linux-kernel - [PATCH mm-new v2 0/3] mm/khugepaged: refactor and merge PTE scanning logic

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Message-ID: <20251006144338.96519-1-lance.yang@linux.dev>
Date: Mon,  6 Oct 2025 22:43:35 +0800
From: Lance Yang <lance.yang@...ux.dev>
To: akpm@...ux-foundation.org,
	david@...hat.com,
	lorenzo.stoakes@...cle.com
Cc: ziy@...dia.com,
	baolin.wang@...ux.alibaba.com,
	Liam.Howlett@...cle.com,
	npache@...hat.com,
	ryan.roberts@....com,
	dev.jain@....com,
	baohua@...nel.org,
	ioworker0@...il.com,
	richard.weiyang@...il.com,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH mm-new v2 0/3] mm/khugepaged: refactor and merge PTE scanning logic

Hi all,

This series cleans up the almost-duplicated PTE scanning logic in the
collapse path.

The first one is a preparatory step that refactors both loops to use
a single if-else-if-else-if chain for checking disjoint PTEs.

The second one replaces VM_BUG_ON_FOLIO() with a more graceful
VM_WARN_ON_FOLIO() for handling non-anonymous folios.

The last one then extracts the common logic into a shared helper.

Thanks,
Lance

---
v1 -> v2:
- #01 Update the changelog (per Dev)
- #01 Collect Reviewed-by from Wei, Dev and Zi - thanks!
- #03 Make more of the scanning logic common between scan_pmd() and
      _isolate() (per Dev)
- https://lore.kernel.org/linux-mm/20251002073255.14867-1-lance.yang@linux.dev

Lance Yang (3):
  mm/khugepaged: optimize PTE scanning with if-else-if-else-if chain
  mm/khugepaged: use VM_WARN_ON_FOLIO instead of VM_BUG_ON_FOLIO for
    non-anon folios
  mm/khugepaged: merge PTE scanning logic into a new helper

 mm/khugepaged.c | 243 ++++++++++++++++++++++++++----------------------
 1 file changed, 131 insertions(+), 112 deletions(-)

-- 
2.49.0