On 6/17/21 9:30 AM, Charan Teja Kalla wrote: > Thanks Vlastimil for your inputs!! > > On 6/16/2021 5:29 PM, Vlastimil Babka wrote: >>> This triggering of proactive compaction is done on a write to >>> sysctl.compaction_proactiveness by user. >>> >>> [1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=facdaa917c4d5a376d09d25865f5a863f906234a >>> >>> Signed-off-by: Charan Teja Reddy <charante@xxxxxxxxxxxxxx> >>> --- >>> changes in V2: >> You forgot to also summarize the changes. Please do in next version. > > I think we can get rid off 'proactive_defer' thread variable with the > timeout approach you suggested. But it is still requires to have one > additional variable 'proactive_compact_trigger', which main purpose is > to decide if the kcompactd wakeup is for proactive compaction or not. > Please see below code: > if (wait_event_freezable_timeout() && !proactive_compact_trigger) { > // do the non-proactive work > continue > } > // do the proactive work > ................. > > Thus I feel that on writing new proactiveness, it is required to do > wakeup_kcomppactd() + set a flag that this wakeup is for proactive work. > > Am I failed to get your point here? The check whether to do non-proactive work is already guarded by kcompactd_work_requested(), which looks at pgdat->kcompactd_max_order and this is set by wakeup_kcompactd(). So with a plain wakeup where we don't set pgdat->kcompactd_max_order will make it consider proactive work instead and we don't need another trigger variable AFAICS.
