On Wed, Apr 7, 2021 at 2:47 PM Daniel Xu <dxu@xxxxxxxxx> wrote: > > There currently does not exist a way to answer the question: "What is in > the page cache?". There are various heuristics and counters but nothing > that can tell you anything like: > > * 3M from /home/dxu/foo.txt > * 5K from ... > * etc. > So, you need the list of inodes for a filesystem that are in memory. With that list, you can open, map and do mincore on them? I don't know of a way to get that inode list. > The answer to the question is particularly useful in the stacked > container world. Stacked containers implies multiple containers are run > on the same physical host. Memory is precious resource on some (if not > most) of these systems. On these systems, it's useful to know how much > duplicated data is in the page cache. Once you know the answer, you can > do something about it. One possible technique would be bind mount common > items from the root host into each container. > Oh you want to share page cache between different containers/jobs? That would complicate charging.
