On Wed, 29 Nov 2023 18:10:33 +0100 Michal Hocko <mhocko@xxxxxxxx> wrote: > > > How? You are only reporting the number of reclaimed pages and no > > > reclaimed pages could be not just because of low/min limits but > > > generally because of other reasons. You would need to report also the > > > number of scanned/isolated pages. > > > > > > > From my perspective, if memory control group (memcg) protection > > restrictions occur, we can identify them by the absence of the end() > > pair of begin(). Other reasons will have both tracepoints raised. > > That is not really great way to detect that TBH. Trace events could be > lost and then you simply do not know what has happened. Note, you can detect dropped events. If there's a dropped event, you can ignore the "missing end" from a beginning. You could also make synthetic events that pair an end event with a beginning event (which uses the last begin event found). Synthetic event creation is not affected by dropped events. There's a lot you can to get information with the prospect of dropped events. I would not use that as rationale for not using events. -- Steve
