On Sat, May 21, 2022 at 04:59:19PM +0800, Qi Zheng wrote: > Hi, > > To reduce the empty user PTE tables, I also introduced a reference > count (pte_ref) for user PTE tables in my patch[1][2], It is used > to track the usage of each user PTE tables. > > The following people will hold a pte_ref: > - The !pte_none() entry, such as regular page table entry that map > physical pages, or swap entry, or migrate entry, etc. > - Visitor to the PTE page table entries, such as page table walker. > > With COW PTE, a new holder (the process using the COW PTE) is added. > > It's funny, it leads me to see more meaning of pte_ref. > > Thanks, > Qi > > [1] [RFC PATCH 00/18] Try to free user PTE page table pages > link: https://lore.kernel.org/lkml/20220429133552.33768-1-zhengqi.arch@xxxxxxxxxxxxx/ > (percpu_ref version) > > [2] [PATCH v3 00/15] Free user PTE page table pages > link: https://lore.kernel.org/lkml/20211110105428.32458-1-zhengqi.arch@xxxxxxxxxxxxx/ > (atomic count version) > > -- > Thanks, > Qi Hi, I saw your patch a few months ago. Actually, my school's independent study is tracing the page table. And one of the topics is your patch. It is really helpful from your pte_ref. It's great to see you have more ideas for your pte_ref. Thanks.
