| Message ID | 6297c9a39cf21c94c65d5a9b3a19e54ba5b8b573.1478217671.git.shli@fb.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Nov 03, 2016 at 05:03:54PM -0700, Shaohua Li wrote: > This is corresponding part for blk-mq. Disk with multiple hardware > queues doesn't need this as we only hold 1 request at most. Any reason you only do this for the SQ and not the MQ case? -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Nov 03, 2016 at 05:09:54PM -0700, Christoph Hellwig wrote: > On Thu, Nov 03, 2016 at 05:03:54PM -0700, Shaohua Li wrote: > > This is corresponding part for blk-mq. Disk with multiple hardware > > queues doesn't need this as we only hold 1 request at most. > > Any reason you only do this for the SQ and not the MQ case? Right above: Disk with multiple hardware queues doesn't need this as we only hold 1 request at most. Thanks, Shaohua -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/03/2016 06:13 PM, Shaohua Li wrote: > On Thu, Nov 03, 2016 at 05:09:54PM -0700, Christoph Hellwig wrote: >> On Thu, Nov 03, 2016 at 05:03:54PM -0700, Shaohua Li wrote: >>> This is corresponding part for blk-mq. Disk with multiple hardware >>> queues doesn't need this as we only hold 1 request at most. >> >> Any reason you only do this for the SQ and not the MQ case? > > Right above: > Disk with multiple hardware queues doesn't need this as we only hold 1 > request at most. I've applied 1-2 for 4.10, but we probably should look into unifying those parts of sq and mq in general. For instance, it doesn't seem to make a lot of sense why we'd depth limit sq and not mq.
On Thu, Nov 03, 2016 at 10:00:58PM -0600, Jens Axboe wrote: > I've applied 1-2 for 4.10, but we probably should look into unifying > those parts of sq and mq in general. For instance, it doesn't seem to > make a lot of sense why we'd depth limit sq and not mq. I've spent some time looking the the make_request_fn and to be honest I think that whole sq vs mq split is pointless. They are about 70-80% the same anyway, and I think everyone would be served much better by merging them. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/04/2016 08:46 AM, Christoph Hellwig wrote: > On Thu, Nov 03, 2016 at 10:00:58PM -0600, Jens Axboe wrote: >> I've applied 1-2 for 4.10, but we probably should look into unifying >> those parts of sq and mq in general. For instance, it doesn't seem to >> make a lot of sense why we'd depth limit sq and not mq. > > I've spent some time looking the the make_request_fn and to be honest > I think that whole sq vs mq split is pointless. They are about 70-80% > the same anyway, and I think everyone would be served much better > by merging them. Yeah, that was my point, at least if we can do it without having too many extra conditionals. Or at least split some of it into helpers.
diff --git a/block/blk-mq.c b/block/blk-mq.c index f3d27a6..a72538a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1401,13 +1401,18 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio) */ plug = current->plug; if (plug) { + struct request *last = NULL; + blk_mq_bio_to_request(rq, bio); if (!request_count) trace_block_plug(q); + else + last = list_entry_rq(plug->mq_list.prev); blk_mq_put_ctx(data.ctx); - if (request_count >= BLK_MAX_REQUEST_COUNT) { + if (request_count >= BLK_MAX_REQUEST_COUNT || (last && + blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { blk_flush_plug_list(plug, false); trace_block_plug(q); }
This is corresponding part for blk-mq. Disk with multiple hardware queues doesn't need this as we only hold 1 request at most. Signed-off-by: Shaohua Li <shli@fb.com> --- block/blk-mq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)