On Tue, 31 May 2022, Sebastian Andrzej Siewior wrote:
On 2022-05-31 16:12:05 [+0100], John Garry wrote:
Sorry, maybe I was not clear, but I was just asking if there was a good
reason to disable interrupts at source while handling the interrupt, and not
the change to stop using a tasklet.
Without reading the patch first: You need to disable the interrupt
source while the tasklet/ threaded interrupt is handled. Otherwise the
interrupt will keep coming and the tasklet/ threaded interrupt will have
no chance to make progress. So the box will lock up. This is often
overseen on fast machines because the interrupt needs a few usecs to
trigger and so the CPU is able to make a little bit of progress between
each trigger.
In addition it keeps current semantics wrt ksoftirqd, so no guarantees
this runs in irq context in the first place.
Thanks,
Davidlohr
