feat(post-install): add optional zram profile and metrics

AppImage/scripts/zram_metrics.py

@@ -0,0 +1,68 @@
+"""Read zram swap metrics from procfs and sysfs."""
+
+import re
+from pathlib import Path
+
+
+def _swap_usage(swaps_path):
+    usage = {}
+    try:
+        lines = Path(swaps_path).read_text(encoding="utf-8").splitlines()
+    except OSError:
+        return usage
+
+    for line in lines[1:]:
+        fields = line.split()
+        if len(fields) < 4:
+            continue
+        name = Path(fields[0]).name
+        if not re.fullmatch(r"zram\d+", name):
+            continue
+        try:
+            usage[name] = int(fields[3]) * 1024
+        except ValueError:
+            continue
+    return usage
+
+
+def read_zram_metrics(sys_block_root="/sys/block", swaps_path="/proc/swaps"):
+    """Return zram device counters with byte units and active swap usage."""
+    root = Path(sys_block_root)
+    try:
+        device_paths = sorted(
+            path for path in root.iterdir()
+            if path.is_dir() and re.fullmatch(r"zram\d+", path.name)
+        )
+    except OSError:
+        device_paths = []
+
+    swap_usage = _swap_usage(swaps_path)
+    devices = []
+    for path in device_paths:
+        try:
+            capacity = int((path / "disksize").read_text(encoding="utf-8").strip())
+            counters = (path / "mm_stat").read_text(encoding="utf-8").split()
+            if len(counters) < 3:
+                continue
+            original, compressed, memory_used = map(int, counters[:3])
+            if min(capacity, original, compressed, memory_used) < 0:
+                continue
+            algorithms = (path / "comp_algorithm").read_text(encoding="utf-8")
+        except (OSError, ValueError):
+            continue
+
+        selected = re.search(r"\[([^\]]+)\]", algorithms)
+        devices.append({
+            "name": path.name,
+            "active": path.name in swap_usage,
+            "capacity_bytes": capacity,
+            "swap_used_bytes": swap_usage.get(path.name, 0),
+            "original_bytes": original,
+            "compressed_bytes": compressed,
+            "memory_used_bytes": memory_used,
+            "algorithm": selected.group(1) if selected else None,
+            "compression_ratio": original / compressed if compressed else None,
+            "saved_bytes": original - memory_used,
+        })
+
+    return {"available": bool(devices), "devices": devices}