From: Christopher Lameter <cl@linux.com>
To: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch] mm, slab: avoid high-order slab pages when it does not reduce waste
Date: Mon, 15 Oct 2018 22:42:42 +0000 [thread overview]
Message-ID: <0100016679e54c6e-67ca8716-c95e-427f-aec9-a5bee5e84792-000000@email.amazonses.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1810121424420.116562@chino.kir.corp.google.com>
On Fri, 12 Oct 2018, David Rientjes wrote:
> @@ -1803,6 +1804,20 @@ static size_t calculate_slab_order(struct kmem_cache *cachep,
> */
> if (left_over * 8 <= (PAGE_SIZE << gfporder))
> break;
> +
> + /*
> + * If a higher gfporder would not reduce internal fragmentation,
> + * no need to continue. The preference is to keep gfporder as
> + * small as possible so slab allocations can be served from
> + * MIGRATE_UNMOVABLE pcp lists to avoid stranding.
> + */
I think either go for order 0 (because then you can use the pcp lists) or
go as high as possible (then you can allocator larger memory areas with a
single pass through the page allocator).
But then I am not sure that the whole approach will do any good.
next prev parent reply other threads:[~2018-10-15 22:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-12 21:24 [patch] mm, slab: avoid high-order slab pages when it does not reduce waste David Rientjes
2018-10-12 22:13 ` Andrew Morton
2018-10-12 23:09 ` David Rientjes
2018-10-15 22:41 ` Christopher Lameter
2018-10-16 0:39 ` David Rientjes
2018-10-16 15:17 ` Christopher Lameter
2018-10-17 9:09 ` Vlastimil Babka
2018-10-17 15:38 ` Christopher Lameter
2018-10-15 22:42 ` Christopher Lameter [this message]
2018-10-16 8:42 ` Vlastimil Babka
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