Re: [PATCH 18/19] io-controller: Debug hierarchical IO scheduling

Gui Jianfeng
2009-06-19T06:28:24Z

Vivek Goyal wrote:
...
> +static inline void bfq_account_for_entity_addition(struct io_entity *entity)
> +{
> + struct io_group *iog = io_entity_to_iog(entity);
> +
> + if (iog) {
> + struct elv_fq_data *efqd;
> + char path[128];
> +
> + /*
> + * Keep track of how many times a group has been removed
> + * from active tree because it did not have any active
> + * backlogged ioq under it
> + */
> + iog->queue++;
> + iog->queue_start = jiffies;
> +
> + /* Log group addition event */
> + rcu_read_lock();
> + efqd = rcu_dereference(iog->key);
> + if (efqd) {
> + io_group_path(iog, path, sizeof(path));
> + elv_log(efqd, "add group=%s weight=%ld", path,
> + iog->entity.weight);

Since cgroup path is already cached, why not use it. :)

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
---
block/elevator-fq.c | 12 ++++--------
1 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/block/elevator-fq.c b/block/elevator-fq.c
index bfa79c9..1a397c3 100644
--- a/block/elevator-fq.c
+++ b/block/elevator-fq.c
@@ -183,7 +183,6 @@ static inline void bfq_account_for_entity_addition(struct io_entity *entity)

if (iog) {
struct elv_fq_data *efqd;
- char path[128];

/*
* Keep track of how many times a group has been removed
@@ -197,9 +196,8 @@ static inline void bfq_account_for_entity_addition(struct io_entity *entity)
rcu_read_lock();
efqd = rcu_dereference(iog->key);
if (efqd) {
- io_group_path(iog, path, sizeof(path));
- elv_log(efqd, "add group=%s weight=%ld", path,
- iog->entity.weight);
+ elv_log(efqd, "add group=%s weight=%ld", iog->path,
+ iog->entity.weight);
}
rcu_read_unlock();
}
@@ -215,7 +213,6 @@ static inline void bfq_account_for_entity_deletion(struct io_entity *entity)

if (iog) {
struct elv_fq_data *efqd;
- char path[128];

iog->dequeue++;
/* Keep a track of how long group was on active tree */
@@ -227,9 +224,8 @@ static inline void bfq_account_for_entity_deletion(struct io_entity *entity)
rcu_read_lock();
efqd = rcu_dereference(iog->key);
if (efqd) {
- io_group_path(iog, path, sizeof(path));
- elv_log(efqd, "del group=%s weight=%ld", path,
- iog->entity.weight);
+ elv_log(efqd, "del group=%s weight=%ld", iog->path,
+ iog->entity.weight);
}
rcu_read_unlock();
}
--
1.5.4.rc3