From: Joonsoo Kim <js1304@gmail.com>
To: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Jesper Dangaard Brouer <brouer@redhat.com>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 09/16] mm/slab: put the freelist at the end of slab page
Date: Fri, 15 Jan 2016 01:21:54 +0900 [thread overview]
Message-ID: <CAAmzW4Mkpfc6_QO3qRqYZXEhAbZa3E2cXKivwyNmu0bm6kwhfQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1601140924520.2145@east.gentwo.org>
2016-01-15 0:26 GMT+09:00 Christoph Lameter <cl@linux.com>:
> On Thu, 14 Jan 2016, Joonsoo Kim wrote:
>
>> Currently, the freelist is at the front of slab page. This requires
>> extra space to meet object alignment requirement. If we put the freelist
>> at the end of slab page, object could start at page boundary and will
>> be at correct alignment. This is possible because freelist has
>> no alignment constraint itself.
>>
>> This gives us two benefits. It removes extra memory space
>> for the freelist alignment and remove complex calculation
>> at cache initialization step. I can't think notable drawback here.
>
>
> The third one is that the padding space at the end of the slab could
> actually be used for the freelist if it fits.
Yes.
> The drawback may be that the location of the freelist at the beginning of
> the page is more cache effective because the cache prefetcher may be able
> to get the following cachelines and effectively hit the first object.
> However, this is rather dubious speculation.
I think so, too. :)
If then, could you give me an ack?
Thanks.
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next prev parent reply other threads:[~2016-01-14 16:21 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-14 5:24 [PATCH 00/16] mm/slab: introduce new freed objects management way, OBJFREELIST_SLAB Joonsoo Kim
2016-01-14 5:24 ` [PATCH 01/16] mm/slab: fix stale code comment Joonsoo Kim
2016-01-14 15:22 ` Christoph Lameter
2016-01-14 5:24 ` [PATCH 02/16] mm/slab: remove useless structure define Joonsoo Kim
2016-01-14 15:22 ` Christoph Lameter
2016-01-14 5:24 ` [PATCH 03/16] mm/slab: remove the checks for slab implementation bug Joonsoo Kim
2016-01-14 15:23 ` Christoph Lameter
2016-01-14 16:20 ` Joonsoo Kim
2016-01-14 5:24 ` [PATCH 04/16] mm/slab: activate debug_pagealloc in SLAB when it is actually enabled Joonsoo Kim
2016-01-14 12:09 ` Jesper Dangaard Brouer
2016-01-14 16:16 ` Joonsoo Kim
2016-01-14 5:24 ` [PATCH 05/16] mm/slab: use more appropriate condition check for debug_pagealloc Joonsoo Kim
2016-01-14 5:24 ` [PATCH 06/16] mm/slab: clean-up DEBUG_PAGEALLOC processing code Joonsoo Kim
2016-01-14 5:24 ` [PATCH 07/16] mm/slab: alternative implementation for DEBUG_SLAB_LEAK Joonsoo Kim
2016-01-14 5:24 ` [PATCH 08/16] mm/slab: remove object status buffer " Joonsoo Kim
2016-01-14 5:24 ` [PATCH 09/16] mm/slab: put the freelist at the end of slab page Joonsoo Kim
2016-01-14 15:26 ` Christoph Lameter
2016-01-14 16:21 ` Joonsoo Kim [this message]
2016-01-14 17:13 ` Christoph Lameter
2016-01-14 5:24 ` [PATCH 10/16] mm/slab: align cache size first before determination of OFF_SLAB candidate Joonsoo Kim
2016-01-14 5:24 ` [PATCH 11/16] mm/slab: clean-up cache type determination Joonsoo Kim
2016-01-14 5:24 ` [PATCH 12/16] mm/slab: do not change cache size if debug pagealloc isn't possible Joonsoo Kim
2016-01-14 5:24 ` [PATCH 13/16] mm/slab: make criteria for off slab determination robust and simple Joonsoo Kim
2016-01-14 5:24 ` [PATCH 14/16] mm/slab: factor out slab list fixup code Joonsoo Kim
2016-01-14 5:24 ` [PATCH 15/16] mm/slab: factor out debugging initialization in cache_init_objs() Joonsoo Kim
2016-01-14 5:24 ` [PATCH 16/16] mm/slab: introduce new slab management type, OBJFREELIST_SLAB Joonsoo Kim
2016-01-14 15:32 ` Christoph Lameter
2016-01-14 16:24 ` Joonsoo Kim
2016-01-27 13:35 ` Vlastimil Babka
2016-01-27 16:48 ` Christoph Lameter
2016-01-27 17:18 ` Vlastimil Babka
2016-01-27 17:55 ` Christoph Lameter
2016-01-28 4:51 ` Joonsoo Kim
2016-01-29 15:21 ` Vlastimil Babka
2016-01-27 4:40 ` [PATCH 00/16] mm/slab: introduce new freed objects management way, OBJFREELIST_SLAB Andrew Morton
2016-01-27 4:46 ` Joonsoo Kim
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