On Tue, Apr 30, 2019 at 03:38:31PM -0700, Florian Fainelli wrote:
> Similar to commits c68b0274fb3cf ("ARM: reduce "Booted secondary
> processor" message to debug level") and 035e787543de7 ("ARM: 8644/1: Reduce
> "CPU:
> shutdown" message to debug level"), demote the secondary_start_kernel()
> and __cpu_die() messages from info, respectively notice to debug. While
> we are at it, also do this for cpu_psci_cpu_kill() which is redundant
> with __cpu_die().
>
> This helps improve the amount of possible hotplug cycles by around +50%
> on ARCH_BRCMSTB.
Could you elaborate on why that matters?
e.g. is this just for testing, or does this matter in some shutdown or
hibernate scenario?
> Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
> ---
> arch/arm64/kernel/psci.c | 2 +-
> arch/arm64/kernel/smp.c | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index 8cdaf25e99cd..a78581046c80 100644
> --- a/arch/arm64/kernel/psci.c
> +++ b/arch/arm64/kernel/psci.c
> @@ -96,7 +96,7 @@ static int cpu_psci_cpu_kill(unsigned int cpu)
> for (i = 0; i < 10; i++) {
> err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
> if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
> - pr_info("CPU%d killed.\n", cpu);
> + pr_debug("CPU%d killed.\n", cpu);
> return 0;
> }
>
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 824de7038967..71fd2b5a3f0e 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -259,7 +259,7 @@ asmlinkage notrace void secondary_start_kernel(void)
> * the CPU migration code to notice that the CPU is online
> * before we continue.
> */
> - pr_info("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n",
> + pr_debug("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n",
> cpu, (unsigned long)mpidr,
> read_cpuid_id());
I generally agree that we don't need to be verbose, and demoting these
to debug is fine, but it's a shame that these won't be accessible in
defconfig.
I wonder if we should enable DYNAMIC_DEBUG so that we can turn these on
from the kernel command line, or if we should have something like a
verbose_hotplug option specifically for these messages.
Thanks,
Mark.
> update_cpu_boot_status(CPU_BOOT_SUCCESS);
> @@ -348,7 +348,7 @@ void __cpu_die(unsigned int cpu)
> pr_crit("CPU%u: cpu didn't die\n", cpu);
> return;
> }
> - pr_notice("CPU%u: shutdown\n", cpu);
> + pr_debug("CPU%u: shutdown\n", cpu);
>
> /*
> * Now that the dying CPU is beyond the point of no return w.r.t.
> --
> 2.17.1
>
