Re: [PATCH v3] memcg: expose socket memory pressure in a cgroup

[Daniel Sedlak <daniel.sedlak@cdn77.com>]

On 7/23/25 7:54 PM, Shakeel Butt wrote:
>>
>> To me, introducing the new PSI for sockets (like for CPU, IO, memory), would
>> be slightly better than cumulative counter because PSI can have the timing
>> information without frequent periodic scrapes. So it may help with live
>> debugs.
> 
> How would this PSI for sockets work? What would be the entry and exit
> points?
> 
Currently, we know the following information:

- we know when the pressure starts
- and we know when the pressure ends if not rearmed (start time + HZ)

 From that, we should be able to calculate a similar triplet to the 
pressure endpoints in the cgroups (cpu|io|memory|irq).pressure. That is, 
how much % of time on average was spent under pressure for avg10, avg60, 
avg300 i.e. average pressure over the past 10 seconds, 60 seconds, and 
300 seconds, respectively. (+ total time spent under pressure)

For example, if we had pressure for 5 seconds straight, then the output 
of socket.pressure could be:

	full avg10=50.00 avg60=8.33 avg300=1.66 total=77777

Do you think this would be feasible? If so, I can try to send it as v4.

Thanks!
Daniel