Re: [PATCH V4 00/10] mm: page_alloc: freelist migratetype hygiene

[Vlastimil Babka]

On 3/20/24 7:02 PM, Johannes Weiner wrote:
> V4:
> - fixed !pcp_order_allowed() case in free_unref_folios()
> - reworded the patch 0 changelog a bit for the git log
> - rebased to mm-everything-2024-03-19-23-01
> - runtime-tested again with various CONFIG_DEBUG_FOOs enabled
> 
> ---
> 
> The page allocator's mobility grouping is intended to keep unmovable
> pages separate from reclaimable/compactable ones to allow on-demand
> defragmentation for higher-order allocations and huge pages.
> 
> Currently, there are several places where accidental type mixing
> occurs: an allocation asks for a page of a certain migratetype and
> receives another. This ruins pageblocks for compaction, which in turn
> makes allocating huge pages more expensive and less reliable.
> 
> The series addresses those causes. The last patch adds type checks on
> all freelist movements to prevent new violations being introduced.
> 
> The benefits can be seen in a mixed workload that stresses the machine
> with a memcache-type workload and a kernel build job while
> periodically attempting to allocate batches of THP. The following data
> is aggregated over 50 consecutive defconfig builds:

Great stuff. What would you say to the following on top?

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