Re: [Crash-utility] [Patch V2 2/2] sparc64 changes

On 03/25/2016 02:03 PM, David Miller wrote: > From: Dave Kleikamp <dave.kleikamp(a)oracle.com&gt; > Date: Fri, 25 Mar 2016 13:22:30 -0500 > >> On 03/24/2016 02:22 PM, David Miller wrote: >>> From: Dave Kleikamp <dave.kleikamp(a)oracle.com&gt; >>> Date: Wed, 23 Mar 2016 17:41:08 -0500 >>> >>>> + /* Check for a huge/THP page */ >>>> + paddr = pmd_is_huge(pte, vaddr, verbose); >>>> + if (paddr) >>>> + goto out; >>> ... >>>> + paddr = pte_to_pa(pte); >>>> + paddr = paddr | (vaddr & ~PAGE_MASK); >>> >>> This handles transparent huge pages installed at the PMD level, but I don't >>> see that it handles huge PTEs properly, which are encoded at the PTE level. >> >> I've been looking at the huge page code again and I'm not sure what I'm >> missing. Isn't there still a huge PTE in the page table for every 8K >> page with the proper physical address bits? > > Yes there is a huge PTE encoded every 8K, but I'm wondering about the > address masking et al. you are doing here... I'm pretty sure it works. In set_huge_pte_at(): for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) { set_pte_at(mm, addr, ptep, entry); ptep++; addr += PAGE_SIZE; pte_val(entry) += PAGE_SIZE; } Each pte correctly addresses an 8K page. The crash code doesn't really need to know it's part of a huge page.