Messages in this thread | | | From | "Luck, Tony" <> | Subject | RE: [RFC][PATCH v4 -next 1/4] Move kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop() | Date | Fri, 3 Feb 2012 22:32:31 +0000 |
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> What if we send the REBOOT_IPI first and let it block for up to a second. > Most code paths that are done with spin_locks will use > spin_lock_irqrestore. As soon as the interrupts are re-enabled the > REBOOT_IPI comes in and takes the processor. If after a second the cpu > still is blocking interrupts, just use the NMI as a big hammer to shut it > down.
This looks good - it certainly deals with my "if we just let them run a bit, they'd release the locks" quibble. One second sounds very generous - but I'm not going to bikeshed that (so long as it is a total of one second - not one second per cpu). So the pseudo-code is:
send_reboot_ipi_to_everyone_else()
wait_1_second()
for_each_cpu_that_didnt_respond_to_reboot_ipi { hit_that_cpu_with_NMI() }
Perhaps a notification printk() if we had to use the NMI hammer?
-Tony
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