[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [RFC] virtio: Report new guest memory statistics pertin

From: Anthony Liguori
Subject: Re: [Qemu-devel] [RFC] virtio: Report new guest memory statistics pertinent to memory ballooning (V2)
Date: Mon, 09 Nov 2009 15:15:30 -0600
User-agent: Thunderbird (X11/20090825)

Jamie Lokier wrote:
Adam Litke wrote:
+        s->stats.pswapin = has_feature(dev, VIRTIO_BALLOON_F_RPT_SWAP_OUT) ?
+                                       dev->stats.pswapin : -1;


Why not simply have the guest fill in the unused fields with -1, and
say that's how "no meaningful value" is represented in the ABI?

All guests have to know about all those fields anyway, for the
structure layout.  Is there any benefit to specifying feature bits in
advance over simply storing -1 there?

Features are negotiated. It lets a host advertise the support of a feature and it lets the guest acknowledge it's support of a feature.

Most importantly, why invent a new mechanism when we already have one?


Anthony Liguori

reply via email to

[Prev in Thread] Current Thread [Next in Thread]