Re: [gentoo-user] Limiting amount of memory a program can use.

[Wols Lists <antlists@youngman.org.uk>]

On 28/08/2022 15:21, Rich Freeman wrote:
> Something I wish linux supported was discardable memory, for
> caches/etc.  A program should be able to allocate memory while passing
> a hint to the kernel saying that the memory is discardable.

Linux DOES have that ...

I'm not sure how to use it, but you can pass a flag to open(), which 
says "do not cache this file". The obvious use case is something like 
cp, but there's plenty of others. Or there are applications which cache 
stuff in the app, so don't want to waste OS cache as well - databases 
are a prime example.

Apparently not only does memory use crash when this is actively used, 
but because the OS does not have to manage cache, speed is actually 
noticeably impacted. Given the obsession kernel devs have with not 
wasting memory and time, this is likely to be actively maintained and 
supported. We just need to find out how to access this from user space.

Cheers,
Wol