Re: [Xen-devel] [PATCH v2] console: allocate ring buffer earlier

[Don Slutz <dslutz@xxxxxxxxxxx>]

On 12/11/14 07:08, Ian Campbell wrote:
> On Tue, 2014-12-09 at 17:34 +0000, Jan Beulich wrote:
>> ... when "conring_size=" was specified on the command line. We can't
>> really do this as early as we would want to when the option was not
>> specified, as the default depends on knowing the system CPU count. Yet
>> the parsing of the ACPI tables is one of the things that generates a
>> lot of output especially on large systems.
>>
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> (ARM  and generic bits)
> 

This change looks good to me, so:

Reviewed-by: Don Slutz <dslutz@xxxxxxxxxxx>

  -Don Slutz

>> ---
>> v2: Also adjust ARM (as requested by Julien). Rename new function to
>>     console_init_ring().
>>
>> --- a/xen/arch/arm/setup.c
>> +++ b/xen/arch/arm/setup.c
>> @@ -745,6 +745,7 @@ void __init start_xen(unsigned long boot
>>  
>>      dt_uart_init();
>>      console_init_preirq();
>> +    console_init_ring();
>>  
>>      system_state = SYS_STATE_boot;
>>  
>> --- a/xen/arch/x86/setup.c
>> +++ b/xen/arch/x86/setup.c
>> @@ -1187,6 +1187,7 @@ void __init noreturn __start_xen(unsigne
>>      }
>>  
>>      vm_init();
>> +    console_init_ring();
>>      vesa_init();
>>  
>>      softirq_init();
>> --- a/xen/drivers/char/console.c
>> +++ b/xen/drivers/char/console.c
>> @@ -744,15 +744,14 @@ void __init console_init_preirq(void)
>>      }
>>  }
>>  
>> -void __init console_init_postirq(void)
>> +void __init console_init_ring(void)
>>  {
>>      char *ring;
>>      unsigned int i, order, memflags;
>> -
>> -    serial_init_postirq();
>> +    unsigned long flags;
>>  
>>      if ( !opt_conring_size )
>> -        opt_conring_size = num_present_cpus() << (9 + xenlog_lower_thresh);
>> +        return;
>>  
>>      order = get_order_from_bytes(max(opt_conring_size, conring_size));
>>      memflags = MEMF_bits(crashinfo_maxaddr_bits);
>> @@ -763,17 +762,30 @@ void __init console_init_postirq(void)
>>      }
>>      opt_conring_size = PAGE_SIZE << order;
>>  
>> -    spin_lock_irq(&console_lock);
>> +    spin_lock_irqsave(&console_lock, flags);
>>      for ( i = conringc ; i != conringp; i++ )
>>          ring[i & (opt_conring_size - 1)] = conring[i & (conring_size - 1)];
>>      conring = ring;
>>      smp_wmb(); /* Allow users of console_force_unlock() to see larger 
>> buffer. */
>>      conring_size = opt_conring_size;
>> -    spin_unlock_irq(&console_lock);
>> +    spin_unlock_irqrestore(&console_lock, flags);
>>  
>>      printk("Allocated console ring of %u KiB.\n", opt_conring_size >> 10);
>>  }
>>  
>> +void __init console_init_postirq(void)
>> +{
>> +    serial_init_postirq();
>> +
>> +    if ( conring != _conring )
>> +        return;
>> +
>> +    if ( !opt_conring_size )
>> +        opt_conring_size = num_present_cpus() << (9 + xenlog_lower_thresh);
>> +
>> +    console_init_ring();
>> +}
>> +
>>  void __init console_endboot(void)
>>  {
>>      int i, j;
>> --- a/xen/include/xen/console.h
>> +++ b/xen/include/xen/console.h
>> @@ -14,6 +14,7 @@ struct xen_sysctl_readconsole;
>>  long read_console_ring(struct xen_sysctl_readconsole *op);
>>  
>>  void console_init_preirq(void);
>> +void console_init_ring(void);
>>  void console_init_postirq(void);
>>  void console_endboot(void);
>>  int console_has(const char *device);
>>
>>
>>
> 
> 
> 
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