From: Tejun Heo <tj@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>, Shaohua Li <shli@fb.com>,
IDE/ATA development list <linux-ide@vger.kernel.org>,
Kernel-team@fb.com, Jens Axboe <axboe@fb.com>
Subject: Re: [PATCH v2 3/3] libata: use blk taging
Date: Thu, 15 Jan 2015 10:02:09 -0500 [thread overview]
Message-ID: <20150115150209.GA25903@htj.dyndns.org> (raw)
In-Reply-To: <20150115092836.GA14051@infradead.org>
Hello,
On Thu, Jan 15, 2015 at 01:28:36AM -0800, Christoph Hellwig wrote:
> libata on the other hand at the moment assigns it's own tags,
> which are only stored in struct ata_queued_cmd, but never in the
> request. libata assigns tags per ata_host. Each ata_host
Per ata_port.
> might have multiple ports, which each get their own Scsi_Host
> allocated.
>
> Given that ATA NCQ has a fairly low queue depth I assume we want
> to stick to assigning ATA tags per-device, but due to the host
> per device scheme libata that even works using scsi-mq. (Q: how do tags
> work when port mulipliers are involved?)
It's still per-port. The same number of tags are shared among all
devices attached via PMs.
Thanks.
--
tejun
next prev parent reply other threads:[~2015-01-15 15:02 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-18 18:46 [PATCH v2 1/3] block: support different tag allocation policy Shaohua Li
2014-12-18 18:46 ` [PATCH v2 2/3] blk-mq: add " Shaohua Li
2014-12-22 23:25 ` Jens Axboe
2015-01-02 19:43 ` Shaohua Li
2014-12-18 18:46 ` [PATCH v2 3/3] libata: use blk taging Shaohua Li
2015-01-09 18:15 ` Shaohua Li
2015-01-09 21:43 ` Tejun Heo
2015-01-09 21:59 ` Shaohua Li
2015-01-09 22:12 ` Shaohua Li
2015-01-14 8:08 ` Dan Williams
2015-01-14 16:30 ` Shaohua Li
2015-01-14 17:09 ` Dan Williams
[not found] ` <CAPcyv4hMwpGzeaovnXtqyYFM46wodRamZd7CNVoR43JJYh0Tjg@mail.gmail.com>
2015-01-14 17:13 ` Shaohua Li
2015-01-14 17:37 ` Dan Williams
2015-01-15 9:28 ` Christoph Hellwig
2015-01-15 15:02 ` Tejun Heo [this message]
2015-01-15 18:40 ` Shaohua Li
2015-01-15 18:57 ` Tejun Heo
2015-01-15 18:59 ` Dan Williams
2015-01-15 19:03 ` Tejun Heo
2015-01-15 19:15 ` Jens Axboe
2015-01-15 19:51 ` Dan Williams
2015-01-15 22:28 ` Jens Axboe
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