Re: Linux I/O stack design question

[Jeff Moyer <jmoyer@xxxxxxxxxx>]

Werner Fischer <devlists@xxxxxxxx> writes:

> Dear fio users and developers,
>
> I have a question regarding the Linux I/O stack (not directly regarding
> fio, but I think fio user's and developers have a lot of knowledge
> here):
>
> I'm trying to better understand the different layers of the Linux I/O
> stack and how they play together. So I have started a diagram showing
> the different layers of the I/O stack:
> http://www.thomas-krenn.com/de/wikiDE/images/0/07/Linux-IO-Stack.png
>
> Is this diagram correct or are there any errors in there?

That's a nice diagram.  :)  A few of things of note:
1) O_DIRECT I/O can bypass the page cache
2) request-based dm targets sit below the I/O scheduler (currently, that
   just means dm-multipath)
3) the fusion IO device driver can hook itself in where you put it, or
   also up above the I/O scheduler (based on a module load option).
4) not sure if you want to cover I/O directly to the device (no file
   system involved)

Cheers,
Jeff
--
To unsubscribe from this list: send the line "unsubscribe fio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html