+        TestRun.LOGGER.info(
+            f"OpenCAS module uses {memory_used_by_cas.get_value(Unit.MiB):.2f} MiB of DRAM."
+        )
+
+    with TestRun.step("Unload OpenCAS module."):
+        unload_kernel_module(CasModule.cache.value)
+        unload_kernel_module(CasModule.disk.value)
+
+    with TestRun.step("Allocate memory leaving not enough memory for OpenCAS module."):
+        memory_to_leave = memory_used_by_cas * (3 / 4)
+        try:
+            allocate_memory(get_free_memory() - memory_to_leave)
+        except Exception as ex:
+            TestRun.LOGGER.error(f"{ex}")
+
+    with TestRun.step(
+            "Try to load OpenCAS module and check if error message is printed on failure."
+    ):
+        output = load_kernel_module(CasModule.cache.value)
+        if output.stderr and output.exit_code != 0:
+            memory_left = get_free_memory()
+            TestRun.LOGGER.info(
+                f"Memory left for OpenCAS module: {memory_left.get_value(Unit.MiB):0.2f} MiB."
+            )
+            TestRun.LOGGER.info(f"Cannot load OpenCAS module as expected.\n{output.stderr}")
+        else:
+            TestRun.LOGGER.error("Loading OpenCAS module successfully finished, but should fail.")
+
+    with TestRun.step("Set memory options to default"):
+        unmount_ramfs()
+        defaultize_memory_affecting_functions()