tmakin/tegra-linux-noble
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

blk-mq: support per-distpatch_queue flush machinery

Browse Source 
This patch supports to run one single flush machinery for
each blk-mq dispatch queue, so that:

- current init_request and exit_request callbacks can
cover flush request too, then the buggy copying way of
initializing flush request's pdu can be fixed

- flushing performance gets improved in case of multi hw-queue

In fio sync write test over virtio-blk(4 hw queues, ioengine=sync,
iodepth=64, numjobs=4, bs=4K), it is observed that througput gets
increased a lot over my test environment:
	- throughput: +70% in case of virtio-blk over null_blk
	- throughput: +30% in case of virtio-blk over SSD image

The multi virtqueue feature isn't merged to QEMU yet, and patches for
the feature can be found in below tree:

	git://kernel.ubuntu.com/ming/qemu.git  	v2.1.0-mq.4

And simply passing 'num_queues=4 vectors=5' should be enough to
enable multi queue(quad queue) feature for QEMU virtio-blk.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Ming Lei
2014-09-25 23:23:47 +08:00
committed by Jens Axboe
parent e97c293cdf
commit f70ced0917
6 changed files with 60 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
block/blk-flush.c
View File

@@ -305,8 +305,15 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq)
fq->flush_pending_idx ^= 1;
blk_rq_init(q, flush_rq);
if (q->mq_ops)
blk_mq_clone_flush_request(flush_rq, first_rq);
/*
* Borrow tag from the first request since they can't
* be in flight at the same time.
*/
if (q->mq_ops) {
flush_rq->mq_ctx = first_rq->mq_ctx;
flush_rq->tag = first_rq->tag;
}
flush_rq->cmd_type = REQ_TYPE_FS;
flush_rq->cmd_flags = WRITE_FLUSH | REQ_FLUSH_SEQ;
@@ -480,22 +487,22 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
}
EXPORT_SYMBOL(blkdev_issue_flush);
struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q)
struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
int node, int cmd_size)
{
struct blk_flush_queue *fq;
int rq_sz = sizeof(struct request);
fq = kzalloc(sizeof(*fq), GFP_KERNEL);
fq = kzalloc_node(sizeof(*fq), GFP_KERNEL, node);
if (!fq)
goto fail;
if (q->mq_ops) {
spin_lock_init(&fq->mq_flush_lock);
rq_sz = round_up(rq_sz + q->tag_set->cmd_size,
cache_line_size());
rq_sz = round_up(rq_sz + cmd_size, cache_line_size());
}
fq->flush_rq = kzalloc(rq_sz, GFP_KERNEL);
fq->flush_rq = kzalloc_node(rq_sz, GFP_KERNEL, node);
if (!fq->flush_rq)
goto fail_rq;