Hi Catalin, Sorry for taking so long to reply to you. On 2020/5/26 22:52, Catalin Marinas wrote: > On Mon, May 25, 2020 at 03:19:42PM +0800, Zhenyu Ye wrote: >> >> tlb_flush_##_pxx##_range() is used to set tlb->cleared_*, >> flush_##_pxx##_tlb_range() will actually flush the TLB entry. >> >> In arch64, tlb_flush_p?d_range() is defined as: >> >> #define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) >> #define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) > > Currently, flush_p??_tlb_range() are generic and defined as above. I > think in the generic code they can remain an alias for > flush_tlb_range(). > > On arm64, we can redefine them as: > > #define flush_pte_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 3) > #define flush_pmd_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 2) > #define flush_pud_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 1) > #define flush_p4d_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 0) > > (unless the compiler optimises away all the mmu_gather stuff in your > macro above but they don't look trivial to me) > I changed generic code before considering that other structures may also use this feature, such as Power9. And Peter may want to replace all flush_tlb_range() by tlb_flush() in the future, see [1] for details. If only enable this feature on aarch64, your codes are better. [1] https://lore.kernel.org/linux-arm-kernel/20200402163849.GM20713@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > Also, I don't see the new flush_pte_* and flush_p4d_* macros used > anywhere and I don't think they are needed. The pte equivalent is > flush_tlb_page() (we need to make sure it's not used on a pmd in the > hugetlb context). > flush_tlb_page() is used to flush only one page. If we add the flush_pte_tlb_range(), then we can use it to flush a range of pages in the future. But flush_pte_* and flush_p4d_* macros are really not used anywhere. I will remove them in next version of series, and add them if someone needs. >> So even if we know the level here, we can not pass the value to tlbi >> instructions (flush_tlb_range() is a common kernel interface and retro-fit it >> needs lots of changes), according to Peter's suggestion, I finally decide to >> pass the value of TTL by the tlb_gather_* frame.[1] > > My comment was about the generic implementation using mmu_gather as you > are proposing. We don't need to change the flush_tlb_range() interface, > nor do we need to rewrite flush_p??_tlb_range(). > Thanks, Zhenyu
