From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Sumanesh Samanta <sumanesh.samanta@broadcom.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Jens Axboe <axboe@kernel.dk>,
Sathya Prakash <sathya.prakash@broadcom.com>,
Chaitra P B <chaitra.basappa@broadcom.com>,
Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>,
Kashyap Desai <kashyap.desai@broadcom.com>,
Shivasharan S <shivasharan.srikanteshwara@broadcom.com>,
"Ewan D . Milne" <emilne@redhat.com>,
Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
Bart Van Assche <bart.vanassche@wdc.com>,
Ming Lei <ming.lei@redhat.com>,
linux-block@vger.kernel.org,
Sumit Saxena <sumit.saxena@broadcom.com>
Subject: Re: [PATCH 5/6] scsi: core: don't limit per-LUN queue depth for SSD when HBA needs
Date: Mon, 27 Jan 2020 23:22:59 -0500 [thread overview]
Message-ID: <yq1blqo9plo.fsf@oracle.com> (raw)
In-Reply-To: <f4f06cf8459c21749335c6b7a4cfe729@mail.gmail.com> (Sumanesh Samanta's message of "Fri, 24 Jan 2020 12:41:20 -0700")
Sumanesh,
> Instead of relying on QUEUE_FULL and some complex heuristics of when
> to start tracking device_busy, why can't we simply use "
> track_queue_depth" ( along with the other flag that Ming added) to
> decide which devices need queue depth tracking, and track device_busy
> only for them?
Because I am interested in addressing the device_busy contention problem
for all of our non-legacy drivers. I.e. not just for controllers that
happen to queue internally.
> I am not sure how we can suddenly start tracking device_busy on the fly,
> if we do not know how many IO are already pending for that device?
We know that from the tags. It's just not hot path material.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2020-01-28 4:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-19 7:14 [PATCH 0/6] scsi: support bypass device busy check for some high end HBA with SSD Ming Lei
2020-01-19 7:14 ` [PATCH 1/6] scsi: mpt3sas: don't use .device_busy in device reset routine Ming Lei
2020-01-19 20:28 ` Bart Van Assche
2020-01-19 7:14 ` [PATCH 2/6] scsi: remove .for_blk_mq Ming Lei
2020-01-19 20:29 ` Bart Van Assche
2020-01-20 10:17 ` John Garry
2020-01-20 22:12 ` Elliott, Robert (Servers)
2020-01-31 6:30 ` Christoph Hellwig
2020-02-05 2:13 ` Martin K. Petersen
2020-01-19 7:14 ` [PATCH 3/6] scsi: sd: register request queue after sd_revalidate_disk is done Ming Lei
2020-01-19 20:36 ` Bart Van Assche
2020-01-19 7:14 ` [PATCH 4/6] block: freeze queue for updating QUEUE_FLAG_NONROT Ming Lei
2020-01-19 20:40 ` Bart Van Assche
2020-01-19 7:14 ` [PATCH 5/6] scsi: core: don't limit per-LUN queue depth for SSD when HBA needs Ming Lei
2020-01-19 20:58 ` Bart Van Assche
2020-01-21 4:52 ` Martin K. Petersen
2020-01-23 2:54 ` Ming Lei
2020-01-24 1:21 ` Martin K. Petersen
2020-01-24 1:59 ` Ming Lei
2020-01-24 12:43 ` Sumit Saxena
2020-01-28 4:04 ` Martin K. Petersen
[not found] ` <ab676c4c-03fb-7eb9-6212-129eb83d0ee8@broadcom.com>
[not found] ` <yq1iml1ehtl.fsf@oracle.com>
2020-01-24 19:41 ` Sumanesh Samanta
2020-01-28 4:22 ` Martin K. Petersen [this message]
2020-01-31 11:39 ` Ming Lei
2020-01-19 7:14 ` [PATCH 6/6] scsi: megaraid: set flag of no_device_queue_for_ssd Ming Lei
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