On Tue, 2011-02-22 at 22:25 +0800, Mel Gorman wrote: > On Mon, Feb 14, 2011 at 10:25:24AM +0800, Shaohua Li wrote: > > On Thu, Feb 03, 2011 at 10:58:08AM +0800, Andrea Arcangeli wrote: > > > On Thu, Jan 27, 2011 at 04:27:55PM +0100, Andrea Arcangeli wrote: > > > > totally untested... I will test.... > > > > > > The below patch is fixing my problem and working fine for me... as > > > expected it can't possibly lead to any D state, it's pretty much like > > > setting min_free_kbytes lower, and it's not going to alter anything > > > other than the levels of free memory kept by kswapd. > > > > > > $ while :; do ps xa|grep [k]swapd; sleep 1; done > > > 452 ? R 1:20 [kswapd0] > > > 452 ? S 1:20 [kswapd0] > > > 452 ? S 1:20 [kswapd0] > > > 452 ? S 1:20 [kswapd0] > > > 452 ? S 1:20 [kswapd0] > > > 452 ? R 1:20 [kswapd0] > > > 452 ? R 1:20 [kswapd0] > > > 452 ? R 1:20 [kswapd0] > > > 452 ? R 1:20 [kswapd0] > > > 452 ? S 1:20 [kswapd0] > > > 452 ? R 1:20 [kswapd0] > > > $ vmstat 1 > > > procs -----------memory---------- ---swap-- -----io---- -system-- > > > ----cpu---- > > > r b swpd free buff cache si so bi bo in cs us > > > sy id wa > > > 2 1 1784 111040 2393336 807924 0 0 63 992 56 70 1 1 96 2 > > > 0 1 1784 108928 2402556 801864 0 0 122624 0 1619 2150 0 5 80 16 > > > 0 1 1784 110664 2401244 801140 0 0 122496 0 1602 2081 0 3 81 16 > > > 0 1 1784 109796 2410184 792984 0 0 122752 0 1685 2149 0 4 80 16 > > > 0 1 1784 110416 2411856 791208 0 0 120448 4 1599 2075 0 4 81 16 > > > 1 0 1784 113516 2415344 785336 0 0 122496 0 1636 2125 0 4 81 15 > > > > > > I doubt we'll get any regression because of the below (see also my > > > prev email in this thread), and I would only expect more cache and > > > maybe better lru. Previously the free memory levels were stuck at > > > ~700M now they're stuck at the right level for a 4G system with THP on > > > (I'd still like to try to reduce the requirements only 1 hugepage for > > > each migratetype in the set_min_free_kbytes to reduce the requirements > > > to the minium, but only if possible..). But this saves 600M over 4G so > > > it's the highest prio to address. > > Sorry for the later response, I offlined several weeks. > > The patch is addressing the 8*high_wmark issue, which isn't the original issue > > I reported (sure the 8*wmark issue should be fixed too). > > min_free_kbytes is set higher and cause more pages freed even no the 8*wmark > > issue. wmark: > > before: min 1424 > > after: min 11178 > > The higher min_free_kbytes is expected as a result of using transparent > hugepages so I don't really consider it a bug. Free memory going up to > about 700M as a result of kswapd is a real bug though. > > > in our test, there is about 50M memory free (originally just about 5M, which > > will cause more swap. Should we also reduce the min_free_kbytes? > > > > Either that or boot with transparent hugepages disabled and > min_free_kbytes will be lower. Fixing it will let more people enable THP by default. but anyway we will disable it now if the issue can't be fixed. -- 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>