Re: [Xen-devel] [PATCH] xen/credit2: Drop unnecessary bit test

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 01/11/2018 04:48 PM, Andrew Cooper wrote:
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> CC: Dario Faggioli <dfaggioli@xxxxxxxx>
> 
> Notices by chance while inspecting the disassembly delta for "x86/bitops:
> Introduce variable/constant pairs for __{set,clear,change}_bit()"
> ---
>  xen/common/sched_credit2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
> index 18f39ca..ee9768e 100644
> --- a/xen/common/sched_credit2.c
> +++ b/xen/common/sched_credit2.c
> @@ -2063,7 +2063,7 @@ csched2_vcpu_sleep(const struct scheduler *ops, struct 
> vcpu *vc)
>          update_load(ops, svc->rqd, svc, -1, NOW());
>          runq_remove(svc);
>      }
> -    else if ( svc->flags & CSFLAG_delayed_runq_add )
> +    else
>          __clear_bit(__CSFLAG_delayed_runq_add, &svc->flags);

There was a reason for this at some point, I'm sure.  Did this used to
be the atomic version (without the __) originally?

 -George

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