Messages in this thread | | | Subject | Re: task switching at Page Faults | From | Andi Kleen <> | Date | Mon, 19 Apr 2004 23:52:48 +0200 |
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Fabiano Ramos <ramos_fabiano@yahoo.com.br> writes: > kernel", about 2.4, and the authors: > 1)assure that there is no process switch during > the execution of an eception handler (aka syscall). > they emphasize it.
They're wrong. First the system call or exception can block and then when kernel code returns to user space it always checks if the time slice hasn't expired.
> 2) say that the execption handler may not generate > exceptions, except for page faults.
That's also incorrect. e.g. it can generate GPFs (e.g. when trying to load a segment register supplied by the user and it is not correct) and a few other exceptions in extreme cases. Usually these exceptions are handled without sleeping though.
-Andi
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