[dm-devel] [PATCH V3 04/13] block: create io poll context for submission and poll task
JeffleXu
jefflexu at linux.alibaba.com
Thu Mar 25 03:01:17 UTC 2021
On 3/25/21 10:51 AM, Ming Lei wrote:
> On Thu, Mar 25, 2021 at 10:34:02AM +0800, JeffleXu wrote:
>>
>>
>> On 3/24/21 8:19 PM, Ming Lei wrote:
>>> Create per-task io poll context for both IO submission and poll task
>>> if the queue is bio based and supports polling.
>>>
>>> This io polling context includes two queues:
>>>
>>> 1) submission queue(sq) for storing HIPRI bio, written by submission task
>>> and read by poll task.
>>> 2) polling queue(pq) for holding data moved from sq, only used in poll
>>> context for running bio polling.
>>>
>>> Following patches will support bio based io polling.
>>>
>>> Signed-off-by: Ming Lei <ming.lei at redhat.com>
>>> ---
>>> block/blk-core.c | 71 ++++++++++++++++++++++++++++++++-------
>>> block/blk-ioc.c | 1 +
>>> block/blk-mq.c | 14 ++++++++
>>> block/blk.h | 45 +++++++++++++++++++++++++
>>> include/linux/iocontext.h | 2 ++
>>> 5 files changed, 121 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/block/blk-core.c b/block/blk-core.c
>>> index d58f8a0c80de..4671bbf31fd3 100644
>>> --- a/block/blk-core.c
>>> +++ b/block/blk-core.c
>>> @@ -792,16 +792,59 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q,
>>> return BLK_STS_OK;
>>> }
>>>
>>> -static inline void blk_create_io_context(struct request_queue *q)
>>> +static inline struct blk_bio_poll_ctx *blk_get_bio_poll_ctx(void)
>>> {
>>> - /*
>>> - * Various block parts want %current->io_context, so allocate it up
>>> - * front rather than dealing with lots of pain to allocate it only
>>> - * where needed. This may fail and the block layer knows how to live
>>> - * with it.
>>> - */
>>> - if (unlikely(!current->io_context))
>>> - create_task_io_context(current, GFP_ATOMIC, q->node);
>>> + struct io_context *ioc = current->io_context;
>>> +
>>> + return ioc ? ioc->data : NULL;
>>> +}
>>> +
>>> +static inline unsigned int bio_grp_list_size(unsigned int nr_grps)
>>> +{
>>> + return sizeof(struct bio_grp_list) + nr_grps *
>>> + sizeof(struct bio_grp_list_data);
>>> +}
>>> +
>>> +static void bio_poll_ctx_init(struct blk_bio_poll_ctx *pc)
>>> +{
>>> + pc->sq = (void *)pc + sizeof(*pc);
>>> + pc->sq->max_nr_grps = BLK_BIO_POLL_SQ_SZ;
>>> +
>>> + pc->pq = (void *)pc->sq + bio_grp_list_size(BLK_BIO_POLL_SQ_SZ);
>>> + pc->pq->max_nr_grps = BLK_BIO_POLL_PQ_SZ;
>>> +
>>> + spin_lock_init(&pc->sq_lock);
>>> + spin_lock_init(&pc->pq_lock);
>>> +}
>>> +
>>> +void bio_poll_ctx_alloc(struct io_context *ioc)
>>> +{
>>> + struct blk_bio_poll_ctx *pc;
>>> + unsigned int size = sizeof(*pc) +
>>> + bio_grp_list_size(BLK_BIO_POLL_SQ_SZ) +
>>> + bio_grp_list_size(BLK_BIO_POLL_PQ_SZ);
>>> +
>>> + pc = kzalloc(GFP_ATOMIC, size);
>>> + if (pc) {
>>> + bio_poll_ctx_init(pc);
>>> + if (cmpxchg(&ioc->data, NULL, (void *)pc))
>>> + kfree(pc);
>>> + }
>>
>> Why don't put these in blk-ioc.c?
>
> It is for implementing bio polling, not necessary for moving it to
> blk-ioc.c.
>
>>
>>
>>> +}
>>> +
>>> +static inline bool blk_queue_support_bio_poll(struct request_queue *q)
>>> +{
>>> + return !queue_is_mq(q) && blk_queue_poll(q);
>>> +}
>>> +
>>> +static inline void blk_bio_poll_preprocess(struct request_queue *q,
>>> + struct bio *bio)
>>> +{
>>> + if (!(bio->bi_opf & REQ_HIPRI))
>>> + return;
>>> +
>>> + if (!blk_queue_poll(q) || (!queue_is_mq(q) && !blk_get_bio_poll_ctx()))
>>> + bio->bi_opf &= ~REQ_HIPRI;
>>> }
>>>
>>> static noinline_for_stack bool submit_bio_checks(struct bio *bio)
>>> @@ -848,10 +891,14 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
>>> }
>>> }
>>>
>>> - blk_create_io_context(q);
>>> + /*
>>> + * Create per-task io poll ctx if bio polling supported and HIPRI
>>> + * set.
>>> + */
>>> + blk_create_io_context(q, blk_queue_support_bio_poll(q) &&
>>> + (bio->bi_opf & REQ_HIPRI));
>>>
>>> - if (!blk_queue_poll(q))
>>> - bio->bi_opf &= ~REQ_HIPRI;
>>> + blk_bio_poll_preprocess(q, bio);
>>>
>>> switch (bio_op(bio)) {
>>> case REQ_OP_DISCARD:
>>> diff --git a/block/blk-ioc.c b/block/blk-ioc.c
>>> index b0cde18c4b8c..5574c398eff6 100644
>>> --- a/block/blk-ioc.c
>>> +++ b/block/blk-ioc.c
>>> @@ -19,6 +19,7 @@ static struct kmem_cache *iocontext_cachep;
>>>
>>> static inline void free_io_context(struct io_context *ioc)
>>> {
>>> + kfree(ioc->data);
>>> kmem_cache_free(iocontext_cachep, ioc);
>>> }
>>>
>>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>>> index 63c81df3b8b5..c832faa52ca0 100644
>>> --- a/block/blk-mq.c
>>> +++ b/block/blk-mq.c
>>> @@ -3852,6 +3852,17 @@ static bool blk_mq_poll_hybrid(struct request_queue *q,
>>> return blk_mq_poll_hybrid_sleep(q, rq);
>>> }
>>>
>>> +static int blk_bio_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
>>> +{
>>> + /*
>>> + * Create poll queue for storing poll bio and its cookie from
>>> + * submission queue
>>> + */
>>> + blk_create_io_context(q, true);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> /**
>>> * blk_poll - poll for IO completions
>>> * @q: the queue
>>> @@ -3875,6 +3886,9 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
>>> if (current->plug)
>>> blk_flush_plug_list(current->plug, false);
>>>
>>> + if (!queue_is_mq(q))
>>> + return blk_bio_poll(q, cookie, spin);
>>> +
>>> hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
>>>
>>> /*
>>> diff --git a/block/blk.h b/block/blk.h
>>> index 3b53e44b967e..424949f2226d 100644
>>> --- a/block/blk.h
>>> +++ b/block/blk.h
>>> @@ -357,4 +357,49 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
>>> struct page *page, unsigned int len, unsigned int offset,
>>> unsigned int max_sectors, bool *same_page);
>>>
>>> +/* Grouping bios that share same data into one list */
>>> +struct bio_grp_list_data {
>>> + void *grp_data;
>>> +
>>> + /* all bios in this list share same 'grp_data' */
>>> + struct bio_list list;
>>> +};
>>> +
>>> +struct bio_grp_list {
>>> + unsigned int max_nr_grps, nr_grps;
>>> + struct bio_grp_list_data head[0];
>>> +};
>>> +
>>> +struct blk_bio_poll_ctx {
>>> + spinlock_t sq_lock;
>>> + struct bio_grp_list *sq;
>>> +
>>> + spinlock_t pq_lock;
>>> + struct bio_grp_list *pq;
>>> +};
>>> +
>>> +#define BLK_BIO_POLL_SQ_SZ 16U
>>> +#define BLK_BIO_POLL_PQ_SZ (BLK_BIO_POLL_SQ_SZ * 2)
>>
>> And these in iocontext.h?
>
> All are internal definition for bio polling, not necessary to put
> it into one public header.
>
Thanks. I missed that blk.h is a private header.
Reviewed-by: Jeffle Xu <jefflexu at linux.alibaba.com>
--
Thanks,
Jeffle
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