diff options
| author | Stephen Hemminger <stephen@networkplumber.org> | 2017-06-25 21:30:28 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-17 17:16:05 +0200 |
| commit | 03bad714a1619c0074eb44d6f217c505fe27030f (patch) | |
| tree | 3185ecea62d5166d5fc711b0b164ff8f7abf933c /drivers/hv | |
| parent | vmbus: eliminate duplicate cached index (diff) | |
| download | linux-03bad714a1619c0074eb44d6f217c505fe27030f.tar.xz linux-03bad714a1619c0074eb44d6f217c505fe27030f.zip | |
vmbus: more host signalling avoidance
Don't signal host if it has disabled interrupts for that
ring buffer. Check the feature bit to see if host supports
pending send size flag.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/ring_buffer.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index b0f79526b86a..741daa6e2fc7 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -396,7 +396,6 @@ void hv_pkt_iter_close(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; u32 orig_write_sz = hv_get_bytes_to_write(rbi); - u32 pending_sz; /* * Make sure all reads are done before we update the read index since @@ -419,15 +418,27 @@ void hv_pkt_iter_close(struct vmbus_channel *channel) */ virt_mb(); - pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); - /* If the other end is not blocked on write don't bother. */ - if (pending_sz == 0) + /* If host has disabled notifications then skip */ + if (rbi->ring_buffer->interrupt_mask) return; - if (hv_get_bytes_to_write(rbi) < pending_sz) - return; + if (rbi->ring_buffer->feature_bits.feat_pending_send_sz) { + u32 pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); - if (orig_write_sz < pending_sz) - vmbus_setevent(channel); + /* + * If there was space before we began iteration, + * then host was not blocked. Also handles case where + * pending_sz is zero then host has nothing pending + * and does not need to be signaled. + */ + if (orig_write_sz > pending_sz) + return; + + /* If pending write will not fit, don't give false hope. */ + if (hv_get_bytes_to_write(rbi) < pending_sz) + return; + } + + vmbus_setevent(channel); } EXPORT_SYMBOL_GPL(hv_pkt_iter_close); |