以编程方式清除Windows 7备用内存

最近我的系统内存耗尽了一些问题。 花了一段时间才发现发生了什么，但我最终确定当我从文件共享中将大量数据复制到我的机器时，等待大量内存被放入“待机”状态。 任务管理器似乎没有显示备用内存使用情况，但资源监视器显示。 起初我只能通过重新启动来恢复内存，但最终我发现SysInternals的人已经编写了一个很棒的实用工具来释放内存（链接如下）。

以下是备用内存的简要介绍：

待机列表包含已从进程工作集中删除的未修改页面，这有效地使备用列表成为缓存。 如果进程需要待机列表中的页面，则内存管理器会立即将页面返回到其工作集。 待机列表中的所有页面都可用于内存分配请求。 如果进程请求内存，则内存管理器可以从待机列表中获取页面，对其进行初始化，并将其分配给调用进程。 这称为重新调整页面。 待机列表中的页面通常来自最近使用的文件。 通过将这些页面保留在待机列表中，内存管理器减少了从磁盘读取信息的需要。 磁盘读取会降低系统响应能力。

（这是来自这里的文件： 内存大小指导

以下是该工具的链接： RAMMap

我的问题是：

有没有人知道如何以编程方式？ 理想情况下我想使用C＃，但我会感谢任何可能帮助我得到答案的指针。

谢谢！

Answer 1

这是我的代码，它是一个必须以管理员权限运行的控制台应用程序。 代码是C＃。 使用EmptyWorkingSet和MemoryPurgeStandbyList。

using System; using System.ComponentModel; using System.Diagnostics; using System.Runtime.InteropServices; using System.Security.Principal; using System.Threading; using System.Collections.Generic; namespace FreeMemory { //Declaration of structures //SYSTEM_CACHE_INFORMATION [StructLayout(LayoutKind.Sequential, Pack = 1)] struct SYSTEM_CACHE_INFORMATION { public uint CurrentSize; public uint PeakSize; public uint PageFaultCount; public uint MinimumWorkingSet; public uint MaximumWorkingSet; public uint Unused1; public uint Unused2; public uint Unused3; public uint Unused4; } //SYSTEM_CACHE_INFORMATION_64_BIT [StructLayout(LayoutKind.Sequential, Pack = 1)] struct SYSTEM_CACHE_INFORMATION_64_BIT { public long CurrentSize; public long PeakSize; public long PageFaultCount; public long MinimumWorkingSet; public long MaximumWorkingSet; public long Unused1; public long Unused2; public long Unused3; public long Unused4; } //TokPriv1Luid [StructLayout(LayoutKind.Sequential, Pack = 1)] internal struct TokPriv1Luid { public int Count; public long Luid; public int Attr; } public class Program { //Declaration of constants const int SE_PRIVILEGE_ENABLED = 2; const string SE_INCREASE_QUOTA_NAME = "SeIncreaseQuotaPrivilege"; const string SE_PROFILE_SINGLE_PROCESS_NAME = "SeProfileSingleProcessPrivilege"; const int SystemFileCacheInformation = 0x0015; const int SystemMemoryListInformation = 0x0050; const int MemoryPurgeStandbyList = 4; const int MemoryEmptyWorkingSets = 2; //Import of DLL's (API) and the necessary functions [DllImport("advapi32.dll", SetLastError = true)] internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid); [DllImport("advapi32.dll", SetLastError = true)] internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall, ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen); [DllImport("ntdll.dll")] public static extern UInt32 NtSetSystemInformation(int InfoClass, IntPtr Info, int Length); [DllImport("psapi.dll")] static extern int EmptyWorkingSet(IntPtr hwProc); //Function to clear working set of all processes public static void EmptyWorkingSetFunction() { //Declaration of variables string ProcessName = string.Empty; Process[] allProcesses = Process.GetProcesses(); List successProcesses = new List(); List failProcesses = new List(); //Cycle through all processes for (int i = 0; i < allProcesses.Length; i++) { Process p = new Process(); p = allProcesses[i]; //Try to empty the working set of the process, if succesfull add to successProcesses, if failed add to failProcesses with error message try { ProcessName = p.ProcessName; EmptyWorkingSet(p.Handle); successProcesses.Add(ProcessName); } catch (Exception ex) { failProcesses.Add(ProcessName + ": " + ex.Message); } } //Print the lists with successful and failed processes Console.WriteLine("SUCCESSFULLY CLEARED PROCESSES: " + successProcesses.Count); Console.WriteLine("-------------------------------"); for (int i = 0; i < successProcesses.Count; i++) { Console.WriteLine(successProcesses[i]); } Console.WriteLine(); Console.WriteLine("FAILED CLEARED PROCESSES: " + failProcesses.Count); Console.WriteLine("-------------------------------"); for (int i = 0; i < failProcesses.Count; i++) { Console.WriteLine(failProcesses[i]); } Console.WriteLine(); } //Function to check if OS is 64-bit or not, returns boolean public static bool Is64BitMode() { return Marshal.SizeOf(typeof(IntPtr)) == 8; } //Function used to clear file system cache, returns boolean public static void ClearFileSystemCache(bool ClearStandbyCache) { try { //Check if privilege can be increased if (SetIncreasePrivilege(SE_INCREASE_QUOTA_NAME)) { uint num1; int SystemInfoLength; GCHandle gcHandle; //First check which version is running, then fill structure with cache information. Throw error is cache information cannot be read. if (!Is64BitMode()) { SYSTEM_CACHE_INFORMATION cacheInformation = new SYSTEM_CACHE_INFORMATION(); cacheInformation.MinimumWorkingSet = uint.MaxValue; cacheInformation.MaximumWorkingSet = uint.MaxValue; SystemInfoLength = Marshal.SizeOf(cacheInformation); gcHandle = GCHandle.Alloc(cacheInformation, GCHandleType.Pinned); num1 = NtSetSystemInformation(SystemFileCacheInformation, gcHandle.AddrOfPinnedObject(), SystemInfoLength); gcHandle.Free(); } else { SYSTEM_CACHE_INFORMATION_64_BIT information64Bit = new SYSTEM_CACHE_INFORMATION_64_BIT(); information64Bit.MinimumWorkingSet = -1L; information64Bit.MaximumWorkingSet = -1L; SystemInfoLength = Marshal.SizeOf(information64Bit); gcHandle = GCHandle.Alloc(information64Bit, GCHandleType.Pinned); num1 = NtSetSystemInformation(SystemFileCacheInformation, gcHandle.AddrOfPinnedObject(), SystemInfoLength); gcHandle.Free(); } if (num1 != 0) throw new Exception("NtSetSystemInformation(SYSTEMCACHEINFORMATION) error: ", new Win32Exception(Marshal.GetLastWin32Error())); } //If passes paramater is 'true' and the privilege can be increased, then clear standby lists through MemoryPurgeStandbyList if (ClearStandbyCache && SetIncreasePrivilege(SE_PROFILE_SINGLE_PROCESS_NAME)) { int SystemInfoLength = Marshal.SizeOf(MemoryPurgeStandbyList); GCHandle gcHandle = GCHandle.Alloc(MemoryPurgeStandbyList, GCHandleType.Pinned); uint num2 = NtSetSystemInformation(SystemMemoryListInformation, gcHandle.AddrOfPinnedObject(), SystemInfoLength); gcHandle.Free(); if (num2 != 0) throw new Exception("NtSetSystemInformation(SYSTEMMEMORYLISTINFORMATION) error: ", new Win32Exception(Marshal.GetLastWin32Error())); } } catch (Exception ex) { Console.Write(ex.ToString()); } } //Function to increase Privilege, returns boolean private static bool SetIncreasePrivilege(string privilegeName) { using (WindowsIdentity current = WindowsIdentity.GetCurrent(TokenAccessLevels.Query | TokenAccessLevels.AdjustPrivileges)) { TokPriv1Luid newst; newst.Count = 1; newst.Luid = 0L; newst.Attr = SE_PRIVILEGE_ENABLED; //Retrieves the LUID used on a specified system to locally represent the specified privilege name if (!LookupPrivilegeValue(null, privilegeName, ref newst.Luid)) throw new Exception("Error in LookupPrivilegeValue: ", new Win32Exception(Marshal.GetLastWin32Error())); //Enables or disables privileges in a specified access token int num = AdjustTokenPrivileges(current.Token, false, ref newst, 0, IntPtr.Zero, IntPtr.Zero) ? 1 : 0; if (num == 0) throw new Exception("Error in AdjustTokenPrivileges: ", new Win32Exception(Marshal.GetLastWin32Error())); return num != 0; } } //MAIN Program static void Main(string[] args) { //Clear working set of all processes EmptyWorkingSetFunction(); //Clear file system cache ClearFileSystemCache(true); //Waiting for input of user to close program Console.WriteLine("Press any key to exit."); Console.ReadKey(); } } } 

Answer 2

秘密似乎是在Process Hacker源代码中（使用c语言）。 查看代码，您将看到一个有前途的命令MemoryPurgeStandbyList ，当我们在GUI中选择“空待机列表”选项时，它似乎被调用。

 memlists.c(227, 35): command = MemoryPurgeStandbyList; ntexapi.h(1475, 5): MemoryPurgeStandbyList, 

http://processhacker.sourceforge.net/

此处也可用作命令行版本。

Answer 3

这概述了在C＃中实现这一目标所需的基本步骤

 using System; using System.Runtime.InteropServices; using System.Security.Principal; public static class MemoryUtility { private static void ClearStandbyCache() { SetIncreasePrivilege(SE_PROFILE_SINGLE_PROCESS_NAME); int iReturn; int iSize = Marshal.SizeOf(ClearStandbyPageList); GCHandle gch = GCHandle.Alloc(ClearStandbyPageList, GCHandleType.Pinned); iReturn = NtSetSystemInformation(SYSTEMMEMORYLISTINFORMATION, gch.AddrOfPinnedObject(), iSize); gch.Free(); if (iReturn != 0) Console.WriteLine("Empty Standby List failed"); else Console.WriteLine("Empty Standby List success"); } [DllImport("NTDLL.dll", SetLastError = true)] internal static extern int NtSetSystemInformation(int SystemInformationClass, IntPtr SystemInfo, int SystemInfoLength); //SystemInformationClass values private static int SYSTEMCACHEINFORMATION = 0x15; private static int SYSTEMMEMORYLISTINFORMATION = 80; //SystemInfo values private static int ClearStandbyPageList = 4; } 

此处还有一个链接到一些文档，其中记录了SetIncreasePrivilege方法，并且还包含许多有关该主题的有用资源： http ：//www.pinvoke.net/default.aspx/ntdll/NtSetSystemInformation.html