From: "Ewan D. Milne" <emilne@redhat.com>
To: Sumanesh Samanta <sumanesh.samanta@broadcom.com>,
axboe@kernel.dk, linux-block@vger.kernel.org, jejb@linux.ibm.com,
martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
ming.lei@redhat.com, sathya.prakash@broadcom.com,
chaitra.basappa@broadcom.com,
suganath-prabu.subramani@broadcom.com,
kashyap.desai@broadcom.com, sumit.saxena@broadcom.com,
shivasharan.srikanteshwara@broadcom.com, hch@lst.de,
hare@suse.de, bart.vanassche@wdc.com
Subject: Re: [PATCH 1/1] scsi core: limit overhead of device_busy counter for SSDs
Date: Tue, 19 Nov 2019 16:01:23 -0500 [thread overview]
Message-ID: <16ea01eb24e349da19bcad725f95b2759973e5e3.camel@redhat.com> (raw)
In-Reply-To: <1574194079-27363-2-git-send-email-sumanesh.samanta@broadcom.com>
On Tue, 2019-11-19 at 12:07 -0800, Sumanesh Samanta wrote:
>
> +#define MAX_PER_CPU_COUNTER_ABSOLUTE_VAL (0xFFFFFFFFFFF)
> +#define PER_CPU_COUNTER_OK_VAL (MAX_PER_CPU_COUNTER_ABSOLUTE_VAL>>16)
> +#define USE_DEVICE_BUSY(sdev) (!(sdev)->host->hostt->use_per_cpu_device_busy \
> + || !blk_queue_nonrot((sdev)->request_queue))
> +
> +
I think this macro, which looks at a couple of different flags, one of
which is keyed off a property of the device, rather than the driver,
needs to be further refined. Also, QUEUE_FLAG_NONROT can be changed by
sysfs, this might cause problems later.
-Ewan
next prev parent reply other threads:[~2019-11-19 21:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 20:07 [PATCH 0/1] : limit overhead of device_busy counter for SSDs Sumanesh Samanta
2019-11-19 20:07 ` [PATCH 1/1] scsi core: " Sumanesh Samanta
2019-11-19 21:01 ` Ewan D. Milne [this message]
2019-11-19 23:22 ` Bart Van Assche
2019-11-19 23:35 ` Sumanesh Samanta
2019-11-20 7:29 ` Ming Lei
2019-11-20 19:59 ` Sumanesh Samanta
2019-11-21 1:34 ` Ming Lei
2019-11-21 1:59 ` Sumanesh Samanta
2019-11-21 2:29 ` Ming Lei
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