On Thu, Dec 13, 2018 at 9:14 AM <jglisse@xxxxxxxxxx> wrote: > > From: Jérôme Glisse <jglisse@xxxxxxxxxx> > > CPU page table update can happens for many reasons, not only as a result > of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also > as a result of kernel activities (memory compression, reclaim, migration, > ...). > > Users of mmu notifier API track changes to the CPU page table and take > specific action for them. While current API only provide range of virtual > address affected by the change, not why the changes is happening. > > This patchset adds event information so that users of mmu notifier can > differentiate among broad category: > - UNMAP: munmap() or mremap() > - CLEAR: page table is cleared (migration, compaction, reclaim, ...) > - PROTECTION_VMA: change in access protections for the range > - PROTECTION_PAGE: change in access protections for page in the range > - SOFT_DIRTY: soft dirtyness tracking > > Being able to identify munmap() and mremap() from other reasons why the > page table is cleared is important to allow user of mmu notifier to > update their own internal tracking structure accordingly (on munmap or > mremap it is not longer needed to track range of virtual address as it > becomes invalid). Who consumes these new enum values? The consumer of the new infrastructure should be included in the patchset that adds the new functionality. So a NAK from me until the consumer is clarified / included.
