On 03/21/2013 08:05 PM, Will Huck wrote:
One offline question, how to understand this in function balance_pgdat: /* * Do some background aging of the anon list, to give * pages a chance to be referenced before reclaiming. */ age_acitve_anon(zone, &sc);
The anon lrus use a two-handed clock algorithm. New anonymous pages start off on the active anon list. Older anonymous pages get moved to the inactive anon list. If they get referenced before they reach the end of the inactive anon list, they get moved back to the active list. If we need to swap something out and find a non-referenced page at the end of the inactive anon list, we will swap it out. In order to make good pageout decisions, pages need to stay on the inactive anon list for a longer time, so they have plenty of time to get referenced, before the reclaim code looks at them. To achieve that, we will move some active anon pages to the inactive anon list even when we do not want to swap anything out - as long as the inactive anon list is below its target size. Does that make sense? -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>