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SubjectRe: [PATCH 043/109] sched: add do_sched_yield() helper; remove in-kernel call to sched_yield()
On Thu, Mar 29, 2018 at 01:23:20PM +0200, Dominik Brodowski wrote:
> Using the sched-internal do_sched_yield() helper allows us to get rid of
> the sched-internal call to the sys_sched_yield() syscall.
>
> This patch is part of a series which removes in-kernel calls to syscalls.
> On this basis, the syscall entry path can be streamlined. For details, see
> http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net
>
> Cc: Ingo Molnar <mingo@redhat.com>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
> ---
> kernel/sched/core.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index e7c535eee0a6..8de4919c889a 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4892,7 +4892,7 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
> *
> * Return: 0.
> */
> -SYSCALL_DEFINE0(sched_yield)
> +static void do_sched_yield(void)
> {
> struct rq_flags rf;
> struct rq *rq;
> @@ -4913,7 +4913,11 @@ SYSCALL_DEFINE0(sched_yield)
> sched_preempt_enable_no_resched();
>
> schedule();
> +}
>
> +SYSCALL_DEFINE0(sched_yield)
> +{
> + do_sched_yield();
> return 0;
> }
>
> @@ -4997,7 +5001,7 @@ EXPORT_SYMBOL(__cond_resched_softirq);
> void __sched yield(void)
> {
> set_current_state(TASK_RUNNING);
> - sys_sched_yield();
> + do_sched_yield();
> }
> EXPORT_SYMBOL(yield);
>
> --
> 2.16.3
>

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