Re: [PATCH 05/11] android: ram_console: split out persistent ram

Colin Cross
2012-03-08T03:06:44Z

On Wed, Mar 7, 2012 at 6:42 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Wed, Mar 07, 2012 at 05:34:32PM -0800, John Stultz wrote:
>> From: Colin Cross <ccross@android.com>
>>
>> Split ram_console into two halves.
>>
>> persistent_ram is a set of apis that handle a block of memory
>> that does not get erased across a reboot.  It provides functions
>> to fill it as a single buffer or a ring buffer, and to extract
>> the old data after a reboot.  It handles ecc on the data to
>> correct bit errors introduced during reboot.
>
> That's a nice idea, but why are you rolling your own interface here and
> not using the built-in one that the kernel already provides?  Is there
> something lacking with what we have today that requires you to create
> something different?  If so, why not just modify the existing interface
> to make it work for you, that way the tools already created will work
> automatically, and you will not have problems later ripping this out and
> porting it to the in-kernel api.

What interface are you referring to, pstore? As I explained in the
email John quoted to you, pstore would be a client of this, and
ramconsole could be moved on top of pstore. This patch is just a
refactoring that splits ramconsole and the persistent storage apart
without significantly changing the api between them, and only makes it
easier to insert pstore between them. As for tools, we've had tools
that use ram_console since 2008.