[LSF/MM/BPF TOPIC] mshare - sharing page tables across processes

[LSF/MM/BPF TOPIC] mshare - sharing page tables across processes

[anthony.yznaga]

mshare is a new form of shared memory that shares resources between 
processes, namely the page tables entries and VMAs of the shared 
objects. Advantages include reduced memory consumption through 
eliminating the need for duplicated PTEs in each process, reduced 
overhead needed to fault shared pages into multiple processes, and the 
ability for updates to the memory such as protection changes to be 
immdediately visible to all sharing processes.

For some time now the proposed API has continued to evolve. With 
feedback from mm maintainers, a new approach using syscalls is being 
taken to create, attach, and deattach mshare regions and to map and 
manipulate the memory objects within a region.

Let's discuss the current state of the API and technical challenges of 
managing and accomodating shared page tables in the kernel.

Anthony


References:

https://lore.kernel.org/linux-mm/20250820010415.699353-1-anthony.yznaga@oracle.com/
https://lore.kernel.org/linux-mm/20250404021902.48863-1-anthony.yznaga@oracle.com/