Re: Is it ok to use debugfs to dump some ucontext-level driver-defined info?

[liweihang <liweihang@huawei.com>]

On 2020/12/31 15:59, Leon Romanovsky wrote:
> On Tue, Dec 29, 2020 at 01:31:39PM +0000, liweihang wrote:
>> Hi all,
>>
>> We want to dump some hns driver-defined information that belongs to a
>> process to keep track of current memory usage. For example, there is
>> a ucontext-level(process-level) memory pool to store WQE which is
>> shared by a lot of QPs, we want to record and query which QPs are using
>> this pool and how much space each QP is using.
>>
>> rdmatool don't have a ucontext-level resource tracking currently, is it
>> ok to achieve that through debugfs?
>>
>> This may looks like:
>>
>> $ echo 1 > <dbgfs_dir>/hns_roce/hns_0/<pid>/qp
>> QPN        Total(kB)  SQ(kB)     SGE(kB)    RQ(kB)
>> 110        6400       256        2048       4096
>> 118        6400       256        2048       0
>>
>> Or should it be achieved in rdmatool?
> 
> I think so, because PID != ucontext. Why can't it be presented as QP
> attribute? Can you please send "rdmatool" example?
> 
> Thanks

Hi Leon,

Thanks for your response. If we can achieve it in rdmatool, it may
looks like:

1) We want to get some information of a ucontext (assuming that each
ucontext has an ID), for example, the size of a memory pool that belongs
to a ucontext as I mentioned above:

$ rdma res show ucontext
uctx_id	1 pid 20 qp_buf_sz 6400 sq_buf_sz 256 sge_buf_sz 2048 rq_buf_sz 4096
uctx_id	2 pid 20 qp_buf_sz 4800 sq_buf_sz 128 sge_buf_sz 2048 rq_buf_sz 2048

2) We want to know which ucontext a QP belongs to:

$ rdma res show qp
link hns_0/1 lqpn 1 type GSI ... uctx_id 1
link hns_0/1 lqpn 2 type RC ... uctx_id 1

So the question is, we don't have a ucontext-level restrack currently, and
there in no 'id' for each ucontext.

Thanks
Weihang