From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>,
Sergey Meirovich <rathamahata@gmail.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Gluk <git.user@gmail.com>
Subject: Re: Terrible performance of sequential O_DIRECT 4k writes in SAN environment. ~3 times slower then Solars 10 with the same HBA/Storage.
Date: Wed, 8 Jan 2014 06:03:43 -0800 [thread overview]
Message-ID: <20140108140343.GB588@infradead.org> (raw)
In-Reply-To: <20140108011713.GA5212@quack.suse.cz>
On Wed, Jan 08, 2014 at 02:17:13AM +0100, Jan Kara wrote:
> Well, I was specifically worried about i_mutex locking. In particular:
> Before we report appending IO completion we need to update i_size.
> To update i_size we need to grab i_mutex.
>
> Now this is unpleasant because inode_dio_wait() happens under i_mutex so
> the above would create lock inversion. And we cannot really do
> inode_dio_done() before grabbing i_mutex as that would open interesting
> races between truncate decreasing i_size and DIO increasing it.
Yeah, XFS splits this between the ilock and iolock, which just makes
life in this area a whole lot easier.
next prev parent reply other threads:[~2014-01-08 14:03 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-06 9:38 Terrible performance of sequential O_DIRECT 4k writes in SAN environment. ~3 times slower then Solars 10 with the same HBA/Storage Sergey Meirovich
2014-01-06 20:10 ` Jan Kara
2014-01-07 9:13 ` Sergey Meirovich
2014-01-07 15:58 ` Christoph Hellwig
2014-01-07 18:37 ` Sergey Meirovich
2014-01-08 14:03 ` Christoph Hellwig
2014-01-08 14:43 ` Sergey Meirovich
2014-01-08 15:26 ` Christoph Hellwig
2014-01-08 17:30 ` Sergey Meirovich
2014-01-08 20:55 ` Jan Kara
2014-01-09 10:11 ` Sergey Meirovich
2014-01-10 9:36 ` Jan Kara
2014-01-10 10:36 ` Sergey Meirovich
2014-01-10 10:48 ` Jan Kara
2014-01-10 14:32 ` Sergey Meirovich
2014-01-10 18:14 ` Sergey Meirovich
2014-01-14 13:30 ` Sergey Meirovich
2014-01-14 13:30 ` Sergey Meirovich
2014-01-15 22:07 ` Dave Chinner
2014-01-15 22:07 ` Dave Chinner
2014-01-20 13:58 ` Christoph Hellwig
2014-01-20 13:58 ` Christoph Hellwig
2014-01-20 22:18 ` Dave Chinner
2014-01-20 22:18 ` Dave Chinner
2014-01-08 1:17 ` Jan Kara
2014-01-08 14:03 ` Christoph Hellwig [this message]
2014-01-07 20:57 ` James Smart
2014-01-08 13:57 ` Sergey Meirovich
2014-01-09 19:54 ` Douglas Gilbert
2014-01-09 21:26 ` Sergey Meirovich
2014-01-09 21:43 ` Sergey Meirovich
-- strict thread matches above, loose matches on Subject: below --
2014-01-06 13:16 Sergey Meirovich
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