Date: Thu, 17 Nov 2005 15:43:23 -0800 (PST)
Message-Id: <20051117.154323.10862063.davem@davemloft.net>
To: hugh@veritas.com
Cc: akpm@osdl.org, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/11] unpaged: unifdefed PageCompound
From: "David S. Miller" <davem@davemloft.net>
In-Reply-To: <Pine.LNX.4.61.0511171931400.4563@goblin.wat.veritas.com>
References: <Pine.LNX.4.61.0511171925290.4563@goblin.wat.veritas.com>
	<Pine.LNX.4.61.0511171931400.4563@goblin.wat.veritas.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1247
Lines: 26

From: Hugh Dickins <hugh@veritas.com>
Date: Thu, 17 Nov 2005 19:32:40 +0000 (GMT)

> It looks like snd_xxx is not the only nopage to be using PageReserved as
> a way of holding a high-order page together: which no longer works, but
> is masked by our failure to free from VM_RESERVED areas.  We cannot fix
> that bug without first substituting another way to hold the high-order
> page together, while farming out the 0-order pages from within it.
> 
> That's just what PageCompound is designed for, but it's been kept under
> CONFIG_HUGETLB_PAGE.  Remove the #ifdefs: which saves some space (out-
> of-line put_page), doesn't slow down what most needs to be fast (already
> using hugetlb), and unifies the way we handle high-order pages.
> 
> Signed-off-by: Hugh Dickins <hugh@veritas.com>

I think this is a good change regardless of the VM_RESERVED issues.

I've been wanting to use this facility in some sparc64 bits in
the past, for example.  But since it was HUGETLB guarded that
wasn't possible.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/