On Thu, 26 Jan 2017 10:09:53 -0700 Dave Jiang <dave.jiang@xxxxxxxxx> wrote: > The current transparent hugepage code only supports PMDs. This patch > adds support for transparent use of PUDs with DAX. It does not include > support for anonymous pages. x86 support code also added. > > Most of this patch simply parallels the work that was done for huge PMDs. > The only major difference is how the new ->pud_entry method in mm_walk > works. The ->pmd_entry method replaces the ->pte_entry method, whereas > the ->pud_entry method works along with either ->pmd_entry or ->pte_entry. > The pagewalk code takes care of locking the PUD before calling ->pud_walk, > so handlers do not need to worry whether the PUD is stable. The patch adds a lot of new BUG()s and BG_ON()s. We'll get in trouble if any of those triggers. Please recheck everything and decide if we really really need them. It's far better to drop a WARN and to back out and recover in some fashion.
