Hi Ravi, On Sat, 3 Oct 2026 13:27:27 -0700 Ravi Jonnalagadda <[email protected]> wrote:
> Add a tracepoint for DAMOS_QUOTA_NODE_ELIGIBLE_MEM_BP quota goal > evaluation. The tracepoint fires once per quota-score computation when > the goal metric is DAMOS_QUOTA_NODE_ELIGIBLE_MEM_BP, exposing > context_idx, scheme_idx, nid, target_value, and current_value. > current_value is reported as the quota tuning sees it, after the goal's > complement setting is applied. > > The DAMOS_QUOTA_NODE_ELIGIBLE_MEM_BP metric expresses node memory > occupancy as basis points of eligible bytes. This information is not > exposed through any existing external interface (perf stat, /proc, or > sysfs), so the tracepoint is the only way for userspace to observe the > target and current eligible-memory basis point values at quota-scoring > time. Thank you for this patch! We have damos_esz tracepoint. Have you considered using it? It doesn't expose the current value, though. I thought it wouldn't be real problem in most cases, but I can show it could be problematic for node_eligible_mem_bp case, as the metric value is not straightforward to see without using DAMON. If you really need to know the current_value, I'm open to add a new tracepoint. But I think it has no reason to make it only eligible_mem_bp specific. How about adding more general purpose tracepoint, and/or update the current_value file [1] under the goal sysfs directory to show the current current_value for all goal types? [1] https://origin.kernel.org/doc/html/latest/admin-guide/mm/damon/usage.html#sysfs-schemes-quota-goals Thanks, SJ [...]
