On Wed, Aug 16, 2023, bibo mao wrote: > > > 在 2023/8/16 15:18, Yan Zhao 写道: > > On Wed, Aug 16, 2023 at 03:29:22PM +0800, bibo mao wrote: > >>> Flush must be done before kvm->mmu_lock is unlocked, otherwise, > >>> confusion will be caused when multiple threads trying to update the > >>> secondary MMU. > >> Since tlb flush is delayed after all pte entries are cleared, and currently > >> there is no tlb flush range supported for secondary mmu. I do know why there > >> is confusion before or after kvm->mmu_lock. > > > > Oh, do you mean only do kvm_unmap_gfn_range() in .invalidate_range_end()? > yes, it is just sketchy thought for numa balance scenery, > do kvm_unmap_gfn_range() in invalidate_range_end rather than > invalidate_range_start. That is not an option, it's a direction violation of the mmu_notifier contract. Secondary MMUs must drop all references before returning from invalidate_range_start().
