Re: [PATCH] sched.h: increment TASK_COMM_LEN to 20 bytes

[Andrew Morton <akpm@osdl.org>]

Luben Tuikov <ltuikov@yahoo.com> wrote:
>
> It is 4 byte aligned anyway.

That's a 64-bitism.  And 32-bit machines are more space-sensitive.

>  This way we can use
> up to 19+1 chars.
> 
> Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
> ---
>  include/linux/sched.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 18f12cb..3fc11bc 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -154,7 +154,7 @@ #define set_current_state(state_value)		
>  	set_mb(current->state, (state_value))
>  
>  /* Task command name length */
> -#define TASK_COMM_LEN 16
> +#define TASK_COMM_LEN 20

So this is basically "increase size of comm[] by 4 bytes, happens to be
zero-cost on 64-bit machines".

We do occasionally hit task_struct.comm[] truncation, when people use
"too-long-a-name%d" for their kernel thread names.  But we seem to manage.