Thread (31 messages) 31 messages, 2 authors, 2025-06-19

Re: [PATCH v2 08/14] mm/khugepaged: Remove redundant pmd_devmap() check

From: David Hildenbrand <hidden>
Date: 2025-06-17 09:44:37
Also in: dri-devel, linux-arm-kernel, linux-cxl, linux-ext4, linux-fsdevel, linux-mm, linux-riscv, linux-xfs, lkml, loongarch, nvdimm

On 16.06.25 13:58, Alistair Popple wrote:
The only users of pmd_devmap were device dax and fs dax. The check for
pmd_devmap() in check_pmd_state() is therefore redundant as callers
explicitly check for is_zone_device_page(), so this check can be dropped.
Looking again, is this true?

If we return "SCAN_SUCCEED", we assume there is a page table there that 
we can map and walk.

But I assume we can drop that check because nobody will ever set 
pmd_devmap() anymore?

So likely just the description+sibject of this patch should be adjusted.

FWIW, I think check_pmd_state() should be changed to work on pmd_leaf() 
etc, but that's something for another day.

-- 
Cheers,

David / dhildenb

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