Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sched_ext: Factor out abbreviated dispatch dequeue into dispatch_dequeue_locked()
move_task_between_dsqs() contains open-coded abbreviated dequeue logic when
moving tasks between non-local DSQs. Factor this out into
dispatch_dequeue_locked() which can be used when both the task's rq and dsq
locks are already held. Add lockdep assertions to both dispatch_dequeue() and
the new helper to verify locking requirements.
This prepares for the load balancer which will need the same abbreviated
dequeue pattern.
Cc: Andrea Righi <arighi@nvidia.com>
Cc: Dan Schatzberg <schatzberg.dan@gmail.com>
Cc: Emil Tsalapatis <etsal@meta.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
+17
-2
+17
-2
kernel/sched/ext.c
+17
-2
kernel/sched/ext.c
···
1106
1106
struct scx_dispatch_q *dsq = p->scx.dsq;
1107
1107
bool is_local = dsq == &rq->scx.local_dsq;
1108
1108
1109
+
lockdep_assert_rq_held(rq);
1110
+
1109
1111
if (!dsq) {
1110
1112
/*
1111
1113
* If !dsq && on-list, @p is on @rq's ddsp_deferred_locals.
···
1152
1150
1153
1151
if (!is_local)
1154
1152
raw_spin_unlock(&dsq->lock);
1153
+
}
1154
+
1155
+
/*
1156
+
* Abbreviated version of dispatch_dequeue() that can be used when both @p's rq
1157
+
* and dsq are locked.
1158
+
*/
1159
+
static void dispatch_dequeue_locked(struct task_struct *p,
1160
+
struct scx_dispatch_q *dsq)
1161
+
{
1162
+
lockdep_assert_rq_held(task_rq(p));
1163
+
lockdep_assert_held(&dsq->lock);
1164
+
1165
+
task_unlink_from_dsq(p, dsq);
1166
+
p->scx.dsq = NULL;
1155
1167
}
1156
1168
1157
1169
static struct scx_dispatch_q *find_dsq_for_dispatch(struct scx_sched *sch,
···
1828
1812
* @p is going from a non-local DSQ to a non-local DSQ. As
1829
1813
* $src_dsq is already locked, do an abbreviated dequeue.
1830
1814
*/
1831
-
task_unlink_from_dsq(p, src_dsq);
1832
-
p->scx.dsq = NULL;
1815
+
dispatch_dequeue_locked(p, src_dsq);
1833
1816
raw_spin_unlock(&src_dsq->lock);
1834
1817
1835
1818
dispatch_enqueue(sch, dst_dsq, p, enq_flags);