On 7/28/23 18:02, Vlastimil Babka wrote:

quoted

There's even a comment to that effect later on in the function:

Hmm, well spotted. But it wouldn't be so great if we now had to lock every
inspected page (and not just dirty pages), just to check the AS_ bit.

But I wonder if this is leftover from previous versions. Are the guest pages
even PageLRU currently? (and should they be, given how they can't be swapped
out or anything?) If not, isolate_migratepages_block will skip them anyway.

No, they're not (migration or even swap-out is not excluded for the 
future, but for now it's left for future work.

Paolo