Code:
/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / whidbey / NetFXspW7 / ndp / fx / src / Misc / HandleCollector.cs / 1 / HandleCollector.cs
#if DEBUG_HANDLECOLLECTOR
using System.Diagnostics;
#endif
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
[module: SuppressMessage("Microsoft.Design", "CA1020:AvoidNamespacesWithFewTypes", Scope="namespace", Target="System.Internal")]
namespace System.Internal {
internal sealed class HandleCollector {
private static HandleType[] handleTypes;
private static int handleTypeCount;
private static int suspendCount;
internal static event HandleChangeEventHandler HandleAdded;
internal static event HandleChangeEventHandler HandleRemoved;
private static object internalSyncObject = new object();
///
/// Adds the given handle to the handle collector. This keeps the
/// handle on a "hot list" of objects that may need to be garbage
/// collected.
///
internal static IntPtr Add(IntPtr handle, int type) {
handleTypes[type - 1].Add(handle);
return handle;
}
///
/// Suspends GC.Collect
///
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
internal static void SuspendCollect() {
lock(internalSyncObject) {
suspendCount++;
}
}
///
/// Resumes GC.Collect
///
[SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods")]
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
internal static void ResumeCollect() {
bool performCollect = false;
lock(internalSyncObject) {
if(suspendCount > 0){
suspendCount--;
}
if(suspendCount == 0)
{
for(int i=0; i < handleTypeCount; i++)
{
lock(handleTypes[i]) {
if (handleTypes[i].NeedCollection())
{
performCollect = true;
}
}
}
}
}
if(performCollect)
{
GC.Collect();
}
}
///
/// Registers a new type of handle with the handle collector.
///
internal static int RegisterType(string typeName, int expense, int initialThreshold) {
lock (internalSyncObject){
if (handleTypeCount == 0 || handleTypeCount == handleTypes.Length) {
HandleType[] newTypes = new HandleType[handleTypeCount + 10];
if (handleTypes != null) {
Array.Copy(handleTypes, 0, newTypes, 0, handleTypeCount);
}
handleTypes = newTypes;
}
handleTypes[handleTypeCount++] = new HandleType(typeName, expense, initialThreshold);
return handleTypeCount;
}
}
///
/// Removes the given handle from the handle collector. Removing a
/// handle removes it from our "hot list" of objects that should be
/// frequently garbage collected.
///
internal static IntPtr Remove(IntPtr handle, int type) {
return handleTypes[type - 1].Remove(handle);
}
///
/// Represents a specific type of handle.
///
private class HandleType {
internal readonly string name;
private int initialThreshHold;
private int threshHold;
private int handleCount;
private readonly int deltaPercent;
#if DEBUG_HANDLECOLLECTOR
private List handles = new List();
#endif
///
/// Creates a new handle type.
///
internal HandleType(string name, int expense, int initialThreshHold) {
this.name = name;
this.initialThreshHold = initialThreshHold;
this.threshHold = initialThreshHold;
this.deltaPercent = 100 - expense;
}
///
/// Adds a handle to this handle type for monitoring.
///
[SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods")]
internal void Add(IntPtr handle) {
if( handle == IntPtr.Zero )
{
return;
}
bool performCollect = false;
int currentCount = 0;
lock(this) {
handleCount++;
#if DEBUG_HANDLECOLLECTOR
Debug.Assert(!handles.Contains(handle));
handles.Add(handle);
#endif
performCollect = NeedCollection();
currentCount = handleCount;
}
lock (internalSyncObject){
if (HandleCollector.HandleAdded != null) {
HandleCollector.HandleAdded(name, handle, currentCount);
}
}
if (!performCollect) {
return;
}
if (performCollect) {
#if DEBUG_HANDLECOLLECTOR
Debug.WriteLine("HC> Forcing garbage collect");
Debug.WriteLine("HC> name :" + name);
Debug.WriteLine("HC> threshHold :" + (threshHold).ToString());
Debug.WriteLine("HC> handleCount :" + (handleCount).ToString());
Debug.WriteLine("HC> deltaPercent:" + (deltaPercent).ToString());
#endif
GC.Collect();
// We just performed a GC. If the main thread is in a tight
// loop there is a this will cause us to increase handles forever and prevent handle collector
// from doing its job. Yield the thread here. This won't totally cause
// a finalization pass but it will effectively elevate the priority
// of the finalizer thread just for an instant. But how long should
// we sleep? We base it on how expensive the handles are because the
// more expensive the handle, the more critical that it be reclaimed.
int sleep = (100 - deltaPercent) / 4;
System.Threading.Thread.Sleep(sleep);
}
}
///
/// Retrieves the outstanding handle count for this
/// handle type.
///
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
internal int GetHandleCount() {
lock(this) {
return handleCount;
}
}
///
/// Determines if this handle type needs a garbage collection pass.
///
internal bool NeedCollection() {
if (suspendCount > 0){
return false;
}
if (handleCount > threshHold) {
threshHold = handleCount + ((handleCount * deltaPercent) / 100);
#if DEBUG_HANDLECOLLECTOR
Debug.WriteLine("HC> NeedCollection: increase threshHold to " + threshHold);
#endif
return true;
}
// If handle count < threshHold, we don't
// need to collect, but if it 10% below the next lowest threshhold we
// will bump down a rung. We need to choose a percentage here or else
// we will oscillate.
//
int oldThreshHold = (100 * threshHold) / (100 + deltaPercent);
if (oldThreshHold >= initialThreshHold && handleCount < (int)(oldThreshHold * .9F)) {
#if DEBUG_HANDLECOLLECTOR
Debug.WriteLine("HC> NeedCollection: throttle threshhold " + threshHold + " down to " + oldThreshHold);
#endif
threshHold = oldThreshHold;
}
return false;
}
///
/// Removes the given handle from our monitor list.
///
internal IntPtr Remove(IntPtr handle) {
if( handle == IntPtr.Zero )
{
return handle;
}
int currentCount = 0;
lock(this) {
handleCount--;
#if DEBUG_HANDLECOLLECTOR
Debug.Assert(handles.Contains(handle));
handles.Remove(handle);
#endif
if (handleCount < 0) {
System.Diagnostics.Debug.Fail("Handle collector underflow for type '" + name + "'");
handleCount = 0;
}
currentCount = handleCount;
}
lock (internalSyncObject){
if (HandleCollector.HandleRemoved != null) {
HandleCollector.HandleRemoved(name, handle, currentCount);
}
}
return handle;
}
}
}
internal delegate void HandleChangeEventHandler(string handleType, IntPtr handleValue, int currentHandleCount);
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
#if DEBUG_HANDLECOLLECTOR
using System.Diagnostics;
#endif
using System.Collections.Generic;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
[module: SuppressMessage("Microsoft.Design", "CA1020:AvoidNamespacesWithFewTypes", Scope="namespace", Target="System.Internal")]
namespace System.Internal {
internal sealed class HandleCollector {
private static HandleType[] handleTypes;
private static int handleTypeCount;
private static int suspendCount;
internal static event HandleChangeEventHandler HandleAdded;
internal static event HandleChangeEventHandler HandleRemoved;
private static object internalSyncObject = new object();
///
/// Adds the given handle to the handle collector. This keeps the
/// handle on a "hot list" of objects that may need to be garbage
/// collected.
///
internal static IntPtr Add(IntPtr handle, int type) {
handleTypes[type - 1].Add(handle);
return handle;
}
///
/// Suspends GC.Collect
///
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
internal static void SuspendCollect() {
lock(internalSyncObject) {
suspendCount++;
}
}
///
/// Resumes GC.Collect
///
[SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods")]
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
internal static void ResumeCollect() {
bool performCollect = false;
lock(internalSyncObject) {
if(suspendCount > 0){
suspendCount--;
}
if(suspendCount == 0)
{
for(int i=0; i < handleTypeCount; i++)
{
lock(handleTypes[i]) {
if (handleTypes[i].NeedCollection())
{
performCollect = true;
}
}
}
}
}
if(performCollect)
{
GC.Collect();
}
}
///
/// Registers a new type of handle with the handle collector.
///
internal static int RegisterType(string typeName, int expense, int initialThreshold) {
lock (internalSyncObject){
if (handleTypeCount == 0 || handleTypeCount == handleTypes.Length) {
HandleType[] newTypes = new HandleType[handleTypeCount + 10];
if (handleTypes != null) {
Array.Copy(handleTypes, 0, newTypes, 0, handleTypeCount);
}
handleTypes = newTypes;
}
handleTypes[handleTypeCount++] = new HandleType(typeName, expense, initialThreshold);
return handleTypeCount;
}
}
///
/// Removes the given handle from the handle collector. Removing a
/// handle removes it from our "hot list" of objects that should be
/// frequently garbage collected.
///
internal static IntPtr Remove(IntPtr handle, int type) {
return handleTypes[type - 1].Remove(handle);
}
///
/// Represents a specific type of handle.
///
private class HandleType {
internal readonly string name;
private int initialThreshHold;
private int threshHold;
private int handleCount;
private readonly int deltaPercent;
#if DEBUG_HANDLECOLLECTOR
private List handles = new List();
#endif
///
/// Creates a new handle type.
///
internal HandleType(string name, int expense, int initialThreshHold) {
this.name = name;
this.initialThreshHold = initialThreshHold;
this.threshHold = initialThreshHold;
this.deltaPercent = 100 - expense;
}
///
/// Adds a handle to this handle type for monitoring.
///
[SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods")]
internal void Add(IntPtr handle) {
if( handle == IntPtr.Zero )
{
return;
}
bool performCollect = false;
int currentCount = 0;
lock(this) {
handleCount++;
#if DEBUG_HANDLECOLLECTOR
Debug.Assert(!handles.Contains(handle));
handles.Add(handle);
#endif
performCollect = NeedCollection();
currentCount = handleCount;
}
lock (internalSyncObject){
if (HandleCollector.HandleAdded != null) {
HandleCollector.HandleAdded(name, handle, currentCount);
}
}
if (!performCollect) {
return;
}
if (performCollect) {
#if DEBUG_HANDLECOLLECTOR
Debug.WriteLine("HC> Forcing garbage collect");
Debug.WriteLine("HC> name :" + name);
Debug.WriteLine("HC> threshHold :" + (threshHold).ToString());
Debug.WriteLine("HC> handleCount :" + (handleCount).ToString());
Debug.WriteLine("HC> deltaPercent:" + (deltaPercent).ToString());
#endif
GC.Collect();
// We just performed a GC. If the main thread is in a tight
// loop there is a this will cause us to increase handles forever and prevent handle collector
// from doing its job. Yield the thread here. This won't totally cause
// a finalization pass but it will effectively elevate the priority
// of the finalizer thread just for an instant. But how long should
// we sleep? We base it on how expensive the handles are because the
// more expensive the handle, the more critical that it be reclaimed.
int sleep = (100 - deltaPercent) / 4;
System.Threading.Thread.Sleep(sleep);
}
}
///
/// Retrieves the outstanding handle count for this
/// handle type.
///
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
internal int GetHandleCount() {
lock(this) {
return handleCount;
}
}
///
/// Determines if this handle type needs a garbage collection pass.
///
internal bool NeedCollection() {
if (suspendCount > 0){
return false;
}
if (handleCount > threshHold) {
threshHold = handleCount + ((handleCount * deltaPercent) / 100);
#if DEBUG_HANDLECOLLECTOR
Debug.WriteLine("HC> NeedCollection: increase threshHold to " + threshHold);
#endif
return true;
}
// If handle count < threshHold, we don't
// need to collect, but if it 10% below the next lowest threshhold we
// will bump down a rung. We need to choose a percentage here or else
// we will oscillate.
//
int oldThreshHold = (100 * threshHold) / (100 + deltaPercent);
if (oldThreshHold >= initialThreshHold && handleCount < (int)(oldThreshHold * .9F)) {
#if DEBUG_HANDLECOLLECTOR
Debug.WriteLine("HC> NeedCollection: throttle threshhold " + threshHold + " down to " + oldThreshHold);
#endif
threshHold = oldThreshHold;
}
return false;
}
///
/// Removes the given handle from our monitor list.
///
internal IntPtr Remove(IntPtr handle) {
if( handle == IntPtr.Zero )
{
return handle;
}
int currentCount = 0;
lock(this) {
handleCount--;
#if DEBUG_HANDLECOLLECTOR
Debug.Assert(handles.Contains(handle));
handles.Remove(handle);
#endif
if (handleCount < 0) {
System.Diagnostics.Debug.Fail("Handle collector underflow for type '" + name + "'");
handleCount = 0;
}
currentCount = handleCount;
}
lock (internalSyncObject){
if (HandleCollector.HandleRemoved != null) {
HandleCollector.HandleRemoved(name, handle, currentCount);
}
}
return handle;
}
}
}
internal delegate void HandleChangeEventHandler(string handleType, IntPtr handleValue, int currentHandleCount);
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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