Re: [Linaro-mm-sig] [PATCH 12/15] drivers: add Contiguous Memory Allocator

From: "Clark, Rob" <rob@ti.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Ohad Ben-Cohen <ohad@wizery.com>,
	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>,
	Jesse Barker <jesse.barker@linaro.org>,
	linux-kernel@vger.kernel.org,
	Michal Nazarewicz <mina86@mina86.com>,
	Dave Hansen <dave@linux.vnet.ibm.com>,
	linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org,
	Kyungmin Park <kyungmin.park@samsung.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-media@vger.kernel.org
Subject: Re: [Linaro-mm-sig] [PATCH 12/15] drivers: add Contiguous Memory Allocator
Date: Fri, 27 Jan 2012 08:27:33 -0600	[thread overview]
Message-ID: <CAO8GWqnQg-W=TEc+CUc8hs=GrdCa9XCCWcedQx34cqURhNwNwA@mail.gmail.com> (raw)
In-Reply-To: <00de01ccdce1$e7c8a360$b759ea20$%szyprowski@samsung.com>

2012/1/27 Marek Szyprowski <m.szyprowski@samsung.com>:
> Hi Ohad,
>
> On Friday, January 27, 2012 10:44 AM Ohad Ben-Cohen wrote:
>
>> With v19, I can't seem to allocate big regions anymore (e.g. 101MiB).
>> In particular, this seems to fail:
>>
>> On Thu, Jan 26, 2012 at 11:00 AM, Marek Szyprowski
>> <m.szyprowski@samsung.com> wrote:
>> > +static int cma_activate_area(unsigned long base_pfn, unsigned long count)
>> > +{
>> > +       unsigned long pfn = base_pfn;
>> > +       unsigned i = count >> pageblock_order;
>> > +       struct zone *zone;
>> > +
>> > +       WARN_ON_ONCE(!pfn_valid(pfn));
>> > +       zone = page_zone(pfn_to_page(pfn));
>> > +
>> > +       do {
>> > +               unsigned j;
>> > +               base_pfn = pfn;
>> > +               for (j = pageblock_nr_pages; j; --j, pfn++) {
>> > +                       WARN_ON_ONCE(!pfn_valid(pfn));
>> > +                       if (page_zone(pfn_to_page(pfn)) != zone)
>> > +                               return -EINVAL;
>>
>> The above WARN_ON_ONCE is triggered, and then the conditional is
>> asserted (page_zone() retuns a "Movable" zone, whereas zone is
>> "Normal") and the function fails.
>>
>> This happens to me on OMAP4 with your 3.3-rc1-cma-v19 branch (and a
>> bunch of remoteproc/rpmsg patches).
>>
>> Do big allocations work for you ?
>
> I've tested it with 256MiB on Exynos4 platform. Could you check if the
> problem also appears on 3.2-cma-v19 branch (I've uploaded it a few hours
> ago) and 3.2-cma-v18? Both are available on our public repo:
> git://git.infradead.org/users/kmpark/linux-samsung/
>
> The above code has not been changed since v16, so I'm really surprised
> that it causes problems. Maybe the memory configuration or layout has
> been changed in 3.3-rc1 for OMAP4?

is highmem still an issue?  I remember hitting this WARN_ON_ONCE() but
went away after I switched to a 2g/2g vm split (which avoids highmem)

BR,
-R

> Best regards
> --
> Marek Szyprowski
> Samsung Poland R&D Center
>
>
>
>
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> http://lists.linaro.org/mailman/listinfo/linaro-mm-sig

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