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| author | Shaohua Li <shaohua.li@intel.com> | 2011-01-14 08:41:03 +0100 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-01-14 08:41:03 +0100 |
| commit | c553f8e335c00a7cff3ab3f13e793b13d3f2207f (patch) | |
| tree | f9371c9e1191711dd2e774e04d99f3fa90d697fa /block | |
| parent | f8ae6e3eb8251be32c6e913393d9f8d9e0609489 (diff) | |
| download | lwn-c553f8e335c00a7cff3ab3f13e793b13d3f2207f.tar.gz lwn-c553f8e335c00a7cff3ab3f13e793b13d3f2207f.zip | |
block cfq: compensate preempted queue even if it has no slice assigned
If a queue is preempted before it gets slice assigned, the queue doesn't get
compensation, which looks unfair. For such queue, we compensate it for a whole
slice.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/cfq-iosched.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 7bfea53c1bb5..501ffdf0399c 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -598,8 +598,8 @@ cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg) return cfq_target_latency * cfqg->weight / st->total_weight; } -static inline void -cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) +static inline unsigned +cfq_scaled_group_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) { unsigned slice = cfq_prio_to_slice(cfqd, cfqq); if (cfqd->cfq_latency) { @@ -625,6 +625,14 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) low_slice); } } + return slice; +} + +static inline void +cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) +{ + unsigned slice = cfq_scaled_group_slice(cfqd, cfqq); + cfqq->slice_start = jiffies; cfqq->slice_end = jiffies + slice; cfqq->allocated_slice = slice; @@ -1661,8 +1669,11 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, /* * store what was left of this slice, if the queue idled/timed out */ - if (timed_out && !cfq_cfqq_slice_new(cfqq)) { - cfqq->slice_resid = cfqq->slice_end - jiffies; + if (timed_out) { + if (cfq_cfqq_slice_new(cfqq)) + cfqq->slice_resid = cfq_scaled_group_slice(cfqd, cfqq); + else + cfqq->slice_resid = cfqq->slice_end - jiffies; cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); } |