Date: Mon, 28 Nov 2016 10:38:58 -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>, 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 v3
In-Reply-To: <20161128162126.ulbqrslpahg4wdk3@techsingularity.net>
Message-ID: <alpine.DEB.2.20.1611281037400.29533@east.gentwo.org>
References: <20161127131954.10026-1-mgorman@techsingularity.net> <alpine.DEB.2.20.1611280934460.28989@east.gentwo.org> <20161128162126.ulbqrslpahg4wdk3@techsingularity.net>
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On Mon, 28 Nov 2016, Mel Gorman wrote:

> Yes, that's a problem for SLUB with or without this patch. It's always
> been the case that SLUB relying on high-order pages for performance is
> problematic.

This is a general issue in the kernel. Performance often requires larger
contiguous ranges of memory.


> > that only insiders know how to tune and an overall fragile solution.
> While I agree with all of this, it's also a problem independent of this
> patch.

It is related. The fundamental issue with fragmentation remain and IMHO we
really need to tackle this.