lkml.org 
[lkml]   [2006]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] 11/15 deadline-iosched: remove elevator private drq request type
Date
A big win, we now save an allocation/free on each request! With the
previous rb/hash abstractions, we can just reuse queuelist/donelist
for the FIFO data and be done with it.

Signed-off-by: Jens Axboe <axboe@suse.de>
---
block/deadline-iosched.c | 194 ++++++++++++----------------------------------
1 files changed, 52 insertions(+), 142 deletions(-)
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index 8300ba1..3b3b441 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -37,7 +37,7 @@ struct deadline_data {
/*
* next in sort order. read, write or both are NULL
*/
- struct deadline_rq *next_drq[2];
+ struct request *next_rq[2];
unsigned int batching; /* number of sequential requests made */
sector_t last_sector; /* head position */
unsigned int starved; /* times reads have starved writes */
@@ -49,34 +49,14 @@ struct deadline_data {
int fifo_batch;
int writes_starved;
int front_merges;
-
- mempool_t *drq_pool;
};

-/*
- * pre-request data.
- */
-struct deadline_rq {
- struct request *request;
-
- /*
- * expire fifo
- */
- struct list_head fifo;
- unsigned long expires;
-};
-
-static void deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq);
-
-static kmem_cache_t *drq_pool;
-
-#define RQ_DATA(rq) ((struct deadline_rq *) (rq)->elevator_private)
+static void deadline_move_request(struct deadline_data *, struct request *);

#define RQ_RB_ROOT(dd, rq) (&(dd)->sort_list[rq_data_dir((rq))])
-#define DRQ_RB_ROOT(dd, drq) RQ_RB_ROOT((drq)->request)

static void
-deadline_add_drq_rb(struct deadline_data *dd, struct request *rq)
+deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
{
struct rb_root *root = RQ_RB_ROOT(dd, rq);
struct request *__alias;
@@ -84,45 +64,43 @@ deadline_add_drq_rb(struct deadline_data
retry:
__alias = elv_rb_add(root, rq);
if (unlikely(__alias)) {
- deadline_move_request(dd, RQ_DATA(__alias));
+ deadline_move_request(dd, __alias);
goto retry;
}
}

static inline void
-deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
+deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
{
- struct request *rq = drq->request;
const int data_dir = rq_data_dir(rq);

- if (dd->next_drq[data_dir] == drq) {
+ if (dd->next_rq[data_dir] == rq) {
struct rb_node *rbnext = rb_next(&rq->rb_node);

- dd->next_drq[data_dir] = NULL;
+ dd->next_rq[data_dir] = NULL;
if (rbnext)
- dd->next_drq[data_dir] = RQ_DATA(rb_entry_rq(rbnext));
+ dd->next_rq[data_dir] = rb_entry_rq(rbnext);
}

elv_rb_del(RQ_RB_ROOT(dd, rq), rq);
}

/*
- * add drq to rbtree and fifo
+ * add rq to rbtree and fifo
*/
static void
deadline_add_request(struct request_queue *q, struct request *rq)
{
struct deadline_data *dd = q->elevator->elevator_data;
- struct deadline_rq *drq = RQ_DATA(rq);
- const int data_dir = rq_data_dir(drq->request);
+ const int data_dir = rq_data_dir(rq);

- deadline_add_drq_rb(dd, rq);
+ deadline_add_rq_rb(dd, rq);

/*
* set expire time (only used for reads) and add to fifo list
*/
- drq->expires = jiffies + dd->fifo_expire[data_dir];
- list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]);
+ rq_set_fifo_time(rq, jiffies + dd->fifo_expire[data_dir]);
+ list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
}

/*
@@ -130,11 +108,10 @@ deadline_add_request(struct request_queu
*/
static void deadline_remove_request(request_queue_t *q, struct request *rq)
{
- struct deadline_rq *drq = RQ_DATA(rq);
struct deadline_data *dd = q->elevator->elevator_data;

- list_del_init(&drq->fifo);
- deadline_del_drq_rb(dd, drq);
+ rq_fifo_clear(rq);
+ deadline_del_rq_rb(dd, rq);
}

static int
@@ -177,7 +154,7 @@ static void deadline_merged_request(requ
*/
if (type == ELEVATOR_FRONT_MERGE) {
elv_rb_del(RQ_RB_ROOT(dd, req), req);
- deadline_add_drq_rb(dd, req);
+ deadline_add_rq_rb(dd, req);
}
}

@@ -185,20 +162,14 @@ static void
deadline_merged_requests(request_queue_t *q, struct request *req,
struct request *next)
{
- struct deadline_rq *drq = RQ_DATA(req);
- struct deadline_rq *dnext = RQ_DATA(next);
-
- BUG_ON(!drq);
- BUG_ON(!dnext);
-
/*
- * if dnext expires before drq, assign its expire time to drq
- * and move into dnext position (dnext will be deleted) in fifo
+ * if next expires before rq, assign its expire time to rq
+ * and move into next position (next will be deleted) in fifo
*/
- if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) {
- if (time_before(dnext->expires, drq->expires)) {
- list_move(&drq->fifo, &dnext->fifo);
- drq->expires = dnext->expires;
+ if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
+ if (time_before(rq_fifo_time(next), rq_fifo_time(req))) {
+ list_move(&req->queuelist, &next->queuelist);
+ rq_set_fifo_time(req, rq_fifo_time(next));
}
}

@@ -212,53 +183,50 @@ deadline_merged_requests(request_queue_t
* move request from sort list to dispatch queue.
*/
static inline void
-deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq)
+deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq)
{
- request_queue_t *q = drq->request->q;
+ request_queue_t *q = rq->q;

- deadline_remove_request(q, drq->request);
- elv_dispatch_add_tail(q, drq->request);
+ deadline_remove_request(q, rq);
+ elv_dispatch_add_tail(q, rq);
}

/*
* move an entry to dispatch queue
*/
static void
-deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq)
+deadline_move_request(struct deadline_data *dd, struct request *rq)
{
- struct request *rq = drq->request;
const int data_dir = rq_data_dir(rq);
struct rb_node *rbnext = rb_next(&rq->rb_node);

- dd->next_drq[READ] = NULL;
- dd->next_drq[WRITE] = NULL;
+ dd->next_rq[READ] = NULL;
+ dd->next_rq[WRITE] = NULL;

if (rbnext)
- dd->next_drq[data_dir] = RQ_DATA(rb_entry_rq(rbnext));
+ dd->next_rq[data_dir] = rb_entry_rq(rbnext);

- dd->last_sector = drq->request->sector + drq->request->nr_sectors;
+ dd->last_sector = rq->sector + rq->nr_sectors;

/*
* take it off the sort and fifo list, move
* to dispatch queue
*/
- deadline_move_to_dispatch(dd, drq);
+ deadline_move_to_dispatch(dd, rq);
}

-#define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo)
-
/*
* deadline_check_fifo returns 0 if there are no expired reads on the fifo,
* 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
*/
static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
{
- struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next);
+ struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next);

/*
- * drq is expired!
+ * rq is expired!
*/
- if (time_after(jiffies, drq->expires))
+ if (time_after(jiffies, rq_fifo_time(rq)))
return 1;

return 0;
@@ -273,21 +241,21 @@ static int deadline_dispatch_requests(re
struct deadline_data *dd = q->elevator->elevator_data;
const int reads = !list_empty(&dd->fifo_list[READ]);
const int writes = !list_empty(&dd->fifo_list[WRITE]);
- struct deadline_rq *drq;
+ struct request *rq;
int data_dir;

/*
* batches are currently reads XOR writes
*/
- if (dd->next_drq[WRITE])
- drq = dd->next_drq[WRITE];
+ if (dd->next_rq[WRITE])
+ rq = dd->next_rq[WRITE];
else
- drq = dd->next_drq[READ];
+ rq = dd->next_rq[READ];

- if (drq) {
+ if (rq) {
/* we have a "next request" */

- if (dd->last_sector != drq->request->sector)
+ if (dd->last_sector != rq->sector)
/* end the batch on a non sequential request */
dd->batching += dd->fifo_batch;

@@ -336,34 +304,33 @@ dispatch_find_request:
if (deadline_check_fifo(dd, data_dir)) {
/* An expired request exists - satisfy it */
dd->batching = 0;
- drq = list_entry_fifo(dd->fifo_list[data_dir].next);
+ rq = rq_entry_fifo(dd->fifo_list[data_dir].next);

- } else if (dd->next_drq[data_dir]) {
+ } else if (dd->next_rq[data_dir]) {
/*
* The last req was the same dir and we have a next request in
* sort order. No expired requests so continue on from here.
*/
- drq = dd->next_drq[data_dir];
+ rq = dd->next_rq[data_dir];
} else {
- struct rb_node *n;
-
+ struct rb_node *node;
/*
* The last req was the other direction or we have run out of
* higher-sectored requests. Go back to the lowest sectored
* request (1 way elevator) and start a new batch.
*/
dd->batching = 0;
- n = rb_first(&dd->sort_list[data_dir]);
- if (n)
- drq = RQ_DATA(rb_entry_rq(n));
+ node = rb_first(&dd->sort_list[data_dir]);
+ if (node)
+ rq = rb_entry_rq(node);
}

dispatch_request:
/*
- * drq is the selected appropriate request.
+ * rq is the selected appropriate request.
*/
dd->batching++;
- deadline_move_request(dd, drq);
+ deadline_move_request(dd, rq);

return 1;
}
@@ -383,33 +350,21 @@ static void deadline_exit_queue(elevator
BUG_ON(!list_empty(&dd->fifo_list[READ]));
BUG_ON(!list_empty(&dd->fifo_list[WRITE]));

- mempool_destroy(dd->drq_pool);
kfree(dd);
}

/*
- * initialize elevator private data (deadline_data), and alloc a drq for
- * each request on the free lists
+ * initialize elevator private data (deadline_data).
*/
static void *deadline_init_queue(request_queue_t *q, elevator_t *e)
{
struct deadline_data *dd;

- if (!drq_pool)
- return NULL;
-
dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
if (!dd)
return NULL;
memset(dd, 0, sizeof(*dd));

- dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
- mempool_free_slab, drq_pool, q->node);
- if (!dd->drq_pool) {
- kfree(dd);
- return NULL;
- }
-
INIT_LIST_HEAD(&dd->fifo_list[READ]);
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
dd->sort_list[READ] = RB_ROOT;
@@ -422,36 +377,6 @@ static void *deadline_init_queue(request
return dd;
}

-static void deadline_put_request(request_queue_t *q, struct request *rq)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
- struct deadline_rq *drq = RQ_DATA(rq);
-
- mempool_free(drq, dd->drq_pool);
- rq->elevator_private = NULL;
-}
-
-static int
-deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
- gfp_t gfp_mask)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
- struct deadline_rq *drq;
-
- drq = mempool_alloc(dd->drq_pool, gfp_mask);
- if (drq) {
- memset(drq, 0, sizeof(*drq));
- drq->request = rq;
-
- INIT_LIST_HEAD(&drq->fifo);
-
- rq->elevator_private = drq;
- return 0;
- }
-
- return 1;
-}
-
/*
* sysfs parts below
*/
@@ -533,8 +458,6 @@ static struct elevator_type iosched_dead
.elevator_queue_empty_fn = deadline_queue_empty,
.elevator_former_req_fn = elv_rb_former_request,
.elevator_latter_req_fn = elv_rb_latter_request,
- .elevator_set_req_fn = deadline_set_request,
- .elevator_put_req_fn = deadline_put_request,
.elevator_init_fn = deadline_init_queue,
.elevator_exit_fn = deadline_exit_queue,
},
@@ -546,24 +469,11 @@ static struct elevator_type iosched_dead

static int __init deadline_init(void)
{
- int ret;
-
- drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq),
- 0, 0, NULL, NULL);
-
- if (!drq_pool)
- return -ENOMEM;
-
- ret = elv_register(&iosched_deadline);
- if (ret)
- kmem_cache_destroy(drq_pool);
-
- return ret;
+ return elv_register(&iosched_deadline);
}

static void __exit deadline_exit(void)
{
- kmem_cache_destroy(drq_pool);
elv_unregister(&iosched_deadline);
}

--
1.4.1.ged0e0
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-07-13 14:51    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site