Re: [PATCH RFC] mm/mglru: lazily activate folios while folios are really mapped

[Barry Song]

On Fri, Mar 20, 2026 at 5:59 PM 郑堂权(Blues Zheng) <zhengtangquan@xxxxxxxx> wrote:
>
> Hi Zicheng,
>
> We ran the same RFC on 6.6, 8 GB, with zstd in our internal whole-system perf model. /proc/vmstat (before → after; % = reduction):
> pgpgin                                          57807848        55738480        −3.58%
> pgpgout                                         31585160        26367420        −16.52%
> pswpin                                          2305528         1534481         −33.44%
> pswpout                                         6618935         5327316         −19.51%
> workingset_refault_anon         2104047         1356316         −35.54%
> workingset_refault_file         9020966         8407346         −6.80%
> workingset_activate_anon        1196828         412937          −65.50%
> workingset_activate_file                2941357         1468218         −50.08%
> workingset_restore_anon         590337          412322          −30.15%
> workingset_restore_file         1801398         1285060         −28.66%
> workingset_nodereclaim          201014          152864          −23.95%
>
> Here both file and anon refault drop—different from your Android run, likely workload/environment.

Thanks to both Tangquan and Zicheng for the data. I’m guessing the
difference might be related to the readahead and fault_around settings
on low-end phones. Tangquan, would you be willing to share whether you’ve
ever adjusted the readahead window or fault-around pages to make the patch
work better?
I guess this could be helpful in shaping a new version.

Thanks
Barry