Re: [PATCH 1/1] sysctl: change watermark_scale_factor max limit to 30%

[Johannes Weiner]

On Wed, Nov 24, 2021 at 11:36:04AM -0800, Suren Baghdasaryan wrote:
> For embedded systems with low total memory, having to run applications
> with relatively large memory requirements, 10% max limitation for
> watermark_scale_factor poses an issue of triggering direct reclaim
> every time such application is started. This results in slow application
> startup times and bad end-user experience.
> By increasing watermark_scale_factor max limit we allow vendors more
> flexibility to choose the right level of kswapd aggressiveness for
> their device and workload requirements.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

No objection from me as this limit was always totally arbitrary. But I
have to say I'm a bit surprised: The current maximum setting will wake
kswapd when free memory drops below 10% and have it reclaim until
20%. This seems like quite a lot? Are there applications that really
want kswapd to wake at 30% and target 60% of memory free?