//returns the number of doubles actually freed
size_t DiskBackedBlockMap::backup_and_free_doubles(size_t requested_doubles_to_free) {
size_t freed_count = 0;
try {
while (freed_count < requested_doubles_to_free) { //if requested_doubles_to_free <= 0, no iterations performed.
ServerBlock* block;
BlockId bid = policy_.get_next_block_for_removal(block);
block->wait();
ServerBlock* blk = block_map_.block(bid);
check(blk == block, "bug in free_doubles");
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->disk_state_.is_valid_on_disk()) {
write_block_to_disk(bid, blk);
blocks_to_disk_.inc();
blk->disk_state_.set_valid_on_disk();
}
double* data_to_free = blk->get_data();
free_data(data_to_free, blk->size()); //this method updates remaining_doubles_
blk->disk_state_.unset_in_memory();
blk->data_ = NULL;
freed_count += blk->size();
}
} catch (const std::out_of_range& oor) {
//ran out of blocks, just return what was freed.
}
return freed_count;
}
