Question

The following call to SetSystemFileCacheSize() fails, however it passes if replace “FILE_CACHE_MIN_HARD_ENABLE ” with 0.

What am I doing wrong?

SIZE_T dwMinimumFileCacheSize = 1048576; // Exact number reported by SetSystemFileCacheSize.
SIZE_T dwMaximumFileCacheSize = 1099511627776; // Exact number reported by SetSystemFileCacheSize.

int result = SetSystemFileCacheSize(
    dwMinimumFileCacheSize, // dwMinimumWorkingSetSize
    dwMaximumFileCacheSize,  // dwMaximumWorkingSetSize,
    FILE_CACHE_MIN_HARD_ENABLE // Works if this flag is set to 0.
  );
if (result == 0)
{
  // Error is "5" if it fails.
  wprintf(L"  Error E2469: Could not set size of system cache, error %u.\n", GetLastError());
}
else
{
  wprintf(L"  Pass.\n");
}

Answer 1

It turns out that dwMinimumFileCacheSize must be 64KB less than dwMaximumFileCacheSize, if FILE_CACHE_MIN_HARD_ENABLE is enabled.

Here is the fix:

int result = SetSystemFileCacheSize(
    dwMinimumFileCacheSize - 64 * 1024, // dwMinimumWorkingSetSize
    dwMaximumFileCacheSize,  // dwMaximumWorkingSetSize,
    FILE_CACHE_MIN_HARD_ENABLE // Works if this flag is set to 0.
  );