On Wed, Apr 22, 2020 at 11:08:10AM -0700, Dave Hansen wrote: > On 4/22/20 7:25 AM, Steven Price wrote: > > Three new hooks are added to the swap code: > > * arch_prepare_to_swap() and > > * arch_swap_invalidate_page() / arch_swap_invalidate_area(). > > One new hook is added to shmem: > > * arch_swap_restore_tags() > > How do the tags get restored outside of the shmem path? I was expecting > to see more arch_swap_restore_tags() sites. The restoring is done via set_pte_at() -> mte_sync_tags() -> mte_restore_tags() in the arch code (see patch 3). arch_swap_restore_tags() just calls mte_restore_tags() directly. shmem is slightly problematic as it moves the page from the swap cache to the shmem one and I think arch_swap_invalidate_page() would have already been called by the time we get to set_pte_at() (Steven can correct me if I got this wrong). -- Catalin
