diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/hv/channel.c | 12 | ||||
| -rw-r--r-- | drivers/hv/hyperv_vmbus.h | 2 | ||||
| -rw-r--r-- | drivers/hv/ring_buffer.c | 51 |
3 files changed, 61 insertions, 4 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 9303252b2e19..064257e79f23 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -735,6 +735,7 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, u32 packetlen; u32 userlen; int ret; + bool signal = false; *buffer_actual_len = 0; *requestid = 0; @@ -761,8 +762,10 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, /* Copy over the packet to the user buffer */ ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen, - (desc.offset8 << 3)); + (desc.offset8 << 3), &signal); + if (signal) + vmbus_setevent(channel); return 0; } @@ -779,6 +782,7 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer, u32 packetlen; u32 userlen; int ret; + bool signal = false; *buffer_actual_len = 0; *requestid = 0; @@ -805,7 +809,11 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer, *requestid = desc.trans_id; /* Copy over the entire packet to the user buffer */ - ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0); + ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0, + &signal); + + if (signal) + vmbus_setevent(channel); return 0; } diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index becb106918d6..ac111f223821 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -550,7 +550,7 @@ int hv_ringbuffer_peek(struct hv_ring_buffer_info *ring_info, void *buffer, int hv_ringbuffer_read(struct hv_ring_buffer_info *ring_info, void *buffer, u32 buflen, - u32 offset); + u32 offset, bool *signal); void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info, diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 2a0babc95709..cafa72ffdc30 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -84,6 +84,50 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi) return false; } +/* + * To optimize the flow management on the send-side, + * when the sender is blocked because of lack of + * sufficient space in the ring buffer, potential the + * consumer of the ring buffer can signal the producer. + * This is controlled by the following parameters: + * + * 1. pending_send_sz: This is the size in bytes that the + * producer is trying to send. + * 2. The feature bit feat_pending_send_sz set to indicate if + * the consumer of the ring will signal when the ring + * state transitions from being full to a state where + * there is room for the producer to send the pending packet. + */ + +static bool hv_need_to_signal_on_read(u32 old_rd, + struct hv_ring_buffer_info *rbi) +{ + u32 prev_write_sz; + u32 cur_write_sz; + u32 r_size; + u32 write_loc = rbi->ring_buffer->write_index; + u32 read_loc = rbi->ring_buffer->read_index; + u32 pending_sz = rbi->ring_buffer->pending_send_sz; + + /* + * If the other end is not blocked on write don't bother. + */ + if (pending_sz == 0) + return false; + + r_size = rbi->ring_datasize; + cur_write_sz = write_loc >= read_loc ? r_size - (write_loc - read_loc) : + read_loc - write_loc; + + prev_write_sz = write_loc >= old_rd ? r_size - (write_loc - old_rd) : + old_rd - write_loc; + + + if ((prev_write_sz < pending_sz) && (cur_write_sz >= pending_sz)) + return true; + + return false; +} /* * hv_get_next_write_location() @@ -461,13 +505,14 @@ int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info, * */ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, - u32 buflen, u32 offset) + u32 buflen, u32 offset, bool *signal) { u32 bytes_avail_towrite; u32 bytes_avail_toread; u32 next_read_location = 0; u64 prev_indices = 0; unsigned long flags; + u32 old_read; if (buflen <= 0) return -EINVAL; @@ -478,6 +523,8 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, &bytes_avail_toread, &bytes_avail_towrite); + old_read = bytes_avail_toread; + /* Make sure there is something to read */ if (bytes_avail_toread < buflen) { spin_unlock_irqrestore(&inring_info->ring_lock, flags); @@ -508,5 +555,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, spin_unlock_irqrestore(&inring_info->ring_lock, flags); + *signal = hv_need_to_signal_on_read(old_read, inring_info); + return 0; } |