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SubjectRe: [PATCH]Timer list init is done AFTER use
Looks ok.  I will give it a spin on Monday.

-g

Andrew Morton wrote:
>
> george anzinger wrote:
> >
> > ...
> > I am not sure. The first question is when does the online
> > bit get set for cpu 0. The next is that it does inhibit a
> > rather large block of printks. Is this ok?
> >
>
> The boot cpu is set online extremely late. Strangely late. Why
> is this?
>
> How about something like the below? We mark the boot cpu
> online in generic code as soon as it has initialised its per-cpu
> storage (seems appropriate?)
>
> This will then allow that cpu to actually start calling into console
> drivers, if they have been registered. If those drivers do a mod_timer()
> (as the vga console does) then that will work OK.
>
> Secondary CPUs also are not marked online until their per-cpu storage is
> initialised, and their notifiers have been called.
>
> If a non-online cpu calls printk, its output will be buffered. It will
> be displayed by the next call to printk by an online CPU.
>
> (The patch needs set_cpu_online()/set_cpu_possible() implementations
> done for the other architectures)
>
> arch/i386/kernel/smpboot.c | 5 -----
> include/asm-i386/smp.h | 29 +++++++++++++++++++++++------
> include/linux/smp.h | 7 ++++++-
> init/main.c | 8 ++++++++
> kernel/printk.c | 6 +++++-
> 5 files changed, 42 insertions(+), 13 deletions(-)
>
> --- 25/kernel/printk.c~ga Sat Dec 21 23:27:08 2002
> +++ 25-akpm/kernel/printk.c Sat Dec 21 23:27:08 2002
> @@ -43,7 +43,11 @@
> #define LOG_BUF_MASK (LOG_BUF_LEN-1)
>
> #ifndef arch_consoles_callable
> -#define arch_consoles_callable() (1)
> +/*
> + * Some console drivers may assume that per-cpu resources have been allocated.
> + * So don't allow them to be called by this CPU until it is officially up.
> + */
> +#define arch_consoles_callable() cpu_online(smp_processor_id())
> #endif
>
> /* printk's without a loglevel use this.. */
> --- 25/init/main.c~ga Sat Dec 21 23:48:03 2002
> +++ 25-akpm/init/main.c Sat Dec 21 23:55:00 2002
> @@ -361,6 +361,14 @@ asmlinkage void __init start_kernel(void
> printk(linux_banner);
> setup_arch(&command_line);
> setup_per_cpu_areas();
> +
> + /*
> + * Once the boot CPU's per-cpu memory is set up it may be considered
> + * online. This is mainly to turn on printk output.
> + */
> + set_cpu_online(smp_processor_id());
> + set_cpu_possible(smp_processor_id());
> +
> build_all_zonelists();
> page_alloc_init();
> printk("Kernel command line: %s\n", saved_command_line);
> --- 25/include/asm-i386/smp.h~ga Sat Dec 21 23:49:43 2002
> +++ 25-akpm/include/asm-i386/smp.h Sat Dec 21 23:54:16 2002
> @@ -80,15 +80,32 @@ extern volatile int logical_apicid_to_cp
>
> extern volatile unsigned long cpu_callout_map;
>
> -#define cpu_possible(cpu) (cpu_callout_map & (1<<(cpu)))
> -#define cpu_online(cpu) (cpu_online_map & (1<<(cpu)))
> +static inline int cpu_possible(int cpu)
> +{
> + return cpu_callout_map & (1 << cpu);
> +}
> +
> +static inline void set_cpu_possible(int cpu)
> +{
> + cpu_callout_map |= (1 << cpu);
> +}
> +
> +static inline int cpu_online(int cpu)
> +{
> + return cpu_online_map & (1 << cpu);
> +}
> +
> +static inline void set_cpu_online(int cpu)
> +{
> + cpu_online_map |= (1 << cpu);
> +}
>
> -extern inline unsigned int num_online_cpus(void)
> +static inline unsigned int num_online_cpus(void)
> {
> return hweight32(cpu_online_map);
> }
>
> -extern inline int any_online_cpu(unsigned int mask)
> +static inline int any_online_cpu(unsigned int mask)
> {
> if (mask & cpu_online_map)
> return __ffs(mask & cpu_online_map);
> @@ -96,13 +113,13 @@ extern inline int any_online_cpu(unsigne
> return -1;
> }
>
> -static __inline int hard_smp_processor_id(void)
> +static inline int hard_smp_processor_id(void)
> {
> /* we don't want to mark this access volatile - bad code generation */
> return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
> }
>
> -static __inline int logical_smp_processor_id(void)
> +static inline int logical_smp_processor_id(void)
> {
> /* we don't want to mark this access volatile - bad code generation */
> return GET_APIC_LOGICAL_ID(*(unsigned long *)(APIC_BASE+APIC_LDR));
> --- 25/arch/i386/kernel/smpboot.c~ga Sat Dec 21 23:52:51 2002
> +++ 25-akpm/arch/i386/kernel/smpboot.c Sat Dec 21 23:54:43 2002
> @@ -992,11 +992,6 @@ static void __init smp_boot_cpus(unsigne
> printk("CPU%d: ", 0);
> print_cpu_info(&cpu_data[0]);
>
> - /*
> - * We have the boot CPU online for sure.
> - */
> - set_bit(0, &cpu_online_map);
> - set_bit(0, &cpu_callout_map);
> boot_cpu_logical_apicid = logical_smp_processor_id();
> map_cpu_to_boot_apicid(0, boot_cpu_apicid);
>
> --- 25/include/linux/smp.h~ga Sun Dec 22 00:29:05 2002
> +++ 25-akpm/include/linux/smp.h Sun Dec 22 00:30:15 2002
> @@ -94,7 +94,12 @@ static inline void smp_send_reschedule_a
> #define cpu_online(cpu) ({ BUG_ON((cpu) != 0); 1; })
> #define num_online_cpus() 1
> #define num_booting_cpus() 1
> -#define cpu_possible(cpu) ({ BUG_ON((cpu) != 0); 1; })
> +#define cpu_possible(cpu) ({ BUG_ON((cpu) != 0); 1; })
> +static inline void set_cpu_online(int cpu)
> +{}
> +static inline void set_cpu_possible(int cpu)
> +{}
> +
>
> struct notifier_block;
>
>
> _
> -
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--
George Anzinger george@mvista.com
High-res-timers:
http://sourceforge.net/projects/high-res-timers/
Preemption patch:
http://www.kernel.org/pub/linux/kernel/people/rml
-
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