Messages in this thread | | | Date | Sun, 01 Apr 2007 23:11:12 +0300 | From | Avi Kivity <> | Subject | Re: [patch 13/13] signal/timer/event fds v9 - KAIO eventfd support example ... |
| |
Davide Libenzi wrote:
>> I think it's a bit too fine grained, and a new system call (io_bindfd()?) >> would be easier to use. In addition, you would move the eventfd_fget() out of >> the submission path. >> > > IMO the cost of the eventfd_fget() (have you seen it?) is not worth adding > a new syscall. >
There's an atomic op there (and another on the way out). Probably on a busy cacheline. Still it's probably lost in the noise.
Regardless of that, I think that specifying the fd per submission is wrong. It feels like a setup thing that needs to be done once. We shouldn't skimp on syscalls, especially on something as important as unifying the async event model.
> Actually, the flags field that Linus suggested may be given an extra meaning of > "bind to ctx", that'd solve the problem w/out new syscalls. > >
I don't see how. It's still per submission. You could do it on the first iocb, but that's just adding warts to the API.
You could add an IO_CMD_BIND_EVENTFD, but that feels wrong too, as it isn't really an I/O command.
-- Do not meddle in the internals of kernels, for they are subtle and quick to panic.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |