On Fri, May 29, 2020 at 10:15:51PM +0200, Arnd Bergmann wrote:
> A 64-bit division was introduced in refperf, breaking compilation
> on all 32-bit architectures:
> 
> kernel/rcu/refperf.o: in function `main_func':
> refperf.c:(.text+0x57c): undefined reference to `__aeabi_uldivmod'
> 
> Work it by using div_u64 to mark the expensive operation.
> 
> Fixes: bd5b16d6c88d ("refperf: Allow decimal nanoseconds")
> Signed-off-by: Arnd Bergmann <a...@arndb.de>

Many thanks, Arnd!

I queued this and reverted my earlier 64-bit-only restriction, pushing
the result out on the -rcu tree's "dev" branch.  I also added a couple
of Reported-by entries.

                                                        Thanx, Paul

> ---
>  kernel/rcu/refperf.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/rcu/refperf.c b/kernel/rcu/refperf.c
> index 47df72c492b3..c2366648981d 100644
> --- a/kernel/rcu/refperf.c
> +++ b/kernel/rcu/refperf.c
> @@ -386,7 +386,7 @@ static int main_func(void *arg)
>               if (torture_must_stop())
>                       goto end;
>  
> -             result_avg[exp] = 1000 * process_durations(nreaders) / 
> (nreaders * loops);
> +             result_avg[exp] = div_u64(1000 * process_durations(nreaders), 
> nreaders * loops);
>       }
>  
>       // Print the average of all experiments
> @@ -397,9 +397,14 @@ static int main_func(void *arg)
>       strcat(buf, "Threads\tTime(ns)\n");
>  
>       for (exp = 0; exp < nruns; exp++) {
> +             u64 avg;
> +             u32 rem;
> +
>               if (errexit)
>                       break;
> -             sprintf(buf1, "%d\t%llu.%03d\n", exp + 1, result_avg[exp] / 
> 1000, (int)(result_avg[exp] % 1000));
> +
> +             avg = div_s64_rem(result_avg[exp], 1000, &rem);
> +             sprintf(buf1, "%d\t%llu.%03d\n", exp + 1, avg, rem);
>               strcat(buf, buf1);
>       }
>  
> -- 
> 2.26.2
> 

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