On Wed, Apr 27, 2011 at 5:34 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > On Wed, 27 Apr 2011 01:25:23 +0900 > Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > >> This patch defines new APIs to putback the page into previous position of LRU. >> The idea is simple. >> >> When we try to putback the page into lru list and if friends(prev, next) of the pages >> still is nearest neighbor, we can insert isolated page into prev's next instead of >> head of LRU list. So it keeps LRU history without losing the LRU information. >> >> Before : >> Â Â Â LRU POV : H - P1 - P2 - P3 - P4 -T >> >> Isolate P3 : >> Â Â Â LRU POV : H - P1 - P2 - P4 - T >> >> Putback P3 : >> Â Â Â if (P2->next == P4) >> Â Â Â Â Â Â Â putback(P3, P2); >> Â Â Â So, >> Â Â Â LRU POV : H - P1 - P2 - P3 - P4 -T >> >> For implement, we defines new structure pages_lru which remebers >> both lru friend pages of isolated one and handling functions. >> >> But this approach has a problem on contiguous pages. >> In this case, my idea can not work since friend pages are isolated, too. >> It means prev_page->next == next_page always is false and both pages are not >> LRU any more at that time. It's pointed out by Rik at LSF/MM summit. >> So for solving the problem, I can change the idea. >> I think we don't need both friend(prev, next) pages relation but >> just consider either prev or next page that it is still same LRU. >> Worset case in this approach, prev or next page is free and allocate new >> so it's in head of LRU and our isolated page is located on next of head. >> But it's almost same situation with current problem. So it doesn't make worse >> than now and it would be rare. But in this version, I implement based on idea >> discussed at LSF/MM. If my new idea makes sense, I will change it. >> > > I think using only 'next'(prev?) pointer will be enough. I think so but let's wait other's opinion. :) -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href