From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Mike Snitzer <snitzer@redhat.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"dm-devel@redhat.com" <dm-devel@redhat.com>,
Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH] block: Improve io_opt limit stacking
Date: Fri, 22 May 2020 09:36:18 -0400 [thread overview]
Message-ID: <yq1ftbsp06e.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <yq1lflkp0b9.fsf@ca-mkp.ca.oracle.com> (Martin K. Petersen's message of "Fri, 22 May 2020 09:28:36 -0400")
>>> + if (t->io_opt & (t->physical_block_size - 1))
>>> + t->io_opt = lcm(t->io_opt, t->physical_block_size);
>
>> Any comment on this patch ? Note: the patch the patch "nvme: Fix
>> io_opt limit setting" is already queued for 5.8.
>
> Setting io_opt to the physical block size is not correct.
Oh, missed the lcm(). But I'm still concerned about twiddling io_opt to
a value different than the one reported by an underlying device.
Setting io_opt to something that's less than a full stripe width in a
RAID, for instance, doesn't produce the expected result. So I think I'd
prefer not to set io_opt at all if it isn't consistent across all the
stacked devices.
Let me chew on it for a bit...
--
Martin K. Petersen Oracle Linux Engineering
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next prev parent reply other threads:[~2020-05-22 13:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-14 6:58 [PATCH] block: Improve io_opt limit stacking Damien Le Moal
2020-05-22 7:27 ` Damien Le Moal
2020-05-22 13:28 ` Martin K. Petersen
2020-05-22 13:36 ` Martin K. Petersen [this message]
2020-05-22 14:14 ` Keith Busch
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