linux-kernel - Re: [PATCH] x86, efi: change name of efi_no_storage_paranoia parameter to efi_storage

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Date:	Wed, 20 Nov 2013 15:26:51 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	Madper Xie <cxie@...hat.com>
CC:	Matt Fleming <matt@...sole-pimps.org>,
	Richard Weinberger <richard@....at>,
	<linux-efi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<matt.fleming@...el.com>, <matthew.garrett@...ula.com>,
	<jlee@...e.com>
Subject: Re: [PATCH] x86, efi: change name of efi_no_storage_paranoia parameter
 to efi_storage_paranoia

(2013/11/19 12:16), Madper Xie wrote:
> 
> isimatu.yasuaki@...fujitsu.com writes:
> 
>> Hi Matt,
>>
>> Sorry for late the reply.
>>
>>
>> (2013/11/11 19:54), Matt Fleming wrote:
>>> On Mon, 11 Nov, at 05:52:59PM, Yasuaki Ishimatsu wrote:
>>>> Hi Matt,
>>>>
>>>> I uses FUJITSU's x86 box.
>>>> This does not become bricked even if I use all efi variable storage.
>>>> Thus I want a way to not need to specify efi_no_storage_paranoia
>>>> parameter.
>>>
>>> The efi_no_storage_paranoia parameter was introduced because some
>>> machines do not initiate garbage collection of the NVRAM until you
>>> allocate all space - basically it's a switch to turn off the "save 5KB
>>> of stoarge at all times" workaround that is needed to avoid bricking
>>> some machines.
>>>
>>> The intention of the switch is not to allow you to fill your NVRAM just
>>> because you can. If that is something you want to do then I think it's
>>> fair to require you to explicitly turn on efi_no_storage_paranoia. But
>>> I'm assuming here that you are doing something like writing lots and
>>> lots of pstore entries and just want to write as many as your variable
>>> storage will allow? Or are you doing something more fundamental like
>>> creating BootXXXX entries?
>>>
>>> What are you doing to run into the 5KB reserve? How much NVRAM does your
>>> machine come with?
>>
>> I just add boot entry to NVRAM by efibootmgr command. But when Linux boots up,
>> the remaining NVRAM is less than 5Kbyte. So I cannnot add new entry.
>>
> Howdy Yasuaki,
>    If the remaining NVRAM is less than 5Kb, your writing will trigger a
>    NVRAM storage reclamation. However you still failed creating entry. So
>    I'm just curious what itmes occupy lots of nvram storage space.

Even if we got EFI_OUT_OF_RESOURCES while running Linux, gc does not run.
Trigger of gc is when EFI_OUT_OF_RESOURCES occurs on pre OS environment with
UEFI. So on my system, if EFI_OUT_OF_RESOURCES occurs by the 5Kbyte threshold,
we cannot use nvram storage until EFI_OUT_OF_RESOURCES occurs on pre OS
environment with UEFI.

Thanks,
Yasuaki Ishimatsu

> 
>> Thanks,
>> Yasuaki Ishimatsu
> 
> --
> Best,
> Madper
> 


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