Le 16/02/2020 à 09:22, Russell King - ARM Linux admin a écrit : > On Sun, Feb 16, 2020 at 10:18:30AM +0200, Mike Rapoport wrote: >> From: Mike Rapoport <rppt****@linux*****> >> >> Hi, >> >> These patches convert several architectures to use page table folding and >> remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h. >> >> The changes are mostly about mechanical replacement of pgd accessors with p4d >> ones and the addition of higher levels to page table traversals. >> >> All the patches were sent separately to the respective arch lists and >> maintainers hence the "v2" prefix. > > You fail to explain why this change which adds 488 additional lines of > code is desirable. > The purpose of the series, ie droping a HACK, is worth it. However looking at the powerpc patch I have the feeling that this series goes behind its purpose. The number additional lines could be deeply reduced I think if we limit the patches to the strict minimum, ie just do things like below instead of adding lots of handling of useless levels. Instead of doing things like: - pud = NULL; + p4d = NULL; if (pgd_present(*pgd)) - pud = pud_offset(pgd, gpa); + p4d = p4d_offset(pgd, gpa); + else + new_p4d = p4d_alloc_one(kvm->mm, gpa); + + pud = NULL; + if (p4d_present(*p4d)) + pud = pud_offset(p4d, gpa); else new_pud = pud_alloc_one(kvm->mm, gpa); It could be limited to: if (pgd_present(*pgd)) - pud = pud_offset(pgd, gpa); + pud = pud_offset(p4d_offset(pgd, gpa), gpa); else new_pud = pud_alloc_one(kvm->mm, gpa); Christophe
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