From: Parav Pandit parav@mellanox.com
[ Upstream commit 39baf10310e6669564a485b55267fae70a4e44ae ]
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: f54816261c2b ("IB/addr: Remove deprecated create_singlethread_workqueue") Fixes: 5fff41e1f89d ("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 Signed-off-by: Sasha Levin alexander.levin@verizon.com --- drivers/infiniband/core/addr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c index 12523f630b61..d2f74721b3ba 100644 --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -852,7 +852,7 @@ static struct notifier_block nb = {
int addr_init(void) { - addr_wq = alloc_ordered_workqueue("ib_addr", WQ_MEM_RECLAIM); + addr_wq = alloc_ordered_workqueue("ib_addr", 0); if (!addr_wq) return -ENOMEM;