Re: [PATCH net] rds: Fix incorrect statistics counting

From: Santosh Shilimkar
Date: Wed Sep 06 2017 - 11:58:19 EST


On 9/6/2017 8:29 AM, HÃkon Bugge wrote:
In rds_send_xmit() there is logic to batch the sends. However, if
another thread has acquired the lock, it is considered a race and we
yield. The code incrementing the s_send_lock_queue_raced statistics
counter did not count this event correctly.

This commit removes a small race in determining the race and
increments the statistics counter correctly.

Signed-off-by: HÃkon Bugge <haakon.bugge@xxxxxxxxxx>
Reviewed-by: Knut Omang <knut.omang@xxxxxxxxxx>
---
net/rds/send.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

Those counters are not really to give that accurate so
am not very keen to add additional cycles in send paths
and add additional code. Have you seen any real issue
or this is just a observation. s_send_lock_queue_raced
counter is never used to check for smaller increments
and hence the question.

Regards,
Santosh