* [PATCH] block: streamline merge possibility checks
@ 2019-12-18 19:41 Dmitry Fomichev
2019-12-19 8:56 ` Bob Liu
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Dmitry Fomichev @ 2019-12-18 19:41 UTC (permalink / raw)
To: linux-block, Jens Axboe; +Cc: Damien Le Moal, Dmitry Fomichev
Checks for data direction in attempt_merge() and blk_rq_merge_ok()
are redundant and will always succeed when the both I/O request
operations are equal. Therefore, remove them.
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
---
block/blk-merge.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index d783bdc4559b..796451aed7d6 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -745,8 +745,7 @@ static struct request *attempt_merge(struct request_queue *q,
if (req_op(req) != req_op(next))
return NULL;
- if (rq_data_dir(req) != rq_data_dir(next)
- || req->rq_disk != next->rq_disk)
+ if (req->rq_disk != next->rq_disk)
return NULL;
if (req_op(req) == REQ_OP_WRITE_SAME &&
@@ -868,10 +867,6 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
if (req_op(rq) != bio_op(bio))
return false;
- /* different data direction or already started, don't merge */
- if (bio_data_dir(bio) != rq_data_dir(rq))
- return false;
-
/* must be same device */
if (rq->rq_disk != bio->bi_disk)
return false;
--
2.21.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] block: streamline merge possibility checks
2019-12-18 19:41 [PATCH] block: streamline merge possibility checks Dmitry Fomichev
@ 2019-12-19 8:56 ` Bob Liu
2019-12-19 10:05 ` Damien Le Moal
` (2 subsequent siblings)
3 siblings, 0 replies; 8+ messages in thread
From: Bob Liu @ 2019-12-19 8:56 UTC (permalink / raw)
To: Dmitry Fomichev, linux-block, Jens Axboe; +Cc: Damien Le Moal
On 12/19/19 3:41 AM, Dmitry Fomichev wrote:
> Checks for data direction in attempt_merge() and blk_rq_merge_ok()
> are redundant and will always succeed when the both I/O request
> operations are equal. Therefore, remove them.
>
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> ---
> block/blk-merge.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index d783bdc4559b..796451aed7d6 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -745,8 +745,7 @@ static struct request *attempt_merge(struct request_queue *q,
> if (req_op(req) != req_op(next))
> return NULL;
>
> - if (rq_data_dir(req) != rq_data_dir(next)
> - || req->rq_disk != next->rq_disk)
> + if (req->rq_disk != next->rq_disk)
> return NULL;
>
> if (req_op(req) == REQ_OP_WRITE_SAME &&
> @@ -868,10 +867,6 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
> if (req_op(rq) != bio_op(bio))
> return false;
>
> - /* different data direction or already started, don't merge */
> - if (bio_data_dir(bio) != rq_data_dir(rq))
> - return false;
> -
Reviewed-by: Bob Liu <bob.liu@oracle.com>
> /* must be same device */
> if (rq->rq_disk != bio->bi_disk)
> return false;
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] block: streamline merge possibility checks
2019-12-18 19:41 [PATCH] block: streamline merge possibility checks Dmitry Fomichev
2019-12-19 8:56 ` Bob Liu
@ 2019-12-19 10:05 ` Damien Le Moal
2019-12-20 6:50 ` Bob Liu
2020-01-08 13:41 ` Christoph Hellwig
3 siblings, 0 replies; 8+ messages in thread
From: Damien Le Moal @ 2019-12-19 10:05 UTC (permalink / raw)
To: Dmitry Fomichev, linux-block, Jens Axboe
On 2019/12/19 4:42, Dmitry Fomichev wrote:
> Checks for data direction in attempt_merge() and blk_rq_merge_ok()
> are redundant and will always succeed when the both I/O request
> operations are equal. Therefore, remove them.
>
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> ---
> block/blk-merge.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index d783bdc4559b..796451aed7d6 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -745,8 +745,7 @@ static struct request *attempt_merge(struct request_queue *q,
> if (req_op(req) != req_op(next))
> return NULL;
>
> - if (rq_data_dir(req) != rq_data_dir(next)
> - || req->rq_disk != next->rq_disk)
> + if (req->rq_disk != next->rq_disk)
> return NULL;
>
> if (req_op(req) == REQ_OP_WRITE_SAME &&
> @@ -868,10 +867,6 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
> if (req_op(rq) != bio_op(bio))
> return false;
>
> - /* different data direction or already started, don't merge */
> - if (bio_data_dir(bio) != rq_data_dir(rq))
> - return false;
> -
> /* must be same device */
> if (rq->rq_disk != bio->bi_disk)
> return false;
>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
--
Damien Le Moal
Western Digital Research
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] block: streamline merge possibility checks
2019-12-18 19:41 [PATCH] block: streamline merge possibility checks Dmitry Fomichev
2019-12-19 8:56 ` Bob Liu
2019-12-19 10:05 ` Damien Le Moal
@ 2019-12-20 6:50 ` Bob Liu
2020-01-08 13:44 ` Christoph Hellwig
2020-01-08 13:41 ` Christoph Hellwig
3 siblings, 1 reply; 8+ messages in thread
From: Bob Liu @ 2019-12-20 6:50 UTC (permalink / raw)
To: Dmitry Fomichev, linux-block, Jens Axboe; +Cc: Damien Le Moal
On 12/19/19 3:41 AM, Dmitry Fomichev wrote:
> Checks for data direction in attempt_merge() and blk_rq_merge_ok()
Speak about these two functions, do you think attempt_merge() can be built on blk_rq_merge_ok()?
Things like..
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 48e6725..2a00c4c 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -724,28 +724,7 @@ static enum elv_merge blk_try_req_merge(struct request *req,
static struct request *attempt_merge(struct request_queue *q,
struct request *req, struct request *next)
{
- if (!rq_mergeable(req) || !rq_mergeable(next))
- return NULL;
-
- if (req_op(req) != req_op(next))
- return NULL;
-
- if (rq_data_dir(req) != rq_data_dir(next)
- || req->rq_disk != next->rq_disk)
- return NULL;
-
- if (req_op(req) == REQ_OP_WRITE_SAME &&
- !blk_write_same_mergeable(req->bio, next->bio))
- return NULL;
-
- /*
- * Don't allow merge of different write hints, or for a hint with
- * non-hint IO.
- */
- if (req->write_hint != next->write_hint)
- return NULL;
-
- if (req->ioprio != next->ioprio)
+ if (!blk_rq_merge_ok(req, next->bio))
return NULL;
> are redundant and will always succeed when the both I/O request
> operations are equal. Therefore, remove them.
>
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> ---
> block/blk-merge.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index d783bdc4559b..796451aed7d6 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -745,8 +745,7 @@ static struct request *attempt_merge(struct request_queue *q,
> if (req_op(req) != req_op(next))
> return NULL;
>
> - if (rq_data_dir(req) != rq_data_dir(next)
> - || req->rq_disk != next->rq_disk)
> + if (req->rq_disk != next->rq_disk)
> return NULL;
>
> if (req_op(req) == REQ_OP_WRITE_SAME &&
> @@ -868,10 +867,6 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
> if (req_op(rq) != bio_op(bio))
> return false;
>
> - /* different data direction or already started, don't merge */
> - if (bio_data_dir(bio) != rq_data_dir(rq))
> - return false;
> -
> /* must be same device */
> if (rq->rq_disk != bio->bi_disk)
> return false;
>
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] block: streamline merge possibility checks
2019-12-18 19:41 [PATCH] block: streamline merge possibility checks Dmitry Fomichev
` (2 preceding siblings ...)
2019-12-20 6:50 ` Bob Liu
@ 2020-01-08 13:41 ` Christoph Hellwig
3 siblings, 0 replies; 8+ messages in thread
From: Christoph Hellwig @ 2020-01-08 13:41 UTC (permalink / raw)
To: Dmitry Fomichev; +Cc: linux-block, Jens Axboe, Damien Le Moal
On Wed, Dec 18, 2019 at 02:41:56PM -0500, Dmitry Fomichev wrote:
> Checks for data direction in attempt_merge() and blk_rq_merge_ok()
> are redundant and will always succeed when the both I/O request
> operations are equal. Therefore, remove them.
>
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] block: streamline merge possibility checks
2019-12-20 6:50 ` Bob Liu
@ 2020-01-08 13:44 ` Christoph Hellwig
2020-01-08 22:02 ` Dmitry Fomichev
0 siblings, 1 reply; 8+ messages in thread
From: Christoph Hellwig @ 2020-01-08 13:44 UTC (permalink / raw)
To: Bob Liu; +Cc: Dmitry Fomichev, linux-block, Jens Axboe, Damien Le Moal
On Fri, Dec 20, 2019 at 02:50:05PM +0800, Bob Liu wrote:
> On 12/19/19 3:41 AM, Dmitry Fomichev wrote:
> > Checks for data direction in attempt_merge() and blk_rq_merge_ok()
>
> Speak about these two functions, do you think attempt_merge() can be built on blk_rq_merge_ok()?
> Things like..
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 48e6725..2a00c4c 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -724,28 +724,7 @@ static enum elv_merge blk_try_req_merge(struct request *req,
> static struct request *attempt_merge(struct request_queue *q,
> struct request *req, struct request *next)
> {
> - if (!rq_mergeable(req) || !rq_mergeable(next))
> - return NULL;
> -
> - if (req_op(req) != req_op(next))
> - return NULL;
> -
> - if (rq_data_dir(req) != rq_data_dir(next)
> - || req->rq_disk != next->rq_disk)
> - return NULL;
> -
> - if (req_op(req) == REQ_OP_WRITE_SAME &&
> - !blk_write_same_mergeable(req->bio, next->bio))
> - return NULL;
> -
> - /*
> - * Don't allow merge of different write hints, or for a hint with
> - * non-hint IO.
> - */
> - if (req->write_hint != next->write_hint)
> - return NULL;
> -
> - if (req->ioprio != next->ioprio)
> + if (!blk_rq_merge_ok(req, next->bio))
> return NULL;
This looks sensible, but we might have to be a bit more careful.
rq_mergeable checks for RQF_NOMERGE_FLAGS and various ops, while
bio_mergeable is missing those. So I think you need to go through
carefully if we need to keep any extra checks, but otherwise using
blk_rq_merge_ok looks sensible.
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [PATCH] block: streamline merge possibility checks
2020-01-08 13:44 ` Christoph Hellwig
@ 2020-01-08 22:02 ` Dmitry Fomichev
2020-01-09 0:56 ` Bob Liu
0 siblings, 1 reply; 8+ messages in thread
From: Dmitry Fomichev @ 2020-01-08 22:02 UTC (permalink / raw)
To: Christoph Hellwig, Bob Liu; +Cc: linux-block, Jens Axboe, Damien Le Moal
> -----Original Message-----
> From: Christoph Hellwig <hch@infradead.org>
> Sent: Wednesday, January 8, 2020 8:45 AM
> To: Bob Liu <bob.liu@oracle.com>
> Cc: Dmitry Fomichev <Dmitry.Fomichev@wdc.com>; linux-
> block@vger.kernel.org; Jens Axboe <axboe@kernel.dk>; Damien Le Moal
> <Damien.LeMoal@wdc.com>
> Subject: Re: [PATCH] block: streamline merge possibility checks
>
> On Fri, Dec 20, 2019 at 02:50:05PM +0800, Bob Liu wrote:
> > On 12/19/19 3:41 AM, Dmitry Fomichev wrote:
> > > Checks for data direction in attempt_merge() and blk_rq_merge_ok()
> >
> > Speak about these two functions, do you think attempt_merge() can be
> built on blk_rq_merge_ok()?
> > Things like..
> > diff --git a/block/blk-merge.c b/block/blk-merge.c
> > index 48e6725..2a00c4c 100644
> > --- a/block/blk-merge.c
> > +++ b/block/blk-merge.c
> > @@ -724,28 +724,7 @@ static enum elv_merge blk_try_req_merge(struct
> request *req,
> > static struct request *attempt_merge(struct request_queue *q,
> > struct request *req, struct request *next)
> > {
> > - if (!rq_mergeable(req) || !rq_mergeable(next))
> > - return NULL;
> > -
> > - if (req_op(req) != req_op(next))
> > - return NULL;
> > -
> > - if (rq_data_dir(req) != rq_data_dir(next)
> > - || req->rq_disk != next->rq_disk)
> > - return NULL;
> > -
> > - if (req_op(req) == REQ_OP_WRITE_SAME &&
> > - !blk_write_same_mergeable(req->bio, next->bio))
> > - return NULL;
> > -
> > - /*
> > - * Don't allow merge of different write hints, or for a hint with
> > - * non-hint IO.
> > - */
> > - if (req->write_hint != next->write_hint)
> > - return NULL;
> > -
> > - if (req->ioprio != next->ioprio)
> > + if (!blk_rq_merge_ok(req, next->bio))
> > return NULL;
>
> This looks sensible, but we might have to be a bit more careful.
> rq_mergeable checks for RQF_NOMERGE_FLAGS and various ops, while
> bio_mergeable is missing those. So I think you need to go through
> carefully if we need to keep any extra checks, but otherwise using
> blk_rq_merge_ok looks sensible.
I tried this patch as is and, indeed, it leads to blktests failures and filesystem
errors, apparently because of the RQF_NOMERGE_FLAGS difference.
However, the patch below seems to work - I've been running my host system
with it for a couple of days with no issues. This one is added on top of
"block: streamline merge possibility checks" patch.
From: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Date: Wed, 8 Jan 2020 14:24:06 -0500
Subject: [PATCH] block: simplify merge checks
The code parts to decide on merge possibility in attempt_merge() and
blk_rq_merge_ok() look very similar. It is possible to move these
checks to a common inline helper function.
Suggested-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
---
block/blk-merge.c | 56 +++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 24 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index f68d67b367d6..49052a53051f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -732,6 +732,36 @@ static enum elv_merge blk_try_req_merge(struct request *req,
return ELEVATOR_NO_MERGE;
}
+static inline bool blk_rq_mergeable(struct request *rq, struct bio *bio)
+{
+ if (!rq_mergeable(rq))
+ return false;
+
+ if (req_op(rq) != bio_op(bio))
+ return false;
+
+ /* must be same device */
+ if (rq->rq_disk != bio->bi_disk)
+ return false;
+
+ /* must be using the same buffer */
+ if (req_op(rq) == REQ_OP_WRITE_SAME &&
+ !blk_write_same_mergeable(rq->bio, bio))
+ return false;
+
+ /*
+ * Don't allow merge of different write hints, or for a hint with
+ * non-hint IO.
+ */
+ if (rq->write_hint != bio->bi_write_hint)
+ return false;
+
+ if (rq->ioprio != bio_prio(bio))
+ return false;
+
+ return true;
+}
+
/*
* For non-mq, this has to be called with the request spinlock acquired.
* For mq with scheduling, the appropriate queue wide lock should be held.
@@ -739,7 +769,7 @@ static enum elv_merge blk_try_req_merge(struct request *req,
static struct request *attempt_merge(struct request_queue *q,
struct request *req, struct request *next)
{
- if (!blk_rq_merge_ok(req, next->bio))
+ if (!rq_mergeable(next) || !blk_rq_mergeable(req, next->bio))
return NULL;
/*
@@ -841,35 +871,13 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
{
- if (!rq_mergeable(rq) || !bio_mergeable(bio))
- return false;
-
- if (req_op(rq) != bio_op(bio))
- return false;
-
- /* must be same device */
- if (rq->rq_disk != bio->bi_disk)
+ if (!bio_mergeable(bio) || !blk_rq_mergeable(rq, bio))
return false;
/* only merge integrity protected bio into ditto rq */
if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
return false;
- /* must be using the same buffer */
- if (req_op(rq) == REQ_OP_WRITE_SAME &&
- !blk_write_same_mergeable(rq->bio, bio))
- return false;
-
- /*
- * Don't allow merge of different write hints, or for a hint with
- * non-hint IO.
- */
- if (rq->write_hint != bio->bi_write_hint)
- return false;
-
- if (rq->ioprio != bio_prio(bio))
- return false;
-
return true;
}
--
2.21.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] block: streamline merge possibility checks
2020-01-08 22:02 ` Dmitry Fomichev
@ 2020-01-09 0:56 ` Bob Liu
0 siblings, 0 replies; 8+ messages in thread
From: Bob Liu @ 2020-01-09 0:56 UTC (permalink / raw)
To: Dmitry Fomichev, Christoph Hellwig
Cc: linux-block, Jens Axboe, Damien Le Moal
On 1/9/20 6:02 AM, Dmitry Fomichev wrote:
>> -----Original Message-----
>> From: Christoph Hellwig <hch@infradead.org>
>> Sent: Wednesday, January 8, 2020 8:45 AM
>> To: Bob Liu <bob.liu@oracle.com>
>> Cc: Dmitry Fomichev <Dmitry.Fomichev@wdc.com>; linux-
>> block@vger.kernel.org; Jens Axboe <axboe@kernel.dk>; Damien Le Moal
>> <Damien.LeMoal@wdc.com>
>> Subject: Re: [PATCH] block: streamline merge possibility checks
>>
>> On Fri, Dec 20, 2019 at 02:50:05PM +0800, Bob Liu wrote:
>>> On 12/19/19 3:41 AM, Dmitry Fomichev wrote:
>>>> Checks for data direction in attempt_merge() and blk_rq_merge_ok()
>>>
>>> Speak about these two functions, do you think attempt_merge() can be
>> built on blk_rq_merge_ok()?
>>> Things like..
>>> diff --git a/block/blk-merge.c b/block/blk-merge.c
>>> index 48e6725..2a00c4c 100644
>>> --- a/block/blk-merge.c
>>> +++ b/block/blk-merge.c
>>> @@ -724,28 +724,7 @@ static enum elv_merge blk_try_req_merge(struct
>> request *req,
>>> static struct request *attempt_merge(struct request_queue *q,
>>> struct request *req, struct request *next)
>>> {
>>> - if (!rq_mergeable(req) || !rq_mergeable(next))
>>> - return NULL;
>>> -
>>> - if (req_op(req) != req_op(next))
>>> - return NULL;
>>> -
>>> - if (rq_data_dir(req) != rq_data_dir(next)
>>> - || req->rq_disk != next->rq_disk)
>>> - return NULL;
>>> -
>>> - if (req_op(req) == REQ_OP_WRITE_SAME &&
>>> - !blk_write_same_mergeable(req->bio, next->bio))
>>> - return NULL;
>>> -
>>> - /*
>>> - * Don't allow merge of different write hints, or for a hint with
>>> - * non-hint IO.
>>> - */
>>> - if (req->write_hint != next->write_hint)
>>> - return NULL;
>>> -
>>> - if (req->ioprio != next->ioprio)
>>> + if (!blk_rq_merge_ok(req, next->bio))
>>> return NULL;
>>
>> This looks sensible, but we might have to be a bit more careful.
>> rq_mergeable checks for RQF_NOMERGE_FLAGS and various ops, while
>> bio_mergeable is missing those. So I think you need to go through
>> carefully if we need to keep any extra checks, but otherwise using
>> blk_rq_merge_ok looks sensible.
>
> I tried this patch as is and, indeed, it leads to blktests failures and filesystem
> errors, apparently because of the RQF_NOMERGE_FLAGS difference.
> However, the patch below seems to work - I've been running my host system
> with it for a couple of days with no issues. This one is added on top of
> "block: streamline merge possibility checks" patch.
>
> From: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> Date: Wed, 8 Jan 2020 14:24:06 -0500
> Subject: [PATCH] block: simplify merge checks
>
> The code parts to decide on merge possibility in attempt_merge() and
> blk_rq_merge_ok() look very similar. It is possible to move these
> checks to a common inline helper function.
>
> Suggested-by: Bob Liu <bob.liu@oracle.com>
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> ---
> block/blk-merge.c | 56 +++++++++++++++++++++++++++--------------------
> 1 file changed, 32 insertions(+), 24 deletions(-)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index f68d67b367d6..49052a53051f 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -732,6 +732,36 @@ static enum elv_merge blk_try_req_merge(struct request *req,
> return ELEVATOR_NO_MERGE;
> }
>
> +static inline bool blk_rq_mergeable(struct request *rq, struct bio *bio)
> +{
> + if (!rq_mergeable(rq))
> + return false;
> +
> + if (req_op(rq) != bio_op(bio))
> + return false;
> +
> + /* must be same device */
> + if (rq->rq_disk != bio->bi_disk)
> + return false;
> +
> + /* must be using the same buffer */
> + if (req_op(rq) == REQ_OP_WRITE_SAME &&
> + !blk_write_same_mergeable(rq->bio, bio))
> + return false;
> +
> + /*
> + * Don't allow merge of different write hints, or for a hint with
> + * non-hint IO.
> + */
> + if (rq->write_hint != bio->bi_write_hint)
> + return false;
> +
> + if (rq->ioprio != bio_prio(bio))
> + return false;
> +
> + return true;
> +}
> +
> /*
> * For non-mq, this has to be called with the request spinlock acquired.
> * For mq with scheduling, the appropriate queue wide lock should be held.
> @@ -739,7 +769,7 @@ static enum elv_merge blk_try_req_merge(struct request *req,
> static struct request *attempt_merge(struct request_queue *q,
> struct request *req, struct request *next)
> {
> - if (!blk_rq_merge_ok(req, next->bio))
> + if (!rq_mergeable(next) || !blk_rq_mergeable(req, next->bio))
> return NULL;
>
> /*
> @@ -841,35 +871,13 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
>
> bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
> {
> - if (!rq_mergeable(rq) || !bio_mergeable(bio))
> - return false;
> -
> - if (req_op(rq) != bio_op(bio))
> - return false;
> -
> - /* must be same device */
> - if (rq->rq_disk != bio->bi_disk)
> + if (!bio_mergeable(bio) || !blk_rq_mergeable(rq, bio))
> return false;
>
Nitpick, I think bio_mergeable(bio) can also put inside blk_rq_mergeable().
Anyway, looks fine to me, thanks!
Reviewed-by: Bob Liu <bob.liu@oracle.com>
> /* only merge integrity protected bio into ditto rq */
> if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
> return false;
>
> - /* must be using the same buffer */
> - if (req_op(rq) == REQ_OP_WRITE_SAME &&
> - !blk_write_same_mergeable(rq->bio, bio))
> - return false;
> -
> - /*
> - * Don't allow merge of different write hints, or for a hint with
> - * non-hint IO.
> - */
> - if (rq->write_hint != bio->bi_write_hint)
> - return false;
> -
> - if (rq->ioprio != bio_prio(bio))
> - return false;
> -
> return true;
> }
>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-01-09 1:00 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-12-18 19:41 [PATCH] block: streamline merge possibility checks Dmitry Fomichev
2019-12-19 8:56 ` Bob Liu
2019-12-19 10:05 ` Damien Le Moal
2019-12-20 6:50 ` Bob Liu
2020-01-08 13:44 ` Christoph Hellwig
2020-01-08 22:02 ` Dmitry Fomichev
2020-01-09 0:56 ` Bob Liu
2020-01-08 13:41 ` Christoph Hellwig
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.