On Thu, Aug 26, 2010 at 6:03 PM, Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > > Hello. > > On Fri, Aug 27, 2010 at 9:11 AM, Ying Han <yinghan@xxxxxxxxxx> wrote: > > Fix a missed place where checks nr_swap_pages to do shrink_active_list. Make the > > change that moves the check to common function inactive_anon_is_low. > > > > Hmm.. AFAIR, we discussed it at that time but we concluded it's not good. > That's because nr_swap_pages < 0 means both "NO SWAP" and "NOT enough > swap space now". If we have a swap device or file but not enough space > now, we need to aging anon pages to make inactive list enough size. > Otherwise, working set pages would be swapped out more fast before > promotion. We found the problem on one of our workloads where more TLB flush happens without the change. Kswapd seems to be calling shrink_active_list() which eventually clears access bit of those ptes and does TLB flush with ptep_clear_flush_young(). This system does not have swap configured, and why aging the anon lru in that case? > That aging is done by kswapd so I think it's not big harmful in the system. > But if you want to remove aging completely in non-swap system, we need > to identify non swap system and not enough swap space. I thought we > need it for embedded system. Lots of TLB flush hurts the performance especially on large smp system. So does it make sense if change it to: + if (nr_swap_pages == 0) + return 0; --Ying > Thanks. > > > -- > 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/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- 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/ . Don't email: <a href