From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Babu Moger <babu.moger@amd.com>
Cc: joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, x86@kernel.org, pbonzini@redhat.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/5] KVM: VMX: Remove ple_window_actual_max
Date: Wed, 28 Mar 2018 22:24:57 +0200 [thread overview]
Message-ID: <20180328202457.GI26753@flask> (raw)
In-Reply-To: <1521232646-79580-3-git-send-email-babu.moger@amd.com>
2018-03-16 16:37-0400, Babu Moger:
> Get rid of ple_window_actual_max, because its benefits are really
> minuscule and the logic is complicated.
>
> The overflows(and underflow) are controlled in __ple_window_grow
> and _ple_window_shrink respectively.
>
> Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
> arch/x86/kvm/vmx.c | 22 +---------------------
> 1 file changed, 1 insertion(+), 21 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> @@ -178,7 +178,6 @@
> module_param(ple_window_shrink, uint, 0444);
>
> /* Default is to compute the maximum so we can never overflow. */
> -static uint ple_window_actual_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX;
> static uint ple_window_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX;
> module_param(ple_window_max, uint, 0444);
>
> @@ -6645,14 +6644,12 @@ static uint __grow_ple_window(uint val)
> if (ple_window_grow < 1)
> return ple_window;
>
> - val = min(val, ple_window_actual_max);
> -
> if (ple_window_grow < ple_window)
> val *= ple_window_grow;
> else
> val += ple_window_grow;
>
> - return val;
> + return min(val, ple_window_max);
I added a bit of logic to avoid wraparounds.
next prev parent reply other threads:[~2018-03-28 20:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-16 20:37 [PATCH v2 0/5] KVM: x86: Implement Pause Loop Exit for SVM Babu Moger
2018-03-16 20:37 ` [PATCH v2 1/5] KVM: VMX: Fix the module parameters for vmx Babu Moger
2018-03-16 20:37 ` [PATCH v2 2/5] KVM: VMX: Remove ple_window_actual_max Babu Moger
2018-03-28 20:24 ` Radim Krčmář [this message]
2018-03-16 20:37 ` [PATCH v2 3/5] KVM: VMX: Bring the common code to header file Babu Moger
2018-03-28 20:26 ` Radim Krčmář
2018-03-28 21:12 ` Moger, Babu
2018-03-16 20:37 ` [PATCH v2 4/5] KVM: SVM: Add pause filter threshold Babu Moger
2018-03-16 20:37 ` [PATCH v2 5/5] KVM: SVM: Implement pause loop exit logic in SVM Babu Moger
2018-03-28 20:30 ` Radim Krčmář
2018-03-28 21:14 ` Moger, Babu
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