Re: [PATCH] mm/khugepaged: continue to collapse on SCAN_PMD_NONE

[Wei Yang <richard.weiyang@gmail.com>]

On Wed, Nov 12, 2025 at 09:28:34AM +0530, Dev Jain wrote:
>
>On 12/11/25 9:10 am, Wei Yang wrote:
>> On Wed, Nov 12, 2025 at 10:37:06AM +0800, Lance Yang wrote:
>> > 
>> > On 2025/11/12 10:00, Wei Yang wrote:
>> > > SCAN_PMD_NONE means current pmd is empty, but we can still continue
>> > > collapse next pmd range.
>> > Right, bailing out of the whole MADV_COLLAPSE request just because
>> > we encounter one empty PMD is too strict ...
>> > 
>> > It makes sense to treat SCAN_PMD_NONE like the other whitelisted cases
>> > (e.g., SCAN_PMD_NULL).
>> > > Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>> > > ---
>> > LGTM.
>> > 
>> > Reviewed-by: Lance Yang <lance.yang@linux.dev>
>> > 
>> Thanks for the review.
>> 
>> I'm currently evaluating the use of SCAN_NULL versus SCAN_NONE. It seems their
>> usage in the current code is intermixed, and I'm questioning if there's a
>> strong, practical reason to maintain a distinction between these two states.
>> Should they be unified?
>
>There was some discussion about that in this thread:
>
>https://lore.kernel.org/all/v5ivpub6z2n2uyemlnxgbilzs52ep4lrary7lm7o6axxoneb75@yfacfl5rkzeh/
>
>There are some cleanups mentioned in the thread which you can try if you want :)
>

Thanks, will take a look.

-- 
Wei Yang
Help you, Help me