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| author | Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> | 2014-08-28 17:14:58 +0900 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-08-28 08:16:29 -0600 |
| commit | 7b5af5cffce569298b1d03af1ddf1dc43570ab42 (patch) | |
| tree | 5dde60d7c4ff816ffd8cb2c48207f7d770718ef8 | |
| parent | e15693ef18e13e3e6bffe891fe140f18b8ff6d07 (diff) | |
| download | linux-7b5af5cffce569298b1d03af1ddf1dc43570ab42.tar.bz2 | |
cfq-iosched: Add comments on update timing of weight
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@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | block/cfq-iosched.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index d7494637c5db..3f31cf9508e6 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); |