ServerBlock* DiskBackedBlockMap::allocate_block(ServerBlock* block, size_t block_size, bool initialize){
/** If enough memory remains, allocates block and returns.
* Otherwise, frees up memory by writing out dirty blocks
* till enough memory has been obtained, then allocates
* and returns block.
*/
std::size_t remaining_mem = max_allocatable_bytes_ - ServerBlock::allocated_bytes();
while (block_size * sizeof(double) > remaining_mem){
try{
BlockId bid = policy_.get_next_block_for_removal();
ServerBlock* blk = block_map_.block(bid);
SIP_LOG(std::cout << "S " << sip_mpi_attr_.company_rank()
<< " : Freeing block " << bid
<< " and writing to disk to make space for new block"
<< std::endl);
if(blk->is_dirty()){
write_block_to_disk(bid, blk);
}
blk->free_in_memory_data();
// Junmin's fix :
// As a result of freeing up block memory, the remaining memory should
// have increased. Otherwise it will go into an infinite loop.
if (!(remaining_mem < max_allocatable_bytes_ - ServerBlock::allocated_bytes())) {
throw std::out_of_range("Break now.");
}
remaining_mem = max_allocatable_bytes_ - ServerBlock::allocated_bytes();
} catch (const std::out_of_range& oor){
std::cerr << " In DiskBackedBlockMap::allocate_block" << std::endl;
std::cerr << oor.what() << std::endl;
std::cerr << *this << std::endl;
fail(" Something got messed up in the internal data structures of the Server", current_line());
} catch(const std::bad_alloc& ba){
std::cerr << " In DiskBackedBlockMap::allocate_block" << std::endl;
std::cerr << ba.what() << std::endl;
std::cerr << *this << std::endl;
fail(" Could not allocate ServerBlock, out of memory", current_line());
}
}
std::stringstream ss;
ss << "S " << sip_mpi_attr_.company_rank() << " : Could not allocate memory for block of size "
<< block_size << ", Memory being used :" << ServerBlock::allocated_bytes() << std::endl;
sip :: check (block_size <= max_allocatable_bytes_ - ServerBlock::allocated_bytes(), ss.str());
if (block == NULL) {
block = new ServerBlock(block_size, initialize);
} else {
block->allocate_in_memory_data();
}
return block;
}
