Re: [PATCH v9 3/3] tools/testing/cxl: Add XOR Math support to cxl_test

[Alison Schofield <alison.schofield@intel.com>]

On Wed, Jan 18, 2023 at 12:20:39PM -0800, Dan Williams wrote:
> alison.schofield@ wrote:
> > From: Alison Schofield <alison.schofield@intel.com>
> > 
> > Expand the cxl_test topology to include CFMWS's that use XOR math
> > for interleave arithmetic, as defined in the CXL Specification 3.0.
> > 
> > With this expanded topology, cxl_test is useful for testing:
> > x1,x2,x4 ways with XOR interleave arithmetic.
> > 
> > Define the additional XOR CFMWS entries to appear only with the
> > module parameter interleave_arithmetic=1. The cxl_test default
> > continues to be modulo math.
> > 
> > modprobe cxl_test interleave_arithmetic=1
> > 
> > Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > ---
> >  tools/testing/cxl/test/cxl.c | 118 ++++++++++++++++++++++++++++++++++-
> >  1 file changed, 115 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> > index 7edce12fd2ce..c7dba7550106 100644
> > --- a/tools/testing/cxl/test/cxl.c
> > +++ b/tools/testing/cxl/test/cxl.c
> [..]
> > @@ -897,6 +997,16 @@ static __init int cxl_test_init(void)
> >  	if (rc)
> >  		goto err_gen_pool_add;
> >  
> > +	if (interleave_arithmetic == 1) {
> > +		cfmws_start = CFMWS_XOR_ARRAY_START;
> > +		cfmws_end = CFMWS_XOR_ARRAY_END;
> > +		dev_dbg(NULL, "cxl_test loading xor math option\n");
> > +	} else {
> > +		cfmws_start = CFMWS_MOD_ARRAY_START;
> > +		cfmws_end = CFMWS_MOD_ARRAY_END;
> > +		dev_dbg(NULL, "cxl_test loading modulo math option\n");
> > +	}
> > +
> 
> Missed this earlier., but noticed now that I am running it. If no device
> is available then just use pr_debug() instead of dev_dbg(). That said,
> these messages could just be skipped altogher and make the value of
> @interleave_arithmetic readable via sysfs if something really needs to
> recall what mode the test module is running in. I.e.:

Understand (now). I'll send a patch like you suggest.
Thanks!

> 
> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 14530fe1edc6..b7d7420e74ea 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c
> @@ -1265,11 +1265,9 @@ static __init int cxl_test_init(void)
>         if (interleave_arithmetic == 1) {
>                 cfmws_start = CFMWS_XOR_ARRAY_START;
>                 cfmws_end = CFMWS_XOR_ARRAY_END;
> -               dev_dbg(NULL, "cxl_test loading xor math option\n");
>         } else {
>                 cfmws_start = CFMWS_MOD_ARRAY_START;
>                 cfmws_end = CFMWS_MOD_ARRAY_END;
> -               dev_dbg(NULL, "cxl_test loading modulo math option\n");
>         }
>  
>         rc = populate_cedt();
> @@ -1456,7 +1454,7 @@ static __exit void cxl_test_exit(void)
>         unregister_cxl_mock_ops(&cxl_mock_ops);
>  }
>  
> -module_param(interleave_arithmetic, int, 0000);
> +module_param(interleave_arithmetic, int, 0444);
>  MODULE_PARM_DESC(interleave_arithmetic, "Modulo:0, XOR:1");
>  module_init(cxl_test_init);
>  module_exit(cxl_test_exit);
> 
> Otherwise, the current code leads to a concerning:
> 
> "[  111.743246] (NULL device *): cxl_test loading modulo math option"
> 
> ...at startup.