Messages in this thread | | | From | (Eric W. Biederman) | Date | Mon, 07 Dec 2009 14:24:13 -0800 | Subject | Re: [rfc] "fair" rw spinlocks |
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"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> writes: > > Is it required that all of the processes see the signal before the > corresponding interrupt handler returns? (My guess is "no", which > enables a trick or two, but thought I should ask.)
Not that I recall. I think it is just an I/O completed signal.
>> The trouble as I recall is how to ensure new processes see the signal. > > And can we afford to serialize signals to groups of processes? Not > necessarily one at a time, but a limited set at a given time? > Alternatively, a long list of pending group signals for each new task to > walk?
Semantically I don't believe there are not any particular ordering requirements, except that the work must be done before we return from the kernel.
In the ideal implementation we could have hundreds of processes sending signals to the same process group without affecting the rest of the kernel. The current implementation is a concern for scaling and we have been removing it where we can.
Eric
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