From: Richard Weinberger <richard@nod.at>
To: Christoph Hellwig <hch@infradead.org>
Cc: user-mode-linux-devel@lists.sourceforge.net, dxld@darkboxed.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] hostfs: Use noop_fsync for directories
Date: Wed, 14 Jan 2015 09:43:53 +0100 [thread overview]
Message-ID: <54B62C49.7030309@nod.at> (raw)
In-Reply-To: <20150114083951.GA29714@infradead.org>
Am 14.01.2015 um 09:39 schrieb Christoph Hellwig:
> On Tue, Jan 13, 2015 at 11:26:38PM +0100, Richard Weinberger wrote:
>> hostfs tries do reduce the amount of syscall between guest and host as much
>> as possible. For file operations it passes everything down to the host but
>> for directory operations only ->iterate() does.
>>
>> It is already horrible slow, if we add an ->open() for directory too it would
>> get even more slower. :-(
>
> This sounds fairlt dangerous. At least add some good documentation
> explaining these semantics.
Understood. Maybe it is time to rebenchmark hostfs with full directory pass-through support.
Daniel, are you interested in a small kernel project?
As explained on IRC adding real support for directory fsync() should be an easy task.
The only interesting point is how much overhead it will add.
Thanks,
//richard
next prev parent reply other threads:[~2015-01-14 8:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-13 22:15 [PATCH] hostfs: Use noop_fsync for directories Richard Weinberger
2015-01-13 22:19 ` Christoph Hellwig
2015-01-13 22:26 ` Richard Weinberger
2015-01-14 8:39 ` Christoph Hellwig
2015-01-14 8:43 ` Richard Weinberger [this message]
2015-01-18 1:08 ` Daniel Gröber
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