Hi David and Anshuman! Björn Töpel <bjorn@xxxxxxxxxx> writes: > David Hildenbrand <david@xxxxxxxxxx> writes: > >> On 12.05.23 16:57, Björn Töpel wrote: >>> From: Björn Töpel <bjorn@xxxxxxxxxxxx> >>> >>> Memory Hot(Un)Plug support for the RISC-V port >>> ============================================== > > [...] > >> >> Cool stuff! I'm fairly busy right now, so some high-level questions upfront: > > No worries, and no rush! I'd say the v1 series was mainly for the RISC-V > folks, and I've got tons of (offline) comments from Alex -- and with > your comments below some more details to figure out. One of the major issues with my v1 patch is around init_mm page table synchronization, and that'll be part of the v2. I've noticed there's a quite a difference between x86-64 and arm64 in terms of locking, when updating (add/remove) the init_mm table. x86-64 uses the usual page table locking mechanisms (used by the generic kernel functions), whereas arm64 does not. How does arm64 manage to mix the "lock-less" updates (READ/WRITE_ONCE, and fences in set_p?d+friends), with the generic kernel ones that uses the regular page locking mechanism? I'm obviously missing something about the locking rules for memory hot add/remove... I've been reading the arm64 memory hot add/remove series, but none the wiser! ;-) Björn
