public void Reserve(string sharedMemName, bool useExistingSharedMemory, long numItems, bool largePages)
{
if (rawMemoryPointer != null)
{
throw new Exception("Internal error: Reserve should be called only once");
}
if (useExistingSharedMemory)
{
throw new NotImplementedException("Use existing shared memory not yet implemented under Linux");
}
if (largePages)
{
throw new NotImplementedException("Large page support not yet implemented under Linux");
}
// We overreserve by one PAGE_SIZE since the OS may not allow partial page allocation
long numBytes = numItems * sizeof(T) + PAGE_SIZE;
rawMemoryPointer = (float *)LinuxAPI.mmap(null, numBytes, LinuxAPI.PROT_NONE, LinuxAPI.MAP_PRIVATE | LinuxAPI.MAP_ANONYMOUS, -1, 0);
if (rawMemoryPointer == null)
{
throw new Exception("Virtual memory reservation of {numBytes} bytes failed using mmap");
}
}
public void InsureAllocated(long numItems)
{
long numBytesNeeded = numItems * sizeof(T);
if (numBytesNeeded > numBytesAllocated)
{
numBytesAllocated += ALLOCATE_INCREMENTAL_BYTES;
numItemsAllocated = numItems;
int resultCode = LinuxAPI.mprotect(rawMemoryPointer, numBytesAllocated, LinuxAPI.PROT_READ | LinuxAPI.PROT_WRITE);
if (resultCode != 0)
{
throw new Exception("Virtual memory extension to size {numBytes} failed");
}
}
}
public long NumItemsAllocated => this.numBytesAllocated / sizeof(T); // TODO: make faster?
public void Dispose()
{
LinuxAPI.munmap(rawMemoryPointer, numBytesAllocated);
numBytesAllocated = 0;
rawMemoryPointer = null;
}
