Commit 29ef4a2f authored by Tejun Heo's avatar Tejun Heo
Browse files

Merge branch 'for-6.14-fixes' into for-6.15 

Pull to receive:

- 2fa0fbeb ("sched_ext: Implement auto local dispatching of migration disabled tasks")
- 32966821 ("sched_ext: Fix migration disabled handling in targeted dispatches")

as planned for-6.15 changes depend on them (e.g. adding event counter for
implicit migration disabled task handling).
parents 38d65cd6 32966821

kernel/sched/ext.c

+36 −4
Original line number Diff line number Diff line
@@ -125,6 +125,19 @@ enum scx_ops_flags { 
	 */

	SCX_OPS_SWITCH_PARTIAL	= 1LLU << 3,



	/*

	 * A migration disabled task can only execute on its current CPU. By

	 * default, such tasks are automatically put on the CPU's local DSQ with

	 * the default slice on enqueue. If this ops flag is set, they also go

	 * through ops.enqueue().

	 *

	 * A migration disabled task never invokes ops.select_cpu() as it can

	 * only select the current CPU. Also, p->cpus_ptr will only contain its

	 * current CPU while p->nr_cpus_allowed keeps tracking p->user_cpus_ptr

	 * and thus may disagree with cpumask_weight(p->cpus_ptr).

	 */

	SCX_OPS_ENQ_MIGRATION_DISABLED = 1LLU << 4,



	/*

	 * CPU cgroup support flags

	 */
@@ -133,6 +146,7 @@ enum scx_ops_flags { 
	SCX_OPS_ALL_FLAGS	= SCX_OPS_KEEP_BUILTIN_IDLE |

				  SCX_OPS_ENQ_LAST |

				  SCX_OPS_ENQ_EXITING |

				  SCX_OPS_ENQ_MIGRATION_DISABLED |

				  SCX_OPS_SWITCH_PARTIAL |

				  SCX_OPS_HAS_CGROUP_WEIGHT,

};
@@ -885,6 +899,7 @@ static bool scx_warned_zero_slice; 


static DEFINE_STATIC_KEY_FALSE(scx_ops_enq_last);

static DEFINE_STATIC_KEY_FALSE(scx_ops_enq_exiting);

static DEFINE_STATIC_KEY_FALSE(scx_ops_enq_migration_disabled);

static DEFINE_STATIC_KEY_FALSE(scx_ops_cpu_preempt);



static struct static_key_false scx_has_op[SCX_OPI_END] =
@@ -2102,6 +2117,11 @@ static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags, 
		goto local;

	}



	/* see %SCX_OPS_ENQ_MIGRATION_DISABLED */

	if (!static_branch_unlikely(&scx_ops_enq_migration_disabled) &&

	    is_migration_disabled(p))

		goto local;



	if (!SCX_HAS_OP(enqueue))

		goto global;
@@ -2407,12 +2427,16 @@ static void move_remote_task_to_local_dsq(struct task_struct *p, u64 enq_flags, 
 *

 * - The BPF scheduler is bypassed while the rq is offline and we can always say

 *   no to the BPF scheduler initiated migrations while offline.

 *

 * The caller must ensure that @p and @rq are on different CPUs.

 */

static bool task_can_run_on_remote_rq(struct task_struct *p, struct rq *rq,

				      bool trigger_error)

{

	int cpu = cpu_of(rq);



	SCHED_WARN_ON(task_cpu(p) == cpu);



	/*

	 * We don't require the BPF scheduler to avoid dispatching to offline

	 * CPUs mostly for convenience but also because CPUs can go offline
@@ -2426,8 +2450,11 @@ static bool task_can_run_on_remote_rq(struct task_struct *p, struct rq *rq, 
		return false;

	}



	if (unlikely(is_migration_disabled(p)))

		return false;

	/*

	 * If @p has migration disabled, @p->cpus_ptr only contains its current

	 * CPU and the above task_allowed_on_cpu() test should have failed.

	 */

	SCHED_WARN_ON(is_migration_disabled(p));



	if (!scx_rq_online(rq))

		return false;
@@ -2531,7 +2558,8 @@ static struct rq *move_task_between_dsqs(struct task_struct *p, u64 enq_flags, 


	if (dst_dsq->id == SCX_DSQ_LOCAL) {

		dst_rq = container_of(dst_dsq, struct rq, scx.local_dsq);

		if (!task_can_run_on_remote_rq(p, dst_rq, true)) {

		if (src_rq != dst_rq &&

		    unlikely(!task_can_run_on_remote_rq(p, dst_rq, true))) {

			dst_dsq = find_global_dsq(p);

			dst_rq = src_rq;

		}
@@ -2685,7 +2713,8 @@ static void dispatch_to_local_dsq(struct rq *rq, struct scx_dispatch_q *dst_dsq, 
	}



#ifdef CONFIG_SMP

	if (unlikely(!task_can_run_on_remote_rq(p, dst_rq, true))) {

	if (src_rq != dst_rq &&

	    unlikely(!task_can_run_on_remote_rq(p, dst_rq, true))) {

		dispatch_enqueue(find_global_dsq(p), p,

				 enq_flags | SCX_ENQ_CLEAR_OPSS);

		__scx_add_event(SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE, 1);
@@ -4666,6 +4695,7 @@ static void scx_ops_disable_workfn(struct kthread_work *work) 
		static_branch_disable(&scx_has_op[i]);

	static_branch_disable(&scx_ops_enq_last);

	static_branch_disable(&scx_ops_enq_exiting);

	static_branch_disable(&scx_ops_enq_migration_disabled);

	static_branch_disable(&scx_ops_cpu_preempt);

	static_branch_disable(&scx_builtin_idle_enabled);

	synchronize_rcu();
@@ -5298,6 +5328,8 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link) 


	if (ops->flags & SCX_OPS_ENQ_EXITING)

		static_branch_enable(&scx_ops_enq_exiting);

	if (ops->flags & SCX_OPS_ENQ_MIGRATION_DISABLED)

		static_branch_enable(&scx_ops_enq_migration_disabled);

	if (scx_ops.cpu_acquire || scx_ops.cpu_release)

		static_branch_enable(&scx_ops_cpu_preempt);

tools/sched_ext/include/scx/common.bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -436,7 +436,7 @@ void bpf_rcu_read_unlock(void) __ksym; 
 */

static inline s64 time_delta(u64 after, u64 before)

{

	return (s64)(after - before) > 0 ? : 0;

	return (s64)(after - before) > 0 ? (s64)(after - before) : 0;

}



/**