On Wed, 13 Sep 2023 02:20:49 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote: > DAMON provides damon_aggregated tracepoint, which exposes details of > each region and its access monitoring results. It is useful for > getting whole monitoring results, e.g., for recording purposes. > > For investigations of DAMOS, DAMON Sysfs interface provides DAMOS > statistics and tried_regions directory. But, those provides only > statistics and snapshots. If the scheme is frequently applied and if > the user needs to know every detail of DAMOS behavior, the > snapshot-based interface could be insufficient and expensive. > > As a last resort, userspace users need to record the all monitoring > results via damon_aggregated tracepoint and simulate how DAMOS would > worked. It is unnecessarily complicated. DAMON kernel API users, > meanwhile, can do that easily via before_damos_apply() callback field of > 'struct damon_callback', though. > > Add a tracepoint that will be called just after before_damos_apply() > callback for more convenient investigations of DAMOS. The tracepoint > exposes all details about each regions, similar to damon_aggregated > tracepoint. > > Please note that DAMOS is currently not only for memory management but > also for query-like efficient monitoring results retrievals (when 'stat' > action is used). Until now, only statistics or snapshots were > supported. Addition of this tracepoint allows efficient full recording > of DAMOS-based filtered monitoring results. > >From a tracing point of view. Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> -- Steve
