Messages in this thread | | | Date | Thu, 9 Dec 2010 20:04:07 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 55 of 66] select CONFIG_COMPACTION if TRANSPARENT_HUGEPAGE enabled |
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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.
BTW, alternatively I could:
unsigned long transparent_hugepage_flags __read_mostly = (1<<TRANSPARENT_HUGEPAGE_FLAG)| +#ifdef CONFIG_COMPACTION + (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| +#endif (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
That would adds GFP_ATOMIC to THP allocation if compaction wasn't selected, but I think having compaction enabled diminish the risk of misconfigured kernels leading to unexpected measurements and behavior, so I feel much safer to keep the select COMPACTION in this patch.
> Acked-by: Mel Gorman <mel@csn.ul.ie>
Added.
Thanks, Andrea
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