[PATCH v5 3/9] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner

2016-10-20 Thread Pan Xinhui
An over-committed guest with more vCPUs than pCPUs has a heavy overload in the two spin_on_owner. This blames on the lock holder preemption issue. Kernel has an interface bool vcpu_is_preempted(int cpu) to see if a vCPU is currently running or not. So break the spin loops on true condition.

[PATCH v5 3/9] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner

2016-10-20 Thread Pan Xinhui
An over-committed guest with more vCPUs than pCPUs has a heavy overload in the two spin_on_owner. This blames on the lock holder preemption issue. Kernel has an interface bool vcpu_is_preempted(int cpu) to see if a vCPU is currently running or not. So break the spin loops on true condition.