While Canonical isn't generally a company that's well received for being a large contributor to the upstream Linux kernel, during the virtual Ubuntu Developer Summit today they proposed a new API for revocable kernel memory. While they have proposed it, they are still early on and apparently haven't even prototyped any code. Coming out of today's session, one of their work items is, "Check with upstream on status and if we can come up with a kernel that has got the revocable memory feature."
The revocable kernel memory feature they're after is for use in low-memory environments where an application can flag a section of its memory as being revocable and when the system is running low on RAM it can then reclaim that memory rather than crashing, closing out the program, or swapping to disk. The program would then still be able to live on and hopefully re-generate its data when needed.
If enough applications were to support and take advantage of this kernel API, it would largely benefit phone/tablet users where there are generally limited amounts of RAM -- but then again with today's high-end phones we're already seeing 2GB become standard. Android currently offers similar functionality with their Ashmem shared memory feature.
Those wishing to learn more can watch the vUDS video embedded below.