Re: [RFC PATCH] x86/sgx: Remove 'reclaim' boolean parameters

Jarkko Sakkinen
2024-02-19T20:42:37Z

On Mon Feb 19, 2024 at 3:56 PM UTC, Dave Hansen wrote:
> On 2/19/24 07:39, Haitao Huang wrote:
> > Remove all boolean parameters for 'reclaim' from the function
> > sgx_alloc_epc_page() and its callers by making two versions of each
> > function.
> >
> > Also opportunistically remove non-static declaration of
> > __sgx_alloc_epc_page() and a typo
> >
> > Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
> > Suggested-by: Jarkko Sakkinen <jarkko@kernel.org>
> > ---
> > arch/x86/kernel/cpu/sgx/encl.c | 56 +++++++++++++++++++++------
> > arch/x86/kernel/cpu/sgx/encl.h | 6 ++-
> > arch/x86/kernel/cpu/sgx/ioctl.c | 23 ++++++++---
> > arch/x86/kernel/cpu/sgx/main.c | 68 ++++++++++++++++++++++-----------
> > arch/x86/kernel/cpu/sgx/sgx.h | 4 +-
> > arch/x86/kernel/cpu/sgx/virt.c | 2 +-
> > 6 files changed, 115 insertions(+), 44 deletions(-)
>
> Jarkko, did this turn out how you expected?
>
> I think passing around a function pointer to *only* communicate 1 bit of
> information is a _bit_ overkill here.
>
> Simply replacing the bool with:
>
> enum sgx_reclaim {
> SGX_NO_RECLAIM,
> SGX_DO_RECLAIM
> };
>
> would do the same thing. Right?
>
> Are you sure you want a function pointer for this?

To look this in context I drafted quickly two branches representing
imaginary next version of the patch set.

I guess this would simpler and totally sufficient approach.

With this approach I'd then change also:

[PATCH v9 04/15] x86/sgx: Implement basic EPC misc cgroup functionality

And add the enum-parameter already in that patch with just "no reclaim"
enum. I.e. then 10/15 will add only "do reclaim" and the new
functionality.

BR, Jarkko