2b5715fc17
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>