since when does ARM map the kernel memory in sections?

[Peter Waechtler]

Hmh,

I'm not 100% sure, but a lot of people made good experience with JFFS2.

Is it that hard to get a log structured file system power fail safe?
Either the end or "commit" block was written or not?

  Peter
 

On 18 Apr, 2011,at 03:52 PM, Pavel Machek <pavel at ucw.cz> wrote:


Hi!

> > > did the ARM Linux 2.6 kernel map the kernel memory in pages in the past?
> > > Or was the memory always mapped in sections?
> > >
> > > I still have to chase a potential memory corruption. The rootfs is located on
> > > a SDcard and gets corrupted even when the filesystem test programs write to
> > > different partitions.
> > > The test scenario includes several dozen or even hundreds of warm and cold
> > > boot sequences, file system write tests with sudden soft resets It's a large
> > > embedded project with a lot of drivers and the fact that always the rootfs and
> > > often the superblock gets damaged let me think of a memory corruption.
> > >
> > 
> > Sorry, I don't want to be obvious, but you mentioned sudden resets
> > while writing, which is almost always going to wind
> > up as fs corruptions, with the severity depending on the level of
> > caching the system is doing to the writes.
> > How are you mounting your rootfs and what file system are you using?
> > What sort of corruptions to the super block are you seeing?
> 
> If everything is implemented correctly, that depends on the type of
> filesystem, block layer and storage. Some are explicitly designed to
> be safe against sudden reboots and power failure - which is an
> important feature of systems where removing the power is how they are
> turned off at night.

...but note that no existing filesystem is safe on media such
as usb sticks, SD and CF cards...

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mffcuni.cz/~pavel/picture/horses/blog.html
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