On 1/28/25 02:18, Andrew Morton wrote: > On Mon, 27 Jan 2025 22:50:20 +0100 Michal Clapinski <mclapinski@xxxxxxxxxx> wrote: > >> Currently, the difference between the high and low watermarks for >> proactive compaction is hardcoded to 10. This hardcoded difference is >> too large for free page reporting to work well. >> >> Add a new sysctl, `compaction_proactiveness_leeway`, to control the >> difference between the high and low watermarks. >> > > Oh dear, yet another tunable. Is there any way in which we can > acceptably improve the kernel without adding this? compaction_proactiveness between 0 and 90 works as usual, thus up to low watermark of 10 and high watermark of 20 compaction_proactiveness between 90 and 100 additionally reduces leeway, with value of 100 resulting of low = high = 0 or some similar scheme, as long as a value of 100 does low = high = 0 It's rather arbitrary but AFAIU does what Michal needs and higher proactiveness means more aggressive compaction. Question is, would anyone else find it useful to have low_watermark of 0 and high watermark of 10?
