blkio: Introduce per cfq group weights and vdisktime calculations (25bc6b07) · Commits · 戴 / test

block/Kconfig.iosched

+8 −1

Original line number	Diff line number	Diff line
		@@ -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

block/cfq-iosched.c

+61 −1

Original line number	Diff line number	Diff line
		@@ -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

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