Re: [PATCH 4/4] taskstats: use div_u64() for the elapsed time in tgid_stats_add_task()

[Balbir Singh]

On 11/1/26 11:57 AM, Bradley Morgan wrote:
> tgid_stats_add_task() converts utime and stime with div_u64() and the
> elapsed time with do_div(), two ways of doing the same 64-bit divide four
> lines apart.  do_div() clobbers its first argument, which is the only
> reason delta needs a statement of its own.  Both end up at a native
> divide on 64-bit and at __div64_32() on 32-bit, so this is only about
> picking one.
> 
> Signed-off-by: Bradley Morgan <brads@xxxxxxxxxxxxxx>
> ---
>  kernel/taskstats.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/taskstats.c b/kernel/taskstats.c
> index 9e11f92216861..2d4ecb9a89a91 100644
> --- a/kernel/taskstats.c
> +++ b/kernel/taskstats.c
> @@ -226,8 +226,7 @@ static void tgid_stats_add_task(struct taskstats *stats,
>  	/* calculate task elapsed time in nsec */
>  	delta = now_ns - tsk->start_time;
>  	/* Convert to micro seconds */
> -	do_div(delta, NSEC_PER_USEC);
> -	stats->ac_etime += delta;
> +	stats->ac_etime += div_u64(delta, NSEC_PER_USEC);
>  
>  	task_cputime(tsk, &utime, &stime);
>  	stats->ac_utime += div_u64(utime, NSEC_PER_USEC);

Thanks!
Reviewed-by: Balbir Singh <balbirs@xxxxxxxxxx>