On 11/01/2017 04:58 PM, Waiman Long wrote:
> +/* TODO: To be removed in a future kernel version */
> static __init int xen_parse_nopvspin(char *arg)
> {
> - xen_pvspin = false;
> + pr_warn("xen_nopvspin is deprecated, replace it with \"pvlock_type=queued\"!\n");
> + if (!pv_spinlock_type)
> + pv_spinlock_type = locktype_queued;
Since we currently end up using unfair locks and because you are
deprecating xen_nopvspin I wonder whether it would be better to set this
to locktype_unfair so that current behavior doesn't change. (Sorry, I
haven't responded to your earlier message before you posted this). Juergen?
I am also not sure I agree with making pv_spinlock an enum *and* a
bitmask at the same time. I understand that it makes checks easier but I
think not assuming a value or a pattern would be better, especially
since none of the uses is on a critical path.
(For example, !pv_spinlock_type is the same as locktype_auto, which is
defined but never used)
-boris
> return 0;
> }
> early_param("xen_nopvspin", xen_parse_nopvspin);
> -
