From: Amit Shah <amit.shah@redhat•com>
To: Miche Baker-Harvey <miche@google•com>
Cc: Stephen Rothwell <sfr@canb•auug.org.au>,
xen-devel@lists•xensource.com,
Konrad Rzeszutek Wilk <konrad.wilk@oracle•com>,
Rusty Russell <rusty@rustcorp•com.au>,
linux-kernel@vger•kernel.org,
virtualization@lists•linux-foundation.org,
Anton Blanchard <anton@samba•org>,
Mike Waychison <mikew@google•com>,
ppc-dev <linuxppc-dev@lists•ozlabs.org>,
Greg Kroah-Hartman <gregkh@suse•de>,
Eric Northrup <digitaleric@google•com>
Subject: Re: [PATCH v3 2/3] hvc_init(): Enforce one-time initialization.
Date: Tue, 29 Nov 2011 19:51:49 +0530 [thread overview]
Message-ID: <20111129142149.GE2822@amit-x200.redhat.com> (raw)
In-Reply-To: <CAB8RdaoDxMCgTjuGP70bGrsrtgh=USYtU3Spo5OPtVMYAM5EzQ@mail.gmail.com>
Hi,
On (Mon) 28 Nov 2011 [15:40:41], Miche Baker-Harvey wrote:
> Amit,
>
> You said that the work would be serialized "due to port additions
> being on work items on the same workqueue". I'm not seeing that.
You leave a lot of questions unanswered. What's your environment?
Are you hot-plugging ports? Are you using qemu? What's your command
line?
> I've double checked this by using a mutex_trylock in
> hvc_console::hvc_alloc(), and here's the relevant output from dmesg:
>
> root@myubuntu:~# dmesg | grep MBH
> [3307216.210274] MBH: got hvc_ports_mutex
> [3307216.210690] MBH: trylock of hvc_ports_mutex failed
> [3307216.211143] MBH: got hvc_ports_mutex
>
> This is in a system with two virtio console ports, each of which is a
> console. I think if the VIRTIO_CONSOLE_CONSOLE_PORT message handling
> were actually being serialized, the trylock should never fail.
Agreed.
> What's the source of the serialization for the workqueue items? At
> first reading it looks like the control_work_handler gets called for
> each virtio interrupt?
It all depends on how you add ports. If you're using qemu, they
happen via the control work handler.
Amit
next prev parent reply other threads:[~2011-11-29 14:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-08 21:44 [PATCH RFC v3 0/3] Support multiple VirtioConsoles Miche Baker-Harvey
2011-11-08 21:44 ` [PATCH v3 1/3] virtio_console: Fix locking of vtermno Miche Baker-Harvey
2011-11-11 4:27 ` Rusty Russell
2011-11-17 19:09 ` Amit Shah
2011-11-08 21:45 ` [PATCH v3 2/3] hvc_init(): Enforce one-time initialization Miche Baker-Harvey
2011-11-09 7:24 ` Michael Ellerman
2011-11-11 4:30 ` Rusty Russell
2011-11-17 18:57 ` Miche Baker-Harvey
2011-11-21 5:01 ` Rusty Russell
2011-11-21 22:16 ` Miche Baker-Harvey
2011-11-22 0:58 ` Rusty Russell
2011-11-23 10:38 ` Amit Shah
2011-11-23 12:56 ` Amit Shah
2011-11-23 13:06 ` Sasha Levin
2011-11-23 13:15 ` Amit Shah
2011-11-28 23:40 ` Miche Baker-Harvey
2011-11-29 14:21 ` Amit Shah [this message]
2011-11-29 17:04 ` Miche Baker-Harvey
2011-11-29 17:50 ` Miche Baker-Harvey
2011-12-05 10:54 ` Amit Shah
2011-12-06 17:05 ` Miche Baker-Harvey
2011-12-08 12:08 ` Amit Shah
2011-12-12 19:11 ` Miche Baker-Harvey
2011-12-12 19:25 ` Amit Shah
2011-12-16 6:00 ` Amit Shah
2011-11-08 21:45 ` [PATCH v3 3/3] Use separate struct console structure for each hvc_console Miche Baker-Harvey
2011-11-09 8:05 ` Michael Ellerman
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