No worries, entirely valid question. There may be ways to tune page cache to be more like this, but my mental model for what we've done is effectively make reads and writes transparently redirect to the equivalent of a tmpfs, up to a certain size. If you reserve 2GB of memory for the cache, and the CI job's read and written files are less than 2GB, then _everything_ stays in RAM, at RAM throughput/IOPS. When you exceed the limit of the cache, blocks are moved to the physical disk in the background. Feels like we have more direct control here than page cache (and the page cache is still helping out in this scenario too, so it's more that we're using both).