From: Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH 3/3] mm: slub: Default slub_max_order to 0
Date: Thu, 12 May 2011 09:43:21 -0500 (CDT)
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Cc: Andrew Morton <akpm@linux-foundation.org>,
  James Bottomley <James.Bottomley@HansenPartnership.com>,
  Colin King <colin.king@canonical.com>,
  Raghavendra D Prabhu <raghu.prabhu13@gmail.com>, Jan Kara <jack@suse.cz>,
  Chris Mason <chris.mason@oracle.com>, Pekka Enberg <penberg@kernel.org>,
  Rik van Riel <riel@redhat.com>, Johannes Weiner <hannes@cmpxchg.org>,
  linux-fsdevel <linux-fsdevel@vger.kernel.org>,
  linux-mm <linux-mm@kvack.org>, linux-kernel <linux-kernel@vger.kernel.org>,
  linux-ext4 <linux-ext4@vger.kernel.org>
To: Mel Gorman <mgorman@suse.de>
Return-path: <owner-linux-mm@kvack.org>
In-Reply-To: <1305127773-10570-4-git-send-email-mgorman@suse.de>
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On Wed, 11 May 2011, Mel Gorman wrote:

> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2198,7 +2198,7 @@ EXPORT_SYMBOL(kmem_cache_free);
>   * take the list_lock.
>   */
>  static int slub_min_order;
> -static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
> +static int slub_max_order;

If we really need to do this then do not push this down to zero please.
SLAB uses order 1 for the meax. Lets at least keep it theere.

We have been using SLUB for a long time. Why is this issue arising now?
Due to compaction etc making reclaim less efficient?

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