[$] Repurposing page->mapping

Post Syndicated from corbet original https://lwn.net/Articles/752564/rss

The page structure is one of the
most complex in the kernel due to the need to cram the maximum amount of
information into as little space as possible. Each field is so heavily
overloaded that developers prefer to avoid making changes to struct
page
if they can avoid
it. That didn’t deter Jérôme Glisse from proposing a significant change
during two plenary sessions at
the 2018 Linux Storage, Filesystem, and Memory-Management Summit, though.
There are some interesting benefits on offer, but getting there will not be
a simple task.