Messages in this thread | | | Date | Tue, 01 Nov 2011 14:58:23 -0500 | From | Anthony Liguori <> | Subject | Re: [PATCH 6/6 V2] Add age out of guest paused flag |
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On 11/01/2011 02:51 PM, Eric B Munson wrote: > On Tue, 01 Nov 2011, Anthony Liguori wrote: > >> On 10/31/2011 03:07 PM, Eric B Munson wrote: >>> The KVM_GUEST_PAUSED flag will prevent a guest from compaining about a soft >>> lockup but it can mask real soft lockups if the flag isn't cleared when it is >>> no longer relevant. This patch adds a kvm ioctl that the hypervisor will use >>> when it resumes a guest to start a timer for aging out the flag. The time out >>> will be specified by the hypervisor in the ioctl call. >>> >>> Signed-off-by: Eric B Munson<emunson@mgebm.net> >> >> Why not have the guest clear the flag when it acknowledges it? >> >> The hypervisor would unconditionally set the bit, and the guest >> would do a testandclear to check if the bit is set. I think that >> avoids the whole aging business. >> >> Regards, >> >> Anthony Liguori > > If you have a look at patch 5 of this series, the flag is cleared when the > guest checks the validity of a soft lockup. However, the aging is meant to > cover the case where the guest never sees a soft lockup. We don't want this > flag to be stored for ever and end up delaying real soft lockup messages. With > that case in mind, I thought this was a good/simple compramise.
If the guest clears the flag, then I don't think you have to worry about this.
Regards,
Anthony Liguori
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