Explain that weight has to be updated on activation.
This complements previous fix e15693ef18e1 ("cfq-iosched: Fix wrong
children_weight calculation").
Signed-off-by: Toshiaki Makita <makita.toshiaki@xxxxxxxxxxxxx>
---
block/cfq-iosched.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d749463..3f31cf9 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1272,6 +1272,9 @@ __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
rb_insert_color(&cfqg->rb_node, &st->rb);
}
+/*
+ * This has to be called only on activation of cfqg
+ */
static void
cfq_update_group_weight(struct cfq_group *cfqg)
{
@@ -1303,6 +1306,11 @@ cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
/* add to the service tree */
BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
+ /*
+ * Update leaf_weight. We cannot update weight at this point
+ * because cfqg might already have been activated and is
+ * contributing its current weight to the parent's child_weight.
+ */
cfq_update_group_leaf_weight(cfqg);
__cfq_group_service_tree_add(st, cfqg);
--
1.8.1.2
--
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