protected override int GetCurrentPressure()
{
// Call GetUpdatedTotalCacheSize to update the total
// cache size, if there has been a recent Gen 2 Collection.
// This update must happen, otherwise the CacheManager won't
// know the total cache size.
int gen2Count = GC.CollectionCount(2);
SRefMultiple sref = _sizedRefMultiple;
if (gen2Count != _gen2Count && sref != null)
{
// update _gen2Count
_gen2Count = gen2Count;
// the SizedRef is only updated after a Gen2 Collection
// increment the index (it's either 1 or 0)
Dbg.Assert(SAMPLE_COUNT == 2);
_idx = _idx ^ 1;
// remember the sample time
_cacheSizeSampleTimes[_idx] = DateTime.UtcNow;
// remember the sample value
_cacheSizeSamples[_idx] = sref.ApproximateSize;
#if DBG
Dbg.Trace("MemoryCacheStats", "SizedRef.ApproximateSize=" + _cacheSizeSamples[_idx]);
#endif
IMemoryCacheManager memoryCacheManager = s_memoryCacheManager;
if (memoryCacheManager != null)
{
memoryCacheManager.UpdateCacheSize(_cacheSizeSamples[_idx], _memoryCache);
}
}
// if there's no memory limit, then there's nothing more to do
if (_memoryLimit <= 0)
{
return(0);
}
long cacheSize = _cacheSizeSamples[_idx];
// use _memoryLimit as an upper bound so that pressure is a percentage (between 0 and 100, inclusive).
if (cacheSize > _memoryLimit)
{
cacheSize = _memoryLimit;
}
// PerfCounter: Cache Percentage Process Memory Limit Used
// = memory used by this process / process memory limit at pressureHigh
// Set private bytes used in kilobytes because the counter is a DWORD
//
int result = (int)(cacheSize * 100 / _memoryLimit);
return(result);
}
public void Dispose()
{
SRefMultiple sref = _sizedRefMultiple;
if (sref != null && Interlocked.CompareExchange(ref _sizedRefMultiple, null, sref) == sref)
{
sref.Dispose();
}
s_memoryCacheManager?.ReleaseCache(_memoryCache);
}
private void InitDisposableMembers(int cacheMemoryLimitMegabytes)
{
bool dispose = true;
try {
_sizedRefMultiple = new SRefMultiple(_memoryCache.AllSRefTargets);
SetLimit(cacheMemoryLimitMegabytes);
InitHistory();
dispose = false;
}
finally {
if (dispose)
{
Dispose();
}
}
}
