On Fri, May 10, 2019 at 03:54:56PM -0700, Ira Weiny wrote: > On Fri, May 10, 2019 at 09:36:12AM -0700, Matthew Wilcox wrote: > > On Fri, May 10, 2019 at 10:12:40AM +0800, Huang, Ying wrote: > > > > + nr_reclaimed += (1 << compound_order(page)); > > > > > > How about to change this to > > > > > > > > > nr_reclaimed += hpage_nr_pages(page); > > > > Please don't. That embeds the knowledge that we can only swap out either > > normal pages or THP sized pages. I'm trying to make the VM capable of > > supporting arbitrary-order pages, and this would be just one more place > > to fix. > > > > I'm sympathetic to the "self documenting" argument. My current tree has > > a patch in it: > > > > mm: Introduce compound_nr > > > > Replace 1 << compound_order(page) with compound_nr(page). Minor > > improvements in readability. > > > > It goes along with this patch: > > > > mm: Introduce page_size() > > > > It's unnecessarily hard to find out the size of a potentially huge page. > > Replace 'PAGE_SIZE << compound_order(page)' with page_size(page). > > > > Better suggestions on naming gratefully received. I'm more happy with > > page_size() than I am with compound_nr(). page_nr() gives the wrong > > impression; page_count() isn't great either. > > Stupid question : what does 'nr' stand for? NumbeR. It's relatively common argot in the Linux kernel (as you can see from the earlier example ... > > > nr_reclaimed += hpage_nr_pages(page); willy@bobo:~/kernel/xarray-2$ git grep -w nr mm |wc -l 388 willy@bobo:~/kernel/xarray-2$ git grep -w nr fs |wc -l 1067
