| Message ID | 1395754523-43697-2-git-send-email-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 25/03/2014 14:35, Christian Borntraeger ha scritto: > We allocate a page for the 2k sca, so lets use the space to improve > hit rate of some internal cpu caches. No need to change the freeing > of the page, as this will shift away the page offset bits anyway. > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> > --- > arch/s390/kvm/kvm-s390.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 7337c57..a02979f 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -215,6 +215,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > { > int rc; > char debug_name[16]; > + static unsigned long sca_offset; > > rc = -EINVAL; > #ifdef CONFIG_KVM_S390_UCONTROL > @@ -236,6 +237,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > kvm->arch.sca = (struct sca_block *) get_zeroed_page(GFP_KERNEL); > if (!kvm->arch.sca) > goto out_err; > + spin_lock(&kvm_lock); > + sca_offset = (sca_offset + 16) & 0x7f0; > + kvm->arch.sca = (struct sca_block *) ((char *) kvm->arch.sca + sca_offset); > + spin_unlock(&kvm_lock); > > sprintf(debug_name, "kvm-%u", current->pid); > > Does this have to remain the same across migration? 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
On 25/03/14 14:53, Paolo Bonzini wrote: > Il 25/03/2014 14:35, Christian Borntraeger ha scritto: >> We allocate a page for the 2k sca, so lets use the space to improve >> hit rate of some internal cpu caches. No need to change the freeing >> of the page, as this will shift away the page offset bits anyway. >> >> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> >> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> >> --- >> arch/s390/kvm/kvm-s390.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index 7337c57..a02979f 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -215,6 +215,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) >> { >> int rc; >> char debug_name[16]; >> + static unsigned long sca_offset; >> >> rc = -EINVAL; >> #ifdef CONFIG_KVM_S390_UCONTROL >> @@ -236,6 +237,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) >> kvm->arch.sca = (struct sca_block *) get_zeroed_page(GFP_KERNEL); >> if (!kvm->arch.sca) >> goto out_err; >> + spin_lock(&kvm_lock); >> + sca_offset = (sca_offset + 16) & 0x7f0; >> + kvm->arch.sca = (struct sca_block *) ((char *) kvm->arch.sca + sca_offset); >> + spin_unlock(&kvm_lock); >> >> sprintf(debug_name, "kvm-%u", current->pid); >> >> > > Does this have to remain the same across migration? Nope, the sca address is just an internal _host_ detail and does not belong/influence the guest. -- 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/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 7337c57..a02979f 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -215,6 +215,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) { int rc; char debug_name[16]; + static unsigned long sca_offset; rc = -EINVAL; #ifdef CONFIG_KVM_S390_UCONTROL @@ -236,6 +237,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.sca = (struct sca_block *) get_zeroed_page(GFP_KERNEL); if (!kvm->arch.sca) goto out_err; + spin_lock(&kvm_lock); + sca_offset = (sca_offset + 16) & 0x7f0; + kvm->arch.sca = (struct sca_block *) ((char *) kvm->arch.sca + sca_offset); + spin_unlock(&kvm_lock); sprintf(debug_name, "kvm-%u", current->pid);