On Thu, Feb 21, 2008 at 7:55 PM, KOSAKI Motohiro <[EMAIL PROTECTED]> wrote: > Hi Kim-san, > > Thank you very much. > btw, what different between <test 1> and <test 2>?
<test 1> have no swap device with 200 tasks by hackbench. But <test 2> have swap device(32M) with 240 tasks by hackbench. If <test2> have no swap device without your patch, <test2> is killed by OOM. <test 1> - NO SWAP Running with 5*40 (== 200) tasks. ... <test 2> - SWAP Running with 6*40 (== 240) tasks. ... > > > It was a very interesting result. > > In embedded system, your patch improve performance a little in case > > without noswap(normal case in embedded system). > > But, more important thing is OOM occured when I made 240 process > > without swap device and vanilla kernel. > > Then, I applied your patch, it worked very well without OOM. > > Wow, it is very interesting result! > I am very happy. > > > > I think that's why zone's page_scanned was six times greater than > > number of lru pages. > > At result, OOM happened. > > please repost question with change subject. > i don't know reason of vanilla kernel behavior, sorry. Normally, embedded linux have only one zone(DMA). If your patch isn't applied, several processes can reclaim memory in parallel. then, DMA zone's pages_scanned is suddenly increased largely. Because embedded linux have no swap device, kernel can't stop to scan lru list until meeting page cache page. so if zone->pages_scanned is greater six time than lru list pages, kernel make the zone with unreclaimable state, As a result, OOM will kill it, too. -- Thanks, barrios -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
