James Bottomley wrote:
So, James, what is your opinion on the above? Or the overall SCSI target
project simplicity doesn't matter much for you and you think it's fine
to duplicate Linux page cache in the user space to keep the in-kernel
part of the project as small as possible?
The answers were pretty much contained here
http://marc.info/?l=linux-scsi&m=120164008302435
and here:
http://marc.info/?l=linux-scsi&m=120171067107293
Weren't they?
No, sorry, it doesn't look so for me. They are about performance, but
I'm asking about the overall project's architecture, namely about one
part of it: simplicity. Particularly, what do you think about
duplicating Linux page cache in the user space to have zero-copy cached
I/O? Or can you suggest another architectural solution for that problem
in the STGT's approach?
Isn't that an advantage of a user space solution? It simply uses the
backing store of whatever device supplies the data. That means it takes
advantage of the existing mechanisms for caching.
No, please reread this thread, especially this message:
http://marc.info/?l=linux-kernel&m=120169189504361&w=2. This is one of
the advantages of the kernel space implementation. The user space
implementation has to have data copied between the cache and user space
buffer, but the kernel space one can use pages in the cache directly,
without extra copy.
Vlad
-
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
