[dm-devel] [RFC PATCH V2 04/13] block: create io poll context for submission and poll task
Ming Lei
ming.lei at redhat.com
Thu Mar 18 16:48:18 UTC 2021
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: submission queue(sq) for
storing HIPRI bio submission result(cookie) and the bio, written
by submission task and read by poll task; polling queue(pq) for holding
data moved from sq, only used in poll context for running bio polling.
Following patches will support bio poll.
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 | 46 +++++++++++++++++++++++++
include/linux/iocontext.h | 2 ++
5 files changed, 122 insertions(+), 12 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index d58f8a0c80de..0b00c21cbefb 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);
+ mutex_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);
+ }
+}
+
+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);
+ /*
+ * Created per-task io poll queue if we supports bio polling
+ * and it is one HIPRI bio.
+ */
+ 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..ae58a706327e 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -357,4 +357,50 @@ 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 belonging to same group into one list */
+struct bio_grp_list_data {
+ /* group 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;
+
+ struct mutex pq_lock;
+ struct bio_grp_list *pq;
+};
+
+#define BLK_BIO_POLL_SQ_SZ 32U
+#define BLK_BIO_POLL_PQ_SZ (BLK_BIO_POLL_SQ_SZ * 2)
+
+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;
};
--
2.29.2
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