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References: <cover.1386790423.git.athorlton@sgi.com> <20131212180050.GC134240@sgi.com>
From: Andy Lutomirski <luto@amacapital.net>
Date: Thu, 12 Dec 2013 12:11:34 -0800
Message-ID: <CALCETrWfFRhjuoK8T9G8hecxsRxFPQ+qA0x7azoof1X5tuxruA@mail.gmail.com>
Subject: Re: [RFC PATCH 2/3] Add tunable to control THP behavior
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To: Alex Thorlton <athorlton@sgi.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Rik van Riel <riel@redhat.com>, Wanpeng Li <liwanp@linux.vnet.ibm.com>, Mel Gorman <mgorman@suse.de>, Michel Lespinasse <walken@google.com>, Benjamin LaHaise <bcrl@kvack.org>, Oleg Nesterov <oleg@redhat.com>, "Eric W. Biederman" <ebiederm@xmission.com>, Al Viro <viro@zeniv.linux.org.uk>, David Rientjes <rientjes@google.com>, Zhang Yanfei <zhangyanfei@cn.fujitsu.com>, Peter Zijlstra <peterz@infradead.org>, Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@suse.cz>, Jiang Liu <jiang.liu@huawei.com>, Cody P Schafer <cody@linux.vnet.ibm.com>, Glauber Costa <glommer@parallels.com>, Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>

On Thu, Dec 12, 2013 at 10:00 AM, Alex Thorlton <athorlton@sgi.com> wrote:
> This part of the patch adds a tunable to
> /sys/kernel/mm/transparent_hugepage called threshold.  This threshold
> determines how many pages a user must fault in from a single node before
> a temporary compound page is turned into a THP.

Is there a setting that will turn off the must-be-the-same-node
behavior?  There are workloads where TLB matters more than cross-node
traffic (or where all the pages are hopelessly shared between nodes,
but hugepages are still useful).

--Andy

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