[PATCH 0/3] alpha SMP fixes for EV7/Marvel

[Matt Turner <mattst88@gmail.com>]

I acquired an AlphaServer ES47 in 2010, and it's never been stable --
deadlocking after random amounts of time. I could never make any
connections with load, uptime, etc.

The only dots I could connect was that the git test suite would always
trigger the deadlock.

I spent some time over the last week playing with Claude and have found
*a* solution. With the first two patches in place, I've successfully run
the git test suite 6 times in a row. I've never previously seen it run
successfully without deadlocking the system.

The first patch is generally applicable (not specific to EV7/Marvel).
I'm unsure why this would never have caused problems on other systems
(or why it would only be relevant for EV7/Marvel). That gives me some
pause.

The second patch applies only to EV7/Marvel, I believe. tl;dr: IPIs seem
to be lost.

The third patch adds some accounting to /proc/interrupts to report the
number of lost interrupts, confirming the problem from patch 2.

Please review.

Matt

Matt Turner (3):
  alpha: smp: Serialize all synchronous IPI operations to fix SMP
    deadlock
  alpha: Fix SMP IPI loss when target CPU is in interrupt handler
  alpha: Break down rescued IPI counter by type in /proc/interrupts

 arch/alpha/include/asm/smp.h  | 12 +++++
 arch/alpha/kernel/irq.c       | 12 +++++
 arch/alpha/kernel/irq_alpha.c | 29 ++++++++++-
 arch/alpha/kernel/proto.h     |  1 +
 arch/alpha/kernel/smp.c       | 97 +++++++++++++++++++++++++++++++++++
 arch/alpha/mm/tlbflush.c      |  3 ++
 6 files changed, 153 insertions(+), 1 deletion(-)

-- 
2.53.0