Oscar Salvador <osalvador@xxxxxxx> writes: > On Tue, Mar 01, 2022 at 09:16:18AM +0800, Huang, Ying wrote: >> Hi, Oscar, > > Hi Huang Ying > >> b. Make kswapd of the fast memory node to reclaim pages until the free >> pages are a little more than the high watermark (named as promo >> watermark). If we want to promote some hot pages from the slow >> memory to the fast memory, but the free pages of the fast memory >> node will become lower than the high watermark after promotion, we >> will wake up kswapd of the fast memory node to demote more cold >> pages in the fast memory node to the slow memory node firstly. This >> will free some extra space in the fast memory node, so the hot pages >> in the slow memory node can be promoted to the fast memory node. > > What about this? Somehow it sounds clear to me. > > "b. Define a new watermark called wmark_promo which is higher than wmark_high, > and have kswapd reclaiming pages until free pages reach such watermark. > The scenario is as follows: when we want to promote hot-pages from a slow > memory to a fast memory, but fast memory's free pages would go lower than > high watermark with such promotion, we wake up kswapd with wmark_promo > watermark in order to demote cold pages and free us up some space. > So, next time we want to promote hot-pages we might have a chance of > doing so." Your version looks better. I will use it. Thanks! > But I am fine with your updated write up as well, so if you spin a new > version: > > Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> Thanks! Best Regards, Huang, Ying
