From cf3e94430dd994114e48f0b488f22e68e14b5976 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 9 Sep 2024 13:42:47 -1000 Subject: [PATCH] sched_ext: Replace consume_local_task() with move_local_task_to_local_dsq() - Rename move_task_to_local_dsq() to move_remote_task_to_local_dsq(). - Rename consume_local_task() to move_local_task_to_local_dsq() and remove task_unlink_from_dsq() and source DSQ unlocking from it. This is to make the migration code easier to reuse. No functional changes intended. Signed-off-by: Tejun Heo Acked-by: David Vernet --- kernel/sched/ext.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index baed98c0ceb3..cfb413285882 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2172,23 +2172,30 @@ static bool yield_to_task_scx(struct rq *rq, struct task_struct *to) return false; } -static void consume_local_task(struct task_struct *p, - struct scx_dispatch_q *dsq, struct rq *rq) +static void move_local_task_to_local_dsq(struct task_struct *p, u64 enq_flags, + struct scx_dispatch_q *src_dsq, + struct rq *dst_rq) { - lockdep_assert_held(&dsq->lock); /* released on return */ + struct scx_dispatch_q *dst_dsq = &dst_rq->scx.local_dsq; + + /* @dsq is locked and @p is on @dst_rq */ + lockdep_assert_held(&src_dsq->lock); + lockdep_assert_rq_held(dst_rq); - /* @dsq is locked and @p is on this rq */ WARN_ON_ONCE(p->scx.holding_cpu >= 0); - task_unlink_from_dsq(p, dsq); - list_add_tail(&p->scx.dsq_list.node, &rq->scx.local_dsq.list); - dsq_mod_nr(&rq->scx.local_dsq, 1); - p->scx.dsq = &rq->scx.local_dsq; - raw_spin_unlock(&dsq->lock); + + if (enq_flags & (SCX_ENQ_HEAD | SCX_ENQ_PREEMPT)) + list_add(&p->scx.dsq_list.node, &dst_dsq->list); + else + list_add_tail(&p->scx.dsq_list.node, &dst_dsq->list); + + dsq_mod_nr(dst_dsq, 1); + p->scx.dsq = dst_dsq; } #ifdef CONFIG_SMP /** - * move_task_to_local_dsq - Move a task from a different rq to a local DSQ + * move_remote_task_to_local_dsq - Move a task from a foreign rq to a local DSQ * @p: task to move * @enq_flags: %SCX_ENQ_* * @src_rq: rq to move the task from, locked on entry, released on return @@ -2196,8 +2203,8 @@ static void consume_local_task(struct task_struct *p, * * Move @p which is currently on @src_rq to @dst_rq's local DSQ. */ -static void move_task_to_local_dsq(struct task_struct *p, u64 enq_flags, - struct rq *src_rq, struct rq *dst_rq) +static void move_remote_task_to_local_dsq(struct task_struct *p, u64 enq_flags, + struct rq *src_rq, struct rq *dst_rq) { lockdep_assert_rq_held(src_rq); @@ -2320,7 +2327,7 @@ static bool consume_remote_task(struct rq *this_rq, struct task_struct *p, raw_spin_rq_unlock(this_rq); if (unlink_dsq_and_lock_src_rq(p, dsq, src_rq)) { - move_task_to_local_dsq(p, 0, src_rq, this_rq); + move_remote_task_to_local_dsq(p, 0, src_rq, this_rq); return true; } else { raw_spin_rq_unlock(src_rq); @@ -2351,7 +2358,9 @@ static bool consume_dispatch_q(struct rq *rq, struct scx_dispatch_q *dsq) struct rq *task_rq = task_rq(p); if (rq == task_rq) { - consume_local_task(p, dsq, rq); + task_unlink_from_dsq(p, dsq); + move_local_task_to_local_dsq(p, 0, dsq, rq); + raw_spin_unlock(&dsq->lock); return true; } @@ -2431,13 +2440,14 @@ static void dispatch_to_local_dsq(struct rq *rq, struct scx_dispatch_q *dst_dsq, /* * If @p is staying on the same rq, there's no need to go * through the full deactivate/activate cycle. Optimize by - * abbreviating the operations in move_task_to_local_dsq(). + * abbreviating move_remote_task_to_local_dsq(). */ if (src_rq == dst_rq) { p->scx.holding_cpu = -1; dispatch_enqueue(&dst_rq->scx.local_dsq, p, enq_flags); } else { - move_task_to_local_dsq(p, enq_flags, src_rq, dst_rq); + move_remote_task_to_local_dsq(p, enq_flags, + src_rq, dst_rq); } /* if the destination CPU is idle, wake it up */