Re: [PATCH mm-unstable v18 06/14] mm/khugepaged: generalize collapse_huge_page for mTHP collapse
From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-06-01 10:09:28
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On 6/1/26 10:44, Lance Yang wrote:
On 2026/6/1 16:15, David Hildenbrand (Arm) wrote:quoted
On 6/1/26 09:49, Lance Yang wrote:quoted
I had Codex do the boring grep-work through the arch update_mmu_cache* code :D MIPS doesn't seem to be the only code doing a re-walk, but it is the only one I found that appears to assume the PMD/PTE walk cannot fail, without checking whether the PMD is none ...Okay, but likely the other code that tries to handle it is also problematic. Best to make sure the page table is already installed when updating the entries.Neat, makes sense to me :D That way the page talbe is back in place before any arch hook gets to look at it :)
Right. I don't think we could run into a deadlock here (nobody should concurrently take a look at the page tables in the first place). Not sure about the memory barrier I dropped: the page tables are already properly set up (just some entries cleared), so I'd assume that barrier might not be required. -- Cheers, David