On Mon, Sep 02, 2024 at 08:24:43PM +0800, Rong Qianfeng wrote: > Reserved pages are basically non-lru pages. This kind of memory can't be > used as migration sources and targets, skip it can bring some performance > benefits. > > Because some drivers may also use PG_reserved, we just set PB_migrate_skip > for those clustered reserved bootmem during memory initialization. > > Signed-off-by: Rong Qianfeng <rongqianfeng@xxxxxxxx> I'm not convinced the savings due to skipping a few pages during the scan would justify the additional code. There would have to be a large number of reserved pages scattered throughout the zone to make a difference and even that situation would be a big surprise. I'm not even sure this can be explicitly tested unless you artifically create reserved pages throughout the zone, which would not be convincing, or know if a driver that exhibits such behaviour in which case my first question is -- what is that driver doing?!? -- Mel Gorman SUSE Labs
