MIME-Version: 1.0
References: <20230303231133.1486085-1-eranian@google.com> <20230306120106.GE1267364@hirez.programming.kicks-ass.net>
 <CAKwvOdnRvd5KK01awAyeyt5S36TPPW4_8Z6YL1r4gB-pBrHTbg@mail.gmail.com>
 <20230307113545.GB2017917@hirez.programming.kicks-ass.net>
 <20230307184315.GS25951@gate.crashing.org> <ZAeh8g0nr3IFRSVI@tucnak>
 <CAHk-=whOLcy=oz=gHyoSSEnqc3M-APKFKTtTvA_3wYYPV8L+oA@mail.gmail.com>
 <SJ1PR11MB6083CADB2B6E859915D456F7FCB79@SJ1PR11MB6083.namprd11.prod.outlook.com>
 <CAKwvOdna5NZ0ZTv0pXVVz15=4FLkw7pfFgr6KsRtXRmi2o1uEw@mail.gmail.com> <CAHk-=wiVP8ezgCyBTq3GV-1ebiOf03Qo_iHnVAR08NJO0jOocg@mail.gmail.com>
In-Reply-To: <CAHk-=wiVP8ezgCyBTq3GV-1ebiOf03Qo_iHnVAR08NJO0jOocg@mail.gmail.com>
From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 7 Mar 2023 13:22:45 -0800
Message-ID: <CAKwvOdk1n2v5Sym14BR0jGWKX8nNP1VL4Z1vXtAOWvQETOCSmQ@mail.gmail.com>
Subject: Re: [PATCH] x86/resctrl: avoid compiler optimization in __resctrl_sched_in
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     "Luck, Tony" <tony.luck@intel.com>,
        Jakub Jelinek <jakub@redhat.com>,
        Segher Boessenkool <segher@kernel.crashing.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Eranian, Stephane" <eranian@google.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Chatre, Reinette" <reinette.chatre@intel.com>,
        "Yu, Fenghua" <fenghua.yu@intel.com>,
        "peternewman@google.com" <peternewman@google.com>,
        "james.morse@arm.com" <james.morse@arm.com>,
        "babu.moger@amd.com" <babu.moger@amd.com>,
        "ananth.narayan@amd.com" <ananth.narayan@amd.com>,
        "vschneid@redhat.com" <vschneid@redhat.com>,
        Nathan Chancellor <nathan@kernel.org>,
        clang-built-linux <llvm@lists.linux.dev>,
        Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "linux-toolchains@vger.kernel.org" <linux-toolchains@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Tue, Mar 7, 2023 at 1:19=E2=80=AFPM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Tue, Mar 7, 2023 at 1:16=E2=80=AFPM Nick Desaulniers <ndesaulniers@goo=
gle.com> wrote:
> >
> > >
> > > Can you expand about part "a" ... Linux has zillions of static inline=
 functions
> > > in header files to handle CONFIG options. One version is the real McC=
oy
> > > while the other is just a stub for the CONFIG=3Dn case.
> >
> > Right, I had the same question.
> >
> > Perhaps it's more so that no one calls __resctrl_sched_in, only
> > resctrl_sched_in, therefor they should be folded into one function?
>
> If you think it should be inlined, it should be marked as such.

Yep, sorry, I missed that `inline` was missing from that definition!

>
> And if you *don't* think it should be inlined - quite possibly the
> right answer here - the definition of that function damn well
> shouldn't be in a header file.
>
> So either way, that __resctrl_sched_in() was wrong, wrong, wrong.
>
>            Linus
>


--=20
Thanks,
~Nick Desaulniers