| Message ID | 1455019243-87616-1-git-send-email-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/09/2016 01:00 PM, Christian Borntraeger wrote: > Right now halt_poll_ns can be change during runtime. The > grow and shrink factors can only be set during module load. > Let's make this consistent and allow changes during runtime. > To avoid dirty tricky like setting shrink to 0 after the > check for 0, use READ_ONCE to get a consistent number for > all cases. > > Cc: Wanpeng Li <wanpeng.li@hotmail.com> > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > virt/kvm/kvm_main.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 726d7c8..eafea6f 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -72,11 +72,11 @@ module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR); > > /* Default doubles per-vcpu halt_poll_ns. */ > static unsigned int halt_poll_ns_grow = 2; > -module_param(halt_poll_ns_grow, int, S_IRUGO); > +module_param(halt_poll_ns_grow, int, S_IRUGO | S_IWUSR); Please let me know if I should respin with a global fixup regarding signedness: Right now we have a mix of uint: > static unsigned int halt_poll_ns_grow = 2; int: > +module_param(halt_poll_ns_grow, int, S_IRUGO | S_IWUSR); int: > - int old, val; I think having everything as unsigned int would be the right thing. Christian -- 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/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 726d7c8..eafea6f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -72,11 +72,11 @@ module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR); /* Default doubles per-vcpu halt_poll_ns. */ static unsigned int halt_poll_ns_grow = 2; -module_param(halt_poll_ns_grow, int, S_IRUGO); +module_param(halt_poll_ns_grow, int, S_IRUGO | S_IWUSR); /* Default resets per-vcpu halt_poll_ns . */ static unsigned int halt_poll_ns_shrink; -module_param(halt_poll_ns_shrink, int, S_IRUGO); +module_param(halt_poll_ns_shrink, int, S_IRUGO | S_IWUSR); /* * Ordering of locks: @@ -1952,14 +1952,15 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty); static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) { - int old, val; + int old, val, grow; - old = val = vcpu->halt_poll_ns; + old = val = READ_ONCE(vcpu->halt_poll_ns); + grow = READ_ONCE(halt_poll_ns_grow); /* 10us base */ - if (val == 0 && halt_poll_ns_grow) + if (val == 0 && grow) val = 10000; else - val *= halt_poll_ns_grow; + val *= grow; vcpu->halt_poll_ns = val; trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old); @@ -1967,13 +1968,14 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu) static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu) { - int old, val; + int old, val, shrink; - old = val = vcpu->halt_poll_ns; - if (halt_poll_ns_shrink == 0) + old = val = READ_ONCE(vcpu->halt_poll_ns); + shrink = READ_ONCE(halt_poll_ns_shrink); + if (shrink == 0) val = 0; else - val /= halt_poll_ns_shrink; + val /= shrink; vcpu->halt_poll_ns = val; trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
Right now halt_poll_ns can be change during runtime. The grow and shrink factors can only be set during module load. Let's make this consistent and allow changes during runtime. To avoid dirty tricky like setting shrink to 0 after the check for 0, use READ_ONCE to get a consistent number for all cases. Cc: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- virt/kvm/kvm_main.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)