Re: [RFC PATCH v2] mm: vmscan: avoid anon scanning for GFP_NOIO with low swapcache in MGLRU

[Xiang Liu]

Hi Barry, Baolin,

Thanks for the review and discussion.

I've seen the RFC v5 "mm: mglru: fix swappiness behavior" series, where
Bo's patch 14/14 addresses the same GFP_NOIO issue on top of the new
scan-budget model.

Baolin wrote on Oct 21:
> IMO, 'swappiness' and 'scan_swappiness' are really confusing.

For a standalone v3, I plan to rename scan_swappiness to
evict_swappiness to make its role clearer, keeping the rest of the v2
implementation unchanged. The split in v2 preserves the original policy
for anon aging, including the page-table walk.

Barry wrote on Oct 22:
> IMHO, this is confusing but this is a possible way to fix it before we
> land something [...]

Before preparing a v3, would a standalone fix against the current MGLRU
code still be useful as an interim fix before the scan-budget series
lands?

Or would you prefer to handle this issue through the new series? In that
case, I can use my GFP_NOIO workload to help test Bo's patch 14/14.

Thanks,
Xiang