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From: "Stefan Riedmüller" <s.riedmueller@phytec.de>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] mtd: ubi: Max out default wear-leveling threshold
Date: Thu, 18 Jul 2019 10:24:52 +0200	[thread overview]
Message-ID: <a845e767-c324-127d-efdd-de5f26bd92c4@phytec.de> (raw)
In-Reply-To: <cdbaf9d5-940e-db3a-3df9-db3bba5a3ed4@phytec.de>

Hi Sascha,

do you guys have an idea or proposal how to disable the wear-leveling 
properly? I will gladly take another look at it and it would be nice to get 
your input as I only started to dive into ubi.

Regards,
Stefan

On 11.07.19 13:04, Stefan Riedmüller wrote:
> Hi Sascha,
> 
> On 11.07.19 09:01, Sascha Hauer wrote:
>> On Wed, Jul 10, 2019 at 01:27:30PM +0200, Stefan Riedmueller wrote:
>>> Due to the recursive ubi_thread implementation in the barebox, a large
>>> amount of wear-leveling can lead to a stack overflow.
>>>
>>> This was observed during extensive ubi stress tests with the linux
>>> kernel and periodic power cycles. We found that if the wear-leveling
>>> threshold is exceeded and a large amount of erase blocks need
>>> wear-leveling the stack can overflow.
>>>
>>> The hardware used to observe this was a phyCORE-i.MX 6 with 1GB NAND flash.
>>>
>>> As the kernel is perfectly capable of handling wear-leveling we can
>>> increase the wear-leveling threshold in the barebox to leave it to the
>>> kernel. To minimize the chance of wear-leveling in the barebox max out
>>> the threshold.
>>
>> I can follow the reasoning and it seems indeed better and more safe to
>> leave the wearleveling to the Kernel. Given that, can't we just disable
>> wear leveling completely in barebox?
> 
> I think it would be best to disable it or at least improve it. But since 
> wear-leveling is not an isolated task but involved in more functionalities I 
> couldn't find an easy way to disable it in a quick way. That is why I went 
> with the threshold enlargement to have at least a quick fix.
> 
> But I agree that at some point in the future the root cause should be 
> handled and not just the symptom.
> 
> Stefan
> 
>>
>> Sascha
>>
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox

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  reply	other threads:[~2019-07-18  8:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-10 11:27 Stefan Riedmueller
2019-07-11  7:01 ` Sascha Hauer
2019-07-11 11:04   ` Stefan Riedmüller
2019-07-18  8:24     ` Stefan Riedmüller [this message]
2019-07-18 12:19       ` Sascha Hauer
2019-07-18 12:27         ` Stefan Riedmüller

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