fix: move root fs configuration into etc/

etc/ssh/sshd_config.d/sshd_harden.conf

@@ -0,0 +1,3 @@
+ChallengeResponseAuthentication no
+PasswordAuthentication no
+PermitRootLogin no

etc/sysctl.d/99-gaming-perf.conf

@@ -0,0 +1,8 @@
+# https://wiki.archlinux.org/title/Gaming#Improving_performance
+vm.compaction_proactiveness = 0
+vm.watermark_boost_factor = 1
+vm.min_free_kbytes = 1048576
+vm.watermark_scale_factor = 500
+vm.swappiness = 10
+vm.zone_reclaim_mode = 0
+vm.page_lock_unfairness = 1

etc/sysctl.d/99-network.conf

@@ -0,0 +1,14 @@
+# Network performance optimizations from Arch Wiki
+# https://wiki.archlinux.org/title/Sysctl#Increase_the_memory_dedicated_to_the_network_interfaces
+net.core.rmem_default = 1048576
+net.core.rmem_max = 16777216
+net.core.wmem_default = 1048576
+net.core.wmem_max = 16777216
+net.core.optmem_max = 65536
+net.ipv4.tcp_rmem = 4096 1048576 2097152
+net.ipv4.tcp_wmem = 4096 65536 16777216
+net.ipv4.udp_rmem_min = 8192
+net.ipv4.udp_wmem_min = 8192
+net.core.netdev_max_backlog = 16384
+net.core.somaxconn = 8192
+net.ipv4.tcp_fastopen = 3

etc/tmpfiles.d/99-gaming-perf.conf

@@ -0,0 +1,6 @@
+# https://wiki.archlinux.org/title/Gaming#Improving_performance
+#   Path                                                Mode    UID GID Age Argument
+w   /sys/kernel/mm/lru_gen/enabled                      -       -   -   -   5
+w   /sys/kernel/mm/transparent_hugepage/enabled         -       -   -   -   madvise
+w   /sys/kernel/mm/transparent_hugepage/shmem_enabled   -       -   -   -   advise
+w   /sys/kernel/mm/transparent_hugepage/defrag          -       -   -   -   never

etc/udev/rules.d/99-perf.rules

@@ -0,0 +1,8 @@
+SUBSYSTEM=="pci", KERNEL=="0000:03:00.0", ACTION=="add|change", \
+  ATTR{power_dpm_force_performance_level}="manual", \
+  ATTR{pp_power_profile_mode}="1"
+
+SUBSYSTEM=="cpu", ACTION=="add|change", \
+  ATTR{cpufreq/scaling_governor}="powersave", \
+  ATTR{cpufreq/energy_performance_preference}="balance_performance"
+