Sorry, my git send-email config seems incorrect. The patch subject is
not right. So NACK this series, will repost v2.
On 01/05/18 at 11:22am, Baoquan He wrote:
> Kdump kernel will become very slow if 'noapic' is specified in kernel
> command line. Normal kernel doesn't have this issue.
>
> This is because the legacy irq mode is disabled in crashed kernel before
> jump jump to kdump kernel since commit 522e66464467 ("x86/apic: Disable I/O
> APIC before shutdown of the local APIC") is merged. While in normal kernel,
> the legacy irq mode has been set in BIOS.
>
> So we need set the delivery mode AS ExtINT for LVT0 of boot CPU's LAPIC
> explicitly if IO-APIC is disabled, to set up through-local-APIC.
>
> Signed-off-by: Baoquan He <b...@redhat.com>
> ---
> arch/x86/kernel/apic/apic.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index 880441f24146..7e613fb90630 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -1521,7 +1521,7 @@ void setup_local_APIC(void)
> * TODO: set up through-local-APIC from through-I/O-APIC? --macro
> */
> value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
> - if (!cpu && (pic_mode || !value)) {
> + if (!cpu && (pic_mode || !value || skip_ioapic_setup)) {
> value = APIC_DM_EXTINT;
> apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", cpu);
> } else {
> --
> 2.5.5
>
