On Sun, Jan 28, 2024 at 08:28:04AM -0800, SeongJae Park wrote: > On Sun, 28 Jan 2024 17:13:00 +0800 cuiyangpei <cuiyangpei@xxxxxxxxx> wrote: > > > On Fri, Jan 26, 2024 at 12:04:54AM -0800, SeongJae Park wrote: > [...] > > > So, 'update_schemes_tried_regions' command is firstly handled by > > > 'damon_sysfs_cmd_request_callback()', which is registered as > > > after_wmarks_check() and after_aggregation() callback. Hence > > > 'update_schemes_tried_regions' command is still effectively working in > > > aggregation interval granularity. I think this is what you found, right? > > > > > Yes. > > > If I'm not wrongly understanding your point, I think the concern is valid. I > > > think we should make it works in sampling interval granularity. I will try to > > > make so. Would that work for your use case? > > > > > It's much better than working in aggregation interval. > > Thank you for confirming. I will start working on this. > Great, looking forward to seeing the progress. > > > > I have a question. Why does the 'update_schemes_tried_regions' command need to work > > in the sampling time or aggregation time? 'update_schemes_tried_regions' is a > > relatively special state that updates the regions that corresponding operation scheme. > > Can it be separated from other states and controlled by sysfs node to respond immediately > > after being written? > > Mainly because the region data is updated by a kdamond thread. To safely > access the region, the accessor should do some kind of synchronization with the > kdamond thread. To minimize such synchronization overhead, DAMON let the API > users (kernel components) to register callbacks which kdamond invokes under > specific events including 'after_sampling' or 'after_aggregate'. Because the > callback is executed in the kdamond thread, callbacks can safely access the > data without additional synchronization. DAMON sysfs interface is using the > callback mechanism, and hence need to work in the sampling or aggregation > times. > Thank you for the detailed explanation. > Thanks, > SJ > > [...]
