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Date: Tue, 21 Jun 2011 15:30:53 +0200
From: Andrea Arcangeli <aarcange@redhat.com>
To: Amerigo Wang <amwang@redhat.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
        Randy Dunlap <rdunlap@xenotime.net>, Rik van Riel <riel@redhat.com>,
        Johannes Weiner <jweiner@redhat.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        linux-doc@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 1/4] mm: completely disable THP by
 transparent_hugepage=0
Message-ID: <20110621133053.GO20843@redhat.com>
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On Tue, Jun 21, 2011 at 04:10:42PM +0800, Amerigo Wang wrote:
> Introduce "transparent_hugepage=0" to totally disable THP.
> "transparent_hugepage=never" means setting THP to be partially
> disabled, we need a new way to totally disable it.
> 

I think I already clarified this is not worth it. Removing sysfs
registration is just pointless. If you really want to save ~8k of RAM,
at most you can try to move the init of the khugepaged slots hash and
the kmem_cache_init to the khugepaged deamon start but even that isn't
so useful. Not registering into sysfs is just pointless and it's a
gratuitous loss of a feature.

From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 21 Jun 2011 15:30:53 +0200
From: Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH v2 1/4] mm: completely disable THP by
 transparent_hugepage=0
Message-ID: <20110621133053.GO20843@redhat.com>
References: <1308643849-3325-1-git-send-email-amwang@redhat.com>
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To: Amerigo Wang <amwang@redhat.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Randy Dunlap <rdunlap@xenotime.net>, Rik van Riel <riel@redhat.com>, Johannes Weiner <jweiner@redhat.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, linux-doc@vger.kernel.org, linux-mm@kvack.org

On Tue, Jun 21, 2011 at 04:10:42PM +0800, Amerigo Wang wrote:
> Introduce "transparent_hugepage=0" to totally disable THP.
> "transparent_hugepage=never" means setting THP to be partially
> disabled, we need a new way to totally disable it.
> 

I think I already clarified this is not worth it. Removing sysfs
registration is just pointless. If you really want to save ~8k of RAM,
at most you can try to move the init of the khugepaged slots hash and
the kmem_cache_init to the khugepaged deamon start but even that isn't
so useful. Not registering into sysfs is just pointless and it's a
gratuitous loss of a feature.

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