From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@techsingularity.net>,
Laura Abbott <lauraa@codeaurora.org>,
Minchan Kim <minchan@kernel.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Michal Nazarewicz <mina86@mina86.com>,
Vlastimil Babka <vbabka@suse.cz>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 0/6] Introduce ZONE_CMA
Date: Wed, 21 Sep 2016 20:17:27 +0530 [thread overview]
Message-ID: <87eg4dwbr4.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <87eg54rx1w.fsf@linux.vnet.ibm.com>
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:
> Joonsoo Kim <iamjoonsoo.kim@lge.com> writes:
>
>> On Tue, Aug 30, 2016 at 04:09:37PM +0530, Aneesh Kumar K.V wrote:
>>> Joonsoo Kim <js1304@gmail.com> writes:
>>>
>>> > 2016-08-29 18:27 GMT+09:00 Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>:
>>> >> js1304@gmail.com writes:
>>> >>
>>> >>> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>>> >>>
>>> >>> Hello,
>>> >>>
>>> >>> Changes from v4
>>> >>> o Rebase on next-20160825
>>> >>> o Add general fix patch for lowmem reserve
>>> >>> o Fix lowmem reserve ratio
>>> >>> o Fix zone span optimizaion per Vlastimil
>>> >>> o Fix pageset initialization
>>> >>> o Change invocation timing on cma_init_reserved_areas()
>>> >>
>>> >> I don't see much information regarding how we interleave between
>>> >> ZONE_CMA and other zones for movable allocation. Is that explained in
>>> >> any of the patch ? The fair zone allocator got removed by
>>> >> e6cbd7f2efb433d717af72aa8510a9db6f7a7e05
>>> >
>>> > Interleaving would not work since the fair zone allocator policy is removed.
>>> > I don't think that it's a big problem because it is just matter of
>>> > timing to fill
>>> > up the memory. Eventually, memory on ZONE_CMA will be fully used in
>>> > any case.
>>>
>>> Does that mean a CMA allocation will now be slower because in most case we
>>> will need to reclaim ? The zone list will now have ZONE_CMA in the
>>> beginning right ?
>>
>> ZONE_CMA will be used first but I don't think that CMA allocation will
>> be slower. In most case, memory would be fully used (usually
>> by page cache). So, we need reclaim or migration in any case.
>
> Considering that the upstream kernel doesn't allow migration of THP
> pages, this would mean that migrate will fail in most case if we have
> THP enabled and the THP allocation request got satisfied via ZONE_CMA.
> Isn't that going to be a problem ?
>
Even though we have the issues of migration failures due to pinned and
THP pages in ZONE_CMA, overall the code is simpler. IMHO we should get
this upstream now and work on solving those issues later.
You can add for the complete series.
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
-aneesh
next prev parent reply other threads:[~2016-09-21 14:47 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-29 5:07 [PATCH v5 0/6] Introduce ZONE_CMA js1304
2016-08-29 5:07 ` [PATCH v5 1/6] mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request js1304
2016-09-16 3:14 ` Aneesh Kumar K.V
2016-09-22 5:30 ` Joonsoo Kim
2016-09-21 9:06 ` Vlastimil Babka
2016-08-29 5:07 ` [PATCH v5 2/6] mm/cma: introduce new zone, ZONE_CMA js1304
2016-08-30 10:35 ` Aneesh Kumar K.V
2016-08-30 12:40 ` Aneesh Kumar K.V
2016-08-31 7:58 ` Joonsoo Kim
2016-09-21 9:11 ` Vlastimil Babka
2016-08-29 5:07 ` [PATCH v5 3/6] mm/cma: populate ZONE_CMA js1304
2016-09-21 9:20 ` Vlastimil Babka
2016-09-22 5:45 ` Joonsoo Kim
2016-09-22 6:50 ` Joonsoo Kim
2016-09-22 15:59 ` Vlastimil Babka
2016-09-28 5:34 ` Joonsoo Kim
2016-08-29 5:07 ` [PATCH v5 4/6] mm/cma: remove ALLOC_CMA js1304
2016-08-29 5:07 ` [PATCH v5 5/6] mm/cma: remove MIGRATE_CMA js1304
2016-08-29 5:07 ` [PATCH v5 6/6] mm/cma: remove per zone CMA stat js1304
2016-08-29 9:27 ` [PATCH v5 0/6] Introduce ZONE_CMA Aneesh Kumar K.V
2016-08-30 8:21 ` Joonsoo Kim
2016-08-30 10:39 ` Aneesh Kumar K.V
2016-08-31 8:03 ` Joonsoo Kim
2016-09-01 5:47 ` Aneesh Kumar K.V
2016-09-01 6:01 ` Joonsoo Kim
2016-09-21 14:47 ` Aneesh Kumar K.V [this message]
2016-09-22 5:32 ` Joonsoo Kim
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