On Thu, May 31, 2007 at 03:07:16PM -0700, Zach Brown wrote:
> Can you explain what motivated you to send out this patch?
>
> It used to return 0. It was changed because, unlike the syslet
> syscalls, sys_io_submit() doesn't have a simple 0 value to indicate
> success. The current implementation wants to return the number of iocbs
> that were processed, including the one which blocked, from the cachemiss
> thread. So before calling into an operation it sets task_ret_ret() so
> that the cachemiss thread can return it if it takes over.
> task_ret_reg() is holding a return value that is being returned by the
> cachemiss thread on behalf of a sys_io_submit() which blocked.
>
> When I made the change I didn't really audit its effect on the other
> paths. I suppose it's time to do that, and you could help by telling me
> if you saw something bad happen :).
The bad thing was sys_async_exec returning -NOSYS every time a new
cachemiss thread was created.
Without this patch, you'll see sys_async_exec failures with either of
the demos I sent out. Dunno about the existing ones, but I bet they do
the same.
Jeff
--
Work email - jdike at linux dot intel dot com
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