Message-Id: <D0ALHYK53O0Z.31OREWUI3J9N2@kernel.org>
Date: Wed, 03 Apr 2024 18:33:20 +0300
From: "Jarkko Sakkinen" <jarkko@...nel.org>
To: "Haitao Huang" <haitao.huang@...ux.intel.com>,
 Michal Koutný <mkoutny@...e.com>
Cc: <dave.hansen@...ux.intel.com>, <tj@...nel.org>,
 <linux-kernel@...r.kernel.org>, <linux-sgx@...r.kernel.org>,
 <x86@...nel.org>, <cgroups@...r.kernel.org>, <tglx@...utronix.de>,
 <mingo@...hat.com>, <bp@...en8.de>, <hpa@...or.com>,
 <sohil.mehta@...el.com>, <tim.c.chen@...ux.intel.com>,
 <zhiquan1.li@...el.com>, <kristen@...ux.intel.com>, <seanjc@...gle.com>,
 <zhanb@...rosoft.com>, <anakrish@...rosoft.com>,
 <mikko.ylinen@...ux.intel.com>, <yangjie@...rosoft.com>,
 <chrisyan@...rosoft.com>
Subject: Re: [PATCH v9 15/15] selftests/sgx: Add scripts for EPC cgroup
 testing

On Tue Apr 2, 2024 at 7:20 PM EEST, Haitao Huang wrote:
> On Tue, 02 Apr 2024 06:58:40 -0500, Jarkko Sakkinen <jarkko@...nel.org>  
> wrote:
>
> > On Tue Apr 2, 2024 at 2:23 PM EEST, Michal Koutný wrote:
> >> Hello.
> >>
> >> On Sat, Mar 30, 2024 at 01:26:08PM +0200, Jarkko Sakkinen  
> >> <jarkko@...nel.org> wrote:
> >> > > > It'd be more complicated and less readable to do all the stuff  
> >> without the
> >> > > > cgroup-tools, esp cgexec. I checked dependency, cgroup-tools only  
> >> depends
> >> > > > on libc so I hope this would not cause too much inconvenience.
> >> > >
> >> > > As per cgroup-tools, please prove this. It makes the job for more
> >> > > complicated *for you* and you are making the job more  complicated
> >> > > to every possible person in the planet running any kernel QA.
> >> > >
> >> > > I weight the latter more than the former. And it is exactly the
> >> > > reason why we did custom user space kselftest in the first place.
> >> > > Let's keep the tradition. All I can say is that kselftest is
> >> > > unfinished in its current form.
> >> > >
> >> > > What is "esp cgexec"?
> >> >
> >> > Also in kselftest we don't drive ultimate simplicity, we drive
> >> > efficient CI/QA. By open coding something like subset of
> >> > cgroup-tools needed to run the test you also help us later
> >> > on to backtrack the kernel changes. With cgroups-tools you
> >> > would have to use strace to get the same info.
> >>
> >> FWIW, see also functions in
> >> tools/testing/selftests/cgroup/cgroup_util.{h,c}.
> >> They likely cover what you need already -- if the tests are in C.
> >>
> >> (I admit that stuff in tools/testing/selftests/cgroup/ is best
> >> understood with strace.)
> >
> > Thanks!
> >
> > My conclusions are that:
> >
> > 1. We probably cannot move the test part of cgroup test itself
> >    given the enclave payload dependency.
> > 2. I think it makes sense to still follow the same pattern as
> >    other cgroups test and re-use cgroup_util.[ch] functionaltiy.
> >
> > So yeah I guess we need two test programs instead of one.
> >
> > Something along the lines:
> >
> > 1. main.[ch] -> test_sgx.[ch]
> > 2. introduce test_sgx_cgroup.c
> >
> > And test_sgx_cgroup.c would be implement similar test as the shell
> > script and would follow the structure of existing cgroups tests.
> >
> >>
> >> HTH,
> >> Michal
> >
> > BR, Jarkko
> >
> Do we really want to have it implemented in c? There are much fewer lines  
> of code in shell scripts. Note we are not really testing basic cgroup  
> stuff. All we needed were creating/deleting cgroups and set limits which I  
> think have been demonstrated feasible in the ash scripts now.
>
> Given Dave's comments, and test scripts being working and cover the cases  
> needed IMHO, I don't see much need to move to c code. I can add more cases  
> if needed and fall back a c implementation later  if any case can't be  
> implemented in scripts. How about that?

We can settle to: ash + no dependencies. I guess you have for that
all the work done already.

BR, Jarkko

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