On Mon, 4 Apr 2016 13:13:37 -0400 Johannes Weiner <han...@cmpxchg.org> wrote:
> Andres Freund observed that his database workload is struggling with > the transaction journal creating pressure on frequently read pages. > > Access patterns like transaction journals frequently write the same > pages over and over, but in the majority of cases those pages are > never read back. There are no caching benefits to be had for those > pages, so activating them and having them put pressure on pages that > do benefit from caching is a bad choice. Read-after-write is a pretty common pattern: temporary files for example. What are the opportunities for regressions here? Did you consider providing userspace with a way to hint "this file is probably write-then-not-read"?
