Hi Will, In addition to what Michal wrote: > As an interim step, why not introduce something like > vmemmap_alloc_block_flags and make the page-table walking opt-out for > architectures that don't want it? Then we can just pass __GFP_ZERO from > our vmemmap_populate where necessary and other architectures can do the > page-table walking dance if they prefer. I do not see the benefit, implementing this approach means that we would need to implement two table walks instead of one: one for x86, another for ARM, as these two architectures support kasan. Also, this would become a requirement for any future architecture that want to add kasan support to add this page table walk implementation. >> IMO, while I understand that it looks strange that we must walk page >> table after creating it, it is a better approach: more enclosed as it >> effects kasan only, and more universal as it is in common code. > > I don't buy the more universal aspect, but I appreciate it's subjective. > Frankly, I'd just sooner not have core code walking early page tables if > it can be avoided, and it doesn't look hard to avoid it in this case. > The fact that you're having to add pmd_large and pud_large, which are > otherwise unused in mm/, is an indication that this isn't quite right imo. 28 +#define pmd_large(pmd) pmd_sect(pmd) 29 +#define pud_large(pud) pud_sect(pud) it is just naming difference, ARM64 calls them pmd_sect, common mm and other arches call them pmd_large/pud_large. Even the ARM has these defines in arm/include/asm/pgtable-3level.h arm/include/asm/pgtable-2level.h Pavel -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
