Report correct memory use on Linux & macOS

Author: CommandMC

src/backend/utils/os/processes/index.ts

@@ -14,7 +14,7 @@ interface SpawnWrapperReturn {
 
 async function genericSpawnWrapper(
   command: string,
-  args: string[],
+  args: string[] = [],
   options: SpawnWrapperOptions = {}
 ): Promise<SpawnWrapperReturn> {
   const child = spawn(command, args)

src/backend/utils/systeminfo/index.ts

@@ -7,6 +7,7 @@ import process from 'process'
 import { filesize } from 'filesize'
 
 import { getGpuInfo } from './gpu'
+import { getMemoryInfo } from './memory'
 import { getOsInfo } from './osInfo'
 import { isSteamDeck } from './steamDeck'
 import { getHeroicVersion } from './heroicVersion'
@@ -70,16 +71,7 @@ async function getSystemInfo(cache = true): Promise<SystemInformation> {
   if (cache && cachedSystemInfo) return cachedSystemInfo
 
   const cpus = os.cpus()
-  const memory = process.getSystemMemoryInfo()
-  // NOTE: Electron's memory statistics seem to be in kibibytes, not in
-  // kilobytes (like the docs say)
-  const totalMemory = memory.total * 1024
-  // FIXME: This is inaccurate, since "free" RAM is not the same as "available"
-  //        RAM on Linux ("free" often only being a couple hundred MB, while
-  //        "available" can be tens of GBs)
-  //        We're probably going to have to write our own function for this that
-  //        interprets the output of the `free` command
-  const usedMemory = (memory.total - memory.free) * 1024
+  const memory = await getMemoryInfo()
   const gpus = await getGpuInfo()
   const detailedOsInfo = await getOsInfo()
   const isDeck = isSteamDeck(cpus, gpus)
@@ -97,10 +89,10 @@ async function getSystemInfo(cache = true): Promise<SystemInformation> {
       cores: cpus.length
     },
     memory: {
-      total: totalMemory,
-      used: usedMemory,
-      totalFormatted: filesize(totalMemory, { base: 2 }) as string,
-      usedFormatted: filesize(usedMemory, { base: 2 }) as string
+      total: memory.total,
+      used: memory.used,
+      totalFormatted: filesize(memory.total, { base: 2 }) as string,
+      usedFormatted: filesize(memory.used, { base: 2 }) as string
     },
     GPUs: gpus,
     OS: {

src/backend/utils/systeminfo/memory/index.ts

@@ -0,0 +1,28 @@
+import type { SystemInformation } from '../index'
+
+type PartialMemoryInfo = Omit<
+  SystemInformation['memory'],
+  'totalFormatted' | 'usedFormatted'
+>
+
+async function getMemoryInfo(): Promise<PartialMemoryInfo> {
+  switch (process.platform) {
+    case 'linux': {
+      const { getMemoryInfo_linux } = await import('./linux')
+      return getMemoryInfo_linux()
+    }
+    case 'win32': {
+      const { getMemoryInfo_windows } = await import('./windows')
+      return getMemoryInfo_windows()
+    }
+    case 'darwin': {
+      const { getMemoryInfo_macos } = await import('./macos')
+      return getMemoryInfo_macos()
+    }
+    default:
+      return { total: 0, used: 0 }
+  }
+}
+
+export { getMemoryInfo }
+export type { PartialMemoryInfo }

src/backend/utils/systeminfo/memory/linux.ts

@@ -0,0 +1,15 @@
+import type { PartialMemoryInfo } from './index'
+import { genericSpawnWrapper } from '../../os/processes'
+
+async function getMemoryInfo_linux(): Promise<PartialMemoryInfo> {
+  const { stdout } = await genericSpawnWrapper('free', ['-b'])
+  const match = stdout.match(/^\w*:\s*(\d*)\s*(\d*)/m)
+  const totalString = match?.[1]
+  const usedString = match?.[2]
+  return {
+    total: Number(totalString),
+    used: Number(usedString)
+  }
+}
+
+export { getMemoryInfo_linux }

src/backend/utils/systeminfo/memory/macos.ts

@@ -0,0 +1,42 @@
+import os from 'os'
+
+import { genericSpawnWrapper } from '../../os/processes'
+
+import type { PartialMemoryInfo } from './index'
+
+const DEFAULT_PAGE_SIZE = 4096
+async function getPageSize(): Promise<number> {
+  const { stdout } = await genericSpawnWrapper('sysctl', ['-n', 'vm.pagesize'])
+  const pageSize = Number(stdout.trim())
+  return Number.isNaN(pageSize) ? DEFAULT_PAGE_SIZE : pageSize
+}
+
+async function getActiveAndWiredPages(): Promise<{
+  activePages: number
+  wiredPages: number
+}> {
+  const { stdout } = await genericSpawnWrapper('vm_stat')
+  const match = stdout.match(
+    /^Pages active:\s*(\d*)[\s\S]*^Pages wired down:\s*(\d*)/m
+  )
+  const activePagesString = match?.[1]
+  const wiredPagesString = match?.[2]
+  if (!activePagesString || !wiredPagesString)
+    return { activePages: 0, wiredPages: 0 }
+  return {
+    activePages: Number(activePagesString),
+    wiredPages: Number(wiredPagesString)
+  }
+}
+
+async function getMemoryInfo_macos(): Promise<PartialMemoryInfo> {
+  const total = os.totalmem()
+
+  const pageSize = await getPageSize()
+  const { activePages, wiredPages } = await getActiveAndWiredPages()
+  const used = activePages * pageSize + wiredPages * pageSize
+
+  return { total, used }
+}
+
+export { getMemoryInfo_macos }

src/backend/utils/systeminfo/memory/windows.ts

@@ -0,0 +1,13 @@
+import process from 'process'
+
+import type { PartialMemoryInfo } from './index'
+
+function getMemoryInfo_windows(): PartialMemoryInfo {
+  const { total, free } = process.getSystemMemoryInfo()
+  return {
+    total: total * 1024,
+    used: (total - free) * 1024
+  }
+}
+
+export { getMemoryInfo_windows }