| Message ID | 1408480536-8240-6-git-send-email-rkrcmar@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 19/08/2014 22:35, Radim Kr?má? ha scritto: > Modifications could get unwanted values of PLE window. (low or negative) > Use ple_window and the maximal value that cannot overflow as bounds. > > ple_window_max defaults to a very high value, but it would make sense to > set it to some fraction of the scheduler tick. > > Signed-off-by: Radim Kr?má? <rkrcmar@redhat.com> > --- > arch/x86/kvm/vmx.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 66259fd..e1192fb 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -144,6 +144,10 @@ module_param(ple_window_grow, int, S_IRUGO); > static int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK; > module_param(ple_window_shrink, int, S_IRUGO); > > +/* Default is to compute the maximum so we can never overflow. */ > +static int ple_window_max = INT_MAX / KVM_VMX_DEFAULT_PLE_WINDOW_GROW; > +module_param(ple_window_max, int, S_IRUGO); > + > extern const ulong vmx_return; > > #define NR_AUTOLOAD_MSRS 8 > @@ -5704,7 +5708,7 @@ static void grow_ple_window(struct kvm_vcpu *vcpu) > else > new = old + ple_window_grow; > > - vmx->ple_window = new; > + vmx->ple_window = min(new, ple_window_max); > } Please introduce a dynamic overflow-avoiding ple_window_max (like what you have in patch 9) already in patch 4... > static void shrink_ple_window(struct kvm_vcpu *vcpu) > @@ -5720,7 +5724,7 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu) > else > new = old - ple_window_shrink; > > - vmx->ple_window = new; > + vmx->ple_window = max(new, ple_window); ... and also squash this in patch 4. This patch can then introduce the ple_window_max module parameter (using module_param_cb to avoid overflows). Paolo > } > > /* > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2014-08-20 09:18+0200, Paolo Bonzini: > Il 19/08/2014 22:35, Radim Kr?má? ha scritto: > > Modifications could get unwanted values of PLE window. (low or negative) > > Use ple_window and the maximal value that cannot overflow as bounds. > > > > ple_window_max defaults to a very high value, but it would make sense to > > set it to some fraction of the scheduler tick. > > > > Signed-off-by: Radim Kr?má? <rkrcmar@redhat.com> > > --- > Please introduce a dynamic overflow-avoiding ple_window_max (like what > you have in patch 9) already in patch 4... > > > static void shrink_ple_window(struct kvm_vcpu *vcpu) > > @@ -5720,7 +5724,7 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu) > > else > > new = old - ple_window_shrink; > > > > - vmx->ple_window = new; > > + vmx->ple_window = max(new, ple_window); > > ... and also squash this in patch 4. > > This patch can then introduce the ple_window_max module parameter (using > module_param_cb to avoid overflows). Will do. --- It is going to make the patches slightly harder to review; Are we doing it because git doesn't bisect on series boundaries? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 66259fd..e1192fb 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -144,6 +144,10 @@ module_param(ple_window_grow, int, S_IRUGO); static int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK; module_param(ple_window_shrink, int, S_IRUGO); +/* Default is to compute the maximum so we can never overflow. */ +static int ple_window_max = INT_MAX / KVM_VMX_DEFAULT_PLE_WINDOW_GROW; +module_param(ple_window_max, int, S_IRUGO); + extern const ulong vmx_return; #define NR_AUTOLOAD_MSRS 8 @@ -5704,7 +5708,7 @@ static void grow_ple_window(struct kvm_vcpu *vcpu) else new = old + ple_window_grow; - vmx->ple_window = new; + vmx->ple_window = min(new, ple_window_max); } static void shrink_ple_window(struct kvm_vcpu *vcpu) @@ -5720,7 +5724,7 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu) else new = old - ple_window_shrink; - vmx->ple_window = new; + vmx->ple_window = max(new, ple_window); } /*
Modifications could get unwanted values of PLE window. (low or negative) Use ple_window and the maximal value that cannot overflow as bounds. ple_window_max defaults to a very high value, but it would make sense to set it to some fraction of the scheduler tick. Signed-off-by: Radim Kr?má? <rkrcmar@redhat.com> --- arch/x86/kvm/vmx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)