Could someone tell me if the fastmap feature in ubi is stable for use in production?

Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Wang, Qiong (Q.)]

Hi experts,

I have found the below link in the linux-mtd website explaining fastmap feature in ubi.
http://linux-mtd.infradead.org/doc/ubi.html#L_fastmap

Our project uses large nand flash and I found that fastmap can reduce the ubi attach process to the time we want. Our concern is, since it is an experimental, is it stable to use in our project? Are there any reported issue of this feature?Our biggest worry is that can it possibly brick our system during the boot up process.  

Best Regards,
汪琼/Wang Qiong

软件与测试部/软件工程师Software Design&Test Dept./Software Engineer
Tel +86 25 8106 9232
E-mail: qwang34@yfve.com.cn
延锋伟世通电子科技（南京）有限公司
Yanfeng Visteon Electronics Technology (Nanjing) Co., Ltd
江苏省南京市江宁区苏源大道19号国际企业总部园C1座7楼
Address: 7F, C1, Jiulonghu International Corporate Headquarters, No. 19 Suyuan Road, Jiangning Development Zone, Nanjing, China

Re: Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Richard Weinberger]

Wang, Qiong (Q.),

On Mon, Apr 9, 2018 at 12:25 PM, Wang, Qiong (Q.) <qwang34@yfve.com.cn> wrote:
> Hi experts,
>
> I have found the below link in the linux-mtd website explaining fastmap feature in ubi.
> http://linux-mtd.infradead.org/doc/ubi.html#L_fastmap
>
> Our project uses large nand flash and I found that fastmap can reduce the ubi attach process to the time we want. Our concern is, since it is an experimental, is it stable to use in our project? Are there any reported issue of this feature?Our biggest worry is that can it possibly brick our system during the boot up process.

Well, it is a non-trvial aggressive optimization.
Lately I planned to mark it finally as stable but then this happened popped up.

[0] http://lists.infradead.org/pipermail/linux-mtd/2018-March/079610.html

On the other hand, if only very few people are using it, we won't find
remaining subtle bugs.

-- 
Thanks,
//richard

Re: Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Ezequiel Garcia]

Wang, Qiong (Q.),


On 9 April 2018 at 07:55, Richard Weinberger
<richard.weinberger@gmail.com> wrote:
> Wang, Qiong (Q.),
>
> On Mon, Apr 9, 2018 at 12:25 PM, Wang, Qiong (Q.) <qwang34@yfve.com.cn> wrote:
>> Hi experts,
>>
>> I have found the below link in the linux-mtd website explaining fastmap feature in ubi.
>> http://linux-mtd.infradead.org/doc/ubi.html#L_fastmap
>>
>> Our project uses large nand flash and I found that fastmap can reduce the ubi attach process to the time we want. Our concern is, since it is an experimental, is it stable to use in our project? Are there any reported issue of this feature?Our biggest worry is that can it possibly brick our system during the boot up process.

For what it's worth, I've used UBI fastmap in production, and so far
we didn't have
issues.

Note that we prepared a lot of tests, based on our particular use
case. If I remember
correctly, we hit one bug and Richard was kind enough to fix it in a few hours.

So my advise is: use it, but by all means test it. As anything else.

Hope it helps,
Eze

RE: Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Wang, Qiong (Q.)]

Hi Richard,

Thank you so much for your information. Our plan is to use it but with all means of test. We will look into the patch that you showed to us and decide if we can add it in our project.

Thanks again.

Best Regards,
汪琼/Wang Qiong

软件与测试部/软件工程师Software Design&Test Dept./Software Engineer
Tel +86 25 8106 9232
E-mail: qwang34@yfve.com.cn
延锋伟世通电子科技（南京）有限公司
Yanfeng Visteon Electronics Technology (Nanjing) Co., Ltd
江苏省南京市江宁区苏源大道19号国际企业总部园C1座7楼
Address: 7F, C1, Jiulonghu International Corporate Headquarters, No. 19 Suyuan Road, Jiangning Development Zone, Nanjing, China


-----Original Message-----
From: Richard Weinberger [mailto:richard.weinberger@gmail.com] 
Sent: 2018年4月9日 18:56
To: Wang, Qiong (Q.)
Cc: linux-mtd@lists.infradead.org
Subject: Re: Could someone tell me if the fastmap feature in ubi is stable for use in production?

Wang, Qiong (Q.),

On Mon, Apr 9, 2018 at 12:25 PM, Wang, Qiong (Q.) <qwang34@yfve.com.cn> wrote:
> Hi experts,
>
> I have found the below link in the linux-mtd website explaining fastmap feature in ubi.
> http://linux-mtd.infradead.org/doc/ubi.html#L_fastmap
>
> Our project uses large nand flash and I found that fastmap can reduce the ubi attach process to the time we want. Our concern is, since it is an experimental, is it stable to use in our project? Are there any reported issue of this feature?Our biggest worry is that can it possibly brick our system during the boot up process.

Well, it is a non-trvial aggressive optimization.
Lately I planned to mark it finally as stable but then this happened popped up.

[0] http://lists.infradead.org/pipermail/linux-mtd/2018-March/079610.html

On the other hand, if only very few people are using it, we won't find remaining subtle bugs.

--
Thanks,
//richard

RE: Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Wang, Qiong (Q.)]

Hi Ezequiel,

Thanks for your advice. May I ask what patch that Richard gave to you to fix your bug? Is it the same as what Richard showed me before in the following link?

http://lists.infradead.org/pipermail/linux-mtd/2018-March/079610.html

Best Regards,
汪琼/Wang Qiong

软件与测试部/软件工程师Software Design&Test Dept./Software Engineer
Tel +86 25 8106 9232
E-mail: qwang34@yfve.com.cn
延锋伟世通电子科技（南京）有限公司
Yanfeng Visteon Electronics Technology (Nanjing) Co., Ltd
江苏省南京市江宁区苏源大道19号国际企业总部园C1座7楼
Address: 7F, C1, Jiulonghu International Corporate Headquarters, No. 19 Suyuan Road, Jiangning Development Zone, Nanjing, China


-----Original Message-----
From: Ezequiel Garcia [mailto:ezequiel@vanguardiasur.com.ar] 
Sent: 2018年4月11日 23:09
To: Richard Weinberger
Cc: Wang, Qiong (Q.); linux-mtd@lists.infradead.org
Subject: Re: Could someone tell me if the fastmap feature in ubi is stable for use in production?

Wang, Qiong (Q.),


On 9 April 2018 at 07:55, Richard Weinberger <richard.weinberger@gmail.com> wrote:
> Wang, Qiong (Q.),
>
> On Mon, Apr 9, 2018 at 12:25 PM, Wang, Qiong (Q.) <qwang34@yfve.com.cn> wrote:
>> Hi experts,
>>
>> I have found the below link in the linux-mtd website explaining fastmap feature in ubi.
>> http://linux-mtd.infradead.org/doc/ubi.html#L_fastmap
>>
>> Our project uses large nand flash and I found that fastmap can reduce the ubi attach process to the time we want. Our concern is, since it is an experimental, is it stable to use in our project? Are there any reported issue of this feature?Our biggest worry is that can it possibly brick our system during the boot up process.

For what it's worth, I've used UBI fastmap in production, and so far we didn't have issues.

Note that we prepared a lot of tests, based on our particular use case. If I remember correctly, we hit one bug and Richard was kind enough to fix it in a few hours.

So my advise is: use it, but by all means test it. As anything else.

Hope it helps,
Eze

Re: Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Richard Weinberger]

Am Donnerstag, 12. April 2018, 03:31:28 CEST schrieb Wang, Qiong (Q.):
> Hi Ezequiel,
> 
> Thanks for your advice. May I ask what patch that Richard gave to you to fix your bug? Is it the same as what Richard showed me before in the following link?
> 
> http://lists.infradead.org/pipermail/linux-mtd/2018-March/079610.html

No. It was this one:
https://git.kernel.org/linus/1900149c835ab5b48bea31a823ea5e5a401fb560

Thanks,
//richard

-- 
sigma star gmbh - Eduard-Bodem-Gasse 6 - 6020 Innsbruck - Austria
ATU66964118 - FN 374287y

Re: Could someone tell me if the fastmap feature in ubi is stable for use in production?

[Richard Weinberger]

Am Donnerstag, 12. April 2018, 03:28:57 CEST schrieb Wang, Qiong (Q.):
> Hi Richard,
> 
> Thank you so much for your information. Our plan is to use it but with all means of test. We will look into the patch that you showed to us and decide if we can add it in our project.

Maybe I was a bit too pessimistic in my first reply.
So far every Fastmap known issue got fixed. Either by me or someone else.
But since it is another level of complexity to UBI there can be more issues hidden.

Thanks,
//richard

-- 
sigma star gmbh - Eduard-Bodem-Gasse 6 - 6020 Innsbruck - Austria
ATU66964118 - FN 374287y