@@ -41,6 +41,15 @@ static inline void yield_to_any(void)
{
plpar_hcall_norets(H_CONFER, -1, 0);
}
+
+/* Find if the previous physical CPU of this vcpu is available_idle or not */
+static inline void pcpu_available_instantly(int vcpu, unsigned long *is_idle)
+{
+ unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+ if (plpar_hcall(H_IDLE_HINT, retbuf, vcpu) == H_SUCCESS)
+ *is_idle = retbuf[0];
+}
#else
static inline bool is_shared_processor(void)
{
@@ -75,6 +84,8 @@ static inline void prod_cpu(int cpu)
#define vcpu_is_preempted vcpu_is_preempted
static inline bool vcpu_is_preempted(int cpu)
{
+ unsigned long is_idle = 0;
+
if (!is_shared_processor())
return false;
@@ -92,8 +103,14 @@ static inline bool vcpu_is_preempted(int cpu)
}
#endif
- if (yield_count_of(cpu) & 1)
- return true;
+ if (yield_count_of(cpu) & 1) {
+#ifdef CONFIG_PPC_SPLPAR
+ pcpu_available_instantly(cpu, &is_idle);
+#endif
+
+ if (!is_idle)
+ return true;
+ }
return false;
}
During checking for an available_idle_cpu, if the vCPU is yielded then check if it will be scheduled instantly by hypervisor or not. From guestOS, use H_IDLE_HINT hcall to ask for this hint from the hypverisor, and consider the yielded vCPU as target for wakeups iff it is hinted to be scheduled instantly. Signed-off-by: Parth Shah <parth@linux.ibm.com> --- arch/powerpc/include/asm/paravirt.h | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)