From: Michal Hocko <mhocko@kernel.org>
To: Avi Kivity <avi@scylladb.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: MAP_POPULATE vs. MADV_HUGEPAGES
Date: Thu, 16 Mar 2017 16:01:53 +0100 [thread overview]
Message-ID: <20170316150153.GK30501@dhcp22.suse.cz> (raw)
In-Reply-To: <53e8bb71-5bf2-2690-f605-aa4d5d50eb90@scylladb.com>
On Thu 16-03-17 16:56:34, Avi Kivity wrote:
> On 03/16/2017 04:48 PM, Michal Hocko wrote:
> >On Thu 16-03-17 15:26:54, Avi Kivity wrote:
[...]
> >>>What is the THP defrag mode
> >>>(/sys/kernel/mm/transparent_hugepage/defrag)?
> >>The default (always).
> >the default has changed since then because the THP faul latencies were
> >just too large. Currently we only allow madvised VMAs to go stall and
> >even then we try hard to back off sooner rather than later. See
> >444eb2a449ef ("mm: thp: set THP defrag by default to madvise and add a
> >stall-free defrag option") merged in 4.4
>
> I see, thanks. So the 4.4 behavior is better mostly due to not trying so
> hard.
Please note there were many other patches in the compaction code as
well.
--
Michal Hocko
SUSE Labs
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prev parent reply other threads:[~2017-03-16 15:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 16:50 Avi Kivity
2017-03-16 12:34 ` Michal Hocko
2017-03-16 13:26 ` Avi Kivity
2017-03-16 14:48 ` Michal Hocko
2017-03-16 14:56 ` Avi Kivity
2017-03-16 15:01 ` Michal Hocko [this message]
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