My memory is from three or four years back now, and there are many more lines of code that have gone over the weir since then, so I am sketchy on certain detail

My memory is from three or four years back now, and there are many more lines of code that have gone over the weir since then, so I am sketchy on certain details but one of the things I looked in to, when working with bcache, was how to disable certain features of the code that were clearly hitting an IOPS limit, one of those being the dirty page cache, rather than letting memory pressure handle the flushing of the cache. I was not smart enough or educated enough about the code to figure it out for myself.