[PATCH v5 08/10] block: flush: avoid to figure out flush queue unnecessarily

Ming Lei
2014-09-25T15:24:41Z

Just figuring out flush queue at the entry of kicking off flush
machinery and request's completion handler, then pass it through.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
block/blk-flush.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/block/blk-flush.c b/block/blk-flush.c
index d66cbf2..9bc5b4f 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -91,7 +91,8 @@ enum {
FLUSH_PENDING_TIMEOUT = 5 * HZ,
};

-static bool blk_kick_flush(struct request_queue *q);
+static bool blk_kick_flush(struct request_queue *q,
+ struct blk_flush_queue *fq);

static unsigned int blk_flush_policy(unsigned int fflags, struct request *rq)
{
@@ -148,6 +149,7 @@ static bool blk_flush_queue_rq(struct request *rq, bool add_front)
/**
* blk_flush_complete_seq - complete flush sequence
* @rq: FLUSH/FUA request being sequenced
+ * @fq: flush queue
* @seq: sequences to complete (mask of %REQ_FSEQ_*, can be zero)
* @error: whether an error occurred
*
@@ -160,11 +162,11 @@ static bool blk_flush_queue_rq(struct request *rq, bool add_front)
* RETURNS:
* %true if requests were added to the dispatch queue, %false otherwise.
*/
-static bool blk_flush_complete_seq(struct request *rq, unsigned int seq,
- int error)
+static bool blk_flush_complete_seq(struct request *rq,
+ struct blk_flush_queue *fq,
+ unsigned int seq, int error)
{
struct request_queue *q = rq->q;
- struct blk_flush_queue *fq = blk_get_flush_queue(q);
struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx];
bool queued = false, kicked;

@@ -210,7 +212,7 @@ static bool blk_flush_complete_seq(struct request *rq, unsigned int seq,
BUG();
}

- kicked = blk_kick_flush(q);
+ kicked = blk_kick_flush(q, fq);
return kicked | queued;
}

@@ -242,7 +244,7 @@ static void flush_end_io(struct request *flush_rq, int error)
unsigned int seq = blk_flush_cur_seq(rq);

BUG_ON(seq != REQ_FSEQ_PREFLUSH && seq != REQ_FSEQ_POSTFLUSH);
- queued |= blk_flush_complete_seq(rq, seq, error);
+ queued |= blk_flush_complete_seq(rq, fq, seq, error);
}

/*
@@ -268,6 +270,7 @@ static void flush_end_io(struct request *flush_rq, int error)
/**
* blk_kick_flush - consider issuing flush request
* @q: request_queue being kicked
+ * @fq: flush queue
*
* Flush related states of @q have changed, consider issuing flush request.
* Please read the comment at the top of this file for more info.
@@ -278,9 +281,8 @@ static void flush_end_io(struct request *flush_rq, int error)
* RETURNS:
* %true if flush was issued, %false otherwise.
*/
-static bool blk_kick_flush(struct request_queue *q)
+static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq)
{
- struct blk_flush_queue *fq = blk_get_flush_queue(q);
struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx];
struct request *first_rq =
list_first_entry(pending, struct request, flush.list);
@@ -317,12 +319,13 @@ static bool blk_kick_flush(struct request_queue *q)
static void flush_data_end_io(struct request *rq, int error)
{
struct request_queue *q = rq->q;
+ struct blk_flush_queue *fq = blk_get_flush_queue(q);

/*
* After populating an empty queue, kick it to avoid stall. Read
* the comment in flush_end_io().
*/
- if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error))
+ if (blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error))
blk_run_queue_async(q);
}

@@ -342,7 +345,7 @@ static void mq_flush_data_end_io(struct request *rq, int error)
* the comment in flush_end_io().
*/
spin_lock_irqsave(&fq->mq_flush_lock, flags);
- if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error))
+ if (blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error))
blk_mq_run_hw_queue(hctx, true);
spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
}
@@ -364,6 +367,7 @@ void blk_insert_flush(struct request *rq)
struct request_queue *q = rq->q;
unsigned int fflags = q->flush_flags; /* may change, cache */
unsigned int policy = blk_flush_policy(fflags, rq);
+ struct blk_flush_queue *fq = blk_get_flush_queue(q);

/*
* @policy now records what operations need to be done. Adjust
@@ -412,18 +416,16 @@ void blk_insert_flush(struct request *rq)
rq->cmd_flags |= REQ_FLUSH_SEQ;
rq->flush.saved_end_io = rq->end_io; /* Usually NULL */
if (q->mq_ops) {
- struct blk_flush_queue *fq = blk_get_flush_queue(q);
-
rq->end_io = mq_flush_data_end_io;

spin_lock_irq(&fq->mq_flush_lock);
- blk_flush_complete_seq(rq, REQ_FSEQ_ACTIONS & ~policy, 0);
+ blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0);
spin_unlock_irq(&fq->mq_flush_lock);
return;
}
rq->end_io = flush_data_end_io;

- blk_flush_complete_seq(rq, REQ_FSEQ_ACTIONS & ~policy, 0);
+ blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0);
}

/**
--
1.7.9.5