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Commit 7b5af5cf authored by Toshiaki Makita's avatar Toshiaki Makita Committed by Jens Axboe
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cfq-iosched: Add comments on update timing of weight 



Explain that weight has to be updated on activation.
This complements previous fix e15693ef ("cfq-iosched: Fix wrong
children_weight calculation").

Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent e15693ef

block/cfq-iosched.c

+8 −0
Original line number Diff line number Diff line
@@ -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);