Re: [RFC PATCH 01/20] x86/sgx: Call cond_resched() at the end of sgx_reclaim_pages()

Jarkko Sakkinen
2022-09-23T12:37:23Z

On Fri, Sep 23, 2022 at 03:35:25PM +0300, Jarkko Sakkinen wrote:
> On Fri, Sep 23, 2022 at 03:32:43PM +0300, Jarkko Sakkinen wrote:
> > On Thu, Sep 22, 2022 at 10:10:38AM -0700, Kristen Carlson Accardi wrote:
> > > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > >
> > > Move the invocation of post-reclaim cond_resched() from the callers of
> > > sgx_reclaim_pages() into the reclaim path itself. sgx_reclaim_pages()
> > > is always called in a loop and is always followed by a call to
> > > cond_resched(). This will hold true for the EPC cgroup as well, which
> > > adds even more calls to sgx_reclaim_pages() and thus cond_resched().
> >
> > This would be in my opinion better:
> >
> > "
> > In order to avoid repetion of cond_sched() in ksgxd() and
> > sgx_alloc_epc_page(), move the call inside sgx_reclaim_pages().
> >
> > This will hold true for the EPC cgroup as well, which adds more
> > call sites sgx_reclaim_pages().
> > "
> >
> > This way it is dead obvious and is better description because
> > it enumerates the consequences (i.e. call sites).
>
> Forgot 3rd call site: sgx_reclaim_direct(), which is used by
> SGX2 ioctls. The call sites of sgx_reclaim_direct() do not
> call cond_resched(). You should address why adding this call
> to those flows is fine.

Ofc adding a parameter to sgx_reclaim_pages() for cond_resched() call is
other option (not emphasising either option).

BR, Jarkko