Messages in this thread | | | Date | Tue, 14 Dec 2010 17:06:37 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 55 of 66] select CONFIG_COMPACTION if TRANSPARENT_HUGEPAGE enabled |
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Hi Mel,
On Tue, Dec 14, 2010 at 09:45:56AM +0000, Mel Gorman wrote: > On Thu, Dec 09, 2010 at 08:04:07PM +0100, Andrea Arcangeli wrote: > > On Thu, Nov 18, 2010 at 04:22:45PM +0000, Mel Gorman wrote: > > > Just to confirm - by hang, you mean grinds to a slow pace as opposed to > > > coming to a complete stop and having to restart? > > > > Hmm it's like if you're gigabytes in swap and apps hangs for a while > > and system is not really usable and it swaps for most new memory > > allocations despite there's plenty of memory free, but it's not a > > deadlock of course. > > > > Ok, but it's likely to be kswapd being very aggressive because it's > woken up frequently and tries to balance all zones. Once it's not > deadlocking entirely, there isn't a more fundamental bug hiding in there > somewhere.
kswapd isn't activated by transhuge allocations because there's khugepaged for that and it's throttle to try a 2m alloc only once per minute if there's fragmentation.
So the reason of the trashing is the direct lumpy.
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