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block/cfq: replace cfq_rb_root leftmost caching

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... with the generic rbtree flavor instead. No changes
in semantics whatsoever.

Link: http://lkml.kernel.org/r/20170719014603.19029-11-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Davidlohr Bueso 2017-09-08 16:15:05 -07:00 committed by Linus Torvalds
parent a23ba907d5
commit 09663c86e2
1 changed files with 21 additions and 51 deletions
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72
block/cfq-iosched.c
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@ -93,13 +93,12 @@ struct cfq_ttime {
* move this into the elevator for the rq sorting as well.
*/
struct cfq_rb_root {
struct rb_root rb;
struct rb_node *left;
struct rb_root_cached rb;
unsigned count;
u64 min_vdisktime;
struct cfq_ttime ttime;
};
#define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \
#define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT_CACHED, \
.ttime = {.last_end_request = ktime_get_ns(),},}
/*
@ -981,10 +980,9 @@ static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime)
static void update_min_vdisktime(struct cfq_rb_root *st)
{
struct cfq_group *cfqg;
if (!RB_EMPTY_ROOT(&st->rb.rb_root)) {
struct cfq_group *cfqg = rb_entry_cfqg(st->rb.rb_leftmost);
if (st->left) {
cfqg = rb_entry_cfqg(st->left);
st->min_vdisktime = max_vdisktime(st->min_vdisktime,
cfqg->vdisktime);
}
@ -1166,46 +1164,25 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2,
}
}
/*
* The below is leftmost cache rbtree addon
*/
static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
{
/* Service tree is empty */
if (!root->count)
return NULL;
if (!root->left)
root->left = rb_first(&root->rb);
if (root->left)
return rb_entry(root->left, struct cfq_queue, rb_node);
return NULL;
return rb_entry(rb_first_cached(&root->rb), struct cfq_queue, rb_node);
}
static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root)
{
if (!root->left)
root->left = rb_first(&root->rb);
if (root->left)
return rb_entry_cfqg(root->left);
return NULL;
}
static void rb_erase_init(struct rb_node *n, struct rb_root *root)
{
rb_erase(n, root);
RB_CLEAR_NODE(n);
return rb_entry_cfqg(rb_first_cached(&root->rb));
}
static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
{
if (root->left == n)
root->left = NULL;
rb_erase_init(n, &root->rb);
rb_erase_cached(n, &root->rb);
RB_CLEAR_NODE(n);
--root->count;
}
@ -1255,11 +1232,11 @@ cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg)
static void
__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
{
struct rb_node **node = &st->rb.rb_node;
struct rb_node **node = &st->rb.rb_root.rb_node;
struct rb_node *parent = NULL;
struct cfq_group *__cfqg;
s64 key = cfqg_key(st, cfqg);
int left = 1;
bool leftmost = true;
while (*node != NULL) {
parent = *node;
@ -1269,15 +1246,12 @@ __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
node = &parent->rb_left;
else {
node = &parent->rb_right;
left = 0;
leftmost = false;
}
}
if (left)
st->left = &cfqg->rb_node;
rb_link_node(&cfqg->rb_node, parent, node);
rb_insert_color(&cfqg->rb_node, &st->rb);
rb_insert_color_cached(&cfqg->rb_node, &st->rb, leftmost);
}
/*
@ -1378,7 +1352,7 @@ cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
* so that groups get lesser vtime based on their weights, so that
* if group does not loose all if it was not continuously backlogged.
*/
n = rb_last(&st->rb);
n = rb_last(&st->rb.rb_root);
if (n) {
__cfqg = rb_entry_cfqg(n);
cfqg->vdisktime = __cfqg->vdisktime +
@ -2220,14 +2194,14 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_queue *__cfqq;
u64 rb_key;
struct cfq_rb_root *st;
int left;
bool leftmost = true;
int new_cfqq = 1;
u64 now = ktime_get_ns();
st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq));
if (cfq_class_idle(cfqq)) {
rb_key = CFQ_IDLE_DELAY;
parent = rb_last(&st->rb);
parent = rb_last(&st->rb.rb_root);
if (parent && parent != &cfqq->rb_node) {
__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
rb_key += __cfqq->rb_key;
@ -2261,10 +2235,9 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->service_tree = NULL;
}
left = 1;
parent = NULL;
cfqq->service_tree = st;
p = &st->rb.rb_node;
p = &st->rb.rb_root.rb_node;
while (*p) {
parent = *p;
__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
@ -2276,16 +2249,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
p = &parent->rb_left;
else {
p = &parent->rb_right;
left = 0;
leftmost = false;
}
}
if (left)
st->left = &cfqq->rb_node;
cfqq->rb_key = rb_key;
rb_link_node(&cfqq->rb_node, parent, p);
rb_insert_color(&cfqq->rb_node, &st->rb);
rb_insert_color_cached(&cfqq->rb_node, &st->rb, leftmost);
st->count++;
if (add_front || !new_cfqq)
return;
@ -2732,7 +2702,7 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
/* There is nothing to dispatch */
if (!st)
return NULL;
if (RB_EMPTY_ROOT(&st->rb))
if (RB_EMPTY_ROOT(&st->rb.rb_root))
return NULL;
return cfq_rb_first(st);
}
@ -3219,7 +3189,7 @@ 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))
if (RB_EMPTY_ROOT(&st->rb.rb_root))
return NULL;
cfqg = cfq_rb_first_group(st);
update_min_vdisktime(st);