linux/drivers/infiniband
Parav Pandit 39baf10310 IB/core: Fix use workqueue without WQ_MEM_RECLAIM
The IB/core provides address resolution service and invokes callback
handler when address resolve request completes of requester in worker
thread context.

Such caller might allocate or free memory in callback handler
depending on the completion status to make further progress or to
terminate a connection. Most ULPs resolve route which involves
allocating route entry and path record elements in callback event handler.

It has been noticed that WQ_MEM_RECLAIM flag should not be used for
workers that tend to allocate memory in this [1] thread discussion.

In order to mitigate this situation, WQ_MEM_RECLAIM flag was dropped for
other such WQs in this [2] patch.

Similar problem might arise with address resolution path, though its not
yet noticed. The ib_addr workqueue is not memory reclaim path due to its
nature of invoking callback that might allocate memory or don't free any
memory under memory pressure.

[1] https://www.spinics.net/lists/linux-rdma/msg53239.html
[2] https://www.spinics.net/lists/linux-rdma/msg53416.html

Fixes: f54816261c ("IB/addr: Remove deprecated create_singlethread_workqueue")
Fixes: 5fff41e1f8 ("IB/core: Fix race condition in resolving IP to MAC")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-10-18 12:10:36 -04:00
..
core IB/core: Fix use workqueue without WQ_MEM_RECLAIM 2017-10-18 12:10:36 -04:00
hw IB: Let ib_core resolve destination mac address 2017-10-18 12:10:36 -04:00
sw IB/rxe: Handle NETDEV_CHANGE events 2017-08-28 19:12:36 -04:00
ulp IB/ipoib: Add ability to set PKEY index to lower device driver 2017-10-14 11:22:08 -07:00
Kconfig IB/core: Expose ioctl interface through experimental Kconfig 2017-08-31 08:35:14 -04:00
Makefile IB/rdmavt: Create module framework and handle driver registration 2016-03-10 20:37:04 -05:00