Re: [PATCH gnumach] smp: Create AP processor set and put all APs inside it

[Samuel Thibault]

Damien Zammit, le dim. 11 févr. 2024 07:10:24 +0000, a ecrit:
> This has the effect of running with one cpu only with smp,
> but has the ability to enable APs in userspace with the right
> processor set RPCs.
> ---
>  ddb/db_print.c   |  4 +++-
>  kern/machine.c   |  7 ++++++-
>  kern/processor.c | 30 +++++++++++++++++++-----------
>  kern/processor.h |  1 +
>  4 files changed, 29 insertions(+), 13 deletions(-)
> 
> diff --git a/ddb/db_print.c b/ddb/db_print.c
> index 028cb887..b5b562fd 100644
> --- a/ddb/db_print.c
> +++ b/ddb/db_print.c
> @@ -347,8 +347,10 @@ db_show_all_runqs(
>  {
>       int i;
>  
> -     db_printf("Processor set runq:\t");
> +     db_printf("Processor set def runq:\t");
>       showrq(&default_pset.runq);
> +     db_printf("Processor set APs runq:\t");
> +     showrq(&ap_pset->runq);

Since userland can create psets as well, better iterate over all_psets.

>       for (i = 0; i < smp_get_numcpus(); i++) {
>           db_printf("Processor #%d runq:\t", i);
>           showrq(&cpu_to_processor(i)->runq);
> diff --git a/kern/machine.c b/kern/machine.c
> index 87fbc4d1..9fbc3871 100644
> --- a/kern/machine.c
> +++ b/kern/machine.c
> @@ -84,6 +84,7 @@ void cpu_up(int cpu)
>  
>       processor = cpu_to_processor(cpu);
>       pset_lock(&default_pset);
> +     pset_lock(ap_pset);

Only #if MACH_HOST

>       s = splsched();
>       processor_lock(processor);
>  #if  NCPUS > 1
> @@ -92,10 +93,14 @@ void cpu_up(int cpu)
>       ms = &machine_slot[cpu];
>       ms->running = TRUE;
>       machine_info.avail_cpus++;
> -     pset_add_processor(&default_pset, processor);
> +     if (cpu == 0)
> +             pset_add_processor(&default_pset, processor);
> +     else
> +             pset_add_processor(ap_pset, processor);

Only #if MACH_HOST

>       processor->state = PROCESSOR_RUNNING;
>       processor_unlock(processor);
>       splx(s);
> +     pset_unlock(ap_pset);
>       pset_unlock(&default_pset);
>  }
>  
> diff --git a/kern/processor.c b/kern/processor.c
> index 76735381..d151f497 100644
> --- a/kern/processor.c
> +++ b/kern/processor.c
> @@ -60,6 +60,7 @@ struct kmem_cache pset_cache;
>  int  master_cpu;
>  
>  struct processor_set default_pset;
> +struct processor_set *ap_pset;

"AP" is an intel name that is mostly unknown otherwise. Since the BSP is
called master processor, we can call the additional pset slaves_pset.

Also only #if MACH_HOST

>  queue_head_t         all_psets;
>  int                  all_psets_count;
> @@ -67,16 +68,13 @@ def_simple_lock_data(, all_psets_lock);
>  
>  processor_t  master_processor;
>  
> -/*
> - *   Bootstrap the processor/pset system so the scheduler can run.
> - */
> -void pset_sys_bootstrap(void)
> +static void pset_sys_bootstrap_real(struct processor_set *pset, int start, 
> int count)

This refactoring doesn't seem to be used?


> @@ -124,6 +130,8 @@ void pset_sys_init(void)
>               ipc_processor_init(processor);
>           }
>       }
> +
> +     processor_set_create(&realhost, &ap_pset, &ap_pset);

>  }
>  #endif       /* MACH_HOST */
>  
> diff --git a/kern/processor.h b/kern/processor.h
> index fc204ffa..29abc99a 100644
> --- a/kern/processor.h
> +++ b/kern/processor.h
> @@ -85,6 +85,7 @@ struct processor_set {
>       long                    sched_load;     /* load avg for scheduler */
>  };
>  extern struct processor_set  default_pset;
> +extern struct processor_set  *ap_pset;
>  
>  struct processor {
>       struct run_queue runq;          /* local runq for this processor */
> -- 
> 2.43.0
> 
> 
>