On Wed, 2 Mar 2011 08:10:35 +0900 Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > On Wed, Mar 2, 2011 at 7:39 AM, Andrea Arcangeli <aarcange@xxxxxxxxxx> wrote: > > On Wed, Mar 02, 2011 at 07:33:13AM +0900, Minchan Kim wrote: > >> Sorry for bothering you but I think you get the data. > >> It helps someone in future very much to know why we determined to > >> remove the feature at that time and they should do what kinds of > >> experiment to prove it has a benefit to add compaction in kswapd > >> again. > > > > This is a benchmark I'm unsure if it's ok to publish results but it > > should be possible to simulate it with a device driver. > > > > Arthur provided kswapd load usage data too, so I hope that's enough. > > > > My other patch (compaction-kswapd-3) is way better than current logic > > and retains compaction in kswapd. That shows slightly higher > > kswapd utilization with Arthur's multimedia workload, and a bit worse > > performance on the network benchmark. So I thought it was better to go > > with the fastest potion as long as we don't have a logic that uses > > compaction and shows improved performance and lower latency than with > > no compaction at all in kswapd. > > > > I didn't notice Arthur's problem. > The patch seems to fix a real problem so I think it's enough. > I wished you wrote down the link url about Arthur on LKML. > > You can remove compact_mode of compact_control. > Otherwise, looks good to me. > I'd be pretty worried about jamming this into 2.6.38 at this late stage. And some vague talk about something Arthur did really doesn't help a lot! It would be better to have some good, solid quantitative justification for what is really an emergency patch. Bear in mind that we always have a middle option: merge a patch into 2.6.39-rc1 and tag it for backporting into 2.6.38.x. That gives us more time to test it and to generally give it a shakedown. But to make decisions like that and to commend a patch to the -stable maintainers, we need to provide better information please. Also, "This goes on top of the two lowlatency fixes for compaction" isn't particularly helpful. I need to verify that the referred-to patches are already in mainline but I don't have a clue what this description refers to. More specificity, please - it helps avoid mistakes. -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>