On 10/19/2017 09:03 PM, Michal Hocko wrote: > On Thu 19-10-17 20:26:57, Anshuman Khandual wrote: >> Its already assumed that the PageActive flag is clear on the input >> page, hence page_lru(page) will pick the base LRU for the page. In >> the same way page_lru(page) will pick active base LRU, once the >> flag PageActive is set on the page. This change of LRU list should >> happen implicitly through the page flags instead of being hard >> coded. > > The patch description tells what but it doesn't explain _why_? Does the > resulting code is better, more optimized or is this a pure readability > thing?
Not really. Not only it removes couple of lines of code but it also makes it look more logical from function flow point of view as well. > > All I can see is that page_lru is more complex and a large part of it > can be optimized away which has been done manually here. I suspect the > compiler can deduce the same thing. Why not ? I mean, that is the essence of the function page_lru() which should get us the exact LRU list the page should be on and hence we should not hand craft these manually.