On Mon, Mar 01, 2021 at 02:50:07PM +0300, Kirill A. Shutemov wrote:

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

quoted

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.

Well, I call it an incremental improvement, and how exactly does it
complicate the picture?

I see your point: you prefer a complete replacement. But my point is
not about the preference; it's about presenting an option: I'm not
saying we have to go with this series; I'm saying if you don't want
to wait, here is something quick but not perfect.