This was intended for future use, but since the code is currently
unused (and therefore dead and unused), remove it.
It can be restored when there is a use case.
Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
---
drivers/hv/channel.c | 2 +-
include/linux/hyperv.h | 36 ------------------------------------
2 files changed, 1 insertion(+), 37 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index deb852238b2d..01d5bdb69770 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -47,7 +47,7 @@ void vmbus_setevent(struct vmbus_channel *channel)
* For channels marked as in "low latency" mode
* bypass the monitor page mechanism.
*/
- if (channel->offermsg.monitor_allocated && !channel->low_latency) {
+ if (channel->offermsg.monitor_allocated) {
vmbus_send_interrupt(channel->offermsg.child_relid);
/* Get the child to parent monitor page */
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index b8807da6ef72..09d10a4a34f4 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -853,32 +853,6 @@ struct vmbus_channel {
struct rcu_head rcu;
/*
- * For performance critical channels (storage, networking
- * etc,), Hyper-V has a mechanism to enhance the throughput
- * at the expense of latency:
- * When the host is to be signaled, we just set a bit in a shared page
- * and this bit will be inspected by the hypervisor within a certain
- * window and if the bit is set, the host will be signaled. The window
- * of time is the monitor latency - currently around 100 usecs. This
- * mechanism improves throughput by:
- *
- * A) Making the host more efficient - each time it wakes up,
- * potentially it will process morev number of packets. The
- * monitor latency allows a batch to build up.
- * B) By deferring the hypercall to signal, we will also minimize
- * the interrupts.
- *
- * Clearly, these optimizations improve throughput at the expense of
- * latency. Furthermore, since the channel is shared for both
- * control and data messages, control messages currently suffer
- * unnecessary latency adversley impacting performance and boot
- * time. To fix this issue, permit tagging the channel as being
- * in "low latency" mode. In this mode, we will bypass the monitor
- * mechanism.
- */
- bool low_latency;
-
- /*
* NUMA distribution policy:
* We support teo policies:
* 1) Balanced: Here all performance critical channels are
@@ -926,16 +900,6 @@ static inline void set_channel_pending_send_size(struct
vmbus_channel *c,
c->outbound.ring_buffer->pending_send_sz = size;
}
-static inline void set_low_latency_mode(struct vmbus_channel *c)
-{
- c->low_latency = true;
-}
-
-static inline void clear_low_latency_mode(struct vmbus_channel *c)
-{
- c->low_latency = false;
-}
-
void vmbus_onmessage(void *context);
int vmbus_request_offers(void);
--
2.11.0
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