提交 41cad6ab 编写于 作者: T Tejun Heo

cfq-iosched: convert cfq_group_slice() to use cfqg->vfraction

cfq_group_slice() calculates slice by taking a fraction of
cfq_target_latency according to the ratio of cfqg->weight against
service_tree->total_weight.  This currently works only because all
cfqgs are treated to be at the same level.

To prepare for proper hierarchy support, convert cfq_group_slice() to
base the calculation on cfqg->vfraction.  As cfqg->vfraction is always
a fraction of 1 and represents the fraction allocated to the cfqg with
hierarchy considered, the slice can be simply calculated by
multiplying cfqg->vfraction to cfq_target_latency (with fixed point
shift factored in).

As vfraction calculation currently treats all non-root cfqgs as
children of the root cfqg, this patch doesn't introduce noticeable
behavior difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
上级 1d3650f7
master alk-4.19.24 alk-4.19.30 alk-4.19.34 alk-4.19.36 alk-4.19.43 alk-4.19.48 alk-4.19.57 ck-4.19.67 ck-4.19.81 ck-4.19.91 github/fork/deepanshu1422/fix-typo-in-comment github/fork/haosdent/fix-typo linux-next v4.19.91 v4.19.90 v4.19.89 v4.19.88 v4.19.87 v4.19.86 v4.19.85 v4.19.84 v4.19.83 v4.19.82 v4.19.81 v4.19.80 v4.19.79 v4.19.78 v4.19.77 v4.19.76 v4.19.75 v4.19.74 v4.19.73 v4.19.72 v4.19.71 v4.19.70 v4.19.69 v4.19.68 v4.19.67 v4.19.66 v4.19.65 v4.19.64 v4.19.63 v4.19.62 v4.19.61 v4.19.60 v4.19.59 v4.19.58 v4.19.57 v4.19.56 v4.19.55 v4.19.54 v4.19.53 v4.19.52 v4.19.51 v4.19.50 v4.19.49 v4.19.48 v4.19.47 v4.19.46 v4.19.45 v4.19.44 v4.19.43 v4.19.42 v4.19.41 v4.19.40 v4.19.39 v4.19.38 v4.19.37 v4.19.36 v4.19.35 v4.19.34 v4.19.33 v4.19.32 v4.19.31 v4.19.30 v4.19.29 v4.19.28 v4.19.27 v4.19.26 v4.19.25 v4.19.24 v4.19.23 v4.19.22 v4.19.21 v4.19.20 v4.19.19 v4.19.18 v4.19.17 v4.19.16 v4.19.15 v4.19.14 v4.19.13 v4.19.12 v4.19.11 v4.19.10 v4.19.9 v4.19.8 v4.19.7 v4.19.6 v4.19.5 v4.19.4 v4.19.3 v4.19.2 v4.19.1 v4.19 v4.19-rc8 v4.19-rc7 v4.19-rc6 v4.19-rc5 v4.19-rc4 v4.19-rc3 v4.19-rc2 v4.19-rc1 ck-release-21 ck-release-20 ck-release-19.2 ck-release-19.1 ck-release-19 ck-release-18 ck-release-17.2 ck-release-17.1 ck-release-17 ck-release-16 ck-release-15.1 ck-release-15 ck-release-14 ck-release-13.2 ck-release-13 ck-release-12 ck-release-11 ck-release-10 ck-release-9 ck-release-7 alk-release-15 alk-release-14 alk-release-13.2 alk-release-13 alk-release-12 alk-release-11 alk-release-10 alk-release-9 alk-release-7
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......@@ -85,7 +85,6 @@ struct cfq_rb_root {
struct rb_root rb;
struct rb_node *left;
unsigned count;
unsigned total_weight;
u64 min_vdisktime;
struct cfq_ttime ttime;
};
......@@ -979,9 +978,7 @@ static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd,
static inline unsigned
cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
struct cfq_rb_root *st = &cfqd->grp_service_tree;
return cfqd->cfq_target_latency * cfqg->weight / st->total_weight;
return cfqd->cfq_target_latency * cfqg->vfraction >> CFQ_SERVICE_SHIFT;
}
static inline unsigned
......@@ -1273,7 +1270,6 @@ cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
cfq_update_group_weight(cfqg);
__cfq_group_service_tree_add(st, cfqg);
st->total_weight += cfqg->weight;
/*
* Activate @cfqg and calculate the portion of vfraction @cfqg is
......@@ -1360,7 +1356,6 @@ cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg)
}
/* remove from the service tree */
st->total_weight -= cfqg->weight;
if (!RB_EMPTY_NODE(&cfqg->rb_node))
cfq_rb_erase(&cfqg->rb_node, st);
}
......
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