On Mon, Nov 15, 2010 at 11:48 PM, Rik van Riel <riel@xxxxxxxxxx> wrote: > On 11/15/2010 04:05 AM, Minchan Kim wrote: >> >> On Mon, Nov 15, 2010 at 5:47 PM, Peter Zijlstra<peterz@xxxxxxxxxxxxx> >> wrote: >>> >>> On Mon, 2010-11-15 at 15:07 +0900, Minchan Kim wrote: > >>>> I wonder what's the problem in Peter's patch 'drop behind'. >>>> http://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg179576.html >>>> >>>> Could anyone tell me why it can't accept upstream? >>> >>> Read the thread, its quite clear nobody got convinced it was a good idea >>> and wanted to fix the use-once policy, then Rik rewrote all of >>> page-reclaim. >>> >> >> Thanks for the information. >> I hope this is a chance to rethink about it. >> Rik, Could you give us to any comment about this idea? Sorry for late reply, Rik. > At the time, there were all kinds of general problems > in page reclaim that all needed to be fixed. Peter's > patch was mostly a band-aid for streaming IO. > > However, now that most of the other page reclaim problems > seem to have been resolved, it would be worthwhile to test > whether Peter's drop-behind approach gives an additional > improvement. Okay. I will have a time to make the workload for testing. > > I could see it help by getting rid of already-read pages > earlier, leaving more space for read-ahead data. Yes. Peter's logic breaks demotion if the page is in active list. But I think if it's just active page like rsync's two touch, we have to move tail of inactive although it's in active list. I will look into this, too. > > I suspect it would do fairly little to protect the working > set, because we do not scan the active file list at all > unless it grows to be larger than the inactive file list. Absolutely. But how about rsync's two touch? It can evict working set. I need the time for investigation. Thanks for the comment. > > -- > All rights reversed > -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href