@@ -359,14 +359,15 @@ TRACE_EVENT(
#endif
TRACE_EVENT(kvm_halt_poll_ns,
- TP_PROTO(bool grow, unsigned int vcpu_id, int new, int old),
+ TP_PROTO(bool grow, unsigned int vcpu_id, unsigned int new,
+ unsigned int old),
TP_ARGS(grow, vcpu_id, new, old),
TP_STRUCT__entry(
__field(bool, grow)
__field(unsigned int, vcpu_id)
- __field(int, new)
- __field(int, old)
+ __field(unsigned int, new)
+ __field(unsigned int, old)
),
TP_fast_assign(
@@ -376,7 +377,7 @@ TRACE_EVENT(kvm_halt_poll_ns,
__entry->old = old;
),
- TP_printk("vcpu %u: halt_poll_ns %d (%s %d)",
+ TP_printk("vcpu %u: halt_poll_ns %u (%s %u)",
__entry->vcpu_id,
__entry->new,
__entry->grow ? "grow" : "shrink",
@@ -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, uint, 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, uint, 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;
+ unsigned int old, val, grow;
old = val = 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;
+ unsigned int old, val, shrink;
old = val = vcpu->halt_poll_ns;
- if (halt_poll_ns_shrink == 0)
+ 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. Lets fix several aspects of grow shrink: - make grow/shrink changeable by root - make all variables unsigned int - read the variables once to prevent races Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- V1->V2: - no need to use READ_ONCE for the vcpu variables - make grow/shrink unsigned everywhere include/trace/events/kvm.h | 9 +++++---- virt/kvm/kvm_main.c | 18 ++++++++++-------- 2 files changed, 15 insertions(+), 12 deletions(-)