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# Copyright (c) Meta Platforms, Inc. and affiliates.
# SPDX-License-Identifier: LGPL-2.1-or-later
import collections
import contextlib
import mmap
import os
from pathlib import Path
import re
import subprocess
import tempfile
from typing import NamedTuple
from drgn.helpers.linux.swap import (
for_each_swap_info,
swap_file_path,
swap_is_file,
swap_total_usage,
swap_usage_in_pages,
total_swapcache_pages,
)
from tests.linux_kernel import (
LinuxKernelTestCase,
MbrPartition,
MbrPartitionType,
fallocate,
meminfo_field_in_pages,
mkswap,
mount,
skip_unless_have_test_disk,
swapoff,
swapon,
umount,
write_mbr,
)
class SwapInfo(NamedTuple):
filename: str
type: str
size: int
used: int
priority: int
def iter_swaps():
with open("/proc/swaps", "rb") as f:
f.readline()
for line in f:
tokens = line.split()
yield SwapInfo(
filename=tokens[0].decode("unicode-escape"),
type=tokens[1].decode("ascii"),
size=int(tokens[2]) * 1024,
used=int(tokens[3]) * 1024,
priority=int(tokens[4]),
)
@contextlib.contextmanager
def tmp_swaps():
disk = os.environ["DRGN_TEST_DISK"]
swaps = []
with contextlib.ExitStack() as exit_stack:
write_mbr(
disk,
[
MbrPartition(
type=MbrPartitionType.LINUX_SWAP,
start=1024 * 1024,
size=8 * 1024 * 1024,
),
MbrPartition(
type=MbrPartitionType.LINUX,
start=9 * 1024 * 1024,
size=8 * 1024 * 1024,
),
],
)
part_prefix = os.environ["DRGN_TEST_DISK"]
if part_prefix[:-1].isdigit():
part_prefix += "p"
part1 = part_prefix + "1"
part2 = part_prefix + "2"
mkswap(part1)
swapon(part1)
exit_stack.callback(swapoff, part1)
swaps.append((part1, False))
subprocess.check_call(["mke2fs", "-qF", part2])
tmp = Path(exit_stack.enter_context(tempfile.TemporaryDirectory()))
mount(part2, tmp, "ext2")
exit_stack.callback(umount, tmp)
swap_file = tmp / "swap_file"
fallocate(swap_file, 0, 1024 * 1024)
mkswap(swap_file)
swapon(swap_file)
exit_stack.callback(swapoff, swap_file)
swaps.append((swap_file, True))
yield swaps
@skip_unless_have_test_disk
class TestSwap(LinuxKernelTestCase):
@classmethod
def setUpClass(cls):
super().setUpClass()
cls.enterClassContext(tmp_swaps())
# There is no test_for_each_swap_info() because we test it implicitly in
# the other tests. These tests also handle duplicate swap filenames, which
# are unlikely but theoretically possible with namespace shenanigans.
def test_swap_file_path(self):
self.assertCountEqual(
[os.fsdecode(swap_file_path(si)) for si in for_each_swap_info(self.prog)],
[swap_info.filename for swap_info in iter_swaps()],
)
def test_swap_is_file(self):
self.assertCountEqual(
[
(os.fsdecode(swap_file_path(si)), swap_is_file(si))
for si in for_each_swap_info(self.prog)
],
[
(swap_info.filename, swap_info.type == "file")
for swap_info in iter_swaps()
],
)
def test_swap_usage_in_pages(self):
actual = collections.Counter()
for si in for_each_swap_info(self.prog):
actual[os.fsdecode(swap_file_path(si))] += (
swap_usage_in_pages(si) * mmap.PAGESIZE
)
expected = collections.Counter()
for swap_info in iter_swaps():
expected[swap_info.filename] += swap_info.used
for filename, used in expected.items():
# Generous delta to allow for stuff getting swapped in/out while
# the test is running.
self.assertAlmostEqual(used, actual[filename], delta=1024 * 1024 * 1024)
def test_swap_total_usage(self):
swap_usage = swap_total_usage(self.prog)
with open("/proc/meminfo", "r") as f:
for line in f:
if match := re.match(r"Swap(Total|Free):\s*([0-9]+)\s*kB", line):
value = int(match.group(2)) * 1024 // mmap.PAGESIZE
if match.group(1) == "Total":
pages = value
else:
free_pages = value
self.assertEqual(swap_usage.pages, pages)
# Generous delta to allow for stuff getting swapped in/out while the
# test is running.
self.assertAlmostEqual(
swap_usage.free_pages, free_pages, delta=1024 * 1024 * 1024
)
def test_total_swapcache_pages(self):
self.assertAlmostEqual(
total_swapcache_pages(self.prog),
meminfo_field_in_pages("SwapCached"),
delta=1024 * 1024 * 1024,
)
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