moss: Prime vfs cache on boot via systemd service

This should serve to make the first blit after boot run against a hot vfs
cache, which should improve the performance of the first blit for Serpent
OS systems installed to ext4 or f2fs roots in particular.

Neither ext4 nor f2fs blits will be as fast as xfs blits (though,
surprisingly enough, ext4 blits come very close w/ hot blits), so xfs
currently remains the recommended root filesystem for Serpent OS.

Additionally, include a oneshot .service for testing the time to prime
w/ a cold vfs cache. Per the request of @ikeycode this service is gated
behind a `ConditionKernelCommandLine=moss.debug` flag, ensuring that it
will never be started by accident.

Users who need this sort of functionality can add a drop-in
`/etc/kernel/cmdline.d/moss.debug.cmdline` snippet to access it.

This PR was also rebased onto the main branch, which now shows blit stats
on actions creating a new fstx.

Signed-off-by: Rune Morling <[email protected]>

m/moss/manifest.x86_64.jsonc

@@ -20,7 +20,9 @@
 				"/usr/lib/kernel/cmdline.d/00-quiet.cmdline",
 				"/usr/lib/kernel/cmdline.d/10-amdgpu.cmdline",
 				"/usr/lib/moss/moss-fstx.sh",
+				"/usr/lib/systemd/system/moss-benchmark-time-to-prime-asset-store-vfs-cache.service",
 				"/usr/lib/systemd/system/moss-fstx.service",
+				"/usr/lib/systemd/system/moss-prime-asset-store-vfs-cache.service",
 				"/usr/share/bash-completion/completions/moss",
 				"/usr/share/defaults/etc/profile.d/80-command-not-found.sh",
 				"/usr/share/fish/completions/moss.fish",
@@ -64,6 +66,6 @@
 		}
 	},
 	"source-name": "moss",
-	"source-release": "77",
+	"source-release": "78",
 	"source-version": "0.25.1+git.e5ea34d"
 }

m/moss/pkg/moss-benchmark-time-to-prime-asset-store-vfs-cache.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Time to prime moss asset store in vfs cache in the background
+RequiresMountsFor=/
+# Avoid the present service being started by accident and slowing down boot
+ConditionKernelCommandLine=moss.debug
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/bash -c "sync && echo 3 > /proc/sys/vm/drop_caches"
+ExecStart=/usr/bin/bash -c "time nice -n20 ionice -c Idle find /.moss/assets |xargs --max-lines=1000 --max-procs=$(nproc) stat -t >/dev/null"

m/moss/pkg/moss-prime-asset-store-vfs-cache.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Prime moss asset store in vfs cache in the background
+RequiresMountsFor=/
+
+[Service]
+Type=simple
+ExecStart=/usr/bin/bash -c "time nice -n20 ionice -c Idle find /.moss/assets |xargs --max-lines=1000 --max-procs=$(nproc) stat -t >/dev/null"
+
+[Install]
+WantedBy=basic.target

m/moss/stone.yaml

@@ -5,7 +5,7 @@
 #
 name        : moss
 version     : 0.25.1+git.e5ea34d
-release     : 77
+release     : 78
 summary     : Serpent OS package manager
 license     : MPL-2.0
 homepage    : https://github.com/serpent-os/tools
@@ -61,3 +61,7 @@ install     : |
     %install_file boot/module/module-setup.sh %(installroot)%(libdir)/dracut/modules.d/90moss/module-setup.sh
     %install_file boot/moss-fstx.service %(installroot)%(libdir)/systemd/system/moss-fstx.service
     %install_exe boot/moss-fstx.sh %(installroot)%(libdir)/moss/moss-fstx.sh
+
+    # Ensure that blits happen against hot vfs cache (quicker first blits)
+    %install_file %(pkgdir)/moss-prime-asset-store-vfs-cache.service %(installroot)%(libdir)/systemd/system/moss-prime-asset-store-vfs-cache.service
+    %install_file %(pkgdir)/moss-benchmark-time-to-prime-asset-store-vfs-cache.service %(installroot)%(libdir)/systemd/system/moss-benchmark-time-to-prime-asset-store-vfs-cache.service