mirrors/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2025-11-04 10:40:15 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

vmbus: more host signalling avoidance

Browse source 
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>
This commit is contained in:
Stephen Hemminger 2017-06-25 12:30:28 -07:00 committed by Greg Kroah-Hartman
parent 05d00bc94a
commit 03bad714a1
1 changed files with 19 additions and 8 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

27
drivers/hv/ring_buffer.c
View file

@ -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);