Messages in this thread | | | Subject | Re: [PATCH v8 13/13] nvmet-passthru: support block accounting | From | Sagi Grimberg <> | Date | Mon, 9 Sep 2019 16:15:25 -0700 |
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>>>>> 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.
Have you considered to have nvmet_passthru_blk_make_request set RQF_FUA for nvme_cmd_flush? this way blk_insert_flush will be called and RQF_FLUSH_SEQ will be set and you don't need to worry about this special casing...
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