Re: [PATCH 4/9] net: openvswitch: use this_cpu_ptr per-cpu helper
flat view
From: Christoph Lameter <hidden>
Date: 2012-10-31 17:39:58
Also in:
lkml
On Wed, 31 Oct 2012, Shan Wei wrote:
quoted hunk ↗ jump to hunk
--- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c@@ -208,7 +208,7 @@ void ovs_dp_process_received_packet(struct vport *p, struct sk_buff *skb) int error; int key_len; - stats = per_cpu_ptr(dp->stats_percpu, smp_processor_id()); + stats = this_cpu_ptr(dp->stats_percpu);
Well this is an improvement and may be ok if the preemption is disabled at this point. There is another possibility here to use this_cpu_read/add/inc instead of determining the pointer to the local cpu first and then performing operations on the fields. The pointer relocation with this_cpu_xxx ops is implicit in the instructions and safe against changing of processors. It would also save us the determination of a pointer to the current cpus stats structure.