diff options
| -rw-r--r-- | block/Kconfig.iosched | 9 | ||||
| -rw-r--r-- | block/cfq-iosched.c | 62 |
2 files changed, 69 insertions, 2 deletions
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched index be0280deec29..fa95fa770570 100644 --- a/block/Kconfig.iosched +++ b/block/Kconfig.iosched @@ -23,7 +23,6 @@ config IOSCHED_DEADLINE config IOSCHED_CFQ tristate "CFQ I/O scheduler" - select BLK_CGROUP default y ---help--- The CFQ I/O scheduler tries to distribute bandwidth equally @@ -33,6 +32,14 @@ config IOSCHED_CFQ This is the default I/O scheduler. +config CFQ_GROUP_IOSCHED + bool "CFQ Group Scheduling support" + depends on IOSCHED_CFQ && CGROUPS + select BLK_CGROUP + default n + ---help--- + Enable group IO scheduling in CFQ. + choice prompt "Default I/O scheduler" default DEFAULT_CFQ diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index e1f822ac4690..019f28eea9df 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -13,6 +13,7 @@ #include <linux/rbtree.h> #include <linux/ioprio.h> #include <linux/blktrace_api.h> +#include "blk-cgroup.h" /* * tunables @@ -49,6 +50,7 @@ static const int cfq_hist_divisor = 4; #define CFQ_SLICE_SCALE (5) #define CFQ_HW_QUEUE_MIN (5) +#define CFQ_SERVICE_SHIFT 12 #define RQ_CIC(rq) \ ((struct cfq_io_context *) (rq)->elevator_private) @@ -79,6 +81,7 @@ struct cfq_rb_root { struct rb_node *left; unsigned count; u64 min_vdisktime; + struct rb_node *active; }; #define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, 0, 0, } @@ -163,6 +166,7 @@ struct cfq_group { /* group service_tree key */ u64 vdisktime; + unsigned int weight; bool on_st; /* number of cfqq currently on this group */ @@ -434,6 +438,51 @@ cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio); } +static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg) +{ + u64 d = delta << CFQ_SERVICE_SHIFT; + + d = d * BLKIO_WEIGHT_DEFAULT; + do_div(d, cfqg->weight); + return d; +} + +static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) +{ + s64 delta = (s64)(vdisktime - min_vdisktime); + if (delta > 0) + min_vdisktime = vdisktime; + + return min_vdisktime; +} + +static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime) +{ + s64 delta = (s64)(vdisktime - min_vdisktime); + if (delta < 0) + min_vdisktime = vdisktime; + + return min_vdisktime; +} + +static void update_min_vdisktime(struct cfq_rb_root *st) +{ + u64 vdisktime = st->min_vdisktime; + struct cfq_group *cfqg; + + if (st->active) { + cfqg = rb_entry_cfqg(st->active); + vdisktime = cfqg->vdisktime; + } + + if (st->left) { + cfqg = rb_entry_cfqg(st->left); + vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime); + } + + st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime); +} + /* * get averaged number of queues of RT/BE priority. * average is updated, with a formula that gives more weight to higher numbers, @@ -734,8 +783,12 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) { struct cfq_rb_root *st = &cfqd->grp_service_tree; + if (st->active == &cfqg->rb_node) + st->active = NULL; + BUG_ON(cfqg->nr_cfqq < 1); cfqg->nr_cfqq--; + /* If there are other cfq queues under this group, don't delete it */ if (cfqg->nr_cfqq) return; @@ -1654,10 +1707,14 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) { struct cfq_rb_root *st = &cfqd->grp_service_tree; + struct cfq_group *cfqg; if (RB_EMPTY_ROOT(&st->rb)) return NULL; - return cfq_rb_first_group(st); + cfqg = cfq_rb_first_group(st); + st->active = &cfqg->rb_node; + update_min_vdisktime(st); + return cfqg; } static void cfq_choose_cfqg(struct cfq_data *cfqd) @@ -3150,6 +3207,9 @@ static void *cfq_init_queue(struct request_queue *q) *st = CFQ_RB_ROOT; RB_CLEAR_NODE(&cfqg->rb_node); + /* Give preference to root group over other groups */ + cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT; + /* * Not strictly needed (since RB_ROOT just clears the node and we * zeroed cfqd on alloc), but better be safe in case someone decides |