Messages in this thread | | | Date | Mon, 27 Apr 2015 16:07:42 -0400 | From | Waiman Long <> | Subject | Re: [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64 |
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On 04/25/2015 01:28 PM, Mel Gorman wrote: > On Fri, Apr 24, 2015 at 03:04:27PM -0400, Waiman Long wrote: >>>> Within a NUMA node, however, we can split the >>>> memory initialization to 2 or more local CPUs if the memory size is >>>> big enough. >>>> >>> I considered it but discarded the idea. It'd be more complex to setup and >>> the two CPUs could simply end up contending on the same memory bus as >>> well as contending on zone->lock. >>> >> I don't think we need that now. However, we may have to consider >> this when one day even a single node can have TBs of memory unless >> we move to a page size larger than 4k. >> > We'll cross that bridge when we come to it. I suspect there is more room > for improvement in the initialisation that would be worth trying before > resorting to more threads. With more threads there is a risk that we hit > memory bus contention and a high risk that it actually is worse due to > contending on zone->lock when freeing the pages. > > In the meantime, do you mind updating the before/after figures for your > test machine with this series please? >
I will test the latest patch once I got my hand on a 12TB machine.
Cheers, Longman
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