[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20180328202457.GI26753@flask>
Date: Wed, 28 Mar 2018 22:24:57 +0200
From: Radim Krčmář <rkrcmar@...hat.com>
To: Babu Moger <babu.moger@....com>
Cc: joro@...tes.org, tglx@...utronix.de, mingo@...hat.com,
hpa@...or.com, x86@...nel.org, pbonzini@...hat.com,
kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/5] KVM: VMX: Remove ple_window_actual_max
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@...hat.com>
> Signed-off-by: Babu Moger <babu.moger@....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.
Powered by blists - more mailing lists