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→Post-copy for shared memory and hugetlbfs
=== Post-copy for shared memory and hugetlbfs ===
=== Post-copy for shared memory and hugetlbfs ===
'''Summary:''' TODO: Short description of the project
'''Summary:''' extend post-copy memory restore and migration to support shared memory and hugeltbfs.
CRIU relies on [[Userfaultfd]] mechanism in the Linux kernel to implement the demand paging in userspace and allow post-copy memory (or lazy) [[Lazy_migration|migration]]. However, currently this support is limited to anonymous private memory mappings, although kernel also supports shared memory areas and hugetlbfs backed memory.
The shared memory support for lazy migration can be added to CRIU without kernel modifications, while proper handling of hugetlbfs would require userfaultfd callbacks for [http://man7.org/linux/man-pages/man2/fallocate.2.html fallocate(PUNCH_HOLE)] and [http://man7.org/linux/man-pages/man2/madvise.2.html madvise(MADV_REMOVE)] system calls.
'''Links:'''
'''Links:'''
* Wiki links to relevant material
* [https://www.kernel.org/doc/html/latest/admin-guide/mm/userfaultfd.html Userfaultfd]
* External links to mailing lists or web sites
* [https://www.kernel.org/doc/html/latest/admin-guide/mm/hugetlbpage.html hugetlbfs]
'''Details:'''
'''Details:'''
* Skill level: beginner or intermediate or advanced
* Skill level: most probably advanced?
* Language: C
* Language: C
* Mentor: Mike Rapoport <rppt@linux.ibm.com>
* Mentor: Mike Rapoport <rppt@linux.ibm.com>
* Suggested by: Mike Rapoport <rppt@linux.ibm.com>
* Suggested by: Mike Rapoport <rppt@linux.ibm.com>
=== Optimize logging engine ===
=== Optimize logging engine ===