Lumpy reclaim might distort the LRU a bit, but think you'll see a nice pattern emerge. If a "hot" page gets reclaimed early because it shares a higher order frame with a "cold" page, the hot page will refault soon and get a new page as an order-0 allocation. I believe this should tend to migrate hot pages to share higher-order frames. Thus, I'd imagine the performance issues might be temporary, and if combined with Mel's code, rare.
Or, I could just be full of it.
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