Add host available memory

jupyter_resource_usage/api.py

@@ -46,6 +46,8 @@ async def get(self):
             except (psutil.NoSuchProcess, psutil.AccessDenied) as e:
                 pass
 
+        available = psutil.virtual_memory().available
+
         if callable(config.mem_limit):
             mem_limit = config.mem_limit(rss=rss, pss=pss)
         else:  # mem_limit is an Int
@@ -58,6 +60,7 @@ async def get(self):
             )
 
         metrics = {"rss": rss, "limits": limits}
+        metrics["mem_avail"] = available
         if pss is not None:
             metrics["pss"] = pss
 

jupyter_resource_usage/config.py

@@ -54,7 +54,10 @@ class ResourceUseDisplay(Configurable):
 
     system_memory_metrics = List(
         trait=PSUtilMetric(),
-        default_value=[{"name": "virtual_memory", "attribute": "total"}],
+        default_value=[
+            {"name": "virtual_memory", "attribute": "total"},
+            {"name": "virtual_memory", "attribute": "available"}
+        ],
     )
 
     process_cpu_metrics = List(

packages/labextension/src/model.ts

@@ -254,9 +254,25 @@ export namespace ResourceUsage {
       this._memoryAvailable = numBytes !== undefined;
       this._currentMemory = currentMemory;
       this._memUnits = memUnits;
-      this._memoryLimit = memoryLimit
-        ? memoryLimit / MEMORY_UNIT_LIMITS[memUnits]
+
+// Use mem_avail if the host exposes it.
+      const hostAvailBytes = value.mem_avail ?? null ;
+      let minMemAvailable = null;
+      let hostMaxBytes = hostAvailBytes ? ( hostAvailBytes + numBytes ) : null;
+
+      if ( memoryLimit && hostMaxBytes ) { minMemAvailable = Math.min(hostMaxBytes,memoryLimit); }
+      else if ( hostMaxBytes ) { minMemAvailable = hostMaxBytes }
+      else if ( memoryLimit ) { minMemAvailable = memoryLimit }
+      else if ( hostAvailBytes ) { minMemAvailable = hostAvailBytes + numBytes; }
+
+      this._memoryLimit = minMemAvailable
+        ? minMemAvailable / MEMORY_UNIT_LIMITS[memUnits]
         : null;
+
+//      this._memoryLimit = memoryLimit
+//        ? memoryLimit / MEMORY_UNIT_LIMITS[memUnits]
+//        : null;
+
       const memoryPercent = this.memoryLimit
         ? Math.min(this._currentMemory / this.memoryLimit, 1)
         : 0;
@@ -373,6 +389,7 @@ namespace Private {
   export interface IMetricRequestResult {
     rss: number;
     pss?: number;
+    mem_avail?: number;
     cpu_percent?: number;
     cpu_count?: number;
     disk_total?: number;