Re: [Yaffs] multithreading question

Hi Charles!

Thanks for your answer. Yes, I was talking about yaffs direct. Page-by-page
locking is of course all right.

I have another question. Our NAND chip has the ability to prefetch pages. I
imagine we could benefit from this. Is there a way to get a hint from yaffs
what it is about to read next? Or do you know some good place to insert such
an optimization?

Best regards,
Johan

----- Original Message -----
From: "Charles Manning" <manningc2@actrix.gen.nz>
To: <yaffs@lists.aleph1.co.uk>
Cc: "Johan Kotlinski" <johan@teenageengineering.com>
Sent: Wednesday, February 03, 2010 1:15 AM
Subject: Re: [Yaffs] multithreading question


> On Tuesday 02 February 2010 00:29:17 Johan Kotlinski wrote:
>> Hi!
>> It appears that Yaffs2 multithreading protection is on a very high level
>> (mutex wrapping entire fread/fwrite calls).
>
> Are you talking about yaffs direct or the Linux yaffs?
> The linux yaffs will be locked on a page-by-page basis and I am going to
> change the way yaffs direct does the reading/writing too to only lock on a
> page-by-page basis.
>
> The underlying NAND is locked on a apge by page basis too (that's a
> limitation
> of the hardware), so is this really a big concern?
>
>
>>
>> My worry is that if a low-priority task does a large fwrite call, it
>> could
>> block high-priority tasks for a long time. Is this an acknowledged
>> problem?
>
> It depends on the OS. Some, without priority inhere, won't have this
> problem.
>> Are there comparable file systems that handle multithreading in a more
>> granular way?
>
>
>
>