Messages in this thread | | | Date | Thu, 31 May 2007 19:39:46 -0400 | From | Jeff Dike <> | Subject | Re: [PATCH] Syslets - Fix cachemiss_thread return value |
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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
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