Re: [PATCH] sched/numa: Fix NULL pointer access to mm_struct durng task swap

["Chen, Yu C" <yu.c.chen@intel.com>]

Hi Peter,

On 7/3/2025 8:36 PM, Peter Zijlstra wrote:
> On Thu, Jul 03, 2025 at 05:20:47AM -0700, Libo Chen wrote:
> 
>> I agree. The other parts, schedstat and vmstat, are still quite helpful.
>> Also tracepoints are more expensive than counters once enabled, I think
>> that's too much for just counting numbers.
> 
> I'm not generally a fan of eBPF, but supposedly it is really good for
> stuff like this.
> 
> Attaching to a tracepoint and distributing into cgroup buckets seems
> like it should be a trivial script.

Yes, it is feasible to use eBPF. On the other hand, if some
existing monitoring programs rely on /proc/{pid}/sched to observe
the NUMA balancing metrics of processes, it might be helpful to
include the NUMA migration/swap information in /proc/{pid}/sched.
This approach can minimize the modifications needed for these
monitoring programs, eliminating the need to add a new BPF script
to obtain NUMA balancing statistics from different sources IMHO.


thanks,
Chenyu