Re: [rfc] "fair" rw spinlocks

Eric W. Biederman
2009-12-07T23:20:06Z

Andi Kleen <andi@firstfloor.org> writes:

> ebiederm@xmission.com (Eric W. Biederman) writes:
>
>> "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.
>
> Wasn't there the sysrq SAK too? That one definitely would need
> to be careful about synchronicity.

SAK from sysrq is done through schedule work, I seem to recall the
locking being impossible otherwise. There is also send_sig_all and a
few others from sysrq. I expect we could legitimately make them
schedule_work as well if needed.

Eric