Re: [RFC][PATCH 4/5] introduce TASK_SIZE_OF() for all arches

[Matt Mackall <mpm@selenic.com>]

On Tue, Aug 07, 2007 at 03:33:03PM -0700, Dave Hansen wrote:
> 
> For the /proc/<pid>/pagemap code[1], we need to able to query how
> much virtual address space a particular task has.  The trick is
> that we do it through /proc and can't use TASK_SIZE since it
> references "current" on some arches.  The process opening the
> /proc file might be a 32-bit process opening a 64-bit process's
> pagemap file.

That seems perfectly sensible to me, but I think you'll need to bounce
it off Andrew at least. (cc:ed)

> x86_64 already has a TASK_SIZE_OF() macro:
> 
> #define TASK_SIZE_OF(child)     ((test_tsk_thread_flag(child, TIF_IA32)) ? IA32_PAGE_OFFSET : TASK_SIZE64)
> 
> I'd like to have that for other architectures.  So, add it
> for all the architectures that actually use "current" in 
> their TASK_SIZE.  For the others, just add a quick #define
> in sched.h to use plain old TASK_SIZE.
> 
> 1. http://www.linuxworld.com/news/2007/042407-kernel.html
> 
> Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
> ---
> 
>  lxc-dave/include/asm-ia64/processor.h    |    3 ++-
>  lxc-dave/include/asm-parisc/processor.h  |    3 ++-
>  lxc-dave/include/asm-powerpc/processor.h |    4 +++-
>  lxc-dave/include/asm-s390/processor.h    |    2 ++
>  lxc-dave/include/linux/sched.h           |    4 ++++
>  5 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff -puN include/asm-ia64/processor.h~task_size_of include/asm-ia64/processor.h
> --- lxc/include/asm-ia64/processor.h~task_size_of	2007-08-07 15:30:54.000000000 -0700
> +++ lxc-dave/include/asm-ia64/processor.h	2007-08-07 15:30:54.000000000 -0700
> @@ -31,7 +31,8 @@
>   * each (assuming 8KB page size), for a total of 8TB of user virtual
>   * address space.
>   */
> -#define TASK_SIZE		(current->thread.task_size)
> +#define TASK_SIZE_OF(tsk)	((tsk)->thread.task_size)
> +#define TASK_SIZE       	TASK_SIZE_OF(current)
>  
>  /*
>   * This decides where the kernel will search for a free chunk of vm
> diff -puN include/asm-parisc/processor.h~task_size_of include/asm-parisc/processor.h
> --- lxc/include/asm-parisc/processor.h~task_size_of	2007-08-07 15:30:54.000000000 -0700
> +++ lxc-dave/include/asm-parisc/processor.h	2007-08-07 15:30:54.000000000 -0700
> @@ -32,7 +32,8 @@
>  #endif
>  #define current_text_addr() ({ void *pc; current_ia(pc); pc; })
>  
> -#define TASK_SIZE               (current->thread.task_size)
> +#define TASK_SIZE_OF(tsk)       ((tsk)->thread.task_size)
> +#define TASK_SIZE	         (current->thread.task_size)
>  #define TASK_UNMAPPED_BASE      (current->thread.map_base)
>  
>  #define DEFAULT_TASK_SIZE32	(0xFFF00000UL)
> diff -puN include/asm-powerpc/processor.h~task_size_of include/asm-powerpc/processor.h
> --- lxc/include/asm-powerpc/processor.h~task_size_of	2007-08-07 15:30:54.000000000 -0700
> +++ lxc-dave/include/asm-powerpc/processor.h	2007-08-07 15:30:54.000000000 -0700
> @@ -107,7 +107,9 @@ extern struct task_struct *last_task_use
>   */
>  #define TASK_SIZE_USER32 (0x0000000100000000UL - (1*PAGE_SIZE))
>  
> -#define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \
> +#define TASK_SIZE	  (test_thread_flag(TIF_32BIT) ? \
> +		TASK_SIZE_USER32 : TASK_SIZE_USER64)
> +#define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
>  		TASK_SIZE_USER32 : TASK_SIZE_USER64)
>  
>  /* This decides where the kernel will search for a free chunk of vm
> diff -puN include/asm-s390/processor.h~task_size_of include/asm-s390/processor.h
> --- lxc/include/asm-s390/processor.h~task_size_of	2007-08-07 15:30:54.000000000 -0700
> +++ lxc-dave/include/asm-s390/processor.h	2007-08-07 15:30:54.000000000 -0700
> @@ -75,6 +75,8 @@ extern struct task_struct *last_task_use
>  
>  # define TASK_SIZE		(test_thread_flag(TIF_31BIT) ? \
>  					(0x80000000UL) : (0x40000000000UL))
> +# define TASK_SIZE_OF(tsk)	(test_tsk_thread_flag(tsk, TIF_31BIT) ? \
> +					(0x80000000UL) : (0x40000000000UL))
>  # define TASK_UNMAPPED_BASE	(TASK_SIZE / 2)
>  # define DEFAULT_TASK_SIZE	(0x40000000000UL)
>  
> diff -puN include/linux/sched.h~task_size_of include/linux/sched.h
> --- lxc/include/linux/sched.h~task_size_of	2007-08-07 15:30:54.000000000 -0700
> +++ lxc-dave/include/linux/sched.h	2007-08-07 15:30:54.000000000 -0700
> @@ -1712,6 +1712,10 @@ static inline void inc_syscw(struct task
>  }
>  #endif
>  
> +#ifndef TASK_SIZE_OF
> +#define TASK_SIZE_OF(tsk)	TASK_SIZE
> +#endif
> +
>  #endif /* __KERNEL__ */
>  
>  #endif
> _

-- 
Mathematics is the supreme nostalgia of our time.