From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Sheng Yang <sheng@linux.intel.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Joerg Roedel <joerg.roedel@amd.com>,
kvm@vger.kernel.org, "Yaozu (Eddie) Dong" <eddie.dong@intel.com>
Subject: Re: [PATCH v5] KVM: VMX: Execute WBINVD to keep data consistency with assigned devices
Date: Tue, 29 Jun 2010 11:31:06 -0300 [thread overview]
Message-ID: <20100629143106.GA29852@amt.cnet> (raw)
In-Reply-To: <4C29FA39.8060908@redhat.com>
On Tue, Jun 29, 2010 at 04:50:49PM +0300, Avi Kivity wrote:
> On 06/29/2010 04:35 PM, Marcelo Tosatti wrote:
> >>>
> >>>work_on_cpu() loop instead of smp_call_function_many(), to avoid executing
> >>>wbinvd with interrupts disabled.
> >>Why? wbinvd is not interruptible.
> >Right. But still, smp_call_function_many() is going to busy-spin until
> >the target CPUs finish their work, while work_on_cpu() will schedule.
> >
>
> Good point. So in the worst case we double the hit.
>
> >Also the IPI request has to handled immediately, bypassing the
> >scheduler.
>
> We're screwed on that point in any case, once wbinvd starts the
> scheduler is bypassed.
>
> But work_on_cpu() has its own problems. It creates a kthread
> (perhaps not too bad). Maybe queue_work_on()?
queue_work_on + flush_work should be equivalent to work_on_cpu (without
thread creation).
next prev parent reply other threads:[~2010-06-29 18:12 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-28 3:36 [PATCH v3] KVM: VMX: Execute WBINVD to keep data consistency with assigned devices Sheng Yang
2010-06-28 3:56 ` Avi Kivity
2010-06-28 6:42 ` Sheng Yang
2010-06-28 6:56 ` Avi Kivity
2010-06-28 6:56 ` Sheng Yang
2010-06-28 7:08 ` Avi Kivity
2010-06-28 7:41 ` Sheng Yang
2010-06-28 8:07 ` Avi Kivity
2010-06-28 8:42 ` [PATCH v4] " Sheng Yang
2010-06-28 9:27 ` Avi Kivity
2010-06-28 9:31 ` Gleb Natapov
2010-06-28 9:35 ` Avi Kivity
2010-06-29 3:16 ` [PATCH v5] " Sheng Yang
2010-06-29 9:39 ` Avi Kivity
2010-06-29 10:32 ` Jan Kiszka
2010-06-29 10:42 ` Avi Kivity
2010-06-29 12:32 ` Roedel, Joerg
2010-06-29 12:37 ` Avi Kivity
2010-06-29 10:14 ` Roedel, Joerg
2010-06-29 10:44 ` Avi Kivity
2010-06-29 12:28 ` Roedel, Joerg
2010-06-29 12:35 ` Avi Kivity
2010-06-29 13:34 ` Roedel, Joerg
2010-06-29 13:25 ` Marcelo Tosatti
2010-06-29 13:28 ` Avi Kivity
2010-06-29 13:35 ` Marcelo Tosatti
2010-06-29 13:50 ` Avi Kivity
2010-06-29 14:31 ` Marcelo Tosatti [this message]
2010-06-28 7:30 ` [PATCH v3] " Dong, Eddie
2010-06-28 8:04 ` Avi Kivity
2010-06-28 8:16 ` Dong, Eddie
2010-06-28 8:45 ` Jan Kiszka
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