Re: computing drop-able caches

[Johannes Weiner]

On Thu, Jan 28, 2016 at 05:29:41PM -0800, Daniel Walker wrote:
> On 01/28/2016 05:03 PM, Daniel Walker wrote:
> [regarding MemAvaiable]
> 
> This new metric purportedly helps usrespace assess available memory. But,
> its again based on heuristic, it takes 1/2 of page cache as reclaimable..

No, it takes the smaller value of cache/2 and the low watermark, which
is a fraction of memory. Actually, that does look a little weird. Rik?

We don't age cache without memory pressure, you don't know how much is
used until you start taking some away. Heuristics is all we can offer.