On Fri, Feb 26, 2021 at 12:13:14PM +0000, Matthew Wilcox wrote:

On Fri, Feb 26, 2021 at 02:17:18AM -0700, Yu Zhao wrote:

quoted

All places but one test, set or clear PG_active and PG_unevictable on
small or head pages. Use compound_head() explicitly for that singleton
so the rest can rid of redundant compound_head().

How do you know it's only one place?  I really wish you'd work with me
on folios.  They make the compiler prove that it's not a tail page.

+1 to this.

The problem with compound_head() is systemic and ad-hoc solution to few
page flags will only complicate the picture.

-- 
 Kirill A. Shutemov