On Tue, Mar 26, 2019 at 01:29:54PM +0100, Rafael J. Wysocki wrote: > On Tue, Mar 26, 2019 at 1:02 PM Leon Romanovsky <[email protected]> wrote: > > > > From: Leon Romanovsky <[email protected]> > > > > Kernel is booted with less possible CPUs (possible_cpus kernel boot > > option) than available CPUs will have prints like this: > > > > [ 1.131039] APIC: NR_CPUS/possible_cpus limit of 8 reached. Processor > > 55/0x1f ignored. > > [ 1.132228] ACPI: Unable to map lapic to logical cpu number > > > > Those warnings are printed for every not-enabled CPU and on the systems > > with large number of such CPUs, we see a lot of those prints for default > > print level. > > > > Simple conversion of those prints to be in debug level removes them > > while leaving the option to debug system. > > But generally dynamic debug must be enabled in order for pr_debug() > prints to be visible which is kind of cumbersome to do via the command > line.
It is doable and documented pretty well, which is uncommon :) https://www.kernel.org/doc/html/latest/admin-guide/dynamic-debug-howto.html#debug-messages-during-boot-process > > > Signed-off-by: Leon Romanovsky <[email protected]> > > --- > > arch/x86/kernel/acpi/boot.c | 2 +- > > arch/x86/kernel/apic/apic.c | 6 +++--- > > 2 files changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > > index 8dcbf6890714..3ef8ab89c02d 100644 > > --- a/arch/x86/kernel/acpi/boot.c > > +++ b/arch/x86/kernel/acpi/boot.c > > @@ -770,7 +770,7 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t > > physid, u32 acpi_id, > > > > cpu = acpi_register_lapic(physid, acpi_id, ACPI_MADT_ENABLED); > > if (cpu < 0) { > > - pr_info(PREFIX "Unable to map lapic to logical cpu > > number\n"); > > + pr_debug(PREFIX "Unable to map lapic to logical cpu > > number\n"); > > And this one is printed sometimes when something really goes wrong > which may be really hard to debug otherwise, so there is value in the > info level here. > > Would it be possible to avoid printing it just in some cases? This can do the trick: diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 3ef8ab89c02d..00212b3991e0 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -770,7 +770,10 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id, cpu = acpi_register_lapic(physid, acpi_id, ACPI_MADT_ENABLED); if (cpu < 0) { - pr_debug(PREFIX "Unable to map lapic to logical cpu number\n"); + if (cpu == -ENOENT) + pr_debug(PREFIX "Unable to map lapic to logical cpu number\n"); + else + pr_info(PREFIX "Unable to map lapic to logical cpu number\n"); return cpu; } diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 8c2a487b5216..2704a2c57df1 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2299,7 +2299,7 @@ int generic_processor_info(int apicid, int version) " Processor %d/0x%x ignored.\n", max, thiscpu, apicid); disabled_cpus++; - return -ENODEV; + return -ENOENT; } if (num_processors >= nr_cpu_ids) {> > > return cpu; > > } > > > > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > > index b7bcdd781651..8c2a487b5216 100644 > > --- a/arch/x86/kernel/apic/apic.c > > +++ b/arch/x86/kernel/apic/apic.c > > @@ -2305,9 +2305,9 @@ int generic_processor_info(int apicid, int version) > > if (num_processors >= nr_cpu_ids) { > > int thiscpu = max + disabled_cpus; > > > > - pr_warning("APIC: NR_CPUS/possible_cpus limit of %i " > > - "reached. Processor %d/0x%x ignored.\n", > > - max, thiscpu, apicid); > > + pr_debug( > > + "APIC: NR_CPUS/possible_cpus limit of %i reached. > > Processor %d/0x%x ignored.\n", > > + max, thiscpu, apicid); > > I completely agree with this change, though. Thanks > > > > > disabled_cpus++; > > return -EINVAL; > > --
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