From: Mel Gorman <mgorman@techsingularity.net>
To: Christoph Lameter <cl@linux.com>
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
Date: Wed, 7 Dec 2016 15:57:50 +0000 [thread overview]
Message-ID: <20161207155750.yfsizliaoodks5k4@techsingularity.net> (raw)
In-Reply-To: <alpine.DEB.2.20.1612070849260.8398@east.gentwo.org>
On Wed, Dec 07, 2016 at 08:52:27AM -0600, Christoph Lameter wrote:
> On Wed, 7 Dec 2016, Mel Gorman wrote:
>
> > SLUB has been the default small kernel object allocator for quite some time
> > but it is not universally used due to performance concerns and a reliance
> > on high-order pages. The high-order concerns has two major components --
>
> SLUB does not rely on high order pages. It falls back to lower order if
> the higher orders are not available. Its a performance concern.
>
Ok -- While SLUB does not rely on high-order pages for functional
correctness, it perfoms better if high-order pages are available.
> This is also an issue for various other kernel subsystems that really
> would like to have larger contiguous memory area. We are often seeing
> performance constraints due to the high number of 4k segments when doing
> large scale block I/O f.e.
>
Which is related to the fundamentals of fragmentation control in
general. At some point there will have to be a revisit to get back to
the type of reliability that existed in 3.0-era without the massive
overhead it incurred. As stated before, I agree it's important but
outside the scope of this patch.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2016-12-07 15:57 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 10:12 [PATCH] mm: page_alloc: High-order per-cpu page allocator v7 Mel Gorman
2016-12-07 14:52 ` Christoph Lameter
2016-12-07 15:57 ` Mel Gorman [this message]
2016-12-07 16:40 ` Christoph Lameter
2016-12-07 16:45 ` Mel Gorman
2016-12-07 17:11 ` Christoph Lameter
2016-12-07 17:35 ` Mel Gorman
2016-12-07 19:00 ` Eric Dumazet
2016-12-07 19:11 ` Eric Dumazet
2016-12-07 19:48 ` Mel Gorman
2016-12-07 20:10 ` Eric Dumazet
2016-12-07 21:19 ` Mel Gorman
2016-12-07 23:25 ` Mel Gorman
2016-12-08 8:22 ` Jesper Dangaard Brouer
2016-12-08 9:18 ` Mel Gorman
2016-12-08 10:43 ` Jesper Dangaard Brouer
2016-12-08 11:06 ` Mel Gorman
2016-12-08 14:48 ` Jesper Dangaard Brouer
2016-12-08 15:11 ` Mel Gorman
2016-12-08 17:19 ` Jesper Dangaard Brouer
2016-12-08 17:39 ` Mel Gorman
2016-12-08 16:04 ` Eric Dumazet
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