From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753243AbdGSHqO (ORCPT ); Wed, 19 Jul 2017 03:46:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:53253 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752799AbdGSHqN (ORCPT ); Wed, 19 Jul 2017 03:46:13 -0400 Date: Wed, 19 Jul 2017 09:46:10 +0200 From: Jan Kara To: Davidlohr Bueso Cc: akpm@linux-foundation.org, mingo@kernel.org, peterz@infradead.org, jack@suse.cz, torvalds@linux-foundation.org, kirill.shutemov@linux.intel.com, hch@infradead.org, ldufour@linux.vnet.ibm.com, mhocko@suse.com, mgorman@techsingularity.net, linux-kernel@vger.kernel.org, axboe@fb.com, linux-block@vger.kernel.org, Davidlohr Bueso Subject: Re: [PATCH 10/17] block/cfq: replace cfq_rb_root leftmost caching Message-ID: <20170719074610.GB12546@quack2.suse.cz> References: <20170719014603.19029-1-dave@stgolabs.net> <20170719014603.19029-11-dave@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170719014603.19029-11-dave@stgolabs.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 18-07-17 18:45:56, Davidlohr Bueso wrote: > ... with the generic rbtree flavor instead. No changes > in semantics whatsoever. > > Cc: axboe@fb.com > Cc: linux-block@vger.kernel.org > Acked-by: Peter Zijlstra (Intel) > Signed-off-by: Davidlohr Bueso Looks good to me. You can add: Reviewed-by: Jan Kara Honza > --- > block/cfq-iosched.c | 70 +++++++++++++++-------------------------------------- > 1 file changed, 20 insertions(+), 50 deletions(-) > > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c > index 3d5c28945719..92c31683a2bb 100644 > --- a/block/cfq-iosched.c > +++ b/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_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); > } > @@ -1169,46 +1167,25 @@ 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; > + 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 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; > @@ -1272,15 +1249,12 @@ __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); > } > > /* > @@ -1381,7 +1355,7 @@ 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 + > @@ -2223,14 +2197,14 @@ 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; > @@ -2264,10 +2238,9 @@ 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); > @@ -2279,16 +2252,13 @@ 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; > @@ -2735,7 +2705,7 @@ 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); > } > @@ -3221,7 +3191,7 @@ 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); > -- > 2.12.0 > -- Jan Kara SUSE Labs, CR