IB/ipath: Head of Line blocking vs forward progress of user apps

There's a conflict between our need to quiesce PSM-based applications
to avoid HoL blocking when the IB link goes down and the apps' desire
to remain running so that their quiescence timout mechanism can keep
running.

The compromise is to STOP the processes for a fixed period of time and
then alternate between CONT and STOP until the link is again active.

If there are poor interactions with subnet manager configuration at a
given site, the interval can be adjusted via a module paramter.

Signed-off-by: John Gregor <john.gregor@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_debug.h b/drivers/infiniband/hw/ipath/ipath_debug.h
index d6f69532d83f..7170bd20cfbb 100644
--- a/drivers/infiniband/hw/ipath/ipath_debug.h
+++ b/drivers/infiniband/hw/ipath/ipath_debug.h
@@ -66,6 +66,7 @@
 #define __IPATH_IPATHERR    0x40000     /* Ethernet (IPATH) errors */
 #define __IPATH_IPATHPD     0x80000     /* Ethernet (IPATH) packet dump */
 #define __IPATH_IPATHTABLE  0x100000    /* Ethernet (IPATH) table dump */
+#define __IPATH_LINKVERBDBG 0x200000    /* very verbose linkchange debug */
 
 #else                           /* _IPATH_DEBUGGING */