The patch titled
Subject: block/cfq: replace cfq_rb_root leftmost caching
has been added to the -mm tree. Its filename is
block-cfq-replace-cfq_rb_root-leftmost-caching.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/block-cfq-replace-cfq_rb_root-leftmost-caching.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/block-cfq-replace-cfq_rb_root-leftmost-caching.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Subject: block/cfq: replace cfq_rb_root leftmost caching
... with the generic rbtree flavor instead. No changes in semantics
whatsoever.
Link: http://lkml.kernel.org/r/20170629171553.2146-6-dave@xxxxxxxxxxxx
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
block/cfq-iosched.c | 70 ++++++++++++------------------------------
1 file changed, 20 insertions(+), 50 deletions(-)
diff -puN block/cfq-iosched.c~block-cfq-replace-cfq_rb_root-leftmost-caching block/cfq-iosched.c
--- a/block/cfq-iosched.c~block-cfq-replace-cfq_rb_root-leftmost-caching
+++ a/block/cfq-iosched.c
@@ -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(),},}
/*
@@ -984,10 +983,9 @@ static inline u64 max_vdisktime(u64 min_
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);
}
@@ -1169,46 +1167,25 @@ cfq_choose_req(struct cfq_data *cfqd, st
}
}
-/*
- * 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;
+ return rb_entry_cfqg(rb_first_cached(&root->rb));
}
-static void rb_erase_init(struct rb_node *n, struct rb_root *root)
+static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
{
- rb_erase(n, root);
+ rb_erase_cached(n, &root->rb);
RB_CLEAR_NODE(n);
-}
-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);
--root->count;
}
@@ -1258,11 +1235,11 @@ cfqg_key(struct cfq_rb_root *st, struct
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;
@@ -1272,15 +1249,12 @@ __cfq_group_service_tree_add(struct cfq_
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);
}
/*
@@ -1381,7 +1355,7 @@ cfq_group_notify_queue_add(struct cfq_da
* 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 +
@@ -2223,14 +2197,14 @@ static void cfq_service_tree_add(struct
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;
@@ -2264,10 +2238,9 @@ static void cfq_service_tree_add(struct
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);
@@ -2279,16 +2252,13 @@ static void cfq_service_tree_add(struct
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;
@@ -2735,7 +2705,7 @@ static struct cfq_queue *cfq_get_next_qu
/* 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);
}
@@ -3221,7 +3191,7 @@ static struct cfq_group *cfq_get_next_cf
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);
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
rbtree-cache-leftmost-node-internally.patch
sched-fair-replace-cfs_rq-rb_leftmost.patch
sched-deadline-replace-earliest-dl-and-rq-leftmost-caching.patch
locking-rtmutex-replace-top-waiter-and-pi_waiters-leftmost-caching.patch
block-cfq-replace-cfq_rb_root-leftmost-caching.patch
lib-interval_tree-fast-overlap-detection.patch
lib-interval-tree-correct-comment-wrt-generic-flavor.patch
procfs-use-faster-rb_first_cached.patch
fs-epoll-use-faster-rb_first_cached.patch
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