On 23 November 2010 10:57, Per Fransson <per.fransson.ml at gmail.com> wrote: >>> Am I right that deadlock can occur only if the same IPI was sent? >> >> Not necessarily. It depends on whether the CPU issuing the IPI needs >> to wait for the completion of the cross-call. If you don't need to >> wait, you can send the IPI with the interrupts disabled (the platform >> smp_cross_call is already called with interrupts disabled). >> > > Well, smp_call_function() only optionally waits. As long as we choose not to, > using that function to ask the other cores to save their states and idle, should > be ok, right? In that case we don't need another ipi_msg_type and we can do > it with the interrupts of the ipi caller disabled. I think that should work but we still have a WARN_ON_ONCE in the generic smp_call_function_*() if interrupts are disabled. -- Catalin
