Merge pull request #1888 from github/henrymercer/constrained-ram

Respect RAM constraints imposed by Linux cgroups

lib/util.js

@@ -148,6 +148,27 @@ function getMemoryFlagValueForPlatform(userInput, totalMemoryBytes, platform) {
     return Math.floor(memoryToUseMegaBytes);
 }
 exports.getMemoryFlagValueForPlatform = getMemoryFlagValueForPlatform;
+/**
+ * Get the total amount of memory available to the Action, taking into account constraints imposed
+ * by cgroups on Linux.
+ */
+function getTotalMemoryAvailable() {
+    if (os.platform() === "linux") {
+        // Respect constraints imposed by Linux cgroups v1 and v2
+        for (const limitFile of [
+            "/sys/fs/cgroup/memory/memory.limit_in_bytes",
+            "/sys/fs/cgroup/memory.max",
+        ]) {
+            if (fs.existsSync(limitFile)) {
+                const limit = Number(fs.readFileSync(limitFile, "utf8"));
+                if (Number.isInteger(limit)) {
+                    return limit;
+                }
+            }
+        }
+    }
+    return os.totalmem();
+}
 /**
  * Get the value of the codeql `--ram` flag as configured by the `ram` input.
  * If no value was specified, the total available memory will be used minus a
@@ -156,7 +177,7 @@ exports.getMemoryFlagValueForPlatform = getMemoryFlagValueForPlatform;
  * @returns {number} the amount of RAM to use, in megabytes
  */
 function getMemoryFlagValue(userInput) {
-    return getMemoryFlagValueForPlatform(userInput, os.totalmem(), process.platform);
+    return getMemoryFlagValueForPlatform(userInput, getTotalMemoryAvailable(), process.platform);
 }
 exports.getMemoryFlagValue = getMemoryFlagValue;
 /**

src/util.ts

@@ -211,6 +211,28 @@ export function getMemoryFlagValueForPlatform(
   return Math.floor(memoryToUseMegaBytes);
 }
 
+/**
+ * Get the total amount of memory available to the Action, taking into account constraints imposed
+ * by cgroups on Linux.
+ */
+function getTotalMemoryAvailable(): number {
+  if (os.platform() === "linux") {
+    // Respect constraints imposed by Linux cgroups v1 and v2
+    for (const limitFile of [
+      "/sys/fs/cgroup/memory/memory.limit_in_bytes",
+      "/sys/fs/cgroup/memory.max",
+    ]) {
+      if (fs.existsSync(limitFile)) {
+        const limit = Number(fs.readFileSync(limitFile, "utf8"));
+        if (Number.isInteger(limit)) {
+          return limit;
+        }
+      }
+    }
+  }
+  return os.totalmem();
+}
+
 /**
  * Get the value of the codeql `--ram` flag as configured by the `ram` input.
  * If no value was specified, the total available memory will be used minus a
@@ -221,7 +243,7 @@ export function getMemoryFlagValueForPlatform(
 export function getMemoryFlagValue(userInput: string | undefined): number {
   return getMemoryFlagValueForPlatform(
     userInput,
-    os.totalmem(),
+    getTotalMemoryAvailable(),
     process.platform,
   );
 }