tests/cgroup: take into account LXCFS support for swap accounting

Older LXCFS versions (4.0.x and 5.0.x branches) do not handle
swap accounting on cgroup2 properly. While we are improving cgroup2
tests for a newer LXD versions we don't want to make tests red on
the older ones. So, let's check if LXCFS declares support for
swap accounting and only in this case make any checks for it.

See also:
lxc/lxcfs#663

Signed-off-by: Alexander Mikhalitsyn <[email protected]>

tests/cgroup

@@ -12,6 +12,13 @@ lxd init --auto
 
 IMAGE="${TEST_IMG:-ubuntu-minimal-daily:24.04}"
 
+rc=0
+journalctl --quiet --no-hostname --no-pager --boot=0 --unit=snap.lxd.daemon.service | grep "Kernel supports swap accounting" || rc="$?"
+LXCFS_SUPPORTS_SWAP_ACCOUNTING=0
+if [ "${rc}" -eq 0 ]; then
+    LXCFS_SUPPORTS_SWAP_ACCOUNTING=1
+fi
+
 # Test
 set -x
 
@@ -22,7 +29,8 @@ lxc launch "${IMAGE}" c1
 echo "==> Validate default values"
 [ "$(lxc exec c1 -- nproc)" = "$(nproc)" ]
 [ "$(lxc exec c1 -- grep ^MemTotal /proc/meminfo)" = "$(grep ^MemTotal /proc/meminfo)" ]
-if [ -e "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes" ] || [ -e "/sys/fs/cgroup/system.slice/memory.swap.max" ]; then
+if [ -e "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes" ] ||
+   { [ -e "/sys/fs/cgroup/system.slice/memory.swap.max" ] && [ "${LXCFS_SUPPORTS_SWAP_ACCOUNTING}" -eq 1 ]; }; then
     [ "$(lxc exec c1 -- grep ^SwapTotal /proc/meminfo)" = "$(grep ^SwapTotal /proc/meminfo)" ]
 else
     [ "$(lxc exec c1 -- grep ^SwapTotal /proc/meminfo)" = "SwapTotal:             0 kB" ]
@@ -110,7 +118,8 @@ echo "==> Testing memory limits"
 MEM_LIMIT_MIB=512
 lxc config set c1 limits.memory="${MEM_LIMIT_MIB}MiB"
 [ "$(lxc exec c1 -- grep ^MemTotal /proc/meminfo)" = "MemTotal:         $((MEM_LIMIT_MIB * 1024)) kB" ]
-if [ -e "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes" ] || [ -e "/sys/fs/cgroup/system.slice/memory.swap.max" ]; then
+if [ -e "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes" ] ||
+   { [ -e "/sys/fs/cgroup/system.slice/memory.swap.max" ] && [ "${LXCFS_SUPPORTS_SWAP_ACCOUNTING}" -eq 1 ]; }; then
     [ "$(lxc exec c1 -- grep ^SwapTotal /proc/meminfo)" = "SwapTotal:        $((MEM_LIMIT_MIB * 1024)) kB" ]
 else
     [ "$(lxc exec c1 -- grep ^SwapTotal /proc/meminfo)" = "SwapTotal:             0 kB" ]
@@ -133,7 +142,8 @@ if [ -e "/sys/fs/cgroup/memory" ]; then
     [ "$(lxc exec c1 -- cat /sys/fs/cgroup/memory/memory.swappiness)" = "65" ]
 fi
 
-if [ -e "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes" ] || [ -e "/sys/fs/cgroup/system.slice/memory.swap.max" ]; then
+if [ -e "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes" ] ||
+   { [ -e "/sys/fs/cgroup/system.slice/memory.swap.max" ] && [ "${LXCFS_SUPPORTS_SWAP_ACCOUNTING}" -eq 1 ]; }; then
     lxc config set c1 limits.memory 128MiB
     [ "$(lxc exec c1 -- grep ^MemTotal /proc/meminfo)" = "MemTotal:         131072 kB" ]