fix(webserver): os.freemem() isn't what it appears to be

Hypfer · May 29, 2021 · 80743f4 · 80743f4
1 parent fd908f6
commit 80743f4
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Showing 2 changed files with 23 additions and 3 deletions.
diff --git a/backend/lib/Valetudo.js b/backend/lib/Valetudo.js
@@ -110,9 +110,11 @@ class Valetudo {
                  * With node v15, we could use process.memoryUsage.rss() which doesn't do that,
                  * but we don't have that version available yet
                  *
-                 * Therefore, we'll only act when the overall memory usage gets somewhat critical
+                 * Unfortunately, os.freemem() doesn't return the actual free memory including buffers, caches etc.
+                 * Therefore, we're using a rather small value here, since the value reported will be much lower
+                 * than the actual available memory
                  */
-                if (os.freemem() <= 52*1024*1024) {
+                if (os.freemem() <= os.totalmem()*0.1) {
                     const rss = process.memoryUsage().rss;
 
                     if (rss > overLimit) {

diff --git a/backend/lib/webserver/SystemRouter.js b/backend/lib/webserver/SystemRouter.js
@@ -1,4 +1,5 @@
 const express = require("express");
+const fs = require("fs");
 const os = require("os");
 
 class SystemRouter {
@@ -20,7 +21,7 @@ class SystemRouter {
                 arch: os.arch(),
                 mem: {
                     total: os.totalmem(),
-                    free: os.freemem(),
+                    free: this.getFreeMemory(),
                     valetudo_current: process.memoryUsage()?.rss,
                     valetudo_max: process.resourceUsage()?.maxRSS * 1024
                 },
@@ -45,6 +46,23 @@ class SystemRouter {
         });
     }
 
+    /**
+     * @private
+     */
+    getFreeMemory() {
+        let free;
+
+        try {
+            const meminfo = fs.readFileSync("/proc/meminfo").toString();
+            free = /MemAvailable:\s*(?<mem_available>\d+) kB/.exec(meminfo)?.groups?.mem_available;
+            free = parseInt(free) * 1024;
+        } catch (e) {
+            //intentional
+        }
+
+        return free ?? os.freemem();
+    }
+
     getRouter() {
         return this.router;
     }