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 <[email protected]>
> ---
>
> 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.
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