On Fri, Feb 26, 2021 at 11:52:03AM +0100, Vlastimil Babka wrote:

On 2/26/21 10:17 AM, Yu Zhao wrote:

quoted

Patch series "mm: lru related cleanups" starting at commit 42895ea73bcd
("mm/vmscan.c: use add_page_to_lru_list()") bloated vmlinux by 1777
bytes, according to:
  https://lore.kernel.org/linux-mm/85b3e8f2-5982-3329-c20d-cf062b8da71e@suse.cz/ (local)

Huh, I thought Andrew didn't want to send it for 5.12:
https://lore.kernel.org/linux-mm/20210223145011.0181eed96ab0091a493b51f6@linux-foundation.org/ (local)

quoted

It turned out many places inline Page{Active,Unevictable} which in
turn include compound_head().

From the v1:
  Removing compound_head() entirely from Page{Active,Unevictable} may
  not be the best option (for the moment) because there may be other
  cases that need compound_head().

In addition to picking a couple pieces of low-hanging fruit, this v2
removes compound_head() completely from Page{Active,Unevictable}.

bloat-o-meter result before and after the series:
  add/remove: 0/0 grow/shrink: 6/92 up/down: 697/-7656 (-6959)

Good that you found a way to more than undo the bloat then. But we need to be
careful so bugs are not introduced due to pressure to not have bloated 5.12.

I was very conservative and only picked a few pieces of low-hanging
fruit. The pressure is good -- if you hadn't noticed it and Andrew
hadn't been emphatic about it, it'd have been left for another time
and to another person, and so on.