[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 02:34:02 UTC 2021
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?
> +}
> +
> +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?
> +
> +void bio_poll_ctx_alloc(struct io_context *ioc);
> +
> +static inline void blk_create_io_context(struct request_queue *q,
> + bool need_poll_ctx)
> +{
> + struct io_context *ioc;
> +
> + /*
> + * 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);
> +
> + ioc = current->io_context;
> + if (need_poll_ctx && unlikely(ioc && !ioc->data))
> + bio_poll_ctx_alloc(ioc);
> +}
> +
> #endif /* BLK_INTERNAL_H */
> diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
> index 0a9dc40b7be8..f9a467571356 100644
> --- a/include/linux/iocontext.h
> +++ b/include/linux/iocontext.h
> @@ -110,6 +110,8 @@ struct io_context {
> struct io_cq __rcu *icq_hint;
> struct hlist_head icq_list;
>
> + void *data;
> +
> struct work_struct release_work;
> };
>
>
--
Thanks,
Jeffle
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