On Tue, Jun 15, 2021 at 11:52 AM Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote: > > On 6/14/21 6:12 PM, Andrew Morton wrote: > > On Sat, 12 Jun 2021 17:45:52 +0800 Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote: > > > >> In order to reduce the difficulty of code review in series[1]. We disable > >> huge PMD mapping of vmemmap pages when that feature is enabled. In this > >> series, we do not disable huge PMD mapping of vmemmap pages anymore. We > >> will split huge PMD mapping when needed. When HugeTLB pages are freed from > >> the pool we do not attempt coalasce and move back to a PMD mapping because > >> it is much more complex. > >> > >> [1] https://lore.kernel.org/linux-doc/20210510030027.56044-1-songmuchun@xxxxxxxxxxxxx/ > > > > [1] had a nice [0/n] description but the v2 series lost that. I could > > copy/paste the v1 changelogging but I am unsure that it has been > > maintained appropriately for the v2 series. > > > > I think I'll pass on this v2 pending additional review input. Please reinstate > > the [0/n] overview if/when resending? > > There may be some confusion. > > This series is a follow on optimization for the functionality provided by > [1]. Early in the development of [1], it was decided to drop some code > for ease of review. Specifically, splitting vmemmap PMD mappings to PTE > mappings as required when hugetlb pages were allocated. The > 'simplification' in [1] is that if the feature is enabled then vmemmap > will only be mapped with PTEs. > > This series provides the ability to split PMD mappings 'on demand' as > hugetlb pages are allocated. As mentioned, it really is a follow on and > optimization to functionality provided in [1]. As such, I am not sure > that repeating the [0/n] description from 1 is necessary here. > > In any case, this should be clearly stated in the [0/n] description of > this series. Thanks for the clarification for me. I totally agree with you. > > BTW- I did get through the series today, and did not discover any > issues. However, I want to sleep on it before signing off. > -- > Mike Kravetz
