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authorThomas Gleixner <tglx@linutronix.de>2024-10-28 14:20:35 +0100
committerPeter Zijlstra <peterz@infradead.org>2024-11-05 12:55:37 +0100
commit0f0d1b8e5010bfe1feeb4d78d137e41946a5370d (patch)
tree8c86a8d25abdf6e1001d283a8f3b20e175ee399f
parentb23decf8ac9102fc52c4de5196f4dc0a5f3eb80b (diff)
sched/ext: Remove sched_fork() hack
Instead of solving the underlying problem of the double invocation of __sched_fork() for idle tasks, sched-ext decided to hack around the issue by partially clearing out the entity struct to preserve the already enqueued node. A provided analysis and solution has been ignored for four months. Now that someone else has taken care of cleaning it up, remove the disgusting hack and clear out the full structure. Remove the comment in the structure declaration as well, as there is no requirement for @node being the last element anymore. Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/87ldy82wkc.ffs@tglx
-rw-r--r--include/linux/sched/ext.h1
-rw-r--r--kernel/sched/ext.c7
2 files changed, 1 insertions, 7 deletions
diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h
index 1ddbde64a31b..2799e7284fff 100644
--- a/include/linux/sched/ext.h
+++ b/include/linux/sched/ext.h
@@ -199,7 +199,6 @@ struct sched_ext_entity {
#ifdef CONFIG_EXT_GROUP_SCHED
struct cgroup *cgrp_moving_from;
#endif
- /* must be the last field, see init_scx_entity() */
struct list_head tasks_node;
};
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 5900b06fd036..f6e9a14042d5 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -3548,12 +3548,7 @@ static void scx_ops_exit_task(struct task_struct *p)
void init_scx_entity(struct sched_ext_entity *scx)
{
- /*
- * init_idle() calls this function again after fork sequence is
- * complete. Don't touch ->tasks_node as it's already linked.
- */
- memset(scx, 0, offsetof(struct sched_ext_entity, tasks_node));
-
+ memset(scx, 0, sizeof(*scx));
INIT_LIST_HEAD(&scx->dsq_list.node);
RB_CLEAR_NODE(&scx->dsq_priq);
scx->sticky_cpu = -1;