From: Marco Elver <elver@google.com>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linuxppc-dev@lists.ozlabs.org, linux-kbuild@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Mike Galbraith <efault@gmx.de>,
Dmitry Vyukov <dvyukov@google.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH v2 4/5] kscan: Use preemption model accessors
Date: Thu, 11 Nov 2021 10:39:49 +0100 [thread overview]
Message-ID: <CANpmjNPvYZSSLnsg_BGfzb=Yu4bTvCp+N14FHcJfUDjDgzrywg@mail.gmail.com> (raw)
In-Reply-To: <YYzeOQNFmuieCk3T@elver.google.com>
On Thu, 11 Nov 2021 at 10:11, Marco Elver <elver@google.com> wrote:
>
> Subject s/kscan/kcsan/
>
> On Wed, Nov 10, 2021 at 08:24PM +0000, Valentin Schneider wrote:
> > Per PREEMPT_DYNAMIC, checking CONFIG_PREEMPT doesn't tell you the actual
> > preemption model of the live kernel. Use the newly-introduced accessors
> > instead.
> >
> > Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
>
> Reviewed-by: Marco Elver <elver@google.com>
>
> Though it currently doesn't compile as a module due to missing
> EXPORT_SYMBOL of is_preempt*().
>
> > ---
> > kernel/kcsan/kcsan_test.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
> > index dc55fd5a36fc..14d811eb9a21 100644
> > --- a/kernel/kcsan/kcsan_test.c
> > +++ b/kernel/kcsan/kcsan_test.c
> > @@ -1005,13 +1005,13 @@ static const void *nthreads_gen_params(const void *prev, char *desc)
> > else
> > nthreads *= 2;
> >
> > - if (!IS_ENABLED(CONFIG_PREEMPT) || !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
> > + if (!is_preempt_full() || !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
In case you introduce the 5th helper I suggested
(is_preempt_full_or_rt() or whatever you'll call it), this one can be
switched, because this check really does want to know if "at least
full preemption" and not "precisely full preemption".
Thanks,
-- Marco
WARNING: multiple messages have this Message-ID (diff)
From: Marco Elver <elver@google.com>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: Michal Marek <michal.lkml@markovi.net>,
linux-kbuild@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Mike Galbraith <efault@gmx.de>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
Paul Mackerras <paulus@samba.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masahiro Yamada <masahiroy@kernel.org>,
linuxppc-dev@lists.ozlabs.org, Ingo Molnar <mingo@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v2 4/5] kscan: Use preemption model accessors
Date: Thu, 11 Nov 2021 10:39:49 +0100 [thread overview]
Message-ID: <CANpmjNPvYZSSLnsg_BGfzb=Yu4bTvCp+N14FHcJfUDjDgzrywg@mail.gmail.com> (raw)
In-Reply-To: <YYzeOQNFmuieCk3T@elver.google.com>
On Thu, 11 Nov 2021 at 10:11, Marco Elver <elver@google.com> wrote:
>
> Subject s/kscan/kcsan/
>
> On Wed, Nov 10, 2021 at 08:24PM +0000, Valentin Schneider wrote:
> > Per PREEMPT_DYNAMIC, checking CONFIG_PREEMPT doesn't tell you the actual
> > preemption model of the live kernel. Use the newly-introduced accessors
> > instead.
> >
> > Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
>
> Reviewed-by: Marco Elver <elver@google.com>
>
> Though it currently doesn't compile as a module due to missing
> EXPORT_SYMBOL of is_preempt*().
>
> > ---
> > kernel/kcsan/kcsan_test.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
> > index dc55fd5a36fc..14d811eb9a21 100644
> > --- a/kernel/kcsan/kcsan_test.c
> > +++ b/kernel/kcsan/kcsan_test.c
> > @@ -1005,13 +1005,13 @@ static const void *nthreads_gen_params(const void *prev, char *desc)
> > else
> > nthreads *= 2;
> >
> > - if (!IS_ENABLED(CONFIG_PREEMPT) || !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
> > + if (!is_preempt_full() || !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
In case you introduce the 5th helper I suggested
(is_preempt_full_or_rt() or whatever you'll call it), this one can be
switched, because this check really does want to know if "at least
full preemption" and not "precisely full preemption".
Thanks,
-- Marco
next prev parent reply other threads:[~2021-11-11 9:40 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-10 20:24 [PATCH v2 0/5] preempt: PREEMPT vs PREEMPT_DYNAMIC configs fixup Valentin Schneider
2021-11-10 20:24 ` Valentin Schneider
2021-11-10 20:24 ` [PATCH v2 1/5] preempt: Restore preemption model selection configs Valentin Schneider
2021-11-10 20:24 ` Valentin Schneider
2021-11-11 8:58 ` Marco Elver
2021-11-11 8:58 ` Marco Elver
2021-11-11 12:22 ` [tip: sched/urgent] " tip-bot2 for Valentin Schneider
2021-11-10 20:24 ` [PATCH v2 2/5] preempt/dynamic: Introduce preempt mode accessors Valentin Schneider
2021-11-10 20:24 ` Valentin Schneider
2021-11-11 3:16 ` Mike Galbraith
2021-11-11 3:16 ` Mike Galbraith
2021-11-11 3:35 ` Mike Galbraith
2021-11-11 3:35 ` Mike Galbraith
2021-11-11 3:47 ` Mike Galbraith
2021-11-11 3:47 ` Mike Galbraith
2021-11-11 3:55 ` Mike Galbraith
2021-11-11 3:55 ` Mike Galbraith
2021-11-11 9:36 ` Marco Elver
2021-11-11 9:36 ` Marco Elver
2021-11-11 10:32 ` Mike Galbraith
2021-11-11 10:32 ` Mike Galbraith
2021-11-11 10:56 ` Valentin Schneider
2021-11-11 10:56 ` Valentin Schneider
2021-11-11 11:09 ` Mike Galbraith
2021-11-11 11:09 ` Mike Galbraith
2021-11-11 8:54 ` Marco Elver
2021-11-11 8:54 ` Marco Elver
2021-11-11 10:56 ` Valentin Schneider
2021-11-11 10:56 ` Valentin Schneider
2021-11-16 13:29 ` Christophe Leroy
2021-11-16 13:29 ` Christophe Leroy
2021-11-22 16:37 ` Valentin Schneider
2021-11-22 16:37 ` Valentin Schneider
2021-11-10 20:24 ` [PATCH v2 3/5] powerpc: Use preemption model accessors Valentin Schneider
2021-11-10 20:24 ` Valentin Schneider
2021-11-11 4:55 ` Michael Ellerman
2021-11-11 4:55 ` Michael Ellerman
2021-11-15 15:29 ` Valentin Schneider
2021-11-15 15:29 ` Valentin Schneider
2021-11-16 13:41 ` Christophe Leroy
2021-11-16 13:41 ` Christophe Leroy
2021-11-22 16:44 ` Valentin Schneider
2021-11-22 16:44 ` Valentin Schneider
2021-11-10 20:24 ` [PATCH v2 4/5] kscan: " Valentin Schneider
2021-11-10 20:24 ` Valentin Schneider
2021-11-11 9:11 ` Marco Elver
2021-11-11 9:11 ` Marco Elver
2021-11-11 9:39 ` Marco Elver [this message]
2021-11-11 9:39 ` Marco Elver
2021-11-11 10:57 ` Valentin Schneider
2021-11-11 10:57 ` Valentin Schneider
2021-11-10 20:24 ` [PATCH v2 5/5] ftrace: Use preemption model accessors for trace header printout Valentin Schneider
2021-11-10 20:24 ` Valentin Schneider
2021-11-10 20:36 ` Steven Rostedt
2021-11-10 20:36 ` Steven Rostedt
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