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From: Logan Gunthorpe <logang@deltatee.com>
To: Sagi Grimberg <sagi@grimberg.me>,
	linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Stephen Bates <sbates@raithlin.com>, Jens Axboe <axboe@fb.com>,
	Keith Busch <kbusch@kernel.org>, Max Gurtovoy <maxg@mellanox.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v8 13/13] nvmet-passthru: support block accounting
Date: Mon, 9 Sep 2019 13:32:56 -0600	[thread overview]
Message-ID: <b23c72b2-c9db-cb8e-5519-63eb195b7fd4@deltatee.com> (raw)
In-Reply-To: <7954e8a4-6026-2210-7192-94a4e483facf@grimberg.me>



On 2019-09-09 1:26 p.m., Sagi Grimberg wrote:
> 
>>>> Support block disk accounting by setting the RQF_IO_STAT flag
>>>> and gendisk in the request.
>>>>
>>>> After this change, IO counts will be reflected correctly in
>>>> /proc/diskstats for drives being used by passthru.
>>>>
>>>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>>>> ---
>>>>    drivers/nvme/target/io-cmd-passthru.c | 5 ++++-
>>>>    1 file changed, 4 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/nvme/target/io-cmd-passthru.c b/drivers/nvme/target/io-cmd-passthru.c
>>>> index 7557927a3451..63f12750a80d 100644
>>>> --- a/drivers/nvme/target/io-cmd-passthru.c
>>>> +++ b/drivers/nvme/target/io-cmd-passthru.c
>>>> @@ -410,6 +410,9 @@ static struct request *nvmet_passthru_blk_make_request(struct nvmet_req *req,
>>>>    	if (unlikely(IS_ERR(rq)))
>>>>    		return rq;
>>>>    
>>>> +	if (blk_queue_io_stat(q) && cmd->common.opcode != nvme_cmd_flush)
>>>> +		rq->rq_flags |= RQF_IO_STAT;
>>
>> Thanks for the review!
>>
>>> Does flush has data bytes in the request? Why the special casing?
>>
>> Well it was special cased in the vanilla blk account flow... But I think
>> it's required to be special cased so the IO and in_flight counts don't
>> count flushes (as they do not for regular block device traffic).
> 
> I think that the accounting exclude I/O that is yielded from the flush
> sequence. Don't think its relevant here...

What? Per blk_account_io_done(), RQF_FLUSH_SEQ will not be set by us for
passthru commands and I don't think it's appropriate to do so. Thus, if
we set RQF_IO_STAT for passthru flush commands, they will be counted
which we do not want.

Logan

  reply	other threads:[~2019-09-09 19:33 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-28 21:54 [PATCH v8 00/13] nvmet: add target passthru commands support Logan Gunthorpe
2019-08-28 21:54 ` [PATCH v8 01/13] nvme-core: introduce nvme_ctrl_get_by_path() Logan Gunthorpe
2019-09-06 23:33   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 02/13] nvme-core: export existing ctrl and ns interfaces Logan Gunthorpe
2019-09-06 23:33   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 03/13] nvmet: add return value to nvmet_add_async_event() Logan Gunthorpe
2019-09-06 23:34   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 04/13] nvmet: make nvmet_copy_ns_identifier() non-static Logan Gunthorpe
2019-09-06 23:34   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 05/13] nvmet-passthru: update KConfig with config passthru option Logan Gunthorpe
2019-09-06 23:35   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 06/13] nvmet-passthru: add passthru code to process commands Logan Gunthorpe
2019-08-28 21:54 ` [PATCH v8 07/13] nvmet-passthru: add enable/disable helpers Logan Gunthorpe
2019-08-28 21:54 ` [PATCH v8 08/13] nvmet-core: don't check the data len for pt-ctrl Logan Gunthorpe
2019-09-06 23:38   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 09/13] nvmet-tcp: don't check data_len in nvmet_tcp_map_data() Logan Gunthorpe
2019-09-06 23:39   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 10/13] nvmet-configfs: introduce passthru configfs interface Logan Gunthorpe
2019-09-06 23:39   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 11/13] block: don't check blk_rq_is_passthrough() in blk_do_io_stat() Logan Gunthorpe
2019-09-06 23:40   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 12/13] block: call blk_account_io_start() in blk_execute_rq_nowait() Logan Gunthorpe
2019-09-06 23:41   ` Sagi Grimberg
2019-08-28 21:54 ` [PATCH v8 13/13] nvmet-passthru: support block accounting Logan Gunthorpe
2019-09-07  0:00   ` Sagi Grimberg
2019-09-09 16:06     ` Logan Gunthorpe
2019-09-09 19:26       ` Sagi Grimberg
2019-09-09 19:32         ` Logan Gunthorpe [this message]
2019-09-09 23:15           ` Sagi Grimberg
2019-09-11 16:53             ` Logan Gunthorpe

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