Commit 7d4dd4f1 authored Mar 14, 2018 by Dominik Brodowski

sched: add do_sched_yield() helper; remove in-kernel call to sched_yield()

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>

parent e530dca5

kernel/sched/core.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -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);