From: Christoph Lameter <cl@linux.com>
To: Joonsoo Kim <js1304@gmail.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-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 16/16] mm/slab: introduce new slab management type, OBJFREELIST_SLAB
Date: Thu, 14 Jan 2016 09:32:19 -0600 (CST) [thread overview]
Message-ID: <alpine.DEB.2.20.1601140929280.2145@east.gentwo.org> (raw)
In-Reply-To: <1452749069-15334-17-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, 14 Jan 2016, Joonsoo Kim wrote:
> SLAB needs a array to manage freed objects in a slab. It is only used
> if some objects are freed so we can use free object itself as this array.
> This requires additional branch in somewhat critical lock path to check
> if it is first freed object or not but that's all we need. Benefits is
> that we can save extra memory usage and reduce some computational
> overhead by allocating a management array when new slab is created.
Hmmm... But then you need to have an offset in the page struct to
figure out where the freelist starts. One additional level of indirection.
Seems to have some negative impact on performance.
> In my system, without enabling CONFIG_DEBUG_SLAB, Almost caches become
> OBJFREELIST_SLAB and NORMAL_SLAB (using leftover) which doesn't waste
> memory. Following is the result of number of caches with specific slab
> management type.
Sounds good.
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next prev parent reply other threads:[~2016-01-14 15:32 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
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 [this message]
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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