On Mon, Aug 12, 2019 at 08:52:23PM -0400, Daniel Jordan wrote:
>
> @@ -191,22 +184,25 @@ static struct padata_priv *padata_get_next(struct 
> parallel_data *pd)
>               padata = list_entry(reorder->list.next,
>                                   struct padata_priv, list);
>  
> -             list_del_init(&padata->list);
> -             atomic_dec(&pd->reorder_objects);
> +             /*
> +              * The check fails in the unlikely event that two or more
> +              * parallel jobs have hashed to the same CPU and one of the
> +              * later ones finishes first.
> +              */
> +             if (padata->seq_nr == pd->processed) {
> +                     list_del_init(&padata->list);
> +                     atomic_dec(&pd->reorder_objects);
Now that you've changed the test for whether there is work to be
done you also need to update the code at the end of padata_reorder
that checks whether there is work to do.  Otherwise we can end up
in a busy loop that just wastes CPU cycles.

Cheers,
-- 
Email: Herbert Xu <herb...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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