From: Maxime Coquelin <maxime.coquelin-nonst@stericsson.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linaro-mm-sig@lists.linaro.org" <linaro-mm-sig@lists.linaro.org>,
'Daniel Walker' <dwalker@codeaurora.org>,
'Russell King' <linux@arm.linux.org.uk>,
'Arnd Bergmann' <arnd@arndb.de>,
'Jonathan Corbet' <corbet@lwn.net>, 'Mel Gorman' <mel@csn.ul.ie>,
'Chunsang Jeong' <chunsang.jeong@linaro.org>,
'Michal Nazarewicz' <mina86@mina86.com>,
'Dave Hansen' <dave@linux.vnet.ibm.com>,
'Jesse Barker' <jesse.barker@linaro.org>,
'Kyungmin Park' <kyungmin.park@samsung.com>,
'Ankita Garg' <ankita@in.ibm.com>,
'Andrew Morton' <akpm@linux-foundation.org>,
'KAMEZAWA Hiroyuki' <kamezawa.hiroyu@jp.fujitsu.com>,
"benjamin.gaignard@linaro.org" <benjamin.gaignard@linaro.org>,
Ludovic BARRE <ludovic.barre@stericsson.com>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>
Subject: Re: [Linaro-mm-sig] [PATCHv16 0/9] Contiguous Memory Allocator
Date: Tue, 11 Oct 2011 09:30:16 +0200 [thread overview]
Message-ID: <4E93F088.60006@stericsson.com> (raw)
In-Reply-To: <00b001cc87e5$dc818cc0$9584a640$%szyprowski@samsung.com>
On 10/11/2011 09:17 AM, Marek Szyprowski wrote:
> On Monday, October 10, 2011 2:08 PM Maxime Coquelin wrote:
>
> During our stress tests, we encountered some problems :
>
> 1) Contiguous allocation lockup:
> When system RAM is full of Anon pages, if we try to allocate a
> contiguous buffer greater than the min_free value, we face a
> dma_alloc_from_contiguous lockup.
> The expected result would be dma_alloc_from_contiguous() to fail.
> The problem is reproduced systematically on our side.
> Thanks for the report. Do you use Android's lowmemorykiller? I haven't
> tested CMA on Android kernel yet. I have no idea how it will interfere
> with Android patches.
>
The software used for this test (v16) is a generic 3.0 Kernel and a
minimal filesystem using Busybox.
With v15 patchset, I also tested it with Android.
IIRC, sometimes the lowmemorykiller succeed to get free space and the
contiguous allocation succeed, sometimes we faced the lockup.
>> 2) Contiguous allocation fail:
>> We have developed a small driver and a shell script to
>> allocate/release contiguous buffers.
>> Sometimes, dma_alloc_from_contiguous() fails to allocate the
>> contiguous buffer (about once every 30 runs).
>> We have 270MB Memory passed to the kernel in our configuration,
>> and the CMA pool is 90MB large.
>> In this setup, the overall memory is either free or full of
>> reclaimable pages.
> Yeah. We also did such stress tests recently and faced this issue. I've
> spent some time investigating it but I have no solution yet.
>
> The problem is caused by a page, which is put in the CMA area. This page
> is movable, but it's address space provides no 'migratepage' method. In
> such case mm subsystem uses fallback_migrate_page() function. Sadly this
> function only returns -EAGAIN. The migration loops a few times over it
> and fails causing the fail in the allocation procedure.
>
> We are investing now which kernel code created/allocated such problematic
> pages and how to add real migration support for them.
>
Ok, thanks for pointing this out.
Regards,
Maxime
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next prev parent reply other threads:[~2011-10-11 7:34 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-06 13:54 [PATCHv16 0/9] Contiguous Memory Allocator Marek Szyprowski
2011-10-06 13:54 ` [PATCH 1/9] mm: move some functions from memory_hotplug.c to page_isolation.c Marek Szyprowski
2011-10-14 23:23 ` Andrew Morton
2011-10-18 12:05 ` Mel Gorman
2011-10-06 13:54 ` [PATCH 2/9] mm: alloc_contig_freed_pages() added Marek Szyprowski
2011-10-14 23:29 ` Andrew Morton
2011-10-16 8:01 ` Michal Nazarewicz
2011-10-16 8:31 ` Andrew Morton
2011-10-16 9:39 ` Michal Nazarewicz
2011-10-17 12:21 ` Marek Szyprowski
2011-10-17 18:39 ` Andrew Morton
2011-10-18 12:21 ` Mel Gorman
2011-10-18 17:26 ` Michal Nazarewicz
2011-10-18 17:48 ` Dave Hansen
2011-10-18 18:00 ` Michal Nazarewicz
2011-10-21 10:06 ` Mel Gorman
2011-10-24 1:00 ` Michal Nazarewicz
2011-10-24 4:05 ` Michal Nazarewicz
2011-10-24 4:05 ` Michal Nazarewicz
2011-10-24 4:05 ` Michal Nazarewicz
2011-11-01 15:04 ` Mel Gorman
2011-11-01 18:06 ` Michal Nazarewicz
2011-11-01 18:47 ` Mel Gorman
2011-10-24 4:05 ` Michal Nazarewicz
2011-10-06 13:54 ` [PATCH 3/9] mm: alloc_contig_range() added Marek Szyprowski
2011-10-14 23:35 ` Andrew Morton
2011-10-18 12:38 ` Mel Gorman
2011-10-06 13:54 ` [PATCH 4/9] mm: MIGRATE_CMA migration type added Marek Szyprowski
2011-10-14 23:38 ` Andrew Morton
2011-10-18 13:08 ` Mel Gorman
2011-10-24 19:32 ` Michal Nazarewicz
2011-10-27 9:10 ` Michal Nazarewicz
2011-10-06 13:54 ` [PATCH 5/9] mm: MIGRATE_CMA isolation functions added Marek Szyprowski
2011-10-06 13:54 ` [PATCH 6/9] drivers: add Contiguous Memory Allocator Marek Szyprowski
2011-10-14 23:57 ` Andrew Morton
2011-10-16 10:08 ` Russell King - ARM Linux
2011-10-18 13:43 ` Mel Gorman
2011-10-24 19:39 ` Michal Nazarewicz
2011-11-04 10:41 ` Marek Szyprowski
2011-10-06 13:54 ` [PATCH 7/7] ARM: integrate CMA with DMA-mapping subsystem Marek Szyprowski
2011-10-06 14:18 ` Marek Szyprowski
2011-10-15 0:03 ` Andrew Morton
2011-10-06 13:54 ` [PATCH 7/9] X86: " Marek Szyprowski
2011-10-06 13:54 ` [PATCH 8/9] ARM: " Marek Szyprowski
2011-10-14 4:33 ` [Linaro-mm-sig] " Subash Patel
2011-10-14 9:14 ` Marek Szyprowski
2011-10-06 13:54 ` [PATCH 9/9] ARM: Samsung: use CMA for 2 memory banks for s5p-mfc device Marek Szyprowski
2011-10-07 16:27 ` [PATCHv16 0/9] Contiguous Memory Allocator Arnd Bergmann
2011-10-10 6:58 ` [Linaro-mm-sig] " Ohad Ben-Cohen
2011-10-10 12:02 ` Clark, Rob
2011-10-10 22:56 ` Andrew Morton
2011-10-11 6:57 ` Marek Szyprowski
2011-10-11 13:52 ` Arnd Bergmann
2011-10-14 23:19 ` Andrew Morton
2011-10-15 14:24 ` Arnd Bergmann
2011-10-10 12:07 ` [Linaro-mm-sig] " Maxime Coquelin
2011-10-11 7:17 ` Marek Szyprowski
2011-10-11 7:30 ` Maxime Coquelin [this message]
2011-10-11 10:50 ` Marek Szyprowski
2011-10-11 11:25 ` Maxime Coquelin
2011-10-11 13:05 ` Marek Szyprowski
2011-10-12 11:08 ` [PATCH] fixup: mm: alloc_contig_range: increase min_free_kbytes during allocation Marek Szyprowski
2011-10-12 13:01 ` Maxime Coquelin
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