lkml.org 
[lkml]   [2015]   [Apr]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 10/13] x86: mm: Enable deferred struct page initialisation on x86-64
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?

--
Mel Gorman
SUSE Labs


\
 
 \ /
  Last update: 2015-04-25 19:41    [W:0.081 / U:1.288 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site