On 2017/2/14 3:00, Paul E. McKenney wrote:
On Mon, Feb 13, 2017 at 09:41:46PM +0800, Yubin Ruan wrote:
Quick quiz B.13:
Suppose that lines 3-5 for CPUs 1 and 2 in Table B.4 are in an
interrupt handler, and that the CPU 2's line 9 is running at process
level. What changes, if any, are required to enable the code to work
correctly, in other words, to prevent the assertion from firing?
I can not come up with any practical material for this quiz, because
I don't really know the implication of "in an interrupt handler",
and "running in process level".
The answer hints that one would need to ensure that the load of "e"
precedes that of "a" and hint the Linux kernel implementation
"barrier()". But how is that exactly? I am going to invest some time
into the Linux kernel implementation. But I would really appreciate
some hints about this, as I don't have so much kernel development
experience before.
I suggest reading an operating-system textbook. The ones I have are quite
old, but here they are anyway in bibtex format. There are probably newer
editions of some of them. The short answer on interrupts is that they
force process-level processing to pause while the "interrupt handler"
~~~~~
until ?
completes.
Thanx, Paul
Actually I have taken a operating system course and know about interrupt
handler. Maybe I don't understand the concepts well. I don't really get
your point here. If you have time, maybe you can provide me more
information, otherwise I would just have to investigate more on this
myself. Thanks.
regards,
Yubin Ruan
------------------------------------------------------------------------
@book{CorbetRubiniKroahHartman
,author="Jonathan Corbet and Alessandro Rubini and Greg Kroah-Hartman"
,title="Linux Device Drivers"
,publisher="O'Reilly Media, Inc."
,year="2005"
,edition="Third"
}
@book{Silberschatz98a
,author="Abraham Silberschatz and Peter Baer Galvin"
,title="Operating System Concepts"
,publisher="Addison-Wesley"
,year="1998"
,edition="Fifth"
}
@book{Vahalia96
,author="Uresh Vahalia"
,title="{UNIX} Internals: The New Frontiers"
,publisher="Prentice Hall"
,year="1996"
}
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