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From: Anthony Liguori <aliguori@us.ibm.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: Ryan Harper <ryanh@us.ibm.com>,
	qemu-devel@nongnu.org, kvm@vger.kernel.org,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH 2/3] Move aio implementation out of raw block driver
Date: Tue, 23 Sep 2008 11:06:27 -0500	[thread overview]
Message-ID: <48D91403.8090007@us.ibm.com> (raw)
In-Reply-To: <48D902EB.8070701@redhat.com>

Gerd Hoffmann wrote:
> Ryan Harper wrote:
>   
>>> So what happens if !defined(CONFIG_AIO)?  By my reading of the code, 
>>> aio_drv will be NULL and this will SEGV.
>>>       
>> raw_aio_read/write/cancel aren't included in the bdrv structure unless
>> CONFIG_AIO is defined.  Rather in bdrv_register, the aio emulation
>> functions are used instead.
>>     
>
> How about providing a aio interface implementation which simply uses
> read/write syscalls (thereby not being really async obviously)?  Then
> use that as fallback instead of aio emulation?  And also drop CONFIG_AIO
> then?
>   

Yeah, this is basically what block-raw-posix does today.  I was thinking 
the same thing.  I was also thinking that you could do an aio 
implementation for win32 and possibly reunify block-raw-posix and 
block-raw-linux.

But before going down this route, I want to see if linux-aio is really 
the right tool for the job.

Regards,

Anthony Liguori

> cheers,
>   Gerd
>   

  reply	other threads:[~2008-09-23 16:07 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-22 23:17 [Qemu-devel] [PATCH 0/3] Refactor AIO to allow multiple AIO implementations Ryan Harper
2008-09-22 23:17 ` [Qemu-devel] [PATCH 1/3] Only call aio flush handler if set Ryan Harper
2008-09-23  2:38   ` [Qemu-devel] " Anthony Liguori
2008-09-23 14:26     ` Ryan Harper
2008-09-23 14:34       ` Anthony Liguori
2008-09-23 14:41         ` Ryan Harper
2008-09-23 14:50           ` Anthony Liguori
2008-09-22 23:17 ` [Qemu-devel] [PATCH 2/3] Move aio implementation out of raw block driver Ryan Harper
2008-09-23  1:16   ` [Qemu-devel] " Ryan Harper
2008-09-23  2:45   ` Anthony Liguori
2008-09-23 14:39     ` Ryan Harper
2008-09-23 14:40       ` Anthony Liguori
2008-09-23 14:53       ` Gerd Hoffmann
2008-09-23 16:06         ` Anthony Liguori [this message]
2008-09-23 18:04           ` Gerd Hoffmann
2008-09-23 18:28             ` Anthony Liguori
2008-09-24 22:31     ` Marcelo Tosatti
2008-09-22 23:17 ` [Qemu-devel] " Ryan Harper
2008-09-23  1:22   ` [Qemu-devel] [PATCH 3/3] Add linux aio implementation for raw block devices Ryan Harper
2008-09-23  3:32 ` [Qemu-devel] Re: [PATCH 0/3] Refactor AIO to allow multiple AIO implementations Anthony Liguori
2008-09-23 14:43   ` Ryan Harper
2008-09-23 14:47     ` Anthony Liguori
2008-09-23 16:09     ` Anthony Liguori
2008-09-23 10:27 ` [Qemu-devel] " Jamie Lokier
2008-10-02 22:41 ` [Qemu-devel] " john cooper
2008-10-03 13:33   ` Ryan Harper

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