On Sat, Jun 27, 2020 at 05:34:49PM +0300, Mike Rapoport wrote:
More elaborate versions on arm64 and x86 account memory for the user page tables and call to pgtable_pmd_page_ctor() as the part of PMD page initialization. Move the arm64 version to include/asm-generic/pgalloc.h and use the generic version on several architectures. The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is not enabled, so there is no functional change for most architectures except of the addition of __GFP_ACCOUNT for allocation of user page tables.
Thanks for including this line; it reminded me that we're not setting the PageTable flag on the page, nor accounting it to the zone page stats. Hope you don't mind me tagging a patch to do that on as 9/8. We could also do with a pud_page_[cd]tor and maybe even p4d/pgd versions. But that brings me to the next question -- could/should some of this be moved over to asm-generic/pgalloc.h? The ctor/dtor aren't called from anywhere else, and there's value to reducing the total amount of code in mm.h, but then there's also value to keeping all the ifdef ARCH_ENABLE_SPLIT_PMD_PTLOCK code together too. So I'm a bit torn. What do you think?
