Excerpts from Ricardo Neri's message of May 6, 2022 9:59 am: > Certain implementations of the hardlockup detector require support for > Inter-Processor Interrupt shorthands. On x86, support for these can only > be determined after all the possible CPUs have booted once (in > smp_init()). Other architectures may not need such check. > > lockup_detector_init() only performs the initializations of data > structures of the lockup detector. Hence, there are no dependencies on > smp_init().
I think this is the only real thing which affects other watchdog types? Not sure if it's a big problem, the secondary CPUs coming up won't have their watchdog active until quite late, and the primary could implement its own timeout in __cpu_up for secondary coming up, and IPI it to get traces if necessary which is probably more robust. Acked-by: Nicholas Piggin <npig...@gmail.com> > > Cc: Andi Kleen <a...@linux.intel.com> > Cc: Nicholas Piggin <npig...@gmail.com> > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Stephane Eranian <eran...@google.com> > Cc: "Ravi V. Shankar" <ravi.v.shan...@intel.com> > Cc: io...@lists.linux-foundation.org > Cc: linuxppc-dev@lists.ozlabs.org > Cc: x...@kernel.org > Reviewed-by: Tony Luck <tony.l...@intel.com> > Signed-off-by: Ricardo Neri <ricardo.neri-calde...@linux.intel.com> > --- > Changes since v5: > * Introduced this patch > > Changes since v4: > * N/A > > Changes since v3: > * N/A > > Changes since v2: > * N/A > > Changes since v1: > * N/A > --- > init/main.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/init/main.c b/init/main.c > index 98182c3c2c4b..62c52c9e4c2b 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -1600,9 +1600,11 @@ static noinline void __init kernel_init_freeable(void) > > rcu_init_tasks_generic(); > do_pre_smp_initcalls(); > - lockup_detector_init(); > > smp_init(); > + > + lockup_detector_init(); > + > sched_init_smp(); > > padata_init(); > -- > 2.17.1 > >
