From: keith.busch@intel.com (Keith Busch)
Subject: Maximum NVMe IO command size > 1MB?
Date: Wed, 6 Jan 2016 22:54:57 +0000 [thread overview]
Message-ID: <20160106225457.GA23888@localhost.localdomain> (raw)
In-Reply-To: <ba6abd8303c84156b1c530dcbf101f40@SC-EXCH01.marvell.com>
On Wed, Jan 06, 2016@09:56:24PM +0000, Xuehua Chen wrote:
> Hi, Keith,
>
> I wonder whether this could be caused by BIO_MAX_PAGES defined as 256, which means 1MB at most.
> What do you think?
I think you got it. You're running O_DIRECT, and fs/direct-io.c,
dio_new_bio() allocates up to BIO_MAX_PAGES.
I can't tell where the value for came from (looks like it was there from
the very first git commit), but maybe you can propose raising it if you
set BIO_MAX_PAGES higher without issue.
next prev parent reply other threads:[~2016-01-06 22:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 19:23 Maximum NVMe IO command size > 1MB? Xuehua Chen
2016-01-06 19:31 ` Keith Busch
2016-01-06 19:51 ` Xuehua Chen
2016-01-06 21:56 ` Xuehua Chen
2016-01-06 22:54 ` Keith Busch [this message]
2016-01-07 17:38 ` Xuehua Chen
2016-01-10 22:16 ` Xuehua Chen
2016-01-07 11:39 ` Sagi Grimberg
2016-01-07 17:34 ` Xuehua Chen
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