Hi Asier, Thanks for the quick feedback.
On 7/20/2026 12:28 PM, Gutierrez Asier wrote: > You should mention why page split is be needed. The fact that page > collapsing exist doesn't necessarily mean that split should exist. Fair point. The underlying problem I'm trying to address is that DAMON's vaddr monitoring loses accuracy under PMD-mapped THP: multiple sampled addresses share a single Accessed bit, so the observed hot set is coarser than the true working set. Split is one way to restore fine-grain monitoring -- by dismantling the PMD mapping, each base page gets its own PTE Accessed bit and DAMON can see the real access distribution again. Split is not the only possible approach, and it is certainly not intended to be "the opposite of collapse". It is just one concrete proposal to start the discussion. What I really care about is whether the community agrees that this monitoring granularity problem is worth solving. If there are better ways to address it, I'm very open to that direction. The RFC is as much about the problem as it is about the mechanism. Feedback on real workloads that suffer from this coarsening, and on alternative approaches, is exactly what I'm hoping for. > Could you add v1 as well? Good catch, will add in the next revision. [1] https://lore.kernel.org/[email protected]/ Thanks, Lian Wang
