From 3a28fa35d6658703cd26f9c16aaea0eae06afd40 Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" Date: Tue, 8 Apr 2014 18:45:54 -0700 Subject: Drivers: hv: vmbus: Implement per-CPU mapping of relid to channel Currently the mapping of the relID to channel is done under the protection of a single spin lock. Starting with ws2012, each channel is bound to a specific VCPU in the guest. Use this binding to eliminate the spin lock by setting up per-cpu state for mapping relId to the channel. Signed-off-by: K. Y. Srinivasan Reviewed-by: Haiyang Zhang Signed-off-by: Greg Kroah-Hartman --- drivers/hv/connection.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'drivers/hv/connection.c') diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index df2363ea017f..7f10c151632a 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -234,6 +234,28 @@ cleanup: return ret; } +/* + * Map the given relid to the corresponding channel based on the + * per-cpu list of channels that have been affinitized to this CPU. + * This will be used in the channel callback path as we can do this + * mapping in a lock-free fashion. + */ +static struct vmbus_channel *pcpu_relid2channel(u32 relid) +{ + struct vmbus_channel *channel; + struct vmbus_channel *found_channel = NULL; + int cpu = smp_processor_id(); + struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; + + list_for_each_entry(channel, pcpu_head, percpu_list) { + if (channel->offermsg.child_relid == relid) { + found_channel = channel; + break; + } + } + + return found_channel; +} /* * relid2channel - Get the channel object given its @@ -285,7 +307,7 @@ static void process_chn_event(u32 relid) * Find the channel based on this relid and invokes the * channel callback to process the event */ - channel = relid2channel(relid); + channel = pcpu_relid2channel(relid); if (!channel) { pr_err("channel not found for relid - %u\n", relid); -- cgit v1.2.3