Date: Wed, 7 Dec 2016 11:11:08 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
To: Mel Gorman <mgorman@techsingularity.net>
cc: Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Linux-MM <linux-mm@kvack.org>,
        Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: page_alloc: High-order per-cpu page allocator v7
In-Reply-To: <20161207164554.b73qjfxy2w3h3ycr@techsingularity.net>
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On Wed, 7 Dec 2016, Mel Gorman wrote:

> 3.0-era kernels had better fragmentation control, higher success rates at
> allocation etc. I vaguely recall that it had fewer sources of high-order
> allocations but I don't remember specifics and part of that could be the
> lack of THP at the time. The overhead was massive due to massive stalls
> and excessive reclaim -- hours to complete some high-allocation stress
> tests even if the success rate was high.

There were a couple of high order page reclaim improvements implemented
at that time that were later abandoned. I think higher order pages were
more available than now. SLUB was regularly able to get higher order pages.