diff options
| author | Håkon Bugge <Haakon.Bugge@oracle.com> | 2017-09-06 18:35:51 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-09-07 20:07:13 -0700 |
| commit | 126f760ca94dae77425695f9f9238b731de86e32 (patch) | |
| tree | 9eb6678bb969d67a8f6cbab6110f0816bbde0798 /net | |
| parent | eef5a7cc2a571eb2176c8b9260d4ccfc9f6be127 (diff) | |
| download | linux-126f760ca94dae77425695f9f9238b731de86e32.tar.bz2 | |
rds: Fix incorrect statistics counting
In rds_send_xmit() there is logic to batch the sends. However, if
another thread has acquired the lock and has incremented the send_gen,
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 counts the race condition correctly.
Changes from v1:
- Removed check for *someone_on_xmit()*
- Fixed incorrect indentation
Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: Knut Omang <knut.omang@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/rds/send.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/net/rds/send.c b/net/rds/send.c index 058a40743041..b52cdc8ae428 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -428,14 +428,18 @@ over_batch: * some work and we will skip our goto */ if (ret == 0) { + bool raced; + smp_mb(); + raced = send_gen != READ_ONCE(cp->cp_send_gen); + if ((test_bit(0, &conn->c_map_queued) || - !list_empty(&cp->cp_send_queue)) && - send_gen == READ_ONCE(cp->cp_send_gen)) { - rds_stats_inc(s_send_lock_queue_raced); + !list_empty(&cp->cp_send_queue)) && !raced) { if (batch_count < send_batch_count) goto restart; queue_delayed_work(rds_wq, &cp->cp_send_w, 1); + } else if (raced) { + rds_stats_inc(s_send_lock_queue_raced); } } out: |