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Re: [Qemu-devel] [RFC PATCH 1/3] balloon: Allow nested inhibits
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [RFC PATCH 1/3] balloon: Allow nested inhibits |
Date: |
Wed, 18 Jul 2018 14:40:15 +0800 |
User-agent: |
Mutt/1.10.0 (2018-05-17) |
On Tue, Jul 17, 2018 at 04:47:37PM -0600, Alex Williamson wrote:
> A simple true/false internal state does not allow multiple users. Fix
> this within the existing interface by converting to a counter, so long
> as the counter is elevated, ballooning is inhibited.
>
> Signed-off-by: Alex Williamson <address@hidden>
> ---
> balloon.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/balloon.c b/balloon.c
> index 6bf0a9681377..2a6a7e1a22a0 100644
> --- a/balloon.c
> +++ b/balloon.c
> @@ -37,16 +37,17 @@
> static QEMUBalloonEvent *balloon_event_fn;
> static QEMUBalloonStatus *balloon_stat_fn;
> static void *balloon_opaque;
> -static bool balloon_inhibited;
> +static int balloon_inhibited;
>
> bool qemu_balloon_is_inhibited(void)
> {
> - return balloon_inhibited;
> + return balloon_inhibited > 0;
> }
>
> void qemu_balloon_inhibit(bool state)
> {
> - balloon_inhibited = state;
> + balloon_inhibited += (state ? 1 : -1);
> + assert(balloon_inhibited >= 0);
Better do it atomically?
> }
>
> static bool have_balloon(Error **errp)
>
>
Regards,
--
Peter Xu