Hello

I reproduced the issue on 5.11.7-rc1, could we port this patch to stable 
branch.

Thanks
Yi


On 2/17/21 9:37 PM, Jason Gunthorpe wrote:

On Fri, Feb 05, 2021 at 09:14:28AM +0100, Nicolas Morey-Chaisemartin wrote:

quoted

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.

Signed-off-by: Nicolas Morey-Chaisemartin <redacted>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
  drivers/infiniband/ulp/srp/ib_srp.c | 110 ++++++++++++----------------
  1 file changed, 45 insertions(+), 65 deletions(-)

Applied to for-next, thanks

Jason