On 2026/2/5 23:09, Dave Hansen wrote:
On 2/5/26 07:01, Lance Yang wrote:
So for now, neither approach looks good: tracking on the read side adss
cost to GUP-fast, and syncing on the write side e.g. synchronize_rcu()
is too slow on large systems.
Which of the writers truly *need* synchronize_rcu()?
What are they doing with the memory that they can't move forward unless
it's quiescent *now*?
Without IPIs or synchronize_rcu(), IIUC, we have no way to know if there
are ongoing concurrent lockless page-table walks — the walkers just disable
IRQs and walk.
