| Message ID | 1476388433-2539-2-git-send-email-adam.manzanares@hgst.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares <adam.manzanares@hgst.com> wrote: > Patch adds an association between iocontext ioprio and the ioprio of a > request. This value is set in blk_rq_set_prio which takes the request and > the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the > iopriority of the request is set as the iopriority of the ioc. In > init_request_from_bio a check is made to see if the ioprio of the bio is > valid and if so then the request prio comes from the bio. > > Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> > --- > block/blk-core.c | 4 +++- > include/linux/blkdev.h | 14 ++++++++++++++ > 2 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 14d7c07..361b1b9 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, > > blk_rq_init(q, rq); > blk_rq_set_rl(rq, rl); > + blk_rq_set_prio(rq, ioc); > req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); > > /* init elvpriv */ > @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) > > req->errors = 0; > req->__sector = bio->bi_iter.bi_sector; > - req->ioprio = bio_prio(bio); > + if (ioprio_valid(bio_prio(bio))) > + req->ioprio = bio_prio(bio); Should we use ioprio_best() here? If req->ioprio and bio_prio() disagree one side has explicitly asked for a higher priority. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/13/2016 02:06 PM, Dan Williams wrote: > On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares > <adam.manzanares@hgst.com> wrote: >> Patch adds an association between iocontext ioprio and the ioprio of a >> request. This value is set in blk_rq_set_prio which takes the request and >> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >> iopriority of the request is set as the iopriority of the ioc. In >> init_request_from_bio a check is made to see if the ioprio of the bio is >> valid and if so then the request prio comes from the bio. >> >> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> >> --- >> block/blk-core.c | 4 +++- >> include/linux/blkdev.h | 14 ++++++++++++++ >> 2 files changed, 17 insertions(+), 1 deletion(-) >> >> diff --git a/block/blk-core.c b/block/blk-core.c >> index 14d7c07..361b1b9 100644 >> --- a/block/blk-core.c >> +++ b/block/blk-core.c >> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, >> >> blk_rq_init(q, rq); >> blk_rq_set_rl(rq, rl); >> + blk_rq_set_prio(rq, ioc); >> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >> >> /* init elvpriv */ >> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) >> >> req->errors = 0; >> req->__sector = bio->bi_iter.bi_sector; >> - req->ioprio = bio_prio(bio); >> + if (ioprio_valid(bio_prio(bio))) >> + req->ioprio = bio_prio(bio); > > Should we use ioprio_best() here? If req->ioprio and bio_prio() > disagree one side has explicitly asked for a higher priority. It's a good question - but if priority has been set in the bio, it makes sense that that would take priority over the general setting for the task/io context. So I think the patch is correct as-is. Adam, you'll want to rewrite the commit message though. A good commit message should explain WHY the change is made, not detail the code implementation of it.
On Thu, Oct 13, 2016 at 1:09 PM, Jens Axboe <axboe@kernel.dk> wrote: > On 10/13/2016 02:06 PM, Dan Williams wrote: >> >> On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares >> <adam.manzanares@hgst.com> wrote: >>> >>> Patch adds an association between iocontext ioprio and the ioprio of a >>> request. This value is set in blk_rq_set_prio which takes the request and >>> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >>> iopriority of the request is set as the iopriority of the ioc. In >>> init_request_from_bio a check is made to see if the ioprio of the bio is >>> valid and if so then the request prio comes from the bio. >>> >>> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> >>> --- >>> block/blk-core.c | 4 +++- >>> include/linux/blkdev.h | 14 ++++++++++++++ >>> 2 files changed, 17 insertions(+), 1 deletion(-) >>> >>> diff --git a/block/blk-core.c b/block/blk-core.c >>> index 14d7c07..361b1b9 100644 >>> --- a/block/blk-core.c >>> +++ b/block/blk-core.c >>> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct >>> request_list *rl, int op, >>> >>> blk_rq_init(q, rq); >>> blk_rq_set_rl(rq, rl); >>> + blk_rq_set_prio(rq, ioc); >>> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >>> >>> /* init elvpriv */ >>> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, >>> struct bio *bio) >>> >>> req->errors = 0; >>> req->__sector = bio->bi_iter.bi_sector; >>> - req->ioprio = bio_prio(bio); >>> + if (ioprio_valid(bio_prio(bio))) >>> + req->ioprio = bio_prio(bio); >> >> >> Should we use ioprio_best() here? If req->ioprio and bio_prio() >> disagree one side has explicitly asked for a higher priority. > > > It's a good question - but if priority has been set in the bio, it makes > sense that that would take priority over the general setting for the > task/io context. So I think the patch is correct as-is. Assuming you always trust the kernel to know the right priority... -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/13/2016 02:19 PM, Dan Williams wrote: > On Thu, Oct 13, 2016 at 1:09 PM, Jens Axboe <axboe@kernel.dk> wrote: >> On 10/13/2016 02:06 PM, Dan Williams wrote: >>> >>> On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares >>> <adam.manzanares@hgst.com> wrote: >>>> >>>> Patch adds an association between iocontext ioprio and the ioprio of a >>>> request. This value is set in blk_rq_set_prio which takes the request and >>>> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >>>> iopriority of the request is set as the iopriority of the ioc. In >>>> init_request_from_bio a check is made to see if the ioprio of the bio is >>>> valid and if so then the request prio comes from the bio. >>>> >>>> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> >>>> --- >>>> block/blk-core.c | 4 +++- >>>> include/linux/blkdev.h | 14 ++++++++++++++ >>>> 2 files changed, 17 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/block/blk-core.c b/block/blk-core.c >>>> index 14d7c07..361b1b9 100644 >>>> --- a/block/blk-core.c >>>> +++ b/block/blk-core.c >>>> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct >>>> request_list *rl, int op, >>>> >>>> blk_rq_init(q, rq); >>>> blk_rq_set_rl(rq, rl); >>>> + blk_rq_set_prio(rq, ioc); >>>> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >>>> >>>> /* init elvpriv */ >>>> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, >>>> struct bio *bio) >>>> >>>> req->errors = 0; >>>> req->__sector = bio->bi_iter.bi_sector; >>>> - req->ioprio = bio_prio(bio); >>>> + if (ioprio_valid(bio_prio(bio))) >>>> + req->ioprio = bio_prio(bio); >>> >>> >>> Should we use ioprio_best() here? If req->ioprio and bio_prio() >>> disagree one side has explicitly asked for a higher priority. >> >> >> It's a good question - but if priority has been set in the bio, it makes >> sense that that would take priority over the general setting for the >> task/io context. So I think the patch is correct as-is. > > Assuming you always trust the kernel to know the right priority... If it set it in the bio, it better know what it's doing. Besides, there's nothing stopping the caller from checking the task priority when it sets it. If we do ioprio_best(), then we are effectively preventing anyone from submitting a bio with a lower priority than the task has generally set. Now, this depends on the priority being set in req->ioprio is exclusively inherited from ioc->ioprio. That's the case for file system requests, but if someone allocated a request and set the priority otherwise, then ioprio_best() would be correct.
On Thu, Oct 13, 2016 at 1:24 PM, Jens Axboe <axboe@kernel.dk> wrote: > On 10/13/2016 02:19 PM, Dan Williams wrote: >> >> On Thu, Oct 13, 2016 at 1:09 PM, Jens Axboe <axboe@kernel.dk> wrote: >>> >>> On 10/13/2016 02:06 PM, Dan Williams wrote: >>>> >>>> >>>> On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares >>>> <adam.manzanares@hgst.com> wrote: >>>>> >>>>> >>>>> Patch adds an association between iocontext ioprio and the ioprio of a >>>>> request. This value is set in blk_rq_set_prio which takes the request >>>>> and >>>>> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >>>>> iopriority of the request is set as the iopriority of the ioc. In >>>>> init_request_from_bio a check is made to see if the ioprio of the bio >>>>> is >>>>> valid and if so then the request prio comes from the bio. >>>>> >>>>> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> >>>>> --- >>>>> block/blk-core.c | 4 +++- >>>>> include/linux/blkdev.h | 14 ++++++++++++++ >>>>> 2 files changed, 17 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/block/blk-core.c b/block/blk-core.c >>>>> index 14d7c07..361b1b9 100644 >>>>> --- a/block/blk-core.c >>>>> +++ b/block/blk-core.c >>>>> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct >>>>> request_list *rl, int op, >>>>> >>>>> blk_rq_init(q, rq); >>>>> blk_rq_set_rl(rq, rl); >>>>> + blk_rq_set_prio(rq, ioc); >>>>> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >>>>> >>>>> /* init elvpriv */ >>>>> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, >>>>> struct bio *bio) >>>>> >>>>> req->errors = 0; >>>>> req->__sector = bio->bi_iter.bi_sector; >>>>> - req->ioprio = bio_prio(bio); >>>>> + if (ioprio_valid(bio_prio(bio))) >>>>> + req->ioprio = bio_prio(bio); >>>> >>>> >>>> >>>> Should we use ioprio_best() here? If req->ioprio and bio_prio() >>>> disagree one side has explicitly asked for a higher priority. >>> >>> >>> >>> It's a good question - but if priority has been set in the bio, it makes >>> sense that that would take priority over the general setting for the >>> task/io context. So I think the patch is correct as-is. >> >> >> Assuming you always trust the kernel to know the right priority... > > > If it set it in the bio, it better know what it's doing. Besides, > there's nothing stopping the caller from checking the task priority when > it sets it. If we do ioprio_best(), then we are effectively preventing > anyone from submitting a bio with a lower priority than the task has > generally set. Ah, that makes sense. Move the ioprio_best() decision out to whatever code is setting bio_prio() to allow for cases where the kernel knows best. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/13/2016 02:59 PM, Dan Williams wrote: > On Thu, Oct 13, 2016 at 1:24 PM, Jens Axboe <axboe@kernel.dk> wrote: >> On 10/13/2016 02:19 PM, Dan Williams wrote: >>> >>> On Thu, Oct 13, 2016 at 1:09 PM, Jens Axboe <axboe@kernel.dk> wrote: >>>> >>>> On 10/13/2016 02:06 PM, Dan Williams wrote: >>>>> >>>>> >>>>> On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares >>>>> <adam.manzanares@hgst.com> wrote: >>>>>> >>>>>> >>>>>> Patch adds an association between iocontext ioprio and the ioprio of a >>>>>> request. This value is set in blk_rq_set_prio which takes the request >>>>>> and >>>>>> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >>>>>> iopriority of the request is set as the iopriority of the ioc. In >>>>>> init_request_from_bio a check is made to see if the ioprio of the bio >>>>>> is >>>>>> valid and if so then the request prio comes from the bio. >>>>>> >>>>>> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> >>>>>> --- >>>>>> block/blk-core.c | 4 +++- >>>>>> include/linux/blkdev.h | 14 ++++++++++++++ >>>>>> 2 files changed, 17 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/block/blk-core.c b/block/blk-core.c >>>>>> index 14d7c07..361b1b9 100644 >>>>>> --- a/block/blk-core.c >>>>>> +++ b/block/blk-core.c >>>>>> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct >>>>>> request_list *rl, int op, >>>>>> >>>>>> blk_rq_init(q, rq); >>>>>> blk_rq_set_rl(rq, rl); >>>>>> + blk_rq_set_prio(rq, ioc); >>>>>> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >>>>>> >>>>>> /* init elvpriv */ >>>>>> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, >>>>>> struct bio *bio) >>>>>> >>>>>> req->errors = 0; >>>>>> req->__sector = bio->bi_iter.bi_sector; >>>>>> - req->ioprio = bio_prio(bio); >>>>>> + if (ioprio_valid(bio_prio(bio))) >>>>>> + req->ioprio = bio_prio(bio); >>>>> >>>>> >>>>> >>>>> Should we use ioprio_best() here? If req->ioprio and bio_prio() >>>>> disagree one side has explicitly asked for a higher priority. >>>> >>>> >>>> >>>> It's a good question - but if priority has been set in the bio, it makes >>>> sense that that would take priority over the general setting for the >>>> task/io context. So I think the patch is correct as-is. >>> >>> >>> Assuming you always trust the kernel to know the right priority... >> >> >> If it set it in the bio, it better know what it's doing. Besides, >> there's nothing stopping the caller from checking the task priority when >> it sets it. If we do ioprio_best(), then we are effectively preventing >> anyone from submitting a bio with a lower priority than the task has >> generally set. > > Ah, that makes sense. Move the ioprio_best() decision out to whatever > code is setting bio_prio() to allow for cases where the kernel knows > best. Yes, precisely.
The 10/13/2016 14:09, Jens Axboe wrote: > On 10/13/2016 02:06 PM, Dan Williams wrote: > >On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares > ><adam.manzanares@hgst.com> wrote: > >>Patch adds an association between iocontext ioprio and the ioprio of a > >>request. This value is set in blk_rq_set_prio which takes the request and > >>the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the > >>iopriority of the request is set as the iopriority of the ioc. In > >>init_request_from_bio a check is made to see if the ioprio of the bio is > >>valid and if so then the request prio comes from the bio. > >> > >>Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> > >>--- > >> block/blk-core.c | 4 +++- > >> include/linux/blkdev.h | 14 ++++++++++++++ > >> 2 files changed, 17 insertions(+), 1 deletion(-) > >> > >>diff --git a/block/blk-core.c b/block/blk-core.c > >>index 14d7c07..361b1b9 100644 > >>--- a/block/blk-core.c > >>+++ b/block/blk-core.c > >>@@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, > >> > >> blk_rq_init(q, rq); > >> blk_rq_set_rl(rq, rl); > >>+ blk_rq_set_prio(rq, ioc); > >> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); > >> > >> /* init elvpriv */ > >>@@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) > >> > >> req->errors = 0; > >> req->__sector = bio->bi_iter.bi_sector; > >>- req->ioprio = bio_prio(bio); > >>+ if (ioprio_valid(bio_prio(bio))) > >>+ req->ioprio = bio_prio(bio); > > > >Should we use ioprio_best() here? If req->ioprio and bio_prio() > >disagree one side has explicitly asked for a higher priority. > > It's a good question - but if priority has been set in the bio, it makes > sense that that would take priority over the general setting for the > task/io context. So I think the patch is correct as-is. > > Adam, you'll want to rewrite the commit message though. A good commit > message should explain WHY the change is made, not detail the code > implementation of it. Got it I'll send something out soon. > > -- > Jens Axboe > Take care, Adam -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/13/2016 09:53 PM, Adam Manzanares wrote: > Patch adds an association between iocontext ioprio and the ioprio of a > request. This value is set in blk_rq_set_prio which takes the request and > the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the > iopriority of the request is set as the iopriority of the ioc. In > init_request_from_bio a check is made to see if the ioprio of the bio is > valid and if so then the request prio comes from the bio. > > Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> > --- > block/blk-core.c | 4 +++- > include/linux/blkdev.h | 14 ++++++++++++++ > 2 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 14d7c07..361b1b9 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, > > blk_rq_init(q, rq); > blk_rq_set_rl(rq, rl); > + blk_rq_set_prio(rq, ioc); > req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); > > /* init elvpriv */ > @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) > > req->errors = 0; > req->__sector = bio->bi_iter.bi_sector; > - req->ioprio = bio_prio(bio); > + if (ioprio_valid(bio_prio(bio))) > + req->ioprio = bio_prio(bio); > blk_rq_bio_prep(req->q, req, bio); > } > > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index c47c358..9a0ceaa 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -934,6 +934,20 @@ static inline unsigned int blk_rq_count_bios(struct request *rq) > } > > /* > + * blk_rq_set_prio - associate a request with prio from ioc > + * @rq: request of interest > + * @ioc: target iocontext > + * > + * Assocate request prio with ioc prio so request based drivers > + * can leverage priority information. > + */ > +static inline void blk_rq_set_prio(struct request *rq, struct io_context *ioc) > +{ > + if (ioc) > + rq->ioprio = ioc->ioprio; > +} > + > +/* > * Request issue related functions. > */ > extern struct request *blk_peek_request(struct request_queue *q); > Don't you need to check for 'ioprio_valid()' here, too? Cheers, Hannes
The 10/14/2016 07:54, Hannes Reinecke wrote: > On 10/13/2016 09:53 PM, Adam Manzanares wrote: > > Patch adds an association between iocontext ioprio and the ioprio of a > > request. This value is set in blk_rq_set_prio which takes the request and > > the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the > > iopriority of the request is set as the iopriority of the ioc. In > > init_request_from_bio a check is made to see if the ioprio of the bio is > > valid and if so then the request prio comes from the bio. > > > > Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> > > --- > > block/blk-core.c | 4 +++- > > include/linux/blkdev.h | 14 ++++++++++++++ > > 2 files changed, 17 insertions(+), 1 deletion(-) > > > > diff --git a/block/blk-core.c b/block/blk-core.c > > index 14d7c07..361b1b9 100644 > > --- a/block/blk-core.c > > +++ b/block/blk-core.c > > @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, > > > > blk_rq_init(q, rq); > > blk_rq_set_rl(rq, rl); > > + blk_rq_set_prio(rq, ioc); > > req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); > > > > /* init elvpriv */ > > @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) > > > > req->errors = 0; > > req->__sector = bio->bi_iter.bi_sector; > > - req->ioprio = bio_prio(bio); > > + if (ioprio_valid(bio_prio(bio))) > > + req->ioprio = bio_prio(bio); > > blk_rq_bio_prep(req->q, req, bio); > > } > > > > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > > index c47c358..9a0ceaa 100644 > > --- a/include/linux/blkdev.h > > +++ b/include/linux/blkdev.h > > @@ -934,6 +934,20 @@ static inline unsigned int blk_rq_count_bios(struct request *rq) > > } > > > > /* > > + * blk_rq_set_prio - associate a request with prio from ioc > > + * @rq: request of interest > > + * @ioc: target iocontext > > + * > > + * Assocate request prio with ioc prio so request based drivers > > + * can leverage priority information. > > + */ > > +static inline void blk_rq_set_prio(struct request *rq, struct io_context *ioc) > > +{ > > + if (ioc) > > + rq->ioprio = ioc->ioprio; > > +} > > + > > +/* > > * Request issue related functions. > > */ > > extern struct request *blk_peek_request(struct request_queue *q); > > > Don't you need to check for 'ioprio_valid()' here, too? I poked around and it should be safe to not check for ioprio valid at this point. ioprio_valid only checks to see if the ioprio is not IOPRIO_CLASS_NONE. The request by default has a ioprio of none so if the ioc has ioprio of none we are not changing anything. The locations in the code that I found where the ioc prio is set are either filtered through the syscall handler, which checks for invalid priority combinations, or have valid priority values. Take care, Adam > > Cheers, > > Hannes > -- > Dr. Hannes Reinecke Teamlead Storage & Networking > hare@suse.de +49 911 74053 688 > SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg > GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton > HRB 21284 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/14/2016 08:35 PM, Adam Manzananares wrote: > The 10/14/2016 07:54, Hannes Reinecke wrote: >> On 10/13/2016 09:53 PM, Adam Manzanares wrote: >>> Patch adds an association between iocontext ioprio and the ioprio of a >>> request. This value is set in blk_rq_set_prio which takes the request and >>> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >>> iopriority of the request is set as the iopriority of the ioc. In >>> init_request_from_bio a check is made to see if the ioprio of the bio is >>> valid and if so then the request prio comes from the bio. >>> >>> Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> >>> --- >>> block/blk-core.c | 4 +++- >>> include/linux/blkdev.h | 14 ++++++++++++++ >>> 2 files changed, 17 insertions(+), 1 deletion(-) >>> >>> diff --git a/block/blk-core.c b/block/blk-core.c >>> index 14d7c07..361b1b9 100644 >>> --- a/block/blk-core.c >>> +++ b/block/blk-core.c >>> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, >>> >>> blk_rq_init(q, rq); >>> blk_rq_set_rl(rq, rl); >>> + blk_rq_set_prio(rq, ioc); >>> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >>> >>> /* init elvpriv */ >>> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) >>> >>> req->errors = 0; >>> req->__sector = bio->bi_iter.bi_sector; >>> - req->ioprio = bio_prio(bio); >>> + if (ioprio_valid(bio_prio(bio))) >>> + req->ioprio = bio_prio(bio); >>> blk_rq_bio_prep(req->q, req, bio); >>> } >>> >>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >>> index c47c358..9a0ceaa 100644 >>> --- a/include/linux/blkdev.h >>> +++ b/include/linux/blkdev.h >>> @@ -934,6 +934,20 @@ static inline unsigned int blk_rq_count_bios(struct request *rq) >>> } >>> >>> /* >>> + * blk_rq_set_prio - associate a request with prio from ioc >>> + * @rq: request of interest >>> + * @ioc: target iocontext >>> + * >>> + * Assocate request prio with ioc prio so request based drivers >>> + * can leverage priority information. >>> + */ >>> +static inline void blk_rq_set_prio(struct request *rq, struct io_context *ioc) >>> +{ >>> + if (ioc) >>> + rq->ioprio = ioc->ioprio; >>> +} >>> + >>> +/* >>> * Request issue related functions. >>> */ >>> extern struct request *blk_peek_request(struct request_queue *q); >>> >> Don't you need to check for 'ioprio_valid()' here, too? > > I poked around and it should be safe to not check for ioprio valid > at this point. ioprio_valid only checks to see if the ioprio is > not IOPRIO_CLASS_NONE. The request by default has a ioprio of none > so if the ioc has ioprio of none we are not changing anything. > > The locations in the code that I found where the ioc prio is set are > either filtered through the syscall handler, which checks for invalid > priority combinations, or have valid priority values. > Thanks for the confirmation, that'll clarifies things. Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
diff --git a/block/blk-core.c b/block/blk-core.c index 14d7c07..361b1b9 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, blk_rq_init(q, rq); blk_rq_set_rl(rq, rl); + blk_rq_set_prio(rq, ioc); req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); /* init elvpriv */ @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) req->errors = 0; req->__sector = bio->bi_iter.bi_sector; - req->ioprio = bio_prio(bio); + if (ioprio_valid(bio_prio(bio))) + req->ioprio = bio_prio(bio); blk_rq_bio_prep(req->q, req, bio); } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index c47c358..9a0ceaa 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -934,6 +934,20 @@ static inline unsigned int blk_rq_count_bios(struct request *rq) } /* + * blk_rq_set_prio - associate a request with prio from ioc + * @rq: request of interest + * @ioc: target iocontext + * + * Assocate request prio with ioc prio so request based drivers + * can leverage priority information. + */ +static inline void blk_rq_set_prio(struct request *rq, struct io_context *ioc) +{ + if (ioc) + rq->ioprio = ioc->ioprio; +} + +/* * Request issue related functions. */ extern struct request *blk_peek_request(struct request_queue *q);
Patch adds an association between iocontext ioprio and the ioprio of a request. This value is set in blk_rq_set_prio which takes the request and the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the iopriority of the request is set as the iopriority of the ioc. In init_request_from_bio a check is made to see if the ioprio of the bio is valid and if so then the request prio comes from the bio. Signed-off-by: Adam Manzananares <adam.manzanares@wdc.com> --- block/blk-core.c | 4 +++- include/linux/blkdev.h | 14 ++++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-)