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From: Steven Rostedt <rostedt@goodmis.org>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Stefano Garzarella <sgarzare@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, Joel Fernandes <joelaf@google.com>,
	Linux Trace Devel <linux-trace-devel@vger.kernel.org>
Subject: Re: [RFC][PATCH] vhost/vsock: Add vsock_list file to map cid with vhost tasks
Date: Thu, 13 May 2021 12:08:42 -0400	[thread overview]
Message-ID: <20210513120842.4ed3fb0e@gandalf.local.home> (raw)
In-Reply-To: <YJ1Mbie1YGKRR6b8@stefanha-x1.localdomain>

On Thu, 13 May 2021 16:57:34 +0100
Stefan Hajnoczi <stefanha@redhat.com> wrote:


> This approach relies on process hierarchy of the VMM (QEMU).
> Multi-process QEMU is in development and will allow VIRTIO devices to
> run as separate processes from the main QEMU. It then becomes harder to
> correlate a VIRTIO device process with its QEMU process.

And we need to know all these mapping regardless, as we need to map each
thread / process to the vCPU in order to correlate between host thread and
vCPU thread for showing in KernelShark.

Thus this mapping to find the main thread/process needs to be done
regardless.

> 
> So I think in the end this approach ends up being as fragile as parsing
> command-lines. The kernel doesn't really have the concept of a "VM" that
> the vhost_vsock is associated with :). Maybe just parse QEMU and crosvm
> command-lines?
>

That's what we do now, and it already broke once, and even parsing the
command line wont be enough for the stated reasons above.

-- Steve

      reply	other threads:[~2021-05-13 16:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-05 20:38 [RFC][PATCH] vhost/vsock: Add vsock_list file to map cid with vhost tasks Steven Rostedt
2021-05-06  1:03 ` Steven Rostedt
2021-05-07 14:11 ` Stefano Garzarella
2021-05-07 14:40   ` Steven Rostedt
2021-05-07 15:43     ` Stefano Garzarella
2021-05-07 16:09       ` Steven Rostedt
2021-05-08 18:32 ` Mike Christie
2021-05-13 15:57 ` Stefan Hajnoczi
2021-05-13 16:08   ` Steven Rostedt [this message]

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