Re: [PATCH linux-2.6-block:master 04/05] blk: remove last_merge handling from ioscheds
From: Tejun Heo
Date: Tue Jul 26 2005 - 09:02:12 EST
04_blk_generic-last_merge-handling-update-for-ioscheds.patch
Remove last_merge handling from all ioscheds. This patch
removes merging capability of noop iosched.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
as-iosched.c | 35 ++++-------------------------------
cfq-iosched.c | 19 +------------------
deadline-iosched.c | 30 ++----------------------------
noop-iosched.c | 31 -------------------------------
4 files changed, 7 insertions(+), 108 deletions(-)
Index: blk-fixes/drivers/block/as-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/as-iosched.c 2005-07-26 22:55:00.000000000 +0900
+++ blk-fixes/drivers/block/as-iosched.c 2005-07-26 22:55:01.000000000 +0900
@@ -279,14 +279,6 @@ static inline void as_del_arq_hash(struc
__as_del_arq_hash(arq);
}
-static void as_remove_merge_hints(request_queue_t *q, struct as_rq *arq)
-{
- as_del_arq_hash(arq);
-
- if (q->last_merge == arq->request)
- q->last_merge = NULL;
-}
-
static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
{
struct request *rq = arq->request;
@@ -330,7 +322,7 @@ static struct request *as_find_arq_hash(
BUG_ON(!arq->on_hash);
if (!rq_mergeable(__rq)) {
- as_remove_merge_hints(ad->q, arq);
+ as_del_arq_hash(arq);
continue;
}
@@ -1040,7 +1032,7 @@ static void as_remove_queued_request(req
ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
list_del_init(&arq->fifo);
- as_remove_merge_hints(q, arq);
+ as_del_arq_hash(arq);
as_del_arq_rb(ad, arq);
}
@@ -1351,7 +1343,7 @@ as_add_aliased_request(struct as_data *a
/*
* Don't want to have to handle merges.
*/
- as_remove_merge_hints(ad->q, arq);
+ as_del_arq_hash(arq);
}
/*
@@ -1392,12 +1384,8 @@ static void as_add_request(request_queue
arq->expires = jiffies + ad->fifo_expire[data_dir];
list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]);
- if (rq_mergeable(arq->request)) {
+ if (rq_mergeable(arq->request))
as_add_arq_hash(ad, arq);
-
- if (!ad->q->last_merge)
- ad->q->last_merge = arq->request;
- }
as_update_arq(ad, arq); /* keep state machine up to date */
} else {
@@ -1487,15 +1475,6 @@ as_merge(request_queue_t *q, struct requ
int ret;
/*
- * try last_merge to avoid going to hash
- */
- ret = elv_try_last_merge(q, bio);
- if (ret != ELEVATOR_NO_MERGE) {
- __rq = q->last_merge;
- goto out_insert;
- }
-
- /*
* see if the merge hash can satisfy a back merge
*/
__rq = as_find_arq_hash(ad, bio->bi_sector);
@@ -1523,9 +1502,6 @@ as_merge(request_queue_t *q, struct requ
return ELEVATOR_NO_MERGE;
out:
- if (rq_mergeable(__rq))
- q->last_merge = __rq;
-out_insert:
if (ret) {
if (rq_mergeable(__rq))
as_hot_arq_hash(ad, RQ_DATA(__rq));
@@ -1572,9 +1548,6 @@ static void as_merged_request(request_qu
* behind the disk head. We currently don't bother adjusting.
*/
}
-
- if (arq->on_hash)
- q->last_merge = req;
}
static void
Index: blk-fixes/drivers/block/cfq-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/cfq-iosched.c 2005-07-26 22:55:00.000000000 +0900
+++ blk-fixes/drivers/block/cfq-iosched.c 2005-07-26 22:55:01.000000000 +0900
@@ -648,8 +648,6 @@ static void cfq_remove_request(struct re
list_del_init(&rq->queuelist);
cfq_del_crq_rb(crq);
cfq_del_crq_hash(crq);
- if (rq->q->last_merge == crq->request)
- rq->q->last_merge = NULL;
}
static int
@@ -659,12 +657,6 @@ cfq_merge(request_queue_t *q, struct req
struct request *__rq;
int ret;
- ret = elv_try_last_merge(q, bio);
- if (ret != ELEVATOR_NO_MERGE) {
- __rq = q->last_merge;
- goto out_insert;
- }
-
__rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
if (__rq) {
BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);
@@ -685,8 +677,6 @@ cfq_merge(request_queue_t *q, struct req
return ELEVATOR_NO_MERGE;
out:
- q->last_merge = __rq;
-out_insert:
*req = __rq;
return ret;
}
@@ -705,8 +695,6 @@ static void cfq_merged_request(request_q
cfq_update_next_crq(crq);
cfq_reposition_crq_rb(cfqq, crq);
}
-
- q->last_merge = req;
}
static void
@@ -1127,12 +1115,8 @@ cfq_insert_request(request_queue_t *q, s
list_add_tail(&crq->request->queuelist, &crq->cfq_queue->fifo[crq->is_sync]);
- if (rq_mergeable(rq)) {
+ if (rq_mergeable(rq))
cfq_add_crq_hash(cfqd, crq);
-
- if (!q->last_merge)
- q->last_merge = rq;
- }
}
static int cfq_queue_empty(request_queue_t *q)
@@ -1251,7 +1235,6 @@ static void cfq_put_request(request_queu
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;
- BUG_ON(q->last_merge == rq);
BUG_ON(!hlist_unhashed(&crq->hash));
if (crq->io_context)
Index: blk-fixes/drivers/block/deadline-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/deadline-iosched.c 2005-07-26 22:55:00.000000000 +0900
+++ blk-fixes/drivers/block/deadline-iosched.c 2005-07-26 22:55:01.000000000 +0900
@@ -112,15 +112,6 @@ static inline void deadline_del_drq_hash
__deadline_del_drq_hash(drq);
}
-static void
-deadline_remove_merge_hints(request_queue_t *q, struct deadline_rq *drq)
-{
- deadline_del_drq_hash(drq);
-
- if (q->last_merge == drq->request)
- q->last_merge = NULL;
-}
-
static inline void
deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
{
@@ -299,12 +290,8 @@ deadline_add_request(struct request_queu
drq->expires = jiffies + dd->fifo_expire[data_dir];
list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]);
- if (rq_mergeable(rq)) {
+ if (rq_mergeable(rq))
deadline_add_drq_hash(dd, drq);
-
- if (!q->last_merge)
- q->last_merge = rq;
- }
}
/*
@@ -316,8 +303,8 @@ static void deadline_remove_request(requ
struct deadline_data *dd = q->elevator->elevator_data;
list_del_init(&drq->fifo);
- deadline_remove_merge_hints(q, drq);
deadline_del_drq_rb(dd, drq);
+ deadline_del_drq_hash(drq);
}
static int
@@ -328,15 +315,6 @@ deadline_merge(request_queue_t *q, struc
int ret;
/*
- * try last_merge to avoid going to hash
- */
- ret = elv_try_last_merge(q, bio);
- if (ret != ELEVATOR_NO_MERGE) {
- __rq = q->last_merge;
- goto out_insert;
- }
-
- /*
* see if the merge hash can satisfy a back merge
*/
__rq = deadline_find_drq_hash(dd, bio->bi_sector);
@@ -368,8 +346,6 @@ deadline_merge(request_queue_t *q, struc
return ELEVATOR_NO_MERGE;
out:
- q->last_merge = __rq;
-out_insert:
if (ret)
deadline_hot_drq_hash(dd, RQ_DATA(__rq));
*req = __rq;
@@ -394,8 +370,6 @@ static void deadline_merged_request(requ
deadline_del_drq_rb(dd, drq);
deadline_add_drq_rb(dd, drq);
}
-
- q->last_merge = req;
}
static void
Index: blk-fixes/drivers/block/noop-iosched.c
===================================================================
--- blk-fixes.orig/drivers/block/noop-iosched.c 2005-07-26 22:55:00.000000000 +0900
+++ blk-fixes/drivers/block/noop-iosched.c 2005-07-26 22:55:01.000000000 +0900
@@ -7,38 +7,9 @@
#include <linux/module.h>
#include <linux/init.h>
-/*
- * See if we can find a request that this buffer can be coalesced with.
- */
-static int elevator_noop_merge(request_queue_t *q, struct request **req,
- struct bio *bio)
-{
- int ret;
-
- ret = elv_try_last_merge(q, bio);
- if (ret != ELEVATOR_NO_MERGE)
- *req = q->last_merge;
-
- return ret;
-}
-
-static void elevator_noop_merge_requests(request_queue_t *q, struct request *req,
- struct request *next)
-{
- list_del_init(&next->queuelist);
-}
-
static void elevator_noop_add_request(request_queue_t *q, struct request *rq)
{
elv_dispatch_insert(q, rq, 0);
-
- /*
- * new merges must not precede this barrier
- */
- if (rq->flags & REQ_HARDBARRIER)
- q->last_merge = NULL;
- else if (!q->last_merge)
- q->last_merge = rq;
}
static int elevator_noop_dispatch(request_queue_t *q, int force)
@@ -48,8 +19,6 @@ static int elevator_noop_dispatch(reques
static struct elevator_type elevator_noop = {
.ops = {
- .elevator_merge_fn = elevator_noop_merge,
- .elevator_merge_req_fn = elevator_noop_merge_requests,
.elevator_dispatch_fn = elevator_noop_dispatch,
.elevator_add_req_fn = elevator_noop_add_request,
},
-
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