From: Iwo Mergler <iwo@call-direct.com.au>
To: Anders Larsen <al@alarsen.net>
Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>,
Ian McDonnell <ian@brightstareng.com>,
Nicolas Pitre <nico@fluxnic.net>,
linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
Matthias Kaehlcke <matthias@kaehlcke.net>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] Fix Oops with Atmel SPI
Date: Thu, 15 Apr 2010 17:32:14 +1000 [thread overview]
Message-ID: <4BC6C0FE.1000701@call-direct.com.au> (raw)
In-Reply-To: <1271231840l.5270l.0l@i-dmzi_al.realan.de>
Hi Anders,
Anders Larsen wrote:
> Hi Iwo,
>
> On 2010-04-14 09:30:41, Iwo Mergler wrote:
>> I wouldn't recommend that. MTD erase blocks are 64K or more. In a typical
>> embedded system you will not be able to kmalloc that much memory after
>> a few day's of operation - the page pool gets fragmented.
>
> the original problem occurs with SPI flashes, which typically have a much
> smaller erase block size (and it only occurs when they are driven by an Atmel
> SoC SPI controller, hence the #ifdefs)
>
>> A possibly better approach is to arrange for that memory to get allocated
>> at driver start time.
>
> The buffer in question is indeed allocated _once_ (at the first write
> operation to the device) and only deallocated when the device is unmounted,
> so allocating it at driver load time wouldn't make much difference IMHO.
>
I'm sorry, I thought you were somewhere else in the MTD source.
The bad block handling code for NAND also has a full erase block
allocation, which happens during runtime.
You are correct in that the mount time allocation should be
safe, for most systems.
Best regards,
Iwo
next prev parent reply other threads:[~2010-04-15 7:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-13 11:31 [PATCH] Fix Oops with Atmel SPI Anders Larsen
2010-04-14 7:30 ` Iwo Mergler
2010-04-14 7:57 ` Anders Larsen
2010-04-14 18:13 ` Kevin Cernekee
2010-04-15 7:32 ` Iwo Mergler [this message]
2010-04-21 22:24 ` Andrew Morton
2010-05-19 11:05 ` Anders Larsen
2010-05-21 19:01 ` Andrew Morton
2010-05-24 15:09 ` Ian McDonnell
2010-05-28 9:27 ` Haavard Skinnemoen
2010-04-27 12:57 ` Artem Bityutskiy
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