Messages in this thread | | | Date | Sat, 11 Mar 2006 20:52:53 +0900 | From | "Magnus Damm" <> | Subject | Re: [PATCH 00/03] Unmapped: Separate unmapped and mapped pages |
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On 3/10/06, Arjan van de Ven <arjan@infradead.org> wrote: > On Fri, 2006-03-10 at 14:19 +0100, Magnus Damm wrote: > > My current code just extends this idea which basically means that > > there is currently no relation between how many pages that sit in each > > LRU. The LRU with the largest amount of pages will be shrunk/rotated > > first. And on top of that is the guarantee logic and the > > reclaim_mapped threshold, ie the unmapped LRU will be shrunk first by > > default. > > that sounds wrong, you lose history this way. There is NO reason to > shrink only the unmapped LRU and not the mapped one. At minimum you > always need to pressure both. How you pressure (absolute versus > percentage) is an interesting question, but to me there is no doubt that > you always need to pressure both, and "equally" to some measure of equal
Regarding if shrinking the unmapped LRU only is bad or not: In the vanilla version of refill_inactive_zone(), if reclaim_mapped is false then mapped pages are rotated on the active list without the young-bits are getting cleared in the PTE:s. I would say this is very similar to leaving the pages on the mapped active list alone as long as reclaim_mapped is false in the dual LRU case. Do you agree?
Also, losing history, do you mean that the order of the pages are not kept? If so, then I think my refill_inactive_zone() rant above shows that the order of the pages are not kept today. But yes, keeping the order is probaly a good idea.
It would be interesting to hear what you mean by "pressure", do you mean that both the active list and inactive list are scanned?
Many thanks,
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