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From: Avi Kivity <avi@redhat.com>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	gleb@redhat.com, kvm@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] eventfd: new EFD_STATE flag
Date: Thu, 20 Aug 2009 20:38:48 +0300	[thread overview]
Message-ID: <4A8D8A28.2050004@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.00.0908200916300.14844@makko.or.mcafeemobile.com>

On 08/20/2009 07:20 PM, Davide Libenzi wrote:
>
> I briefly looked at this while in vacation, although I did not reply
> hoping the horrible feeling about this code would go away.
> It didn't.
> I find this to be an ugly and ad-hoc multiplexing of eventfd with added
> functionalities of questionable general use.
> I'm pretty sure you can do better on KVM side, to solve the problem w/out
> littering eventfd.
>
>    

While we could argue about this my feeling is that we should drop this, 
at least until we can quantify what benefit it has and whether there are 
any Davide-acceptable alternatives.

In the meanwhile, we can let vhost-net support edge-triggered interrupts 
only, let qemu terminate those eventfds and convert then to 
level-triggered interrupts (which it can then inject using the existing 
ioctl).  It will keep vhost-net and kvm simpler at the cost of some 
performance penalty to guests using level interrupts.  These suck anyway 
so we'll point users at msi.

-- 
I have a truly marvellous patch that fixes the bug which thisb
signature is too narrow to contain.


  reply	other threads:[~2009-08-20 17:38 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-20 15:56 [PATCH 0/2] eventfd: new EFD_STATE flag Michael S. Tsirkin
2009-08-20 16:20 ` Davide Libenzi
2009-08-20 17:38   ` Avi Kivity [this message]
2009-08-20 17:44     ` Davide Libenzi
2009-08-20 17:56       ` Paolo Bonzini
2009-08-21 17:21         ` Davide Libenzi
2009-08-20 17:55     ` Michael S. Tsirkin
2009-08-20 18:06       ` Avi Kivity
2009-08-20 18:28         ` Michael S. Tsirkin
2009-08-23 13:01           ` Avi Kivity
2009-08-23 13:36             ` Michael S. Tsirkin
2009-08-23 13:40               ` Avi Kivity
2009-08-23 14:30                 ` Michael S. Tsirkin
2009-08-23 16:51                   ` Paolo Bonzini
2009-08-24 18:25                   ` Davide Libenzi
2009-08-24 18:31                     ` Avi Kivity
2009-08-24 22:08                       ` Davide Libenzi
2009-08-24 22:10                         ` Paolo Bonzini
2009-08-24 22:32                           ` Davide Libenzi
2009-08-25  6:59                             ` Paolo Bonzini
2009-08-25  4:26                         ` Avi Kivity
2009-08-24 21:49                     ` Michael S. Tsirkin
2009-08-24 22:15                       ` Davide Libenzi
2009-08-25  7:22                         ` Michael S. Tsirkin
2009-08-25 21:57                           ` Davide Libenzi
2009-08-26 10:29                             ` Michael S. Tsirkin
2009-08-26 10:41                               ` Avi Kivity
2009-08-26 17:45                               ` Davide Libenzi
2009-08-26 18:58                                 ` Avi Kivity
2009-08-26 19:13                                   ` Davide Libenzi
2009-08-26 19:42                                     ` Avi Kivity
2009-08-26 19:44                                       ` Davide Libenzi
2009-08-26 23:30                                         ` Davide Libenzi
2009-08-27  4:13                                           ` Avi Kivity
2009-08-27  8:06                                             ` Michael S. Tsirkin
2009-08-27 14:20                                               ` Davide Libenzi
2009-08-26 19:50                                       ` Gleb Natapov
2009-08-26 20:04                                         ` Davide Libenzi
2009-08-27  5:25                                           ` Gleb Natapov
2009-08-27  9:05                                     ` Paolo Bonzini
2009-08-27  9:09                                       ` Michael S. Tsirkin
2009-08-27 14:21                                       ` Davide Libenzi
2009-08-27 14:30                                         ` Michael S. Tsirkin
2009-08-27 14:38                                           ` Davide Libenzi
2009-08-27 14:49                                             ` Michael S. Tsirkin
2009-08-27 15:29                                               ` Davide Libenzi
2009-08-27 17:09                                                 ` Davide Libenzi
     [not found]                                                   ` <alpine.DEB.2.00.0908311644410.17349@makko.or.mcafeemobile.com>
     [not found]                                                     ` <4A9CB318.7030401@redhat.com>
     [not found]                                                       ` <alpine.DEB.2.00.0909010723380.28172@makko.or.mcafeemobile.com>
2010-01-06 19:33                                                         ` Michael S. Tsirkin
2010-01-06 20:43                                                           ` Davide Libenzi
2010-01-06 20:55                                                             ` Michael S. Tsirkin
2010-01-06 21:17                                                               ` Davide Libenzi
2010-01-06 22:29                                                                 ` Michael S. Tsirkin
2010-01-06 22:46                                                                   ` Davide Libenzi
2010-01-06 23:45                                                                     ` Michael S. Tsirkin
2010-01-06 23:59                                                                       ` Davide Libenzi
2010-01-07  0:02                                                                         ` Michael S. Tsirkin
2010-01-07  6:45                                                                         ` Michael S. Tsirkin
2010-01-07  7:25                                                                           ` Davide Libenzi
2010-01-07 10:36                                                                             ` Michael S. Tsirkin
2010-01-07 23:37                                                                               ` Davide Libenzi
2010-01-08  0:13                                                                                 ` Davide Libenzi
2010-01-08  0:26                                                                               ` Davide Libenzi
2010-01-10 10:30                                                                                 ` Michael S. Tsirkin
2010-01-10 15:26                                                                                   ` Davide Libenzi
2010-01-10 16:22                                                                                     ` Michael S. Tsirkin
2010-01-10 17:27                                                                                       ` Davide Libenzi
2010-01-10 17:35                                                                                         ` Michael S. Tsirkin
2010-01-10 19:04                                                                                           ` Davide Libenzi
2010-01-11  7:34                                                                                             ` Michael S. Tsirkin
2010-01-11 19:14                                                                                               ` Davide Libenzi
2010-01-11 19:19                                                                                                 ` Michael S. Tsirkin
2010-01-11 22:53                                                                                                   ` Davide Libenzi
2010-01-13 17:07                                                                                                     ` Michael S. Tsirkin
2010-01-11  9:01                                                                               ` Gleb Natapov
2010-01-11  9:02                                                                                 ` Michael S. Tsirkin
2010-01-11  9:08                                                                                   ` Gleb Natapov
2010-01-11  9:19                                                                                     ` Michael S. Tsirkin
2010-01-11  9:36                                                                                       ` Gleb Natapov
2010-01-11  9:41                                                                                         ` Michael S. Tsirkin

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