Re: [PATCH 3/8] mm/vmscan: introduce helper function reclaim_page_list()

[Matthew Wilcox <willy@infradead.org>]

On Wed, Mar 30, 2022 at 10:04:54AM +0800, Miaohe Lin wrote:
> On 2022/3/29 21:50, Matthew Wilcox wrote:
> >> +	while (!list_empty(page_list)) {
> >> +		page = lru_to_page(page_list);
> >> +		list_del(&page->lru);
> >> +		putback_lru_page(page);
> > 
> > Why wouldn't you use a folio here?
> > 
> 
> I was just wanting to keep the code consistent with the previous one. Am I supposed to
> use a folio here ? If so, will do it in V2.

The distinction we're trying to make (and obviously we have a long way
to go before we're finished) is between the structure that describes
PAGE_SIZE bytes of memory and the structure that manages the memory
allocation.  This function is clearly handling the entire memory
allocation, so it should be using a folio.  Eventually, page->lru
should disappear, but there's 180 places to figure out what we need to
do instead.