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Date: Thu, 5 Mar 2015 18:07:52 +0100
From: Andres Freund <andres@anarazel.de>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Davidlohr Bueso <dave@stgolabs.net>, linux-mm@kvack.org,
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        Robert Haas <robertmhaas@gmail.com>, Josh Berkus <josh@agliodbs.com>
Subject: Re: [RFC 0/6] the big khugepaged redesign
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On 2015-03-05 18:01:08 +0100, Vlastimil Babka wrote:
> On 03/05/2015 05:52 PM, Andres Freund wrote:
> > What exactly counts as "recent" in this context? Most of the bigger
> > installations where we found THP to be absolutely prohibitive (slowdowns
> > on the order of a magnitude, huge latency spikes) unfortunately run
> > quite old kernels...  I guess 3.11 does *not* count :/? That'd be a
> 
> Yeah that's too old :/

Guessed so.

> I also noticed that you now support hugetlbfs. That could be also interesting
> data point, if the hugetlbfs usage helped because THP code wouldn't
> trigger.

Well, mmap(MAP_HUGETLB), but yea.

Will let you know once I know whether it's possible to get a newer kernel.

Greetings,

Andres Freund

-- 
 Andres Freund	                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services