linux-sg2042/drivers/infiniband/ulp/srp
Nicolas Morey-Chaisemartin 2b5715fc17 RDMA/srp: Fix support for unpopulated and unbalanced NUMA nodes
The current code computes a number of channels per SRP target and spreads
them equally across all online NUMA nodes.  Each channel is then assigned
a CPU within this node.

In the case of unbalanced, or even unpopulated nodes, some channels do not
get a CPU associated and thus do not get connected.  This causes the SRP
connection to fail.

This patch solves the issue by rewriting channel computation and
allocation:

- Drop channel to node/CPU association as it had no real effect on
  locality but added unnecessary complexity.

- Tweak the number of channels allocated to reduce CPU contention when
  possible:
  - Up to one channel per CPU (instead of up to 4 by node)
  - At least 4 channels per node, unless ch_count module parameter is
    used.

Link: https://lore.kernel.org/r/9cb4d9d3-30ad-2276-7eff-e85f7ddfb411@suse.com
Signed-off-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2021-02-16 20:01:50 -04:00
..
Kbuild treewide: Add SPDX license identifier - Kbuild 2019-05-30 11:32:33 -07:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
ib_srp.c RDMA/srp: Fix support for unpopulated and unbalanced NUMA nodes 2021-02-16 20:01:50 -04:00
ib_srp.h RDMA/srp: Remove support for FMR memory registration 2020-06-02 20:32:53 -03:00