From: Rik van Riel <riel@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/3] context_tracking: avoid irq_save/irq_restore on guest entry and exit
Date: Mon, 09 Nov 2015 08:58:22 -0500 [thread overview]
Message-ID: <5640A67E.6060605@redhat.com> (raw)
In-Reply-To: <1445996397-32703-3-git-send-email-pbonzini@redhat.com>
On 10/27/2015 09:39 PM, Paolo Bonzini wrote:
> guest_enter and guest_exit must be called with interrupts disabled,
> since they take the vtime_seqlock with write_seq{lock,unlock}.
> Therefore, it is not necessary to check for exceptions, nor to
> save/restore the IRQ state, when context tracking functions are
> called by guest_enter and guest_exit.
>
> Split the body of context_tracking_entry and context_tracking_exit
> out to __-prefixed functions, and use them from KVM.
>
> Rik van Riel has measured this to speed up a tight vmentry/vmexit
> loop by about 2%.
>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Tested-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
next prev parent reply other threads:[~2015-11-09 13:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-28 1:39 [PATCH 0/3] context_tracking: streamline code, avoid IRQ save/restore Paolo Bonzini
2015-10-28 1:39 ` [PATCH 1/3] context_tracking: remove duplicate enabled check Paolo Bonzini
2015-10-28 5:19 ` Andy Lutomirski
2015-11-07 9:38 ` Paolo Bonzini
2015-11-09 13:57 ` Rik van Riel
2015-10-28 1:39 ` [PATCH 2/3] context_tracking: avoid irq_save/irq_restore on guest entry and exit Paolo Bonzini
2015-10-28 5:20 ` Andy Lutomirski
2015-11-09 13:58 ` Rik van Riel [this message]
2015-10-28 1:39 ` [PATCH 3/3] x86: context_tracking: avoid irq_save/irq_restore on kernel " Paolo Bonzini
2015-10-28 5:22 ` Andy Lutomirski
2015-10-28 14:51 ` Paolo Bonzini
2016-03-14 19:23 ` Andy Lutomirski
2016-03-15 8:51 ` Paolo Bonzini
2015-10-28 2:05 ` [PATCH 0/3] context_tracking: streamline code, avoid IRQ save/restore Paolo Bonzini
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