Re: [RFC][PATCH] Make MAX_RT_PRIO and MAX_USER_RT_PRIO configurable

[Daniel Walker <dwalker@mvista.com>]

Don't you break sched_find_first_bit() , seems it's dependent on a 
140-bit bitmap .

Daniel


On Wed, 2005-07-27 at 10:13 -0400, Steven Rostedt wrote:
> The following patch makes the MAX_RT_PRIO and MAX_USER_RT_PRIO
> configurable from the make *config.  This is more of a proposal since
> I'm not really sure where in Kconfig this would best fit. I don't see
> why these options shouldn't be user configurable without going into the
> kernel headers to change them.
> 
> Also, is there a way in the Kconfig to force the checking of
> MAX_USER_RT_PRIO <= MAX_RT_PRIO?
> 
> -- Steve
> 
> (Patched against 2.6.12.2)
> 
> Index: vanilla_kernel/include/linux/sched.h
> ===================================================================
> --- vanilla_kernel/include/linux/sched.h	(revision 263)
> +++ vanilla_kernel/include/linux/sched.h	(working copy)
> @@ -389,9 +389,13 @@
>   * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
>   */
>  
> -#define MAX_USER_RT_PRIO	100
> -#define MAX_RT_PRIO		MAX_USER_RT_PRIO
> +#define MAX_USER_RT_PRIO	CONFIG_MAX_USER_RT_PRIO
> +#define MAX_RT_PRIO		CONFIG_MAX_RT_PRIO
>  
> +#if MAX_USER_RT_PRIO > MAX_RT_PRIO
> +#error MAX_USER_RT_PRIO must not be greater than MAX_RT_PRIO
> +#endif
> +
>  #define MAX_PRIO		(MAX_RT_PRIO + 40)
>  
>  #define rt_task(p)		(unlikely((p)->prio < MAX_RT_PRIO))
> Index: vanilla_kernel/init/Kconfig
> ===================================================================
> --- vanilla_kernel/init/Kconfig	(revision 263)
> +++ vanilla_kernel/init/Kconfig	(working copy)
> @@ -162,6 +162,32 @@
>  	  building a kernel for install/rescue disks or your system is very
>  	  limited in memory.
>  
> +config MAX_RT_PRIO
> +	int "Maximum RT priority"
> +	default 100
> +	help
> +	  The real-time priority of threads that have the policy of SCHED_FIFO
> +	  or SCHED_RR have a priority higher than normal threads.  This range
> +	  can be set here, where the range starts from 0 to MAX_RT_PRIO-1.
> +	  If this range is higher than MAX_USER_RT_PRIO than kernel threads
> +	  may have a higher priority than any user thread.
> +
> +	  This may be the same as MAX_USER_RT_PRIO, but do not set this 
> +	  to be less than MAX_USER_RT_PRIO.
> +
> +config MAX_USER_RT_PRIO
> +	int "Maximum User RT priority"
> +	default 100
> +	help
> +	  The real-time priority of threads that have the policy of SCHED_FIFO
> +	  or SCHED_RR have a priority higher than normal threads.  This range
> +	  can be set here, where the range starts from 0 to MAX_USER_RT_PRIO-1.
> +	  If this range is lower than MAX_RT_PRIO, than kernel threads may have
> +	  a higher priority than any user thread.
> +
> +	  This may be the same as MAX_RT_PRIO, but do not set this to be
> +	  greater than MAX_RT_PRIO.
> +	  
>  config AUDIT
>  	bool "Auditing support"
>  	default y if SECURITY_SELINUX
> 
> 
> -
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