Messages in this thread | | | Subject | Re: Can we move device drivers into user-space? | From | Valdis.Kletnieks@vt ... | Date | Fri, 24 Feb 2012 10:58:06 -0500 |
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On Fri, 24 Feb 2012 10:19:36 EST, Jidong Xiao said:
> Actually, my major concern is, since UIO has been accepted, then why > don't we move all the rest device drivers into user space as well. As > I understand, currently, some of device drivers are running on user > space, while the other (or say the majority of) device drivers are > running on kernel space, so why don't we maintain a consistent device > drivers infrastructure, say, either all in user space, or all in > kernel space. (Sure some critical device drivers still need to be kept > in kernel space.)
Sure we could do that, if you deal with all of the following issues: 1) All I/O would take a lot more CPU, due to the additional context switching that would be required to start an I/O and handle the completion interrupt. 2) It makes it a lot harder to do zero-copy I/O. 3) Once we push the API to userspace, we're stuck with it. See Documentation/stable_api_nonsense.txt for the details.
And finally:
4) -ENOPATCH. You think it's a good idea, do up a patch that works at least as well as what we have now... [unhandled content-type:application/pgp-signature] | |